--- /dev/null
+/*
+ * RDMA protocol and interfaces
+ *
+ * Copyright IBM, Corp. 2010-2013
+ *
+ * Authors:
+ * Michael R. Hines <mrhines@us.ibm.com>
+ * Jiuxing Liu <jl@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later. See the COPYING file in the top-level directory.
+ *
+ */
+#include "qemu-common.h"
+#include "migration/migration.h"
+#include "migration/qemu-file.h"
+#include "exec/cpu-common.h"
+#include "qemu/error-report.h"
+#include "qemu/main-loop.h"
+#include "qemu/sockets.h"
+#include "qemu/bitmap.h"
+#include "block/coroutine.h"
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <arpa/inet.h>
+#include <string.h>
+#include <rdma/rdma_cma.h>
+#include "trace.h"
+
+/*
+ * Print and error on both the Monitor and the Log file.
+ */
+#define ERROR(errp, fmt, ...) \
+ do { \
+ fprintf(stderr, "RDMA ERROR: " fmt "\n", ## __VA_ARGS__); \
+ if (errp && (*(errp) == NULL)) { \
+ error_setg(errp, "RDMA ERROR: " fmt, ## __VA_ARGS__); \
+ } \
+ } while (0)
+
+#define RDMA_RESOLVE_TIMEOUT_MS 10000
+
+/* Do not merge data if larger than this. */
+#define RDMA_MERGE_MAX (2 * 1024 * 1024)
+#define RDMA_SIGNALED_SEND_MAX (RDMA_MERGE_MAX / 4096)
+
+#define RDMA_REG_CHUNK_SHIFT 20 /* 1 MB */
+
+/*
+ * This is only for non-live state being migrated.
+ * Instead of RDMA_WRITE messages, we use RDMA_SEND
+ * messages for that state, which requires a different
+ * delivery design than main memory.
+ */
+#define RDMA_SEND_INCREMENT 32768
+
+/*
+ * Maximum size infiniband SEND message
+ */
+#define RDMA_CONTROL_MAX_BUFFER (512 * 1024)
+#define RDMA_CONTROL_MAX_COMMANDS_PER_MESSAGE 4096
+
+#define RDMA_CONTROL_VERSION_CURRENT 1
+/*
+ * Capabilities for negotiation.
+ */
+#define RDMA_CAPABILITY_PIN_ALL 0x01
+
+/*
+ * Add the other flags above to this list of known capabilities
+ * as they are introduced.
+ */
+static uint32_t known_capabilities = RDMA_CAPABILITY_PIN_ALL;
+
+#define CHECK_ERROR_STATE() \
+ do { \
+ if (rdma->error_state) { \
+ if (!rdma->error_reported) { \
+ error_report("RDMA is in an error state waiting migration" \
+ " to abort!"); \
+ rdma->error_reported = 1; \
+ } \
+ return rdma->error_state; \
+ } \
+ } while (0);
+
+/*
+ * A work request ID is 64-bits and we split up these bits
+ * into 3 parts:
+ *
+ * bits 0-15 : type of control message, 2^16
+ * bits 16-29: ram block index, 2^14
+ * bits 30-63: ram block chunk number, 2^34
+ *
+ * The last two bit ranges are only used for RDMA writes,
+ * in order to track their completion and potentially
+ * also track unregistration status of the message.
+ */
+#define RDMA_WRID_TYPE_SHIFT 0UL
+#define RDMA_WRID_BLOCK_SHIFT 16UL
+#define RDMA_WRID_CHUNK_SHIFT 30UL
+
+#define RDMA_WRID_TYPE_MASK \
+ ((1UL << RDMA_WRID_BLOCK_SHIFT) - 1UL)
+
+#define RDMA_WRID_BLOCK_MASK \
+ (~RDMA_WRID_TYPE_MASK & ((1UL << RDMA_WRID_CHUNK_SHIFT) - 1UL))
+
+#define RDMA_WRID_CHUNK_MASK (~RDMA_WRID_BLOCK_MASK & ~RDMA_WRID_TYPE_MASK)
+
+/*
+ * RDMA migration protocol:
+ * 1. RDMA Writes (data messages, i.e. RAM)
+ * 2. IB Send/Recv (control channel messages)
+ */
+enum {
+ RDMA_WRID_NONE = 0,
+ RDMA_WRID_RDMA_WRITE = 1,
+ RDMA_WRID_SEND_CONTROL = 2000,
+ RDMA_WRID_RECV_CONTROL = 4000,
+};
+
+static const char *wrid_desc[] = {
+ [RDMA_WRID_NONE] = "NONE",
+ [RDMA_WRID_RDMA_WRITE] = "WRITE RDMA",
+ [RDMA_WRID_SEND_CONTROL] = "CONTROL SEND",
+ [RDMA_WRID_RECV_CONTROL] = "CONTROL RECV",
+};
+
+/*
+ * Work request IDs for IB SEND messages only (not RDMA writes).
+ * This is used by the migration protocol to transmit
+ * control messages (such as device state and registration commands)
+ *
+ * We could use more WRs, but we have enough for now.
+ */
+enum {
+ RDMA_WRID_READY = 0,
+ RDMA_WRID_DATA,
+ RDMA_WRID_CONTROL,
+ RDMA_WRID_MAX,
+};
+
+/*
+ * SEND/RECV IB Control Messages.
+ */
+enum {
+ RDMA_CONTROL_NONE = 0,
+ RDMA_CONTROL_ERROR,
+ RDMA_CONTROL_READY, /* ready to receive */
+ RDMA_CONTROL_QEMU_FILE, /* QEMUFile-transmitted bytes */
+ RDMA_CONTROL_RAM_BLOCKS_REQUEST, /* RAMBlock synchronization */
+ RDMA_CONTROL_RAM_BLOCKS_RESULT, /* RAMBlock synchronization */
+ RDMA_CONTROL_COMPRESS, /* page contains repeat values */
+ RDMA_CONTROL_REGISTER_REQUEST, /* dynamic page registration */
+ RDMA_CONTROL_REGISTER_RESULT, /* key to use after registration */
+ RDMA_CONTROL_REGISTER_FINISHED, /* current iteration finished */
+ RDMA_CONTROL_UNREGISTER_REQUEST, /* dynamic UN-registration */
+ RDMA_CONTROL_UNREGISTER_FINISHED, /* unpinning finished */
+};
+
+static const char *control_desc[] = {
+ [RDMA_CONTROL_NONE] = "NONE",
+ [RDMA_CONTROL_ERROR] = "ERROR",
+ [RDMA_CONTROL_READY] = "READY",
+ [RDMA_CONTROL_QEMU_FILE] = "QEMU FILE",
+ [RDMA_CONTROL_RAM_BLOCKS_REQUEST] = "RAM BLOCKS REQUEST",
+ [RDMA_CONTROL_RAM_BLOCKS_RESULT] = "RAM BLOCKS RESULT",
+ [RDMA_CONTROL_COMPRESS] = "COMPRESS",
+ [RDMA_CONTROL_REGISTER_REQUEST] = "REGISTER REQUEST",
+ [RDMA_CONTROL_REGISTER_RESULT] = "REGISTER RESULT",
+ [RDMA_CONTROL_REGISTER_FINISHED] = "REGISTER FINISHED",
+ [RDMA_CONTROL_UNREGISTER_REQUEST] = "UNREGISTER REQUEST",
+ [RDMA_CONTROL_UNREGISTER_FINISHED] = "UNREGISTER FINISHED",
+};
+
+/*
+ * Memory and MR structures used to represent an IB Send/Recv work request.
+ * This is *not* used for RDMA writes, only IB Send/Recv.
+ */
+typedef struct {
+ uint8_t control[RDMA_CONTROL_MAX_BUFFER]; /* actual buffer to register */
+ struct ibv_mr *control_mr; /* registration metadata */
+ size_t control_len; /* length of the message */
+ uint8_t *control_curr; /* start of unconsumed bytes */
+} RDMAWorkRequestData;
+
+/*
+ * Negotiate RDMA capabilities during connection-setup time.
+ */
+typedef struct {
+ uint32_t version;
+ uint32_t flags;
+} RDMACapabilities;
+
+static void caps_to_network(RDMACapabilities *cap)
+{
+ cap->version = htonl(cap->version);
+ cap->flags = htonl(cap->flags);
+}
+
+static void network_to_caps(RDMACapabilities *cap)
+{
+ cap->version = ntohl(cap->version);
+ cap->flags = ntohl(cap->flags);
+}
+
+/*
+ * Representation of a RAMBlock from an RDMA perspective.
+ * This is not transmitted, only local.
+ * This and subsequent structures cannot be linked lists
+ * because we're using a single IB message to transmit
+ * the information. It's small anyway, so a list is overkill.
+ */
+typedef struct RDMALocalBlock {
+ char *block_name;
+ uint8_t *local_host_addr; /* local virtual address */
+ uint64_t remote_host_addr; /* remote virtual address */
+ uint64_t offset;
+ uint64_t length;
+ struct ibv_mr **pmr; /* MRs for chunk-level registration */
+ struct ibv_mr *mr; /* MR for non-chunk-level registration */
+ uint32_t *remote_keys; /* rkeys for chunk-level registration */
+ uint32_t remote_rkey; /* rkeys for non-chunk-level registration */
+ int index; /* which block are we */
+ unsigned int src_index; /* (Only used on dest) */
+ bool is_ram_block;
+ int nb_chunks;
+ unsigned long *transit_bitmap;
+ unsigned long *unregister_bitmap;
+} RDMALocalBlock;
+
+/*
+ * Also represents a RAMblock, but only on the dest.
+ * This gets transmitted by the dest during connection-time
+ * to the source VM and then is used to populate the
+ * corresponding RDMALocalBlock with
+ * the information needed to perform the actual RDMA.
+ */
+typedef struct QEMU_PACKED RDMADestBlock {
+ uint64_t remote_host_addr;
+ uint64_t offset;
+ uint64_t length;
+ uint32_t remote_rkey;
+ uint32_t padding;
+} RDMADestBlock;
+
+static uint64_t htonll(uint64_t v)
+{
+ union { uint32_t lv[2]; uint64_t llv; } u;
+ u.lv[0] = htonl(v >> 32);
+ u.lv[1] = htonl(v & 0xFFFFFFFFULL);
+ return u.llv;
+}
+
+static uint64_t ntohll(uint64_t v) {
+ union { uint32_t lv[2]; uint64_t llv; } u;
+ u.llv = v;
+ return ((uint64_t)ntohl(u.lv[0]) << 32) | (uint64_t) ntohl(u.lv[1]);
+}
+
+static void dest_block_to_network(RDMADestBlock *db)
+{
+ db->remote_host_addr = htonll(db->remote_host_addr);
+ db->offset = htonll(db->offset);
+ db->length = htonll(db->length);
+ db->remote_rkey = htonl(db->remote_rkey);
+}
+
+static void network_to_dest_block(RDMADestBlock *db)
+{
+ db->remote_host_addr = ntohll(db->remote_host_addr);
+ db->offset = ntohll(db->offset);
+ db->length = ntohll(db->length);
+ db->remote_rkey = ntohl(db->remote_rkey);
+}
+
+/*
+ * Virtual address of the above structures used for transmitting
+ * the RAMBlock descriptions at connection-time.
+ * This structure is *not* transmitted.
+ */
+typedef struct RDMALocalBlocks {
+ int nb_blocks;
+ bool init; /* main memory init complete */
+ RDMALocalBlock *block;
+} RDMALocalBlocks;
+
+/*
+ * Main data structure for RDMA state.
+ * While there is only one copy of this structure being allocated right now,
+ * this is the place where one would start if you wanted to consider
+ * having more than one RDMA connection open at the same time.
+ */
+typedef struct RDMAContext {
+ char *host;
+ int port;
+
+ RDMAWorkRequestData wr_data[RDMA_WRID_MAX];
+
+ /*
+ * This is used by *_exchange_send() to figure out whether or not
+ * the initial "READY" message has already been received or not.
+ * This is because other functions may potentially poll() and detect
+ * the READY message before send() does, in which case we need to
+ * know if it completed.
+ */
+ int control_ready_expected;
+
+ /* number of outstanding writes */
+ int nb_sent;
+
+ /* store info about current buffer so that we can
+ merge it with future sends */
+ uint64_t current_addr;
+ uint64_t current_length;
+ /* index of ram block the current buffer belongs to */
+ int current_index;
+ /* index of the chunk in the current ram block */
+ int current_chunk;
+
+ bool pin_all;
+
+ /*
+ * infiniband-specific variables for opening the device
+ * and maintaining connection state and so forth.
+ *
+ * cm_id also has ibv_context, rdma_event_channel, and ibv_qp in
+ * cm_id->verbs, cm_id->channel, and cm_id->qp.
+ */
+ struct rdma_cm_id *cm_id; /* connection manager ID */
+ struct rdma_cm_id *listen_id;
+ bool connected;
+
+ struct ibv_context *verbs;
+ struct rdma_event_channel *channel;
+ struct ibv_qp *qp; /* queue pair */
+ struct ibv_comp_channel *comp_channel; /* completion channel */
+ struct ibv_pd *pd; /* protection domain */
+ struct ibv_cq *cq; /* completion queue */
+
+ /*
+ * If a previous write failed (perhaps because of a failed
+ * memory registration, then do not attempt any future work
+ * and remember the error state.
+ */
+ int error_state;
+ int error_reported;
+
+ /*
+ * Description of ram blocks used throughout the code.
+ */
+ RDMALocalBlocks local_ram_blocks;
+ RDMADestBlock *dest_blocks;
+
+ /* Index of the next RAMBlock received during block registration */
+ unsigned int next_src_index;
+
+ /*
+ * Migration on *destination* started.
+ * Then use coroutine yield function.
+ * Source runs in a thread, so we don't care.
+ */
+ int migration_started_on_destination;
+
+ int total_registrations;
+ int total_writes;
+
+ int unregister_current, unregister_next;
+ uint64_t unregistrations[RDMA_SIGNALED_SEND_MAX];
+
+ GHashTable *blockmap;
+} RDMAContext;
+
+/*
+ * Interface to the rest of the migration call stack.
+ */
+typedef struct QEMUFileRDMA {
+ RDMAContext *rdma;
+ size_t len;
+ void *file;
+} QEMUFileRDMA;
+
+/*
+ * Main structure for IB Send/Recv control messages.
+ * This gets prepended at the beginning of every Send/Recv.
+ */
+typedef struct QEMU_PACKED {
+ uint32_t len; /* Total length of data portion */
+ uint32_t type; /* which control command to perform */
+ uint32_t repeat; /* number of commands in data portion of same type */
+ uint32_t padding;
+} RDMAControlHeader;
+
+static void control_to_network(RDMAControlHeader *control)
+{
+ control->type = htonl(control->type);
+ control->len = htonl(control->len);
+ control->repeat = htonl(control->repeat);
+}
+
+static void network_to_control(RDMAControlHeader *control)
+{
+ control->type = ntohl(control->type);
+ control->len = ntohl(control->len);
+ control->repeat = ntohl(control->repeat);
+}
+
+/*
+ * Register a single Chunk.
+ * Information sent by the source VM to inform the dest
+ * to register an single chunk of memory before we can perform
+ * the actual RDMA operation.
+ */
+typedef struct QEMU_PACKED {
+ union QEMU_PACKED {
+ uint64_t current_addr; /* offset into the ram_addr_t space */
+ uint64_t chunk; /* chunk to lookup if unregistering */
+ } key;
+ uint32_t current_index; /* which ramblock the chunk belongs to */
+ uint32_t padding;
+ uint64_t chunks; /* how many sequential chunks to register */
+} RDMARegister;
+
+static void register_to_network(RDMAContext *rdma, RDMARegister *reg)
+{
+ RDMALocalBlock *local_block;
+ local_block = &rdma->local_ram_blocks.block[reg->current_index];
+
+ if (local_block->is_ram_block) {
+ /*
+ * current_addr as passed in is an address in the local ram_addr_t
+ * space, we need to translate this for the destination
+ */
+ reg->key.current_addr -= local_block->offset;
+ reg->key.current_addr += rdma->dest_blocks[reg->current_index].offset;
+ }
+ reg->key.current_addr = htonll(reg->key.current_addr);
+ reg->current_index = htonl(reg->current_index);
+ reg->chunks = htonll(reg->chunks);
+}
+
+static void network_to_register(RDMARegister *reg)
+{
+ reg->key.current_addr = ntohll(reg->key.current_addr);
+ reg->current_index = ntohl(reg->current_index);
+ reg->chunks = ntohll(reg->chunks);
+}
+
+typedef struct QEMU_PACKED {
+ uint32_t value; /* if zero, we will madvise() */
+ uint32_t block_idx; /* which ram block index */
+ uint64_t offset; /* Address in remote ram_addr_t space */
+ uint64_t length; /* length of the chunk */
+} RDMACompress;
+
+static void compress_to_network(RDMAContext *rdma, RDMACompress *comp)
+{
+ comp->value = htonl(comp->value);
+ /*
+ * comp->offset as passed in is an address in the local ram_addr_t
+ * space, we need to translate this for the destination
+ */
+ comp->offset -= rdma->local_ram_blocks.block[comp->block_idx].offset;
+ comp->offset += rdma->dest_blocks[comp->block_idx].offset;
+ comp->block_idx = htonl(comp->block_idx);
+ comp->offset = htonll(comp->offset);
+ comp->length = htonll(comp->length);
+}
+
+static void network_to_compress(RDMACompress *comp)
+{
+ comp->value = ntohl(comp->value);
+ comp->block_idx = ntohl(comp->block_idx);
+ comp->offset = ntohll(comp->offset);
+ comp->length = ntohll(comp->length);
+}
+
+/*
+ * The result of the dest's memory registration produces an "rkey"
+ * which the source VM must reference in order to perform
+ * the RDMA operation.
+ */
+typedef struct QEMU_PACKED {
+ uint32_t rkey;
+ uint32_t padding;
+ uint64_t host_addr;
+} RDMARegisterResult;
+
+static void result_to_network(RDMARegisterResult *result)
+{
+ result->rkey = htonl(result->rkey);
+ result->host_addr = htonll(result->host_addr);
+};
+
+static void network_to_result(RDMARegisterResult *result)
+{
+ result->rkey = ntohl(result->rkey);
+ result->host_addr = ntohll(result->host_addr);
+};
+
+const char *print_wrid(int wrid);
+static int qemu_rdma_exchange_send(RDMAContext *rdma, RDMAControlHeader *head,
+ uint8_t *data, RDMAControlHeader *resp,
+ int *resp_idx,
+ int (*callback)(RDMAContext *rdma));
+
+static inline uint64_t ram_chunk_index(const uint8_t *start,
+ const uint8_t *host)
+{
+ return ((uintptr_t) host - (uintptr_t) start) >> RDMA_REG_CHUNK_SHIFT;
+}
+
+static inline uint8_t *ram_chunk_start(const RDMALocalBlock *rdma_ram_block,
+ uint64_t i)
+{
+ return (uint8_t *)(uintptr_t)(rdma_ram_block->local_host_addr +
+ (i << RDMA_REG_CHUNK_SHIFT));
+}
+
+static inline uint8_t *ram_chunk_end(const RDMALocalBlock *rdma_ram_block,
+ uint64_t i)
+{
+ uint8_t *result = ram_chunk_start(rdma_ram_block, i) +
+ (1UL << RDMA_REG_CHUNK_SHIFT);
+
+ if (result > (rdma_ram_block->local_host_addr + rdma_ram_block->length)) {
+ result = rdma_ram_block->local_host_addr + rdma_ram_block->length;
+ }
+
+ return result;
+}
+
+static int rdma_add_block(RDMAContext *rdma, const char *block_name,
+ void *host_addr,
+ ram_addr_t block_offset, uint64_t length)
+{
+ RDMALocalBlocks *local = &rdma->local_ram_blocks;
+ RDMALocalBlock *block;
+ RDMALocalBlock *old = local->block;
+
+ local->block = g_malloc0(sizeof(RDMALocalBlock) * (local->nb_blocks + 1));
+
+ if (local->nb_blocks) {
+ int x;
+
+ if (rdma->blockmap) {
+ for (x = 0; x < local->nb_blocks; x++) {
+ g_hash_table_remove(rdma->blockmap,
+ (void *)(uintptr_t)old[x].offset);
+ g_hash_table_insert(rdma->blockmap,
+ (void *)(uintptr_t)old[x].offset,
+ &local->block[x]);
+ }
+ }
+ memcpy(local->block, old, sizeof(RDMALocalBlock) * local->nb_blocks);
+ g_free(old);
+ }
+
+ block = &local->block[local->nb_blocks];
+
+ block->block_name = g_strdup(block_name);
+ block->local_host_addr = host_addr;
+ block->offset = block_offset;
+ block->length = length;
+ block->index = local->nb_blocks;
+ block->src_index = ~0U; /* Filled in by the receipt of the block list */
+ block->nb_chunks = ram_chunk_index(host_addr, host_addr + length) + 1UL;
+ block->transit_bitmap = bitmap_new(block->nb_chunks);
+ bitmap_clear(block->transit_bitmap, 0, block->nb_chunks);
+ block->unregister_bitmap = bitmap_new(block->nb_chunks);
+ bitmap_clear(block->unregister_bitmap, 0, block->nb_chunks);
+ block->remote_keys = g_malloc0(block->nb_chunks * sizeof(uint32_t));
+
+ block->is_ram_block = local->init ? false : true;
+
+ if (rdma->blockmap) {
+ g_hash_table_insert(rdma->blockmap, (void *) block_offset, block);
+ }
+
+ trace_rdma_add_block(block_name, local->nb_blocks,
+ (uintptr_t) block->local_host_addr,
+ block->offset, block->length,
+ (uintptr_t) (block->local_host_addr + block->length),
+ BITS_TO_LONGS(block->nb_chunks) *
+ sizeof(unsigned long) * 8,
+ block->nb_chunks);
+
+ local->nb_blocks++;
+
+ return 0;
+}
+
+/*
+ * Memory regions need to be registered with the device and queue pairs setup
+ * in advanced before the migration starts. This tells us where the RAM blocks
+ * are so that we can register them individually.
+ */
+static int qemu_rdma_init_one_block(const char *block_name, void *host_addr,
+ ram_addr_t block_offset, ram_addr_t length, void *opaque)
+{
+ return rdma_add_block(opaque, block_name, host_addr, block_offset, length);
+}
+
+/*
+ * Identify the RAMBlocks and their quantity. They will be references to
+ * identify chunk boundaries inside each RAMBlock and also be referenced
+ * during dynamic page registration.
+ */
+static int qemu_rdma_init_ram_blocks(RDMAContext *rdma)
+{
+ RDMALocalBlocks *local = &rdma->local_ram_blocks;
+
+ assert(rdma->blockmap == NULL);
+ memset(local, 0, sizeof *local);
+ qemu_ram_foreach_block(qemu_rdma_init_one_block, rdma);
+ trace_qemu_rdma_init_ram_blocks(local->nb_blocks);
+ rdma->dest_blocks = (RDMADestBlock *) g_malloc0(sizeof(RDMADestBlock) *
+ rdma->local_ram_blocks.nb_blocks);
+ local->init = true;
+ return 0;
+}
+
+/*
+ * Note: If used outside of cleanup, the caller must ensure that the destination
+ * block structures are also updated
+ */
+static int rdma_delete_block(RDMAContext *rdma, RDMALocalBlock *block)
+{
+ RDMALocalBlocks *local = &rdma->local_ram_blocks;
+ RDMALocalBlock *old = local->block;
+ int x;
+
+ if (rdma->blockmap) {
+ g_hash_table_remove(rdma->blockmap, (void *)(uintptr_t)block->offset);
+ }
+ if (block->pmr) {
+ int j;
+
+ for (j = 0; j < block->nb_chunks; j++) {
+ if (!block->pmr[j]) {
+ continue;
+ }
+ ibv_dereg_mr(block->pmr[j]);
+ rdma->total_registrations--;
+ }
+ g_free(block->pmr);
+ block->pmr = NULL;
+ }
+
+ if (block->mr) {
+ ibv_dereg_mr(block->mr);
+ rdma->total_registrations--;
+ block->mr = NULL;
+ }
+
+ g_free(block->transit_bitmap);
+ block->transit_bitmap = NULL;
+
+ g_free(block->unregister_bitmap);
+ block->unregister_bitmap = NULL;
+
+ g_free(block->remote_keys);
+ block->remote_keys = NULL;
+
+ g_free(block->block_name);
+ block->block_name = NULL;
+
+ if (rdma->blockmap) {
+ for (x = 0; x < local->nb_blocks; x++) {
+ g_hash_table_remove(rdma->blockmap,
+ (void *)(uintptr_t)old[x].offset);
+ }
+ }
+
+ if (local->nb_blocks > 1) {
+
+ local->block = g_malloc0(sizeof(RDMALocalBlock) *
+ (local->nb_blocks - 1));
+
+ if (block->index) {
+ memcpy(local->block, old, sizeof(RDMALocalBlock) * block->index);
+ }
+
+ if (block->index < (local->nb_blocks - 1)) {
+ memcpy(local->block + block->index, old + (block->index + 1),
+ sizeof(RDMALocalBlock) *
+ (local->nb_blocks - (block->index + 1)));
+ }
+ } else {
+ assert(block == local->block);
+ local->block = NULL;
+ }
+
+ trace_rdma_delete_block(block, (uintptr_t)block->local_host_addr,
+ block->offset, block->length,
+ (uintptr_t)(block->local_host_addr + block->length),
+ BITS_TO_LONGS(block->nb_chunks) *
+ sizeof(unsigned long) * 8, block->nb_chunks);
+
+ g_free(old);
+
+ local->nb_blocks--;
+
+ if (local->nb_blocks && rdma->blockmap) {
+ for (x = 0; x < local->nb_blocks; x++) {
+ g_hash_table_insert(rdma->blockmap,
+ (void *)(uintptr_t)local->block[x].offset,
+ &local->block[x]);
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Put in the log file which RDMA device was opened and the details
+ * associated with that device.
+ */
+static void qemu_rdma_dump_id(const char *who, struct ibv_context *verbs)
+{
+ struct ibv_port_attr port;
+
+ if (ibv_query_port(verbs, 1, &port)) {
+ error_report("Failed to query port information");
+ return;
+ }
+
+ printf("%s RDMA Device opened: kernel name %s "
+ "uverbs device name %s, "
+ "infiniband_verbs class device path %s, "
+ "infiniband class device path %s, "
+ "transport: (%d) %s\n",
+ who,
+ verbs->device->name,
+ verbs->device->dev_name,
+ verbs->device->dev_path,
+ verbs->device->ibdev_path,
+ port.link_layer,
+ (port.link_layer == IBV_LINK_LAYER_INFINIBAND) ? "Infiniband" :
+ ((port.link_layer == IBV_LINK_LAYER_ETHERNET)
+ ? "Ethernet" : "Unknown"));
+}
+
+/*
+ * Put in the log file the RDMA gid addressing information,
+ * useful for folks who have trouble understanding the
+ * RDMA device hierarchy in the kernel.
+ */
+static void qemu_rdma_dump_gid(const char *who, struct rdma_cm_id *id)
+{
+ char sgid[33];
+ char dgid[33];
+ inet_ntop(AF_INET6, &id->route.addr.addr.ibaddr.sgid, sgid, sizeof sgid);
+ inet_ntop(AF_INET6, &id->route.addr.addr.ibaddr.dgid, dgid, sizeof dgid);
+ trace_qemu_rdma_dump_gid(who, sgid, dgid);
+}
+
+/*
+ * As of now, IPv6 over RoCE / iWARP is not supported by linux.
+ * We will try the next addrinfo struct, and fail if there are
+ * no other valid addresses to bind against.
+ *
+ * If user is listening on '[::]', then we will not have a opened a device
+ * yet and have no way of verifying if the device is RoCE or not.
+ *
+ * In this case, the source VM will throw an error for ALL types of
+ * connections (both IPv4 and IPv6) if the destination machine does not have
+ * a regular infiniband network available for use.
+ *
+ * The only way to guarantee that an error is thrown for broken kernels is
+ * for the management software to choose a *specific* interface at bind time
+ * and validate what time of hardware it is.
+ *
+ * Unfortunately, this puts the user in a fix:
+ *
+ * If the source VM connects with an IPv4 address without knowing that the
+ * destination has bound to '[::]' the migration will unconditionally fail
+ * unless the management software is explicitly listening on the the IPv4
+ * address while using a RoCE-based device.
+ *
+ * If the source VM connects with an IPv6 address, then we're OK because we can
+ * throw an error on the source (and similarly on the destination).
+ *
+ * But in mixed environments, this will be broken for a while until it is fixed
+ * inside linux.
+ *
+ * We do provide a *tiny* bit of help in this function: We can list all of the
+ * devices in the system and check to see if all the devices are RoCE or
+ * Infiniband.
+ *
+ * If we detect that we have a *pure* RoCE environment, then we can safely
+ * thrown an error even if the management software has specified '[::]' as the
+ * bind address.
+ *
+ * However, if there is are multiple hetergeneous devices, then we cannot make
+ * this assumption and the user just has to be sure they know what they are
+ * doing.
+ *
+ * Patches are being reviewed on linux-rdma.
+ */
+static int qemu_rdma_broken_ipv6_kernel(Error **errp, struct ibv_context *verbs)
+{
+ struct ibv_port_attr port_attr;
+
+ /* This bug only exists in linux, to our knowledge. */
+#ifdef CONFIG_LINUX
+
+ /*
+ * Verbs are only NULL if management has bound to '[::]'.
+ *
+ * Let's iterate through all the devices and see if there any pure IB
+ * devices (non-ethernet).
+ *
+ * If not, then we can safely proceed with the migration.
+ * Otherwise, there are no guarantees until the bug is fixed in linux.
+ */
+ if (!verbs) {
+ int num_devices, x;
+ struct ibv_device ** dev_list = ibv_get_device_list(&num_devices);
+ bool roce_found = false;
+ bool ib_found = false;
+
+ for (x = 0; x < num_devices; x++) {
+ verbs = ibv_open_device(dev_list[x]);
+ if (!verbs) {
+ if (errno == EPERM) {
+ continue;
+ } else {
+ return -EINVAL;
+ }
+ }
+
+ if (ibv_query_port(verbs, 1, &port_attr)) {
+ ibv_close_device(verbs);
+ ERROR(errp, "Could not query initial IB port");
+ return -EINVAL;
+ }
+
+ if (port_attr.link_layer == IBV_LINK_LAYER_INFINIBAND) {
+ ib_found = true;
+ } else if (port_attr.link_layer == IBV_LINK_LAYER_ETHERNET) {
+ roce_found = true;
+ }
+
+ ibv_close_device(verbs);
+
+ }
+
+ if (roce_found) {
+ if (ib_found) {
+ fprintf(stderr, "WARN: migrations may fail:"
+ " IPv6 over RoCE / iWARP in linux"
+ " is broken. But since you appear to have a"
+ " mixed RoCE / IB environment, be sure to only"
+ " migrate over the IB fabric until the kernel "
+ " fixes the bug.\n");
+ } else {
+ ERROR(errp, "You only have RoCE / iWARP devices in your systems"
+ " and your management software has specified '[::]'"
+ ", but IPv6 over RoCE / iWARP is not supported in Linux.");
+ return -ENONET;
+ }
+ }
+
+ return 0;
+ }
+
+ /*
+ * If we have a verbs context, that means that some other than '[::]' was
+ * used by the management software for binding. In which case we can
+ * actually warn the user about a potentially broken kernel.
+ */
+
+ /* IB ports start with 1, not 0 */
+ if (ibv_query_port(verbs, 1, &port_attr)) {
+ ERROR(errp, "Could not query initial IB port");
+ return -EINVAL;
+ }
+
+ if (port_attr.link_layer == IBV_LINK_LAYER_ETHERNET) {
+ ERROR(errp, "Linux kernel's RoCE / iWARP does not support IPv6 "
+ "(but patches on linux-rdma in progress)");
+ return -ENONET;
+ }
+
+#endif
+
+ return 0;
+}
+
+/*
+ * Figure out which RDMA device corresponds to the requested IP hostname
+ * Also create the initial connection manager identifiers for opening
+ * the connection.
+ */
+static int qemu_rdma_resolve_host(RDMAContext *rdma, Error **errp)
+{
+ int ret;
+ struct rdma_addrinfo *res;
+ char port_str[16];
+ struct rdma_cm_event *cm_event;
+ char ip[40] = "unknown";
+ struct rdma_addrinfo *e;
+
+ if (rdma->host == NULL || !strcmp(rdma->host, "")) {
+ ERROR(errp, "RDMA hostname has not been set");
+ return -EINVAL;
+ }
+
+ /* create CM channel */
+ rdma->channel = rdma_create_event_channel();
+ if (!rdma->channel) {
+ ERROR(errp, "could not create CM channel");
+ return -EINVAL;
+ }
+
+ /* create CM id */
+ ret = rdma_create_id(rdma->channel, &rdma->cm_id, NULL, RDMA_PS_TCP);
+ if (ret) {
+ ERROR(errp, "could not create channel id");
+ goto err_resolve_create_id;
+ }
+
+ snprintf(port_str, 16, "%d", rdma->port);
+ port_str[15] = '\0';
+
+ ret = rdma_getaddrinfo(rdma->host, port_str, NULL, &res);
+ if (ret < 0) {
+ ERROR(errp, "could not rdma_getaddrinfo address %s", rdma->host);
+ goto err_resolve_get_addr;
+ }
+
+ for (e = res; e != NULL; e = e->ai_next) {
+ inet_ntop(e->ai_family,
+ &((struct sockaddr_in *) e->ai_dst_addr)->sin_addr, ip, sizeof ip);
+ trace_qemu_rdma_resolve_host_trying(rdma->host, ip);
+
+ ret = rdma_resolve_addr(rdma->cm_id, NULL, e->ai_dst_addr,
+ RDMA_RESOLVE_TIMEOUT_MS);
+ if (!ret) {
+ if (e->ai_family == AF_INET6) {
+ ret = qemu_rdma_broken_ipv6_kernel(errp, rdma->cm_id->verbs);
+ if (ret) {
+ continue;
+ }
+ }
+ goto route;
+ }
+ }
+
+ ERROR(errp, "could not resolve address %s", rdma->host);
+ goto err_resolve_get_addr;
+
+route:
+ qemu_rdma_dump_gid("source_resolve_addr", rdma->cm_id);
+
+ ret = rdma_get_cm_event(rdma->channel, &cm_event);
+ if (ret) {
+ ERROR(errp, "could not perform event_addr_resolved");
+ goto err_resolve_get_addr;
+ }
+
+ if (cm_event->event != RDMA_CM_EVENT_ADDR_RESOLVED) {
+ ERROR(errp, "result not equal to event_addr_resolved %s",
+ rdma_event_str(cm_event->event));
+ perror("rdma_resolve_addr");
+ rdma_ack_cm_event(cm_event);
+ ret = -EINVAL;
+ goto err_resolve_get_addr;
+ }
+ rdma_ack_cm_event(cm_event);
+
+ /* resolve route */
+ ret = rdma_resolve_route(rdma->cm_id, RDMA_RESOLVE_TIMEOUT_MS);
+ if (ret) {
+ ERROR(errp, "could not resolve rdma route");
+ goto err_resolve_get_addr;
+ }
+
+ ret = rdma_get_cm_event(rdma->channel, &cm_event);
+ if (ret) {
+ ERROR(errp, "could not perform event_route_resolved");
+ goto err_resolve_get_addr;
+ }
+ if (cm_event->event != RDMA_CM_EVENT_ROUTE_RESOLVED) {
+ ERROR(errp, "result not equal to event_route_resolved: %s",
+ rdma_event_str(cm_event->event));
+ rdma_ack_cm_event(cm_event);
+ ret = -EINVAL;
+ goto err_resolve_get_addr;
+ }
+ rdma_ack_cm_event(cm_event);
+ rdma->verbs = rdma->cm_id->verbs;
+ qemu_rdma_dump_id("source_resolve_host", rdma->cm_id->verbs);
+ qemu_rdma_dump_gid("source_resolve_host", rdma->cm_id);
+ return 0;
+
+err_resolve_get_addr:
+ rdma_destroy_id(rdma->cm_id);
+ rdma->cm_id = NULL;
+err_resolve_create_id:
+ rdma_destroy_event_channel(rdma->channel);
+ rdma->channel = NULL;
+ return ret;
+}
+
+/*
+ * Create protection domain and completion queues
+ */
+static int qemu_rdma_alloc_pd_cq(RDMAContext *rdma)
+{
+ /* allocate pd */
+ rdma->pd = ibv_alloc_pd(rdma->verbs);
+ if (!rdma->pd) {
+ error_report("failed to allocate protection domain");
+ return -1;
+ }
+
+ /* create completion channel */
+ rdma->comp_channel = ibv_create_comp_channel(rdma->verbs);
+ if (!rdma->comp_channel) {
+ error_report("failed to allocate completion channel");
+ goto err_alloc_pd_cq;
+ }
+
+ /*
+ * Completion queue can be filled by both read and write work requests,
+ * so must reflect the sum of both possible queue sizes.
+ */
+ rdma->cq = ibv_create_cq(rdma->verbs, (RDMA_SIGNALED_SEND_MAX * 3),
+ NULL, rdma->comp_channel, 0);
+ if (!rdma->cq) {
+ error_report("failed to allocate completion queue");
+ goto err_alloc_pd_cq;
+ }
+
+ return 0;
+
+err_alloc_pd_cq:
+ if (rdma->pd) {
+ ibv_dealloc_pd(rdma->pd);
+ }
+ if (rdma->comp_channel) {
+ ibv_destroy_comp_channel(rdma->comp_channel);
+ }
+ rdma->pd = NULL;
+ rdma->comp_channel = NULL;
+ return -1;
+
+}
+
+/*
+ * Create queue pairs.
+ */
+static int qemu_rdma_alloc_qp(RDMAContext *rdma)
+{
+ struct ibv_qp_init_attr attr = { 0 };
+ int ret;
+
+ attr.cap.max_send_wr = RDMA_SIGNALED_SEND_MAX;
+ attr.cap.max_recv_wr = 3;
+ attr.cap.max_send_sge = 1;
+ attr.cap.max_recv_sge = 1;
+ attr.send_cq = rdma->cq;
+ attr.recv_cq = rdma->cq;
+ attr.qp_type = IBV_QPT_RC;
+
+ ret = rdma_create_qp(rdma->cm_id, rdma->pd, &attr);
+ if (ret) {
+ return -1;
+ }
+
+ rdma->qp = rdma->cm_id->qp;
+ return 0;
+}
+
+static int qemu_rdma_reg_whole_ram_blocks(RDMAContext *rdma)
+{
+ int i;
+ RDMALocalBlocks *local = &rdma->local_ram_blocks;
+
+ for (i = 0; i < local->nb_blocks; i++) {
+ local->block[i].mr =
+ ibv_reg_mr(rdma->pd,
+ local->block[i].local_host_addr,
+ local->block[i].length,
+ IBV_ACCESS_LOCAL_WRITE |
+ IBV_ACCESS_REMOTE_WRITE
+ );
+ if (!local->block[i].mr) {
+ perror("Failed to register local dest ram block!\n");
+ break;
+ }
+ rdma->total_registrations++;
+ }
+
+ if (i >= local->nb_blocks) {
+ return 0;
+ }
+
+ for (i--; i >= 0; i--) {
+ ibv_dereg_mr(local->block[i].mr);
+ rdma->total_registrations--;
+ }
+
+ return -1;
+
+}
+
+/*
+ * Find the ram block that corresponds to the page requested to be
+ * transmitted by QEMU.
+ *
+ * Once the block is found, also identify which 'chunk' within that
+ * block that the page belongs to.
+ *
+ * This search cannot fail or the migration will fail.
+ */
+static int qemu_rdma_search_ram_block(RDMAContext *rdma,
+ uintptr_t block_offset,
+ uint64_t offset,
+ uint64_t length,
+ uint64_t *block_index,
+ uint64_t *chunk_index)
+{
+ uint64_t current_addr = block_offset + offset;
+ RDMALocalBlock *block = g_hash_table_lookup(rdma->blockmap,
+ (void *) block_offset);
+ assert(block);
+ assert(current_addr >= block->offset);
+ assert((current_addr + length) <= (block->offset + block->length));
+
+ *block_index = block->index;
+ *chunk_index = ram_chunk_index(block->local_host_addr,
+ block->local_host_addr + (current_addr - block->offset));
+
+ return 0;
+}
+
+/*
+ * Register a chunk with IB. If the chunk was already registered
+ * previously, then skip.
+ *
+ * Also return the keys associated with the registration needed
+ * to perform the actual RDMA operation.
+ */
+static int qemu_rdma_register_and_get_keys(RDMAContext *rdma,
+ RDMALocalBlock *block, uintptr_t host_addr,
+ uint32_t *lkey, uint32_t *rkey, int chunk,
+ uint8_t *chunk_start, uint8_t *chunk_end)
+{
+ if (block->mr) {
+ if (lkey) {
+ *lkey = block->mr->lkey;
+ }
+ if (rkey) {
+ *rkey = block->mr->rkey;
+ }
+ return 0;
+ }
+
+ /* allocate memory to store chunk MRs */
+ if (!block->pmr) {
+ block->pmr = g_malloc0(block->nb_chunks * sizeof(struct ibv_mr *));
+ }
+
+ /*
+ * If 'rkey', then we're the destination, so grant access to the source.
+ *
+ * If 'lkey', then we're the source VM, so grant access only to ourselves.
+ */
+ if (!block->pmr[chunk]) {
+ uint64_t len = chunk_end - chunk_start;
+
+ trace_qemu_rdma_register_and_get_keys(len, chunk_start);
+
+ block->pmr[chunk] = ibv_reg_mr(rdma->pd,
+ chunk_start, len,
+ (rkey ? (IBV_ACCESS_LOCAL_WRITE |
+ IBV_ACCESS_REMOTE_WRITE) : 0));
+
+ if (!block->pmr[chunk]) {
+ perror("Failed to register chunk!");
+ fprintf(stderr, "Chunk details: block: %d chunk index %d"
+ " start %" PRIuPTR " end %" PRIuPTR
+ " host %" PRIuPTR
+ " local %" PRIuPTR " registrations: %d\n",
+ block->index, chunk, (uintptr_t)chunk_start,
+ (uintptr_t)chunk_end, host_addr,
+ (uintptr_t)block->local_host_addr,
+ rdma->total_registrations);
+ return -1;
+ }
+ rdma->total_registrations++;
+ }
+
+ if (lkey) {
+ *lkey = block->pmr[chunk]->lkey;
+ }
+ if (rkey) {
+ *rkey = block->pmr[chunk]->rkey;
+ }
+ return 0;
+}
+
+/*
+ * Register (at connection time) the memory used for control
+ * channel messages.
+ */
+static int qemu_rdma_reg_control(RDMAContext *rdma, int idx)
+{
+ rdma->wr_data[idx].control_mr = ibv_reg_mr(rdma->pd,
+ rdma->wr_data[idx].control, RDMA_CONTROL_MAX_BUFFER,
+ IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE);
+ if (rdma->wr_data[idx].control_mr) {
+ rdma->total_registrations++;
+ return 0;
+ }
+ error_report("qemu_rdma_reg_control failed");
+ return -1;
+}
+
+const char *print_wrid(int wrid)
+{
+ if (wrid >= RDMA_WRID_RECV_CONTROL) {
+ return wrid_desc[RDMA_WRID_RECV_CONTROL];
+ }
+ return wrid_desc[wrid];
+}
+
+/*
+ * RDMA requires memory registration (mlock/pinning), but this is not good for
+ * overcommitment.
+ *
+ * In preparation for the future where LRU information or workload-specific
+ * writable writable working set memory access behavior is available to QEMU
+ * it would be nice to have in place the ability to UN-register/UN-pin
+ * particular memory regions from the RDMA hardware when it is determine that
+ * those regions of memory will likely not be accessed again in the near future.
+ *
+ * While we do not yet have such information right now, the following
+ * compile-time option allows us to perform a non-optimized version of this
+ * behavior.
+ *
+ * By uncommenting this option, you will cause *all* RDMA transfers to be
+ * unregistered immediately after the transfer completes on both sides of the
+ * connection. This has no effect in 'rdma-pin-all' mode, only regular mode.
+ *
+ * This will have a terrible impact on migration performance, so until future
+ * workload information or LRU information is available, do not attempt to use
+ * this feature except for basic testing.
+ */
+//#define RDMA_UNREGISTRATION_EXAMPLE
+
+/*
+ * Perform a non-optimized memory unregistration after every transfer
+ * for demonstration purposes, only if pin-all is not requested.
+ *
+ * Potential optimizations:
+ * 1. Start a new thread to run this function continuously
+ - for bit clearing
+ - and for receipt of unregister messages
+ * 2. Use an LRU.
+ * 3. Use workload hints.
+ */
+static int qemu_rdma_unregister_waiting(RDMAContext *rdma)
+{
+ while (rdma->unregistrations[rdma->unregister_current]) {
+ int ret;
+ uint64_t wr_id = rdma->unregistrations[rdma->unregister_current];
+ uint64_t chunk =
+ (wr_id & RDMA_WRID_CHUNK_MASK) >> RDMA_WRID_CHUNK_SHIFT;
+ uint64_t index =
+ (wr_id & RDMA_WRID_BLOCK_MASK) >> RDMA_WRID_BLOCK_SHIFT;
+ RDMALocalBlock *block =
+ &(rdma->local_ram_blocks.block[index]);
+ RDMARegister reg = { .current_index = index };
+ RDMAControlHeader resp = { .type = RDMA_CONTROL_UNREGISTER_FINISHED,
+ };
+ RDMAControlHeader head = { .len = sizeof(RDMARegister),
+ .type = RDMA_CONTROL_UNREGISTER_REQUEST,
+ .repeat = 1,
+ };
+
+ trace_qemu_rdma_unregister_waiting_proc(chunk,
+ rdma->unregister_current);
+
+ rdma->unregistrations[rdma->unregister_current] = 0;
+ rdma->unregister_current++;
+
+ if (rdma->unregister_current == RDMA_SIGNALED_SEND_MAX) {
+ rdma->unregister_current = 0;
+ }
+
+
+ /*
+ * Unregistration is speculative (because migration is single-threaded
+ * and we cannot break the protocol's inifinband message ordering).
+ * Thus, if the memory is currently being used for transmission,
+ * then abort the attempt to unregister and try again
+ * later the next time a completion is received for this memory.
+ */
+ clear_bit(chunk, block->unregister_bitmap);
+
+ if (test_bit(chunk, block->transit_bitmap)) {
+ trace_qemu_rdma_unregister_waiting_inflight(chunk);
+ continue;
+ }
+
+ trace_qemu_rdma_unregister_waiting_send(chunk);
+
+ ret = ibv_dereg_mr(block->pmr[chunk]);
+ block->pmr[chunk] = NULL;
+ block->remote_keys[chunk] = 0;
+
+ if (ret != 0) {
+ perror("unregistration chunk failed");
+ return -ret;
+ }
+ rdma->total_registrations--;
+
+ reg.key.chunk = chunk;
+ register_to_network(rdma, ®);
+ ret = qemu_rdma_exchange_send(rdma, &head, (uint8_t *) ®,
+ &resp, NULL, NULL);
+ if (ret < 0) {
+ return ret;
+ }
+
+ trace_qemu_rdma_unregister_waiting_complete(chunk);
+ }
+
+ return 0;
+}
+
+static uint64_t qemu_rdma_make_wrid(uint64_t wr_id, uint64_t index,
+ uint64_t chunk)
+{
+ uint64_t result = wr_id & RDMA_WRID_TYPE_MASK;
+
+ result |= (index << RDMA_WRID_BLOCK_SHIFT);
+ result |= (chunk << RDMA_WRID_CHUNK_SHIFT);
+
+ return result;
+}
+
+/*
+ * Set bit for unregistration in the next iteration.
+ * We cannot transmit right here, but will unpin later.
+ */
+static void qemu_rdma_signal_unregister(RDMAContext *rdma, uint64_t index,
+ uint64_t chunk, uint64_t wr_id)
+{
+ if (rdma->unregistrations[rdma->unregister_next] != 0) {
+ error_report("rdma migration: queue is full");
+ } else {
+ RDMALocalBlock *block = &(rdma->local_ram_blocks.block[index]);
+
+ if (!test_and_set_bit(chunk, block->unregister_bitmap)) {
+ trace_qemu_rdma_signal_unregister_append(chunk,
+ rdma->unregister_next);
+
+ rdma->unregistrations[rdma->unregister_next++] =
+ qemu_rdma_make_wrid(wr_id, index, chunk);
+
+ if (rdma->unregister_next == RDMA_SIGNALED_SEND_MAX) {
+ rdma->unregister_next = 0;
+ }
+ } else {
+ trace_qemu_rdma_signal_unregister_already(chunk);
+ }
+ }
+}
+
+/*
+ * Consult the connection manager to see a work request
+ * (of any kind) has completed.
+ * Return the work request ID that completed.
+ */
+static uint64_t qemu_rdma_poll(RDMAContext *rdma, uint64_t *wr_id_out,
+ uint32_t *byte_len)
+{
+ int ret;
+ struct ibv_wc wc;
+ uint64_t wr_id;
+
+ ret = ibv_poll_cq(rdma->cq, 1, &wc);
+
+ if (!ret) {
+ *wr_id_out = RDMA_WRID_NONE;
+ return 0;
+ }
+
+ if (ret < 0) {
+ error_report("ibv_poll_cq return %d", ret);
+ return ret;
+ }
+
+ wr_id = wc.wr_id & RDMA_WRID_TYPE_MASK;
+
+ if (wc.status != IBV_WC_SUCCESS) {
+ fprintf(stderr, "ibv_poll_cq wc.status=%d %s!\n",
+ wc.status, ibv_wc_status_str(wc.status));
+ fprintf(stderr, "ibv_poll_cq wrid=%s!\n", wrid_desc[wr_id]);
+
+ return -1;
+ }
+
+ if (rdma->control_ready_expected &&
+ (wr_id >= RDMA_WRID_RECV_CONTROL)) {
+ trace_qemu_rdma_poll_recv(wrid_desc[RDMA_WRID_RECV_CONTROL],
+ wr_id - RDMA_WRID_RECV_CONTROL, wr_id, rdma->nb_sent);
+ rdma->control_ready_expected = 0;
+ }
+
+ if (wr_id == RDMA_WRID_RDMA_WRITE) {
+ uint64_t chunk =
+ (wc.wr_id & RDMA_WRID_CHUNK_MASK) >> RDMA_WRID_CHUNK_SHIFT;
+ uint64_t index =
+ (wc.wr_id & RDMA_WRID_BLOCK_MASK) >> RDMA_WRID_BLOCK_SHIFT;
+ RDMALocalBlock *block = &(rdma->local_ram_blocks.block[index]);
+
+ trace_qemu_rdma_poll_write(print_wrid(wr_id), wr_id, rdma->nb_sent,
+ index, chunk, block->local_host_addr,
+ (void *)(uintptr_t)block->remote_host_addr);
+
+ clear_bit(chunk, block->transit_bitmap);
+
+ if (rdma->nb_sent > 0) {
+ rdma->nb_sent--;
+ }
+
+ if (!rdma->pin_all) {
+ /*
+ * FYI: If one wanted to signal a specific chunk to be unregistered
+ * using LRU or workload-specific information, this is the function
+ * you would call to do so. That chunk would then get asynchronously
+ * unregistered later.
+ */
+#ifdef RDMA_UNREGISTRATION_EXAMPLE
+ qemu_rdma_signal_unregister(rdma, index, chunk, wc.wr_id);
+#endif
+ }
+ } else {
+ trace_qemu_rdma_poll_other(print_wrid(wr_id), wr_id, rdma->nb_sent);
+ }
+
+ *wr_id_out = wc.wr_id;
+ if (byte_len) {
+ *byte_len = wc.byte_len;
+ }
+
+ return 0;
+}
+
+/*
+ * Block until the next work request has completed.
+ *
+ * First poll to see if a work request has already completed,
+ * otherwise block.
+ *
+ * If we encounter completed work requests for IDs other than
+ * the one we're interested in, then that's generally an error.
+ *
+ * The only exception is actual RDMA Write completions. These
+ * completions only need to be recorded, but do not actually
+ * need further processing.
+ */
+static int qemu_rdma_block_for_wrid(RDMAContext *rdma, int wrid_requested,
+ uint32_t *byte_len)
+{
+ int num_cq_events = 0, ret = 0;
+ struct ibv_cq *cq;
+ void *cq_ctx;
+ uint64_t wr_id = RDMA_WRID_NONE, wr_id_in;
+
+ if (ibv_req_notify_cq(rdma->cq, 0)) {
+ return -1;
+ }
+ /* poll cq first */
+ while (wr_id != wrid_requested) {
+ ret = qemu_rdma_poll(rdma, &wr_id_in, byte_len);
+ if (ret < 0) {
+ return ret;
+ }
+
+ wr_id = wr_id_in & RDMA_WRID_TYPE_MASK;
+
+ if (wr_id == RDMA_WRID_NONE) {
+ break;
+ }
+ if (wr_id != wrid_requested) {
+ trace_qemu_rdma_block_for_wrid_miss(print_wrid(wrid_requested),
+ wrid_requested, print_wrid(wr_id), wr_id);
+ }
+ }
+
+ if (wr_id == wrid_requested) {
+ return 0;
+ }
+
+ while (1) {
+ /*
+ * Coroutine doesn't start until process_incoming_migration()
+ * so don't yield unless we know we're running inside of a coroutine.
+ */
+ if (rdma->migration_started_on_destination) {
+ yield_until_fd_readable(rdma->comp_channel->fd);
+ }
+
+ if (ibv_get_cq_event(rdma->comp_channel, &cq, &cq_ctx)) {
+ perror("ibv_get_cq_event");
+ goto err_block_for_wrid;
+ }
+
+ num_cq_events++;
+
+ if (ibv_req_notify_cq(cq, 0)) {
+ goto err_block_for_wrid;
+ }
+
+ while (wr_id != wrid_requested) {
+ ret = qemu_rdma_poll(rdma, &wr_id_in, byte_len);
+ if (ret < 0) {
+ goto err_block_for_wrid;
+ }
+
+ wr_id = wr_id_in & RDMA_WRID_TYPE_MASK;
+
+ if (wr_id == RDMA_WRID_NONE) {
+ break;
+ }
+ if (wr_id != wrid_requested) {
+ trace_qemu_rdma_block_for_wrid_miss(print_wrid(wrid_requested),
+ wrid_requested, print_wrid(wr_id), wr_id);
+ }
+ }
+
+ if (wr_id == wrid_requested) {
+ goto success_block_for_wrid;
+ }
+ }
+
+success_block_for_wrid:
+ if (num_cq_events) {
+ ibv_ack_cq_events(cq, num_cq_events);
+ }
+ return 0;
+
+err_block_for_wrid:
+ if (num_cq_events) {
+ ibv_ack_cq_events(cq, num_cq_events);
+ }
+ return ret;
+}
+
+/*
+ * Post a SEND message work request for the control channel
+ * containing some data and block until the post completes.
+ */
+static int qemu_rdma_post_send_control(RDMAContext *rdma, uint8_t *buf,
+ RDMAControlHeader *head)
+{
+ int ret = 0;
+ RDMAWorkRequestData *wr = &rdma->wr_data[RDMA_WRID_CONTROL];
+ struct ibv_send_wr *bad_wr;
+ struct ibv_sge sge = {
+ .addr = (uintptr_t)(wr->control),
+ .length = head->len + sizeof(RDMAControlHeader),
+ .lkey = wr->control_mr->lkey,
+ };
+ struct ibv_send_wr send_wr = {
+ .wr_id = RDMA_WRID_SEND_CONTROL,
+ .opcode = IBV_WR_SEND,
+ .send_flags = IBV_SEND_SIGNALED,
+ .sg_list = &sge,
+ .num_sge = 1,
+ };
+
+ trace_qemu_rdma_post_send_control(control_desc[head->type]);
+
+ /*
+ * We don't actually need to do a memcpy() in here if we used
+ * the "sge" properly, but since we're only sending control messages
+ * (not RAM in a performance-critical path), then its OK for now.
+ *
+ * The copy makes the RDMAControlHeader simpler to manipulate
+ * for the time being.
+ */
+ assert(head->len <= RDMA_CONTROL_MAX_BUFFER - sizeof(*head));
+ memcpy(wr->control, head, sizeof(RDMAControlHeader));
+ control_to_network((void *) wr->control);
+
+ if (buf) {
+ memcpy(wr->control + sizeof(RDMAControlHeader), buf, head->len);
+ }
+
+
+ ret = ibv_post_send(rdma->qp, &send_wr, &bad_wr);
+
+ if (ret > 0) {
+ error_report("Failed to use post IB SEND for control");
+ return -ret;
+ }
+
+ ret = qemu_rdma_block_for_wrid(rdma, RDMA_WRID_SEND_CONTROL, NULL);
+ if (ret < 0) {
+ error_report("rdma migration: send polling control error");
+ }
+
+ return ret;
+}
+
+/*
+ * Post a RECV work request in anticipation of some future receipt
+ * of data on the control channel.
+ */
+static int qemu_rdma_post_recv_control(RDMAContext *rdma, int idx)
+{
+ struct ibv_recv_wr *bad_wr;
+ struct ibv_sge sge = {
+ .addr = (uintptr_t)(rdma->wr_data[idx].control),
+ .length = RDMA_CONTROL_MAX_BUFFER,
+ .lkey = rdma->wr_data[idx].control_mr->lkey,
+ };
+
+ struct ibv_recv_wr recv_wr = {
+ .wr_id = RDMA_WRID_RECV_CONTROL + idx,
+ .sg_list = &sge,
+ .num_sge = 1,
+ };
+
+
+ if (ibv_post_recv(rdma->qp, &recv_wr, &bad_wr)) {
+ return -1;
+ }
+
+ return 0;
+}
+
+/*
+ * Block and wait for a RECV control channel message to arrive.
+ */
+static int qemu_rdma_exchange_get_response(RDMAContext *rdma,
+ RDMAControlHeader *head, int expecting, int idx)
+{
+ uint32_t byte_len;
+ int ret = qemu_rdma_block_for_wrid(rdma, RDMA_WRID_RECV_CONTROL + idx,
+ &byte_len);
+
+ if (ret < 0) {
+ error_report("rdma migration: recv polling control error!");
+ return ret;
+ }
+
+ network_to_control((void *) rdma->wr_data[idx].control);
+ memcpy(head, rdma->wr_data[idx].control, sizeof(RDMAControlHeader));
+
+ trace_qemu_rdma_exchange_get_response_start(control_desc[expecting]);
+
+ if (expecting == RDMA_CONTROL_NONE) {
+ trace_qemu_rdma_exchange_get_response_none(control_desc[head->type],
+ head->type);
+ } else if (head->type != expecting || head->type == RDMA_CONTROL_ERROR) {
+ error_report("Was expecting a %s (%d) control message"
+ ", but got: %s (%d), length: %d",
+ control_desc[expecting], expecting,
+ control_desc[head->type], head->type, head->len);
+ return -EIO;
+ }
+ if (head->len > RDMA_CONTROL_MAX_BUFFER - sizeof(*head)) {
+ error_report("too long length: %d", head->len);
+ return -EINVAL;
+ }
+ if (sizeof(*head) + head->len != byte_len) {
+ error_report("Malformed length: %d byte_len %d", head->len, byte_len);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/*
+ * When a RECV work request has completed, the work request's
+ * buffer is pointed at the header.
+ *
+ * This will advance the pointer to the data portion
+ * of the control message of the work request's buffer that
+ * was populated after the work request finished.
+ */
+static void qemu_rdma_move_header(RDMAContext *rdma, int idx,
+ RDMAControlHeader *head)
+{
+ rdma->wr_data[idx].control_len = head->len;
+ rdma->wr_data[idx].control_curr =
+ rdma->wr_data[idx].control + sizeof(RDMAControlHeader);
+}
+
+/*
+ * This is an 'atomic' high-level operation to deliver a single, unified
+ * control-channel message.
+ *
+ * Additionally, if the user is expecting some kind of reply to this message,
+ * they can request a 'resp' response message be filled in by posting an
+ * additional work request on behalf of the user and waiting for an additional
+ * completion.
+ *
+ * The extra (optional) response is used during registration to us from having
+ * to perform an *additional* exchange of message just to provide a response by
+ * instead piggy-backing on the acknowledgement.
+ */
+static int qemu_rdma_exchange_send(RDMAContext *rdma, RDMAControlHeader *head,
+ uint8_t *data, RDMAControlHeader *resp,
+ int *resp_idx,
+ int (*callback)(RDMAContext *rdma))
+{
+ int ret = 0;
+
+ /*
+ * Wait until the dest is ready before attempting to deliver the message
+ * by waiting for a READY message.
+ */
+ if (rdma->control_ready_expected) {
+ RDMAControlHeader resp;
+ ret = qemu_rdma_exchange_get_response(rdma,
+ &resp, RDMA_CONTROL_READY, RDMA_WRID_READY);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ /*
+ * If the user is expecting a response, post a WR in anticipation of it.
+ */
+ if (resp) {
+ ret = qemu_rdma_post_recv_control(rdma, RDMA_WRID_DATA);
+ if (ret) {
+ error_report("rdma migration: error posting"
+ " extra control recv for anticipated result!");
+ return ret;
+ }
+ }
+
+ /*
+ * Post a WR to replace the one we just consumed for the READY message.
+ */
+ ret = qemu_rdma_post_recv_control(rdma, RDMA_WRID_READY);
+ if (ret) {
+ error_report("rdma migration: error posting first control recv!");
+ return ret;
+ }
+
+ /*
+ * Deliver the control message that was requested.
+ */
+ ret = qemu_rdma_post_send_control(rdma, data, head);
+
+ if (ret < 0) {
+ error_report("Failed to send control buffer!");
+ return ret;
+ }
+
+ /*
+ * If we're expecting a response, block and wait for it.
+ */
+ if (resp) {
+ if (callback) {
+ trace_qemu_rdma_exchange_send_issue_callback();
+ ret = callback(rdma);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ trace_qemu_rdma_exchange_send_waiting(control_desc[resp->type]);
+ ret = qemu_rdma_exchange_get_response(rdma, resp,
+ resp->type, RDMA_WRID_DATA);
+
+ if (ret < 0) {
+ return ret;
+ }
+
+ qemu_rdma_move_header(rdma, RDMA_WRID_DATA, resp);
+ if (resp_idx) {
+ *resp_idx = RDMA_WRID_DATA;
+ }
+ trace_qemu_rdma_exchange_send_received(control_desc[resp->type]);
+ }
+
+ rdma->control_ready_expected = 1;
+
+ return 0;
+}
+
+/*
+ * This is an 'atomic' high-level operation to receive a single, unified
+ * control-channel message.
+ */
+static int qemu_rdma_exchange_recv(RDMAContext *rdma, RDMAControlHeader *head,
+ int expecting)
+{
+ RDMAControlHeader ready = {
+ .len = 0,
+ .type = RDMA_CONTROL_READY,
+ .repeat = 1,
+ };
+ int ret;
+
+ /*
+ * Inform the source that we're ready to receive a message.
+ */
+ ret = qemu_rdma_post_send_control(rdma, NULL, &ready);
+
+ if (ret < 0) {
+ error_report("Failed to send control buffer!");
+ return ret;
+ }
+
+ /*
+ * Block and wait for the message.
+ */
+ ret = qemu_rdma_exchange_get_response(rdma, head,
+ expecting, RDMA_WRID_READY);
+
+ if (ret < 0) {
+ return ret;
+ }
+
+ qemu_rdma_move_header(rdma, RDMA_WRID_READY, head);
+
+ /*
+ * Post a new RECV work request to replace the one we just consumed.
+ */
+ ret = qemu_rdma_post_recv_control(rdma, RDMA_WRID_READY);
+ if (ret) {
+ error_report("rdma migration: error posting second control recv!");
+ return ret;
+ }
+
+ return 0;
+}
+
+/*
+ * Write an actual chunk of memory using RDMA.
+ *
+ * If we're using dynamic registration on the dest-side, we have to
+ * send a registration command first.
+ */
+static int qemu_rdma_write_one(QEMUFile *f, RDMAContext *rdma,
+ int current_index, uint64_t current_addr,
+ uint64_t length)
+{
+ struct ibv_sge sge;
+ struct ibv_send_wr send_wr = { 0 };
+ struct ibv_send_wr *bad_wr;
+ int reg_result_idx, ret, count = 0;
+ uint64_t chunk, chunks;
+ uint8_t *chunk_start, *chunk_end;
+ RDMALocalBlock *block = &(rdma->local_ram_blocks.block[current_index]);
+ RDMARegister reg;
+ RDMARegisterResult *reg_result;
+ RDMAControlHeader resp = { .type = RDMA_CONTROL_REGISTER_RESULT };
+ RDMAControlHeader head = { .len = sizeof(RDMARegister),
+ .type = RDMA_CONTROL_REGISTER_REQUEST,
+ .repeat = 1,
+ };
+
+retry:
+ sge.addr = (uintptr_t)(block->local_host_addr +
+ (current_addr - block->offset));
+ sge.length = length;
+
+ chunk = ram_chunk_index(block->local_host_addr,
+ (uint8_t *)(uintptr_t)sge.addr);
+ chunk_start = ram_chunk_start(block, chunk);
+
+ if (block->is_ram_block) {
+ chunks = length / (1UL << RDMA_REG_CHUNK_SHIFT);
+
+ if (chunks && ((length % (1UL << RDMA_REG_CHUNK_SHIFT)) == 0)) {
+ chunks--;
+ }
+ } else {
+ chunks = block->length / (1UL << RDMA_REG_CHUNK_SHIFT);
+
+ if (chunks && ((block->length % (1UL << RDMA_REG_CHUNK_SHIFT)) == 0)) {
+ chunks--;
+ }
+ }
+
+ trace_qemu_rdma_write_one_top(chunks + 1,
+ (chunks + 1) *
+ (1UL << RDMA_REG_CHUNK_SHIFT) / 1024 / 1024);
+
+ chunk_end = ram_chunk_end(block, chunk + chunks);
+
+ if (!rdma->pin_all) {
+#ifdef RDMA_UNREGISTRATION_EXAMPLE
+ qemu_rdma_unregister_waiting(rdma);
+#endif
+ }
+
+ while (test_bit(chunk, block->transit_bitmap)) {
+ (void)count;
+ trace_qemu_rdma_write_one_block(count++, current_index, chunk,
+ sge.addr, length, rdma->nb_sent, block->nb_chunks);
+
+ ret = qemu_rdma_block_for_wrid(rdma, RDMA_WRID_RDMA_WRITE, NULL);
+
+ if (ret < 0) {
+ error_report("Failed to Wait for previous write to complete "
+ "block %d chunk %" PRIu64
+ " current %" PRIu64 " len %" PRIu64 " %d",
+ current_index, chunk, sge.addr, length, rdma->nb_sent);
+ return ret;
+ }
+ }
+
+ if (!rdma->pin_all || !block->is_ram_block) {
+ if (!block->remote_keys[chunk]) {
+ /*
+ * This chunk has not yet been registered, so first check to see
+ * if the entire chunk is zero. If so, tell the other size to
+ * memset() + madvise() the entire chunk without RDMA.
+ */
+
+ if (can_use_buffer_find_nonzero_offset((void *)(uintptr_t)sge.addr,
+ length)
+ && buffer_find_nonzero_offset((void *)(uintptr_t)sge.addr,
+ length) == length) {
+ RDMACompress comp = {
+ .offset = current_addr,
+ .value = 0,
+ .block_idx = current_index,
+ .length = length,
+ };
+
+ head.len = sizeof(comp);
+ head.type = RDMA_CONTROL_COMPRESS;
+
+ trace_qemu_rdma_write_one_zero(chunk, sge.length,
+ current_index, current_addr);
+
+ compress_to_network(rdma, &comp);
+ ret = qemu_rdma_exchange_send(rdma, &head,
+ (uint8_t *) &comp, NULL, NULL, NULL);
+
+ if (ret < 0) {
+ return -EIO;
+ }
+
+ acct_update_position(f, sge.length, true);
+
+ return 1;
+ }
+
+ /*
+ * Otherwise, tell other side to register.
+ */
+ reg.current_index = current_index;
+ if (block->is_ram_block) {
+ reg.key.current_addr = current_addr;
+ } else {
+ reg.key.chunk = chunk;
+ }
+ reg.chunks = chunks;
+
+ trace_qemu_rdma_write_one_sendreg(chunk, sge.length, current_index,
+ current_addr);
+
+ register_to_network(rdma, ®);
+ ret = qemu_rdma_exchange_send(rdma, &head, (uint8_t *) ®,
+ &resp, ®_result_idx, NULL);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /* try to overlap this single registration with the one we sent. */
+ if (qemu_rdma_register_and_get_keys(rdma, block, sge.addr,
+ &sge.lkey, NULL, chunk,
+ chunk_start, chunk_end)) {
+ error_report("cannot get lkey");
+ return -EINVAL;
+ }
+
+ reg_result = (RDMARegisterResult *)
+ rdma->wr_data[reg_result_idx].control_curr;
+
+ network_to_result(reg_result);
+
+ trace_qemu_rdma_write_one_recvregres(block->remote_keys[chunk],
+ reg_result->rkey, chunk);
+
+ block->remote_keys[chunk] = reg_result->rkey;
+ block->remote_host_addr = reg_result->host_addr;
+ } else {
+ /* already registered before */
+ if (qemu_rdma_register_and_get_keys(rdma, block, sge.addr,
+ &sge.lkey, NULL, chunk,
+ chunk_start, chunk_end)) {
+ error_report("cannot get lkey!");
+ return -EINVAL;
+ }
+ }
+
+ send_wr.wr.rdma.rkey = block->remote_keys[chunk];
+ } else {
+ send_wr.wr.rdma.rkey = block->remote_rkey;
+
+ if (qemu_rdma_register_and_get_keys(rdma, block, sge.addr,
+ &sge.lkey, NULL, chunk,
+ chunk_start, chunk_end)) {
+ error_report("cannot get lkey!");
+ return -EINVAL;
+ }
+ }
+
+ /*
+ * Encode the ram block index and chunk within this wrid.
+ * We will use this information at the time of completion
+ * to figure out which bitmap to check against and then which
+ * chunk in the bitmap to look for.
+ */
+ send_wr.wr_id = qemu_rdma_make_wrid(RDMA_WRID_RDMA_WRITE,
+ current_index, chunk);
+
+ send_wr.opcode = IBV_WR_RDMA_WRITE;
+ send_wr.send_flags = IBV_SEND_SIGNALED;
+ send_wr.sg_list = &sge;
+ send_wr.num_sge = 1;
+ send_wr.wr.rdma.remote_addr = block->remote_host_addr +
+ (current_addr - block->offset);
+
+ trace_qemu_rdma_write_one_post(chunk, sge.addr, send_wr.wr.rdma.remote_addr,
+ sge.length);
+
+ /*
+ * ibv_post_send() does not return negative error numbers,
+ * per the specification they are positive - no idea why.
+ */
+ ret = ibv_post_send(rdma->qp, &send_wr, &bad_wr);
+
+ if (ret == ENOMEM) {
+ trace_qemu_rdma_write_one_queue_full();
+ ret = qemu_rdma_block_for_wrid(rdma, RDMA_WRID_RDMA_WRITE, NULL);
+ if (ret < 0) {
+ error_report("rdma migration: failed to make "
+ "room in full send queue! %d", ret);
+ return ret;
+ }
+
+ goto retry;
+
+ } else if (ret > 0) {
+ perror("rdma migration: post rdma write failed");
+ return -ret;
+ }
+
+ set_bit(chunk, block->transit_bitmap);
+ acct_update_position(f, sge.length, false);
+ rdma->total_writes++;
+
+ return 0;
+}
+
+/*
+ * Push out any unwritten RDMA operations.
+ *
+ * We support sending out multiple chunks at the same time.
+ * Not all of them need to get signaled in the completion queue.
+ */
+static int qemu_rdma_write_flush(QEMUFile *f, RDMAContext *rdma)
+{
+ int ret;
+
+ if (!rdma->current_length) {
+ return 0;
+ }
+
+ ret = qemu_rdma_write_one(f, rdma,
+ rdma->current_index, rdma->current_addr, rdma->current_length);
+
+ if (ret < 0) {
+ return ret;
+ }
+
+ if (ret == 0) {
+ rdma->nb_sent++;
+ trace_qemu_rdma_write_flush(rdma->nb_sent);
+ }
+
+ rdma->current_length = 0;
+ rdma->current_addr = 0;
+
+ return 0;
+}
+
+static inline int qemu_rdma_buffer_mergable(RDMAContext *rdma,
+ uint64_t offset, uint64_t len)
+{
+ RDMALocalBlock *block;
+ uint8_t *host_addr;
+ uint8_t *chunk_end;
+
+ if (rdma->current_index < 0) {
+ return 0;
+ }
+
+ if (rdma->current_chunk < 0) {
+ return 0;
+ }
+
+ block = &(rdma->local_ram_blocks.block[rdma->current_index]);
+ host_addr = block->local_host_addr + (offset - block->offset);
+ chunk_end = ram_chunk_end(block, rdma->current_chunk);
+
+ if (rdma->current_length == 0) {
+ return 0;
+ }
+
+ /*
+ * Only merge into chunk sequentially.
+ */
+ if (offset != (rdma->current_addr + rdma->current_length)) {
+ return 0;
+ }
+
+ if (offset < block->offset) {
+ return 0;
+ }
+
+ if ((offset + len) > (block->offset + block->length)) {
+ return 0;
+ }
+
+ if ((host_addr + len) > chunk_end) {
+ return 0;
+ }
+
+ return 1;
+}
+
+/*
+ * We're not actually writing here, but doing three things:
+ *
+ * 1. Identify the chunk the buffer belongs to.
+ * 2. If the chunk is full or the buffer doesn't belong to the current
+ * chunk, then start a new chunk and flush() the old chunk.
+ * 3. To keep the hardware busy, we also group chunks into batches
+ * and only require that a batch gets acknowledged in the completion
+ * qeueue instead of each individual chunk.
+ */
+static int qemu_rdma_write(QEMUFile *f, RDMAContext *rdma,
+ uint64_t block_offset, uint64_t offset,
+ uint64_t len)
+{
+ uint64_t current_addr = block_offset + offset;
+ uint64_t index = rdma->current_index;
+ uint64_t chunk = rdma->current_chunk;
+ int ret;
+
+ /* If we cannot merge it, we flush the current buffer first. */
+ if (!qemu_rdma_buffer_mergable(rdma, current_addr, len)) {
+ ret = qemu_rdma_write_flush(f, rdma);
+ if (ret) {
+ return ret;
+ }
+ rdma->current_length = 0;
+ rdma->current_addr = current_addr;
+
+ ret = qemu_rdma_search_ram_block(rdma, block_offset,
+ offset, len, &index, &chunk);
+ if (ret) {
+ error_report("ram block search failed");
+ return ret;
+ }
+ rdma->current_index = index;
+ rdma->current_chunk = chunk;
+ }
+
+ /* merge it */
+ rdma->current_length += len;
+
+ /* flush it if buffer is too large */
+ if (rdma->current_length >= RDMA_MERGE_MAX) {
+ return qemu_rdma_write_flush(f, rdma);
+ }
+
+ return 0;
+}
+
+static void qemu_rdma_cleanup(RDMAContext *rdma)
+{
+ struct rdma_cm_event *cm_event;
+ int ret, idx;
+
+ if (rdma->cm_id && rdma->connected) {
+ if (rdma->error_state) {
+ RDMAControlHeader head = { .len = 0,
+ .type = RDMA_CONTROL_ERROR,
+ .repeat = 1,
+ };
+ error_report("Early error. Sending error.");
+ qemu_rdma_post_send_control(rdma, NULL, &head);
+ }
+
+ ret = rdma_disconnect(rdma->cm_id);
+ if (!ret) {
+ trace_qemu_rdma_cleanup_waiting_for_disconnect();
+ ret = rdma_get_cm_event(rdma->channel, &cm_event);
+ if (!ret) {
+ rdma_ack_cm_event(cm_event);
+ }
+ }
+ trace_qemu_rdma_cleanup_disconnect();
+ rdma->connected = false;
+ }
+
+ g_free(rdma->dest_blocks);
+ rdma->dest_blocks = NULL;
+
+ for (idx = 0; idx < RDMA_WRID_MAX; idx++) {
+ if (rdma->wr_data[idx].control_mr) {
+ rdma->total_registrations--;
+ ibv_dereg_mr(rdma->wr_data[idx].control_mr);
+ }
+ rdma->wr_data[idx].control_mr = NULL;
+ }
+
+ if (rdma->local_ram_blocks.block) {
+ while (rdma->local_ram_blocks.nb_blocks) {
+ rdma_delete_block(rdma, &rdma->local_ram_blocks.block[0]);
+ }
+ }
+
+ if (rdma->qp) {
+ rdma_destroy_qp(rdma->cm_id);
+ rdma->qp = NULL;
+ }
+ if (rdma->cq) {
+ ibv_destroy_cq(rdma->cq);
+ rdma->cq = NULL;
+ }
+ if (rdma->comp_channel) {
+ ibv_destroy_comp_channel(rdma->comp_channel);
+ rdma->comp_channel = NULL;
+ }
+ if (rdma->pd) {
+ ibv_dealloc_pd(rdma->pd);
+ rdma->pd = NULL;
+ }
+ if (rdma->cm_id) {
+ rdma_destroy_id(rdma->cm_id);
+ rdma->cm_id = NULL;
+ }
+ if (rdma->listen_id) {
+ rdma_destroy_id(rdma->listen_id);
+ rdma->listen_id = NULL;
+ }
+ if (rdma->channel) {
+ rdma_destroy_event_channel(rdma->channel);
+ rdma->channel = NULL;
+ }
+ g_free(rdma->host);
+ rdma->host = NULL;
+}
+
+
+static int qemu_rdma_source_init(RDMAContext *rdma, Error **errp, bool pin_all)
+{
+ int ret, idx;
+ Error *local_err = NULL, **temp = &local_err;
+
+ /*
+ * Will be validated against destination's actual capabilities
+ * after the connect() completes.
+ */
+ rdma->pin_all = pin_all;
+
+ ret = qemu_rdma_resolve_host(rdma, temp);
+ if (ret) {
+ goto err_rdma_source_init;
+ }
+
+ ret = qemu_rdma_alloc_pd_cq(rdma);
+ if (ret) {
+ ERROR(temp, "rdma migration: error allocating pd and cq! Your mlock()"
+ " limits may be too low. Please check $ ulimit -a # and "
+ "search for 'ulimit -l' in the output");
+ goto err_rdma_source_init;
+ }
+
+ ret = qemu_rdma_alloc_qp(rdma);
+ if (ret) {
+ ERROR(temp, "rdma migration: error allocating qp!");
+ goto err_rdma_source_init;
+ }
+
+ ret = qemu_rdma_init_ram_blocks(rdma);
+ if (ret) {
+ ERROR(temp, "rdma migration: error initializing ram blocks!");
+ goto err_rdma_source_init;
+ }
+
+ /* Build the hash that maps from offset to RAMBlock */
+ rdma->blockmap = g_hash_table_new(g_direct_hash, g_direct_equal);
+ for (idx = 0; idx < rdma->local_ram_blocks.nb_blocks; idx++) {
+ g_hash_table_insert(rdma->blockmap,
+ (void *)(uintptr_t)rdma->local_ram_blocks.block[idx].offset,
+ &rdma->local_ram_blocks.block[idx]);
+ }
+
+ for (idx = 0; idx < RDMA_WRID_MAX; idx++) {
+ ret = qemu_rdma_reg_control(rdma, idx);
+ if (ret) {
+ ERROR(temp, "rdma migration: error registering %d control!",
+ idx);
+ goto err_rdma_source_init;
+ }
+ }
+
+ return 0;
+
+err_rdma_source_init:
+ error_propagate(errp, local_err);
+ qemu_rdma_cleanup(rdma);
+ return -1;
+}
+
+static int qemu_rdma_connect(RDMAContext *rdma, Error **errp)
+{
+ RDMACapabilities cap = {
+ .version = RDMA_CONTROL_VERSION_CURRENT,
+ .flags = 0,
+ };
+ struct rdma_conn_param conn_param = { .initiator_depth = 2,
+ .retry_count = 5,
+ .private_data = &cap,
+ .private_data_len = sizeof(cap),
+ };
+ struct rdma_cm_event *cm_event;
+ int ret;
+
+ /*
+ * Only negotiate the capability with destination if the user
+ * on the source first requested the capability.
+ */
+ if (rdma->pin_all) {
+ trace_qemu_rdma_connect_pin_all_requested();
+ cap.flags |= RDMA_CAPABILITY_PIN_ALL;
+ }
+
+ caps_to_network(&cap);
+
+ ret = rdma_connect(rdma->cm_id, &conn_param);
+ if (ret) {
+ perror("rdma_connect");
+ ERROR(errp, "connecting to destination!");
+ goto err_rdma_source_connect;
+ }
+
+ ret = rdma_get_cm_event(rdma->channel, &cm_event);
+ if (ret) {
+ perror("rdma_get_cm_event after rdma_connect");
+ ERROR(errp, "connecting to destination!");
+ rdma_ack_cm_event(cm_event);
+ goto err_rdma_source_connect;
+ }
+
+ if (cm_event->event != RDMA_CM_EVENT_ESTABLISHED) {
+ perror("rdma_get_cm_event != EVENT_ESTABLISHED after rdma_connect");
+ ERROR(errp, "connecting to destination!");
+ rdma_ack_cm_event(cm_event);
+ goto err_rdma_source_connect;
+ }
+ rdma->connected = true;
+
+ memcpy(&cap, cm_event->param.conn.private_data, sizeof(cap));
+ network_to_caps(&cap);
+
+ /*
+ * Verify that the *requested* capabilities are supported by the destination
+ * and disable them otherwise.
+ */
+ if (rdma->pin_all && !(cap.flags & RDMA_CAPABILITY_PIN_ALL)) {
+ ERROR(errp, "Server cannot support pinning all memory. "
+ "Will register memory dynamically.");
+ rdma->pin_all = false;
+ }
+
+ trace_qemu_rdma_connect_pin_all_outcome(rdma->pin_all);
+
+ rdma_ack_cm_event(cm_event);
+
+ ret = qemu_rdma_post_recv_control(rdma, RDMA_WRID_READY);
+ if (ret) {
+ ERROR(errp, "posting second control recv!");
+ goto err_rdma_source_connect;
+ }
+
+ rdma->control_ready_expected = 1;
+ rdma->nb_sent = 0;
+ return 0;
+
+err_rdma_source_connect:
+ qemu_rdma_cleanup(rdma);
+ return -1;
+}
+
+static int qemu_rdma_dest_init(RDMAContext *rdma, Error **errp)
+{
+ int ret, idx;
+ struct rdma_cm_id *listen_id;
+ char ip[40] = "unknown";
+ struct rdma_addrinfo *res, *e;
+ char port_str[16];
+
+ for (idx = 0; idx < RDMA_WRID_MAX; idx++) {
+ rdma->wr_data[idx].control_len = 0;
+ rdma->wr_data[idx].control_curr = NULL;
+ }
+
+ if (!rdma->host || !rdma->host[0]) {
+ ERROR(errp, "RDMA host is not set!");
+ rdma->error_state = -EINVAL;
+ return -1;
+ }
+ /* create CM channel */
+ rdma->channel = rdma_create_event_channel();
+ if (!rdma->channel) {
+ ERROR(errp, "could not create rdma event channel");
+ rdma->error_state = -EINVAL;
+ return -1;
+ }
+
+ /* create CM id */
+ ret = rdma_create_id(rdma->channel, &listen_id, NULL, RDMA_PS_TCP);
+ if (ret) {
+ ERROR(errp, "could not create cm_id!");
+ goto err_dest_init_create_listen_id;
+ }
+
+ snprintf(port_str, 16, "%d", rdma->port);
+ port_str[15] = '\0';
+
+ ret = rdma_getaddrinfo(rdma->host, port_str, NULL, &res);
+ if (ret < 0) {
+ ERROR(errp, "could not rdma_getaddrinfo address %s", rdma->host);
+ goto err_dest_init_bind_addr;
+ }
+
+ for (e = res; e != NULL; e = e->ai_next) {
+ inet_ntop(e->ai_family,
+ &((struct sockaddr_in *) e->ai_dst_addr)->sin_addr, ip, sizeof ip);
+ trace_qemu_rdma_dest_init_trying(rdma->host, ip);
+ ret = rdma_bind_addr(listen_id, e->ai_dst_addr);
+ if (ret) {
+ continue;
+ }
+ if (e->ai_family == AF_INET6) {
+ ret = qemu_rdma_broken_ipv6_kernel(errp, listen_id->verbs);
+ if (ret) {
+ continue;
+ }
+ }
+ break;
+ }
+
+ if (!e) {
+ ERROR(errp, "Error: could not rdma_bind_addr!");
+ goto err_dest_init_bind_addr;
+ }
+
+ rdma->listen_id = listen_id;
+ qemu_rdma_dump_gid("dest_init", listen_id);
+ return 0;
+
+err_dest_init_bind_addr:
+ rdma_destroy_id(listen_id);
+err_dest_init_create_listen_id:
+ rdma_destroy_event_channel(rdma->channel);
+ rdma->channel = NULL;
+ rdma->error_state = ret;
+ return ret;
+
+}
+
+static void *qemu_rdma_data_init(const char *host_port, Error **errp)
+{
+ RDMAContext *rdma = NULL;
+ InetSocketAddress *addr;
+
+ if (host_port) {
+ rdma = g_malloc0(sizeof(RDMAContext));
+ rdma->current_index = -1;
+ rdma->current_chunk = -1;
+
+ addr = inet_parse(host_port, NULL);
+ if (addr != NULL) {
+ rdma->port = atoi(addr->port);
+ rdma->host = g_strdup(addr->host);
+ } else {
+ ERROR(errp, "bad RDMA migration address '%s'", host_port);
+ g_free(rdma);
+ rdma = NULL;
+ }
+
+ qapi_free_InetSocketAddress(addr);
+ }
+
+ return rdma;
+}
+
+/*
+ * QEMUFile interface to the control channel.
+ * SEND messages for control only.
+ * VM's ram is handled with regular RDMA messages.
+ */
+static int qemu_rdma_put_buffer(void *opaque, const uint8_t *buf,
+ int64_t pos, int size)
+{
+ QEMUFileRDMA *r = opaque;
+ QEMUFile *f = r->file;
+ RDMAContext *rdma = r->rdma;
+ size_t remaining = size;
+ uint8_t * data = (void *) buf;
+ int ret;
+
+ CHECK_ERROR_STATE();
+
+ /*
+ * Push out any writes that
+ * we're queued up for VM's ram.
+ */
+ ret = qemu_rdma_write_flush(f, rdma);
+ if (ret < 0) {
+ rdma->error_state = ret;
+ return ret;
+ }
+
+ while (remaining) {
+ RDMAControlHeader head;
+
+ r->len = MIN(remaining, RDMA_SEND_INCREMENT);
+ remaining -= r->len;
+
+ head.len = r->len;
+ head.type = RDMA_CONTROL_QEMU_FILE;
+
+ ret = qemu_rdma_exchange_send(rdma, &head, data, NULL, NULL, NULL);
+
+ if (ret < 0) {
+ rdma->error_state = ret;
+ return ret;
+ }
+
+ data += r->len;
+ }
+
+ return size;
+}
+
+static size_t qemu_rdma_fill(RDMAContext *rdma, uint8_t *buf,
+ int size, int idx)
+{
+ size_t len = 0;
+
+ if (rdma->wr_data[idx].control_len) {
+ trace_qemu_rdma_fill(rdma->wr_data[idx].control_len, size);
+
+ len = MIN(size, rdma->wr_data[idx].control_len);
+ memcpy(buf, rdma->wr_data[idx].control_curr, len);
+ rdma->wr_data[idx].control_curr += len;
+ rdma->wr_data[idx].control_len -= len;
+ }
+
+ return len;
+}
+
+/*
+ * QEMUFile interface to the control channel.
+ * RDMA links don't use bytestreams, so we have to
+ * return bytes to QEMUFile opportunistically.
+ */
+static int qemu_rdma_get_buffer(void *opaque, uint8_t *buf,
+ int64_t pos, int size)
+{
+ QEMUFileRDMA *r = opaque;
+ RDMAContext *rdma = r->rdma;
+ RDMAControlHeader head;
+ int ret = 0;
+
+ CHECK_ERROR_STATE();
+
+ /*
+ * First, we hold on to the last SEND message we
+ * were given and dish out the bytes until we run
+ * out of bytes.
+ */
+ r->len = qemu_rdma_fill(r->rdma, buf, size, 0);
+ if (r->len) {
+ return r->len;
+ }
+
+ /*
+ * Once we run out, we block and wait for another
+ * SEND message to arrive.
+ */
+ ret = qemu_rdma_exchange_recv(rdma, &head, RDMA_CONTROL_QEMU_FILE);
+
+ if (ret < 0) {
+ rdma->error_state = ret;
+ return ret;
+ }
+
+ /*
+ * SEND was received with new bytes, now try again.
+ */
+ return qemu_rdma_fill(r->rdma, buf, size, 0);
+}
+
+/*
+ * Block until all the outstanding chunks have been delivered by the hardware.
+ */
+static int qemu_rdma_drain_cq(QEMUFile *f, RDMAContext *rdma)
+{
+ int ret;
+
+ if (qemu_rdma_write_flush(f, rdma) < 0) {
+ return -EIO;
+ }
+
+ while (rdma->nb_sent) {
+ ret = qemu_rdma_block_for_wrid(rdma, RDMA_WRID_RDMA_WRITE, NULL);
+ if (ret < 0) {
+ error_report("rdma migration: complete polling error!");
+ return -EIO;
+ }
+ }
+
+ qemu_rdma_unregister_waiting(rdma);
+
+ return 0;
+}
+
+static int qemu_rdma_close(void *opaque)
+{
+ trace_qemu_rdma_close();
+ QEMUFileRDMA *r = opaque;
+ if (r->rdma) {
+ qemu_rdma_cleanup(r->rdma);
+ g_free(r->rdma);
+ }
+ g_free(r);
+ return 0;
+}
+
+/*
+ * Parameters:
+ * @offset == 0 :
+ * This means that 'block_offset' is a full virtual address that does not
+ * belong to a RAMBlock of the virtual machine and instead
+ * represents a private malloc'd memory area that the caller wishes to
+ * transfer.
+ *
+ * @offset != 0 :
+ * Offset is an offset to be added to block_offset and used
+ * to also lookup the corresponding RAMBlock.
+ *
+ * @size > 0 :
+ * Initiate an transfer this size.
+ *
+ * @size == 0 :
+ * A 'hint' or 'advice' that means that we wish to speculatively
+ * and asynchronously unregister this memory. In this case, there is no
+ * guarantee that the unregister will actually happen, for example,
+ * if the memory is being actively transmitted. Additionally, the memory
+ * may be re-registered at any future time if a write within the same
+ * chunk was requested again, even if you attempted to unregister it
+ * here.
+ *
+ * @size < 0 : TODO, not yet supported
+ * Unregister the memory NOW. This means that the caller does not
+ * expect there to be any future RDMA transfers and we just want to clean
+ * things up. This is used in case the upper layer owns the memory and
+ * cannot wait for qemu_fclose() to occur.
+ *
+ * @bytes_sent : User-specificed pointer to indicate how many bytes were
+ * sent. Usually, this will not be more than a few bytes of
+ * the protocol because most transfers are sent asynchronously.
+ */
+static size_t qemu_rdma_save_page(QEMUFile *f, void *opaque,
+ ram_addr_t block_offset, ram_addr_t offset,
+ size_t size, uint64_t *bytes_sent)
+{
+ QEMUFileRDMA *rfile = opaque;
+ RDMAContext *rdma = rfile->rdma;
+ int ret;
+
+ CHECK_ERROR_STATE();
+
+ qemu_fflush(f);
+
+ if (size > 0) {
+ /*
+ * Add this page to the current 'chunk'. If the chunk
+ * is full, or the page doen't belong to the current chunk,
+ * an actual RDMA write will occur and a new chunk will be formed.
+ */
+ ret = qemu_rdma_write(f, rdma, block_offset, offset, size);
+ if (ret < 0) {
+ error_report("rdma migration: write error! %d", ret);
+ goto err;
+ }
+
+ /*
+ * We always return 1 bytes because the RDMA
+ * protocol is completely asynchronous. We do not yet know
+ * whether an identified chunk is zero or not because we're
+ * waiting for other pages to potentially be merged with
+ * the current chunk. So, we have to call qemu_update_position()
+ * later on when the actual write occurs.
+ */
+ if (bytes_sent) {
+ *bytes_sent = 1;
+ }
+ } else {
+ uint64_t index, chunk;
+
+ /* TODO: Change QEMUFileOps prototype to be signed: size_t => long
+ if (size < 0) {
+ ret = qemu_rdma_drain_cq(f, rdma);
+ if (ret < 0) {
+ fprintf(stderr, "rdma: failed to synchronously drain"
+ " completion queue before unregistration.\n");
+ goto err;
+ }
+ }
+ */
+
+ ret = qemu_rdma_search_ram_block(rdma, block_offset,
+ offset, size, &index, &chunk);
+
+ if (ret) {
+ error_report("ram block search failed");
+ goto err;
+ }
+
+ qemu_rdma_signal_unregister(rdma, index, chunk, 0);
+
+ /*
+ * TODO: Synchronous, guaranteed unregistration (should not occur during
+ * fast-path). Otherwise, unregisters will process on the next call to
+ * qemu_rdma_drain_cq()
+ if (size < 0) {
+ qemu_rdma_unregister_waiting(rdma);
+ }
+ */
+ }
+
+ /*
+ * Drain the Completion Queue if possible, but do not block,
+ * just poll.
+ *
+ * If nothing to poll, the end of the iteration will do this
+ * again to make sure we don't overflow the request queue.
+ */
+ while (1) {
+ uint64_t wr_id, wr_id_in;
+ int ret = qemu_rdma_poll(rdma, &wr_id_in, NULL);
+ if (ret < 0) {
+ error_report("rdma migration: polling error! %d", ret);
+ goto err;
+ }
+
+ wr_id = wr_id_in & RDMA_WRID_TYPE_MASK;
+
+ if (wr_id == RDMA_WRID_NONE) {
+ break;
+ }
+ }
+
+ return RAM_SAVE_CONTROL_DELAYED;
+err:
+ rdma->error_state = ret;
+ return ret;
+}
+
+static int qemu_rdma_accept(RDMAContext *rdma)
+{
+ RDMACapabilities cap;
+ struct rdma_conn_param conn_param = {
+ .responder_resources = 2,
+ .private_data = &cap,
+ .private_data_len = sizeof(cap),
+ };
+ struct rdma_cm_event *cm_event;
+ struct ibv_context *verbs;
+ int ret = -EINVAL;
+ int idx;
+
+ ret = rdma_get_cm_event(rdma->channel, &cm_event);
+ if (ret) {
+ goto err_rdma_dest_wait;
+ }
+
+ if (cm_event->event != RDMA_CM_EVENT_CONNECT_REQUEST) {
+ rdma_ack_cm_event(cm_event);
+ goto err_rdma_dest_wait;
+ }
+
+ memcpy(&cap, cm_event->param.conn.private_data, sizeof(cap));
+
+ network_to_caps(&cap);
+
+ if (cap.version < 1 || cap.version > RDMA_CONTROL_VERSION_CURRENT) {
+ error_report("Unknown source RDMA version: %d, bailing...",
+ cap.version);
+ rdma_ack_cm_event(cm_event);
+ goto err_rdma_dest_wait;
+ }
+
+ /*
+ * Respond with only the capabilities this version of QEMU knows about.
+ */
+ cap.flags &= known_capabilities;
+
+ /*
+ * Enable the ones that we do know about.
+ * Add other checks here as new ones are introduced.
+ */
+ if (cap.flags & RDMA_CAPABILITY_PIN_ALL) {
+ rdma->pin_all = true;
+ }
+
+ rdma->cm_id = cm_event->id;
+ verbs = cm_event->id->verbs;
+
+ rdma_ack_cm_event(cm_event);
+
+ trace_qemu_rdma_accept_pin_state(rdma->pin_all);
+
+ caps_to_network(&cap);
+
+ trace_qemu_rdma_accept_pin_verbsc(verbs);
+
+ if (!rdma->verbs) {
+ rdma->verbs = verbs;
+ } else if (rdma->verbs != verbs) {
+ error_report("ibv context not matching %p, %p!", rdma->verbs,
+ verbs);
+ goto err_rdma_dest_wait;
+ }
+
+ qemu_rdma_dump_id("dest_init", verbs);
+
+ ret = qemu_rdma_alloc_pd_cq(rdma);
+ if (ret) {
+ error_report("rdma migration: error allocating pd and cq!");
+ goto err_rdma_dest_wait;
+ }
+
+ ret = qemu_rdma_alloc_qp(rdma);
+ if (ret) {
+ error_report("rdma migration: error allocating qp!");
+ goto err_rdma_dest_wait;
+ }
+
+ ret = qemu_rdma_init_ram_blocks(rdma);
+ if (ret) {
+ error_report("rdma migration: error initializing ram blocks!");
+ goto err_rdma_dest_wait;
+ }
+
+ for (idx = 0; idx < RDMA_WRID_MAX; idx++) {
+ ret = qemu_rdma_reg_control(rdma, idx);
+ if (ret) {
+ error_report("rdma: error registering %d control", idx);
+ goto err_rdma_dest_wait;
+ }
+ }
+
+ qemu_set_fd_handler(rdma->channel->fd, NULL, NULL, NULL);
+
+ ret = rdma_accept(rdma->cm_id, &conn_param);
+ if (ret) {
+ error_report("rdma_accept returns %d", ret);
+ goto err_rdma_dest_wait;
+ }
+
+ ret = rdma_get_cm_event(rdma->channel, &cm_event);
+ if (ret) {
+ error_report("rdma_accept get_cm_event failed %d", ret);
+ goto err_rdma_dest_wait;
+ }
+
+ if (cm_event->event != RDMA_CM_EVENT_ESTABLISHED) {
+ error_report("rdma_accept not event established");
+ rdma_ack_cm_event(cm_event);
+ goto err_rdma_dest_wait;
+ }
+
+ rdma_ack_cm_event(cm_event);
+ rdma->connected = true;
+
+ ret = qemu_rdma_post_recv_control(rdma, RDMA_WRID_READY);
+ if (ret) {
+ error_report("rdma migration: error posting second control recv");
+ goto err_rdma_dest_wait;
+ }
+
+ qemu_rdma_dump_gid("dest_connect", rdma->cm_id);
+
+ return 0;
+
+err_rdma_dest_wait:
+ rdma->error_state = ret;
+ qemu_rdma_cleanup(rdma);
+ return ret;
+}
+
+static int dest_ram_sort_func(const void *a, const void *b)
+{
+ unsigned int a_index = ((const RDMALocalBlock *)a)->src_index;
+ unsigned int b_index = ((const RDMALocalBlock *)b)->src_index;
+
+ return (a_index < b_index) ? -1 : (a_index != b_index);
+}
+
+/*
+ * During each iteration of the migration, we listen for instructions
+ * by the source VM to perform dynamic page registrations before they
+ * can perform RDMA operations.
+ *
+ * We respond with the 'rkey'.
+ *
+ * Keep doing this until the source tells us to stop.
+ */
+static int qemu_rdma_registration_handle(QEMUFile *f, void *opaque)
+{
+ RDMAControlHeader reg_resp = { .len = sizeof(RDMARegisterResult),
+ .type = RDMA_CONTROL_REGISTER_RESULT,
+ .repeat = 0,
+ };
+ RDMAControlHeader unreg_resp = { .len = 0,
+ .type = RDMA_CONTROL_UNREGISTER_FINISHED,
+ .repeat = 0,
+ };
+ RDMAControlHeader blocks = { .type = RDMA_CONTROL_RAM_BLOCKS_RESULT,
+ .repeat = 1 };
+ QEMUFileRDMA *rfile = opaque;
+ RDMAContext *rdma = rfile->rdma;
+ RDMALocalBlocks *local = &rdma->local_ram_blocks;
+ RDMAControlHeader head;
+ RDMARegister *reg, *registers;
+ RDMACompress *comp;
+ RDMARegisterResult *reg_result;
+ static RDMARegisterResult results[RDMA_CONTROL_MAX_COMMANDS_PER_MESSAGE];
+ RDMALocalBlock *block;
+ void *host_addr;
+ int ret = 0;
+ int idx = 0;
+ int count = 0;
+ int i = 0;
+
+ CHECK_ERROR_STATE();
+
+ do {
+ trace_qemu_rdma_registration_handle_wait();
+
+ ret = qemu_rdma_exchange_recv(rdma, &head, RDMA_CONTROL_NONE);
+
+ if (ret < 0) {
+ break;
+ }
+
+ if (head.repeat > RDMA_CONTROL_MAX_COMMANDS_PER_MESSAGE) {
+ error_report("rdma: Too many requests in this message (%d)."
+ "Bailing.", head.repeat);
+ ret = -EIO;
+ break;
+ }
+
+ switch (head.type) {
+ case RDMA_CONTROL_COMPRESS:
+ comp = (RDMACompress *) rdma->wr_data[idx].control_curr;
+ network_to_compress(comp);
+
+ trace_qemu_rdma_registration_handle_compress(comp->length,
+ comp->block_idx,
+ comp->offset);
+ if (comp->block_idx >= rdma->local_ram_blocks.nb_blocks) {
+ error_report("rdma: 'compress' bad block index %u (vs %d)",
+ (unsigned int)comp->block_idx,
+ rdma->local_ram_blocks.nb_blocks);
+ ret = -EIO;
+ goto out;
+ }
+ block = &(rdma->local_ram_blocks.block[comp->block_idx]);
+
+ host_addr = block->local_host_addr +
+ (comp->offset - block->offset);
+
+ ram_handle_compressed(host_addr, comp->value, comp->length);
+ break;
+
+ case RDMA_CONTROL_REGISTER_FINISHED:
+ trace_qemu_rdma_registration_handle_finished();
+ goto out;
+
+ case RDMA_CONTROL_RAM_BLOCKS_REQUEST:
+ trace_qemu_rdma_registration_handle_ram_blocks();
+
+ /* Sort our local RAM Block list so it's the same as the source,
+ * we can do this since we've filled in a src_index in the list
+ * as we received the RAMBlock list earlier.
+ */
+ qsort(rdma->local_ram_blocks.block,
+ rdma->local_ram_blocks.nb_blocks,
+ sizeof(RDMALocalBlock), dest_ram_sort_func);
+ if (rdma->pin_all) {
+ ret = qemu_rdma_reg_whole_ram_blocks(rdma);
+ if (ret) {
+ error_report("rdma migration: error dest "
+ "registering ram blocks");
+ goto out;
+ }
+ }
+
+ /*
+ * Dest uses this to prepare to transmit the RAMBlock descriptions
+ * to the source VM after connection setup.
+ * Both sides use the "remote" structure to communicate and update
+ * their "local" descriptions with what was sent.
+ */
+ for (i = 0; i < local->nb_blocks; i++) {
+ rdma->dest_blocks[i].remote_host_addr =
+ (uintptr_t)(local->block[i].local_host_addr);
+
+ if (rdma->pin_all) {
+ rdma->dest_blocks[i].remote_rkey = local->block[i].mr->rkey;
+ }
+
+ rdma->dest_blocks[i].offset = local->block[i].offset;
+ rdma->dest_blocks[i].length = local->block[i].length;
+
+ dest_block_to_network(&rdma->dest_blocks[i]);
+ trace_qemu_rdma_registration_handle_ram_blocks_loop(
+ local->block[i].block_name,
+ local->block[i].offset,
+ local->block[i].length,
+ local->block[i].local_host_addr,
+ local->block[i].src_index);
+ }
+
+ blocks.len = rdma->local_ram_blocks.nb_blocks
+ * sizeof(RDMADestBlock);
+
+
+ ret = qemu_rdma_post_send_control(rdma,
+ (uint8_t *) rdma->dest_blocks, &blocks);
+
+ if (ret < 0) {
+ error_report("rdma migration: error sending remote info");
+ goto out;
+ }
+
+ break;
+ case RDMA_CONTROL_REGISTER_REQUEST:
+ trace_qemu_rdma_registration_handle_register(head.repeat);
+
+ reg_resp.repeat = head.repeat;
+ registers = (RDMARegister *) rdma->wr_data[idx].control_curr;
+
+ for (count = 0; count < head.repeat; count++) {
+ uint64_t chunk;
+ uint8_t *chunk_start, *chunk_end;
+
+ reg = ®isters[count];
+ network_to_register(reg);
+
+ reg_result = &results[count];
+
+ trace_qemu_rdma_registration_handle_register_loop(count,
+ reg->current_index, reg->key.current_addr, reg->chunks);
+
+ if (reg->current_index >= rdma->local_ram_blocks.nb_blocks) {
+ error_report("rdma: 'register' bad block index %u (vs %d)",
+ (unsigned int)reg->current_index,
+ rdma->local_ram_blocks.nb_blocks);
+ ret = -ENOENT;
+ goto out;
+ }
+ block = &(rdma->local_ram_blocks.block[reg->current_index]);
+ if (block->is_ram_block) {
+ if (block->offset > reg->key.current_addr) {
+ error_report("rdma: bad register address for block %s"
+ " offset: %" PRIx64 " current_addr: %" PRIx64,
+ block->block_name, block->offset,
+ reg->key.current_addr);
+ ret = -ERANGE;
+ goto out;
+ }
+ host_addr = (block->local_host_addr +
+ (reg->key.current_addr - block->offset));
+ chunk = ram_chunk_index(block->local_host_addr,
+ (uint8_t *) host_addr);
+ } else {
+ chunk = reg->key.chunk;
+ host_addr = block->local_host_addr +
+ (reg->key.chunk * (1UL << RDMA_REG_CHUNK_SHIFT));
+ /* Check for particularly bad chunk value */
+ if (host_addr < (void *)block->local_host_addr) {
+ error_report("rdma: bad chunk for block %s"
+ " chunk: %" PRIx64,
+ block->block_name, reg->key.chunk);
+ ret = -ERANGE;
+ goto out;
+ }
+ }
+ chunk_start = ram_chunk_start(block, chunk);
+ chunk_end = ram_chunk_end(block, chunk + reg->chunks);
+ if (qemu_rdma_register_and_get_keys(rdma, block,
+ (uintptr_t)host_addr, NULL, ®_result->rkey,
+ chunk, chunk_start, chunk_end)) {
+ error_report("cannot get rkey");
+ ret = -EINVAL;
+ goto out;
+ }
+
+ reg_result->host_addr = (uintptr_t)block->local_host_addr;
+
+ trace_qemu_rdma_registration_handle_register_rkey(
+ reg_result->rkey);
+
+ result_to_network(reg_result);
+ }
+
+ ret = qemu_rdma_post_send_control(rdma,
+ (uint8_t *) results, ®_resp);
+
+ if (ret < 0) {
+ error_report("Failed to send control buffer");
+ goto out;
+ }
+ break;
+ case RDMA_CONTROL_UNREGISTER_REQUEST:
+ trace_qemu_rdma_registration_handle_unregister(head.repeat);
+ unreg_resp.repeat = head.repeat;
+ registers = (RDMARegister *) rdma->wr_data[idx].control_curr;
+
+ for (count = 0; count < head.repeat; count++) {
+ reg = ®isters[count];
+ network_to_register(reg);
+
+ trace_qemu_rdma_registration_handle_unregister_loop(count,
+ reg->current_index, reg->key.chunk);
+
+ block = &(rdma->local_ram_blocks.block[reg->current_index]);
+
+ ret = ibv_dereg_mr(block->pmr[reg->key.chunk]);
+ block->pmr[reg->key.chunk] = NULL;
+
+ if (ret != 0) {
+ perror("rdma unregistration chunk failed");
+ ret = -ret;
+ goto out;
+ }
+
+ rdma->total_registrations--;
+
+ trace_qemu_rdma_registration_handle_unregister_success(
+ reg->key.chunk);
+ }
+
+ ret = qemu_rdma_post_send_control(rdma, NULL, &unreg_resp);
+
+ if (ret < 0) {
+ error_report("Failed to send control buffer");
+ goto out;
+ }
+ break;
+ case RDMA_CONTROL_REGISTER_RESULT:
+ error_report("Invalid RESULT message at dest.");
+ ret = -EIO;
+ goto out;
+ default:
+ error_report("Unknown control message %s", control_desc[head.type]);
+ ret = -EIO;
+ goto out;
+ }
+ } while (1);
+out:
+ if (ret < 0) {
+ rdma->error_state = ret;
+ }
+ return ret;
+}
+
+/* Destination:
+ * Called via a ram_control_load_hook during the initial RAM load section which
+ * lists the RAMBlocks by name. This lets us know the order of the RAMBlocks
+ * on the source.
+ * We've already built our local RAMBlock list, but not yet sent the list to
+ * the source.
+ */
+static int rdma_block_notification_handle(QEMUFileRDMA *rfile, const char *name)
+{
+ RDMAContext *rdma = rfile->rdma;
+ int curr;
+ int found = -1;
+
+ /* Find the matching RAMBlock in our local list */
+ for (curr = 0; curr < rdma->local_ram_blocks.nb_blocks; curr++) {
+ if (!strcmp(rdma->local_ram_blocks.block[curr].block_name, name)) {
+ found = curr;
+ break;
+ }
+ }
+
+ if (found == -1) {
+ error_report("RAMBlock '%s' not found on destination", name);
+ return -ENOENT;
+ }
+
+ rdma->local_ram_blocks.block[curr].src_index = rdma->next_src_index;
+ trace_rdma_block_notification_handle(name, rdma->next_src_index);
+ rdma->next_src_index++;
+
+ return 0;
+}
+
+static int rdma_load_hook(QEMUFile *f, void *opaque, uint64_t flags, void *data)
+{
+ switch (flags) {
+ case RAM_CONTROL_BLOCK_REG:
+ return rdma_block_notification_handle(opaque, data);
+
+ case RAM_CONTROL_HOOK:
+ return qemu_rdma_registration_handle(f, opaque);
+
+ default:
+ /* Shouldn't be called with any other values */
+ abort();
+ }
+}
+
+static int qemu_rdma_registration_start(QEMUFile *f, void *opaque,
+ uint64_t flags, void *data)
+{
+ QEMUFileRDMA *rfile = opaque;
+ RDMAContext *rdma = rfile->rdma;
+
+ CHECK_ERROR_STATE();
+
+ trace_qemu_rdma_registration_start(flags);
+ qemu_put_be64(f, RAM_SAVE_FLAG_HOOK);
+ qemu_fflush(f);
+
+ return 0;
+}
+
+/*
+ * Inform dest that dynamic registrations are done for now.
+ * First, flush writes, if any.
+ */
+static int qemu_rdma_registration_stop(QEMUFile *f, void *opaque,
+ uint64_t flags, void *data)
+{
+ Error *local_err = NULL, **errp = &local_err;
+ QEMUFileRDMA *rfile = opaque;
+ RDMAContext *rdma = rfile->rdma;
+ RDMAControlHeader head = { .len = 0, .repeat = 1 };
+ int ret = 0;
+
+ CHECK_ERROR_STATE();
+
+ qemu_fflush(f);
+ ret = qemu_rdma_drain_cq(f, rdma);
+
+ if (ret < 0) {
+ goto err;
+ }
+
+ if (flags == RAM_CONTROL_SETUP) {
+ RDMAControlHeader resp = {.type = RDMA_CONTROL_RAM_BLOCKS_RESULT };
+ RDMALocalBlocks *local = &rdma->local_ram_blocks;
+ int reg_result_idx, i, nb_dest_blocks;
+
+ head.type = RDMA_CONTROL_RAM_BLOCKS_REQUEST;
+ trace_qemu_rdma_registration_stop_ram();
+
+ /*
+ * Make sure that we parallelize the pinning on both sides.
+ * For very large guests, doing this serially takes a really
+ * long time, so we have to 'interleave' the pinning locally
+ * with the control messages by performing the pinning on this
+ * side before we receive the control response from the other
+ * side that the pinning has completed.
+ */
+ ret = qemu_rdma_exchange_send(rdma, &head, NULL, &resp,
+ ®_result_idx, rdma->pin_all ?
+ qemu_rdma_reg_whole_ram_blocks : NULL);
+ if (ret < 0) {
+ ERROR(errp, "receiving remote info!");
+ return ret;
+ }
+
+ nb_dest_blocks = resp.len / sizeof(RDMADestBlock);
+
+ /*
+ * The protocol uses two different sets of rkeys (mutually exclusive):
+ * 1. One key to represent the virtual address of the entire ram block.
+ * (dynamic chunk registration disabled - pin everything with one rkey.)
+ * 2. One to represent individual chunks within a ram block.
+ * (dynamic chunk registration enabled - pin individual chunks.)
+ *
+ * Once the capability is successfully negotiated, the destination transmits
+ * the keys to use (or sends them later) including the virtual addresses
+ * and then propagates the remote ram block descriptions to his local copy.
+ */
+
+ if (local->nb_blocks != nb_dest_blocks) {
+ ERROR(errp, "ram blocks mismatch (Number of blocks %d vs %d) "
+ "Your QEMU command line parameters are probably "
+ "not identical on both the source and destination.",
+ local->nb_blocks, nb_dest_blocks);
+ rdma->error_state = -EINVAL;
+ return -EINVAL;
+ }
+
+ qemu_rdma_move_header(rdma, reg_result_idx, &resp);
+ memcpy(rdma->dest_blocks,
+ rdma->wr_data[reg_result_idx].control_curr, resp.len);
+ for (i = 0; i < nb_dest_blocks; i++) {
+ network_to_dest_block(&rdma->dest_blocks[i]);
+
+ /* We require that the blocks are in the same order */
+ if (rdma->dest_blocks[i].length != local->block[i].length) {
+ ERROR(errp, "Block %s/%d has a different length %" PRIu64
+ "vs %" PRIu64, local->block[i].block_name, i,
+ local->block[i].length,
+ rdma->dest_blocks[i].length);
+ rdma->error_state = -EINVAL;
+ return -EINVAL;
+ }
+ local->block[i].remote_host_addr =
+ rdma->dest_blocks[i].remote_host_addr;
+ local->block[i].remote_rkey = rdma->dest_blocks[i].remote_rkey;
+ }
+ }
+
+ trace_qemu_rdma_registration_stop(flags);
+
+ head.type = RDMA_CONTROL_REGISTER_FINISHED;
+ ret = qemu_rdma_exchange_send(rdma, &head, NULL, NULL, NULL, NULL);
+
+ if (ret < 0) {
+ goto err;
+ }
+
+ return 0;
+err:
+ rdma->error_state = ret;
+ return ret;
+}
+
+static int qemu_rdma_get_fd(void *opaque)
+{
+ QEMUFileRDMA *rfile = opaque;
+ RDMAContext *rdma = rfile->rdma;
+
+ return rdma->comp_channel->fd;
+}
+
+static const QEMUFileOps rdma_read_ops = {
+ .get_buffer = qemu_rdma_get_buffer,
+ .get_fd = qemu_rdma_get_fd,
+ .close = qemu_rdma_close,
+ .hook_ram_load = rdma_load_hook,
+};
+
+static const QEMUFileOps rdma_write_ops = {
+ .put_buffer = qemu_rdma_put_buffer,
+ .close = qemu_rdma_close,
+ .before_ram_iterate = qemu_rdma_registration_start,
+ .after_ram_iterate = qemu_rdma_registration_stop,
+ .save_page = qemu_rdma_save_page,
+};
+
+static void *qemu_fopen_rdma(RDMAContext *rdma, const char *mode)
+{
+ QEMUFileRDMA *r;
+
+ if (qemu_file_mode_is_not_valid(mode)) {
+ return NULL;
+ }
+
+ r = g_malloc0(sizeof(QEMUFileRDMA));
+ r->rdma = rdma;
+
+ if (mode[0] == 'w') {
+ r->file = qemu_fopen_ops(r, &rdma_write_ops);
+ } else {
+ r->file = qemu_fopen_ops(r, &rdma_read_ops);
+ }
+
+ return r->file;
+}
+
+static void rdma_accept_incoming_migration(void *opaque)
+{
+ RDMAContext *rdma = opaque;
+ int ret;
+ QEMUFile *f;
+ Error *local_err = NULL, **errp = &local_err;
+
+ trace_qemu_rdma_accept_incoming_migration();
+ ret = qemu_rdma_accept(rdma);
+
+ if (ret) {
+ ERROR(errp, "RDMA Migration initialization failed!");
+ return;
+ }
+
+ trace_qemu_rdma_accept_incoming_migration_accepted();
+
+ f = qemu_fopen_rdma(rdma, "rb");
+ if (f == NULL) {
+ ERROR(errp, "could not qemu_fopen_rdma!");
+ qemu_rdma_cleanup(rdma);
+ return;
+ }
+
+ rdma->migration_started_on_destination = 1;
+ process_incoming_migration(f);
+}
+
+void rdma_start_incoming_migration(const char *host_port, Error **errp)
+{
+ int ret;
+ RDMAContext *rdma;
+ Error *local_err = NULL;
+
+ trace_rdma_start_incoming_migration();
+ rdma = qemu_rdma_data_init(host_port, &local_err);
+
+ if (rdma == NULL) {
+ goto err;
+ }
+
+ ret = qemu_rdma_dest_init(rdma, &local_err);
+
+ if (ret) {
+ goto err;
+ }
+
+ trace_rdma_start_incoming_migration_after_dest_init();
+
+ ret = rdma_listen(rdma->listen_id, 5);
+
+ if (ret) {
+ ERROR(errp, "listening on socket!");
+ goto err;
+ }
+
+ trace_rdma_start_incoming_migration_after_rdma_listen();
+
+ qemu_set_fd_handler(rdma->channel->fd, rdma_accept_incoming_migration,
+ NULL, (void *)(intptr_t)rdma);
+ return;
+err:
+ error_propagate(errp, local_err);
+ g_free(rdma);
+}
+
+void rdma_start_outgoing_migration(void *opaque,
+ const char *host_port, Error **errp)
+{
+ MigrationState *s = opaque;
+ Error *local_err = NULL, **temp = &local_err;
+ RDMAContext *rdma = qemu_rdma_data_init(host_port, &local_err);
+ int ret = 0;
+
+ if (rdma == NULL) {
+ ERROR(temp, "Failed to initialize RDMA data structures! %d", ret);
+ goto err;
+ }
+
+ ret = qemu_rdma_source_init(rdma, &local_err,
+ s->enabled_capabilities[MIGRATION_CAPABILITY_RDMA_PIN_ALL]);
+
+ if (ret) {
+ goto err;
+ }
+
+ trace_rdma_start_outgoing_migration_after_rdma_source_init();
+ ret = qemu_rdma_connect(rdma, &local_err);
+
+ if (ret) {
+ goto err;
+ }
+
+ trace_rdma_start_outgoing_migration_after_rdma_connect();
+
+ s->file = qemu_fopen_rdma(rdma, "wb");
+ migrate_fd_connect(s);
+ return;
+err:
+ error_propagate(errp, local_err);
+ g_free(rdma);
+ migrate_fd_error(s);
+}
Code Review / kvmfornfv.git / blobdiff