--- /dev/null
+/*
+ * xen paravirt block device backend
+ *
+ * (c) Gerd Hoffmann <kraxel@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; under version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Contributions after 2012-01-13 are licensed under the terms of the
+ * GNU GPL, version 2 or (at your option) any later version.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+#include <inttypes.h>
+#include <time.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <sys/uio.h>
+
+#include "hw/hw.h"
+#include "hw/xen/xen_backend.h"
+#include "xen_blkif.h"
+#include "sysemu/blockdev.h"
+#include "sysemu/block-backend.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qmp/qstring.h"
+
+/* ------------------------------------------------------------- */
+
+static int batch_maps = 0;
+
+static int max_requests = 32;
+
+/* ------------------------------------------------------------- */
+
+#define BLOCK_SIZE 512
+#define IOCB_COUNT (BLKIF_MAX_SEGMENTS_PER_REQUEST + 2)
+
+struct PersistentGrant {
+ void *page;
+ struct XenBlkDev *blkdev;
+};
+
+typedef struct PersistentGrant PersistentGrant;
+
+struct PersistentRegion {
+ void *addr;
+ int num;
+};
+
+typedef struct PersistentRegion PersistentRegion;
+
+struct ioreq {
+ blkif_request_t req;
+ int16_t status;
+
+ /* parsed request */
+ off_t start;
+ QEMUIOVector v;
+ int presync;
+ int postsync;
+ uint8_t mapped;
+
+ /* grant mapping */
+ uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ int prot;
+ void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ void *pages;
+ int num_unmap;
+
+ /* aio status */
+ int aio_inflight;
+ int aio_errors;
+
+ struct XenBlkDev *blkdev;
+ QLIST_ENTRY(ioreq) list;
+ BlockAcctCookie acct;
+};
+
+struct XenBlkDev {
+ struct XenDevice xendev; /* must be first */
+ char *params;
+ char *mode;
+ char *type;
+ char *dev;
+ char *devtype;
+ bool directiosafe;
+ const char *fileproto;
+ const char *filename;
+ int ring_ref;
+ void *sring;
+ int64_t file_blk;
+ int64_t file_size;
+ int protocol;
+ blkif_back_rings_t rings;
+ int more_work;
+ int cnt_map;
+
+ /* request lists */
+ QLIST_HEAD(inflight_head, ioreq) inflight;
+ QLIST_HEAD(finished_head, ioreq) finished;
+ QLIST_HEAD(freelist_head, ioreq) freelist;
+ int requests_total;
+ int requests_inflight;
+ int requests_finished;
+
+ /* Persistent grants extension */
+ gboolean feature_discard;
+ gboolean feature_persistent;
+ GTree *persistent_gnts;
+ GSList *persistent_regions;
+ unsigned int persistent_gnt_count;
+ unsigned int max_grants;
+
+ /* qemu block driver */
+ DriveInfo *dinfo;
+ BlockBackend *blk;
+ QEMUBH *bh;
+};
+
+/* ------------------------------------------------------------- */
+
+static void ioreq_reset(struct ioreq *ioreq)
+{
+ memset(&ioreq->req, 0, sizeof(ioreq->req));
+ ioreq->status = 0;
+ ioreq->start = 0;
+ ioreq->presync = 0;
+ ioreq->postsync = 0;
+ ioreq->mapped = 0;
+
+ memset(ioreq->domids, 0, sizeof(ioreq->domids));
+ memset(ioreq->refs, 0, sizeof(ioreq->refs));
+ ioreq->prot = 0;
+ memset(ioreq->page, 0, sizeof(ioreq->page));
+ ioreq->pages = NULL;
+
+ ioreq->aio_inflight = 0;
+ ioreq->aio_errors = 0;
+
+ ioreq->blkdev = NULL;
+ memset(&ioreq->list, 0, sizeof(ioreq->list));
+ memset(&ioreq->acct, 0, sizeof(ioreq->acct));
+
+ qemu_iovec_reset(&ioreq->v);
+}
+
+static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
+{
+ uint ua = GPOINTER_TO_UINT(a);
+ uint ub = GPOINTER_TO_UINT(b);
+ return (ua > ub) - (ua < ub);
+}
+
+static void destroy_grant(gpointer pgnt)
+{
+ PersistentGrant *grant = pgnt;
+ XenGnttab gnt = grant->blkdev->xendev.gnttabdev;
+
+ if (xc_gnttab_munmap(gnt, grant->page, 1) != 0) {
+ xen_be_printf(&grant->blkdev->xendev, 0,
+ "xc_gnttab_munmap failed: %s\n",
+ strerror(errno));
+ }
+ grant->blkdev->persistent_gnt_count--;
+ xen_be_printf(&grant->blkdev->xendev, 3,
+ "unmapped grant %p\n", grant->page);
+ g_free(grant);
+}
+
+static void remove_persistent_region(gpointer data, gpointer dev)
+{
+ PersistentRegion *region = data;
+ struct XenBlkDev *blkdev = dev;
+ XenGnttab gnt = blkdev->xendev.gnttabdev;
+
+ if (xc_gnttab_munmap(gnt, region->addr, region->num) != 0) {
+ xen_be_printf(&blkdev->xendev, 0,
+ "xc_gnttab_munmap region %p failed: %s\n",
+ region->addr, strerror(errno));
+ }
+ xen_be_printf(&blkdev->xendev, 3,
+ "unmapped grant region %p with %d pages\n",
+ region->addr, region->num);
+ g_free(region);
+}
+
+static struct ioreq *ioreq_start(struct XenBlkDev *blkdev)
+{
+ struct ioreq *ioreq = NULL;
+
+ if (QLIST_EMPTY(&blkdev->freelist)) {
+ if (blkdev->requests_total >= max_requests) {
+ goto out;
+ }
+ /* allocate new struct */
+ ioreq = g_malloc0(sizeof(*ioreq));
+ ioreq->blkdev = blkdev;
+ blkdev->requests_total++;
+ qemu_iovec_init(&ioreq->v, BLKIF_MAX_SEGMENTS_PER_REQUEST);
+ } else {
+ /* get one from freelist */
+ ioreq = QLIST_FIRST(&blkdev->freelist);
+ QLIST_REMOVE(ioreq, list);
+ }
+ QLIST_INSERT_HEAD(&blkdev->inflight, ioreq, list);
+ blkdev->requests_inflight++;
+
+out:
+ return ioreq;
+}
+
+static void ioreq_finish(struct ioreq *ioreq)
+{
+ struct XenBlkDev *blkdev = ioreq->blkdev;
+
+ QLIST_REMOVE(ioreq, list);
+ QLIST_INSERT_HEAD(&blkdev->finished, ioreq, list);
+ blkdev->requests_inflight--;
+ blkdev->requests_finished++;
+}
+
+static void ioreq_release(struct ioreq *ioreq, bool finish)
+{
+ struct XenBlkDev *blkdev = ioreq->blkdev;
+
+ QLIST_REMOVE(ioreq, list);
+ ioreq_reset(ioreq);
+ ioreq->blkdev = blkdev;
+ QLIST_INSERT_HEAD(&blkdev->freelist, ioreq, list);
+ if (finish) {
+ blkdev->requests_finished--;
+ } else {
+ blkdev->requests_inflight--;
+ }
+}
+
+/*
+ * translate request into iovec + start offset
+ * do sanity checks along the way
+ */
+static int ioreq_parse(struct ioreq *ioreq)
+{
+ struct XenBlkDev *blkdev = ioreq->blkdev;
+ uintptr_t mem;
+ size_t len;
+ int i;
+
+ xen_be_printf(&blkdev->xendev, 3,
+ "op %d, nr %d, handle %d, id %" PRId64 ", sector %" PRId64 "\n",
+ ioreq->req.operation, ioreq->req.nr_segments,
+ ioreq->req.handle, ioreq->req.id, ioreq->req.sector_number);
+ switch (ioreq->req.operation) {
+ case BLKIF_OP_READ:
+ ioreq->prot = PROT_WRITE; /* to memory */
+ break;
+ case BLKIF_OP_FLUSH_DISKCACHE:
+ ioreq->presync = 1;
+ if (!ioreq->req.nr_segments) {
+ return 0;
+ }
+ /* fall through */
+ case BLKIF_OP_WRITE:
+ ioreq->prot = PROT_READ; /* from memory */
+ break;
+ case BLKIF_OP_DISCARD:
+ return 0;
+ default:
+ xen_be_printf(&blkdev->xendev, 0, "error: unknown operation (%d)\n",
+ ioreq->req.operation);
+ goto err;
+ };
+
+ if (ioreq->req.operation != BLKIF_OP_READ && blkdev->mode[0] != 'w') {
+ xen_be_printf(&blkdev->xendev, 0, "error: write req for ro device\n");
+ goto err;
+ }
+
+ ioreq->start = ioreq->req.sector_number * blkdev->file_blk;
+ for (i = 0; i < ioreq->req.nr_segments; i++) {
+ if (i == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
+ xen_be_printf(&blkdev->xendev, 0, "error: nr_segments too big\n");
+ goto err;
+ }
+ if (ioreq->req.seg[i].first_sect > ioreq->req.seg[i].last_sect) {
+ xen_be_printf(&blkdev->xendev, 0, "error: first > last sector\n");
+ goto err;
+ }
+ if (ioreq->req.seg[i].last_sect * BLOCK_SIZE >= XC_PAGE_SIZE) {
+ xen_be_printf(&blkdev->xendev, 0, "error: page crossing\n");
+ goto err;
+ }
+
+ ioreq->domids[i] = blkdev->xendev.dom;
+ ioreq->refs[i] = ioreq->req.seg[i].gref;
+
+ mem = ioreq->req.seg[i].first_sect * blkdev->file_blk;
+ len = (ioreq->req.seg[i].last_sect - ioreq->req.seg[i].first_sect + 1) * blkdev->file_blk;
+ qemu_iovec_add(&ioreq->v, (void*)mem, len);
+ }
+ if (ioreq->start + ioreq->v.size > blkdev->file_size) {
+ xen_be_printf(&blkdev->xendev, 0, "error: access beyond end of file\n");
+ goto err;
+ }
+ return 0;
+
+err:
+ ioreq->status = BLKIF_RSP_ERROR;
+ return -1;
+}
+
+static void ioreq_unmap(struct ioreq *ioreq)
+{
+ XenGnttab gnt = ioreq->blkdev->xendev.gnttabdev;
+ int i;
+
+ if (ioreq->num_unmap == 0 || ioreq->mapped == 0) {
+ return;
+ }
+ if (batch_maps) {
+ if (!ioreq->pages) {
+ return;
+ }
+ if (xc_gnttab_munmap(gnt, ioreq->pages, ioreq->num_unmap) != 0) {
+ xen_be_printf(&ioreq->blkdev->xendev, 0, "xc_gnttab_munmap failed: %s\n",
+ strerror(errno));
+ }
+ ioreq->blkdev->cnt_map -= ioreq->num_unmap;
+ ioreq->pages = NULL;
+ } else {
+ for (i = 0; i < ioreq->num_unmap; i++) {
+ if (!ioreq->page[i]) {
+ continue;
+ }
+ if (xc_gnttab_munmap(gnt, ioreq->page[i], 1) != 0) {
+ xen_be_printf(&ioreq->blkdev->xendev, 0, "xc_gnttab_munmap failed: %s\n",
+ strerror(errno));
+ }
+ ioreq->blkdev->cnt_map--;
+ ioreq->page[i] = NULL;
+ }
+ }
+ ioreq->mapped = 0;
+}
+
+static int ioreq_map(struct ioreq *ioreq)
+{
+ XenGnttab gnt = ioreq->blkdev->xendev.gnttabdev;
+ uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ int i, j, new_maps = 0;
+ PersistentGrant *grant;
+ PersistentRegion *region;
+ /* domids and refs variables will contain the information necessary
+ * to map the grants that are needed to fulfill this request.
+ *
+ * After mapping the needed grants, the page array will contain the
+ * memory address of each granted page in the order specified in ioreq
+ * (disregarding if it's a persistent grant or not).
+ */
+
+ if (ioreq->v.niov == 0 || ioreq->mapped == 1) {
+ return 0;
+ }
+ if (ioreq->blkdev->feature_persistent) {
+ for (i = 0; i < ioreq->v.niov; i++) {
+ grant = g_tree_lookup(ioreq->blkdev->persistent_gnts,
+ GUINT_TO_POINTER(ioreq->refs[i]));
+
+ if (grant != NULL) {
+ page[i] = grant->page;
+ xen_be_printf(&ioreq->blkdev->xendev, 3,
+ "using persistent-grant %" PRIu32 "\n",
+ ioreq->refs[i]);
+ } else {
+ /* Add the grant to the list of grants that
+ * should be mapped
+ */
+ domids[new_maps] = ioreq->domids[i];
+ refs[new_maps] = ioreq->refs[i];
+ page[i] = NULL;
+ new_maps++;
+ }
+ }
+ /* Set the protection to RW, since grants may be reused later
+ * with a different protection than the one needed for this request
+ */
+ ioreq->prot = PROT_WRITE | PROT_READ;
+ } else {
+ /* All grants in the request should be mapped */
+ memcpy(refs, ioreq->refs, sizeof(refs));
+ memcpy(domids, ioreq->domids, sizeof(domids));
+ memset(page, 0, sizeof(page));
+ new_maps = ioreq->v.niov;
+ }
+
+ if (batch_maps && new_maps) {
+ ioreq->pages = xc_gnttab_map_grant_refs
+ (gnt, new_maps, domids, refs, ioreq->prot);
+ if (ioreq->pages == NULL) {
+ xen_be_printf(&ioreq->blkdev->xendev, 0,
+ "can't map %d grant refs (%s, %d maps)\n",
+ new_maps, strerror(errno), ioreq->blkdev->cnt_map);
+ return -1;
+ }
+ for (i = 0, j = 0; i < ioreq->v.niov; i++) {
+ if (page[i] == NULL) {
+ page[i] = ioreq->pages + (j++) * XC_PAGE_SIZE;
+ }
+ }
+ ioreq->blkdev->cnt_map += new_maps;
+ } else if (new_maps) {
+ for (i = 0; i < new_maps; i++) {
+ ioreq->page[i] = xc_gnttab_map_grant_ref
+ (gnt, domids[i], refs[i], ioreq->prot);
+ if (ioreq->page[i] == NULL) {
+ xen_be_printf(&ioreq->blkdev->xendev, 0,
+ "can't map grant ref %d (%s, %d maps)\n",
+ refs[i], strerror(errno), ioreq->blkdev->cnt_map);
+ ioreq->mapped = 1;
+ ioreq_unmap(ioreq);
+ return -1;
+ }
+ ioreq->blkdev->cnt_map++;
+ }
+ for (i = 0, j = 0; i < ioreq->v.niov; i++) {
+ if (page[i] == NULL) {
+ page[i] = ioreq->page[j++];
+ }
+ }
+ }
+ if (ioreq->blkdev->feature_persistent && new_maps != 0 &&
+ (!batch_maps || (ioreq->blkdev->persistent_gnt_count + new_maps <=
+ ioreq->blkdev->max_grants))) {
+ /*
+ * If we are using persistent grants and batch mappings only
+ * add the new maps to the list of persistent grants if the whole
+ * area can be persistently mapped.
+ */
+ if (batch_maps) {
+ region = g_malloc0(sizeof(*region));
+ region->addr = ioreq->pages;
+ region->num = new_maps;
+ ioreq->blkdev->persistent_regions = g_slist_append(
+ ioreq->blkdev->persistent_regions,
+ region);
+ }
+ while ((ioreq->blkdev->persistent_gnt_count < ioreq->blkdev->max_grants)
+ && new_maps) {
+ /* Go through the list of newly mapped grants and add as many
+ * as possible to the list of persistently mapped grants.
+ *
+ * Since we start at the end of ioreq->page(s), we only need
+ * to decrease new_maps to prevent this granted pages from
+ * being unmapped in ioreq_unmap.
+ */
+ grant = g_malloc0(sizeof(*grant));
+ new_maps--;
+ if (batch_maps) {
+ grant->page = ioreq->pages + (new_maps) * XC_PAGE_SIZE;
+ } else {
+ grant->page = ioreq->page[new_maps];
+ }
+ grant->blkdev = ioreq->blkdev;
+ xen_be_printf(&ioreq->blkdev->xendev, 3,
+ "adding grant %" PRIu32 " page: %p\n",
+ refs[new_maps], grant->page);
+ g_tree_insert(ioreq->blkdev->persistent_gnts,
+ GUINT_TO_POINTER(refs[new_maps]),
+ grant);
+ ioreq->blkdev->persistent_gnt_count++;
+ }
+ assert(!batch_maps || new_maps == 0);
+ }
+ for (i = 0; i < ioreq->v.niov; i++) {
+ ioreq->v.iov[i].iov_base += (uintptr_t)page[i];
+ }
+ ioreq->mapped = 1;
+ ioreq->num_unmap = new_maps;
+ return 0;
+}
+
+static int ioreq_runio_qemu_aio(struct ioreq *ioreq);
+
+static void qemu_aio_complete(void *opaque, int ret)
+{
+ struct ioreq *ioreq = opaque;
+
+ if (ret != 0) {
+ xen_be_printf(&ioreq->blkdev->xendev, 0, "%s I/O error\n",
+ ioreq->req.operation == BLKIF_OP_READ ? "read" : "write");
+ ioreq->aio_errors++;
+ }
+
+ ioreq->aio_inflight--;
+ if (ioreq->presync) {
+ ioreq->presync = 0;
+ ioreq_runio_qemu_aio(ioreq);
+ return;
+ }
+ if (ioreq->aio_inflight > 0) {
+ return;
+ }
+ if (ioreq->postsync) {
+ ioreq->postsync = 0;
+ ioreq->aio_inflight++;
+ blk_aio_flush(ioreq->blkdev->blk, qemu_aio_complete, ioreq);
+ return;
+ }
+
+ ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY;
+ ioreq_unmap(ioreq);
+ ioreq_finish(ioreq);
+ switch (ioreq->req.operation) {
+ case BLKIF_OP_WRITE:
+ case BLKIF_OP_FLUSH_DISKCACHE:
+ if (!ioreq->req.nr_segments) {
+ break;
+ }
+ case BLKIF_OP_READ:
+ block_acct_done(blk_get_stats(ioreq->blkdev->blk), &ioreq->acct);
+ break;
+ case BLKIF_OP_DISCARD:
+ default:
+ break;
+ }
+ qemu_bh_schedule(ioreq->blkdev->bh);
+}
+
+static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
+{
+ struct XenBlkDev *blkdev = ioreq->blkdev;
+
+ if (ioreq->req.nr_segments && ioreq_map(ioreq) == -1) {
+ goto err_no_map;
+ }
+
+ ioreq->aio_inflight++;
+ if (ioreq->presync) {
+ blk_aio_flush(ioreq->blkdev->blk, qemu_aio_complete, ioreq);
+ return 0;
+ }
+
+ switch (ioreq->req.operation) {
+ case BLKIF_OP_READ:
+ block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct,
+ ioreq->v.size, BLOCK_ACCT_READ);
+ ioreq->aio_inflight++;
+ blk_aio_readv(blkdev->blk, ioreq->start / BLOCK_SIZE,
+ &ioreq->v, ioreq->v.size / BLOCK_SIZE,
+ qemu_aio_complete, ioreq);
+ break;
+ case BLKIF_OP_WRITE:
+ case BLKIF_OP_FLUSH_DISKCACHE:
+ if (!ioreq->req.nr_segments) {
+ break;
+ }
+
+ block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct,
+ ioreq->v.size, BLOCK_ACCT_WRITE);
+ ioreq->aio_inflight++;
+ blk_aio_writev(blkdev->blk, ioreq->start / BLOCK_SIZE,
+ &ioreq->v, ioreq->v.size / BLOCK_SIZE,
+ qemu_aio_complete, ioreq);
+ break;
+ case BLKIF_OP_DISCARD:
+ {
+ struct blkif_request_discard *discard_req = (void *)&ioreq->req;
+ ioreq->aio_inflight++;
+ blk_aio_discard(blkdev->blk,
+ discard_req->sector_number, discard_req->nr_sectors,
+ qemu_aio_complete, ioreq);
+ break;
+ }
+ default:
+ /* unknown operation (shouldn't happen -- parse catches this) */
+ goto err;
+ }
+
+ qemu_aio_complete(ioreq, 0);
+
+ return 0;
+
+err:
+ ioreq_unmap(ioreq);
+err_no_map:
+ ioreq_finish(ioreq);
+ ioreq->status = BLKIF_RSP_ERROR;
+ return -1;
+}
+
+static int blk_send_response_one(struct ioreq *ioreq)
+{
+ struct XenBlkDev *blkdev = ioreq->blkdev;
+ int send_notify = 0;
+ int have_requests = 0;
+ blkif_response_t resp;
+ void *dst;
+
+ resp.id = ioreq->req.id;
+ resp.operation = ioreq->req.operation;
+ resp.status = ioreq->status;
+
+ /* Place on the response ring for the relevant domain. */
+ switch (blkdev->protocol) {
+ case BLKIF_PROTOCOL_NATIVE:
+ dst = RING_GET_RESPONSE(&blkdev->rings.native, blkdev->rings.native.rsp_prod_pvt);
+ break;
+ case BLKIF_PROTOCOL_X86_32:
+ dst = RING_GET_RESPONSE(&blkdev->rings.x86_32_part,
+ blkdev->rings.x86_32_part.rsp_prod_pvt);
+ break;
+ case BLKIF_PROTOCOL_X86_64:
+ dst = RING_GET_RESPONSE(&blkdev->rings.x86_64_part,
+ blkdev->rings.x86_64_part.rsp_prod_pvt);
+ break;
+ default:
+ dst = NULL;
+ return 0;
+ }
+ memcpy(dst, &resp, sizeof(resp));
+ blkdev->rings.common.rsp_prod_pvt++;
+
+ RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blkdev->rings.common, send_notify);
+ if (blkdev->rings.common.rsp_prod_pvt == blkdev->rings.common.req_cons) {
+ /*
+ * Tail check for pending requests. Allows frontend to avoid
+ * notifications if requests are already in flight (lower
+ * overheads and promotes batching).
+ */
+ RING_FINAL_CHECK_FOR_REQUESTS(&blkdev->rings.common, have_requests);
+ } else if (RING_HAS_UNCONSUMED_REQUESTS(&blkdev->rings.common)) {
+ have_requests = 1;
+ }
+
+ if (have_requests) {
+ blkdev->more_work++;
+ }
+ return send_notify;
+}
+
+/* walk finished list, send outstanding responses, free requests */
+static void blk_send_response_all(struct XenBlkDev *blkdev)
+{
+ struct ioreq *ioreq;
+ int send_notify = 0;
+
+ while (!QLIST_EMPTY(&blkdev->finished)) {
+ ioreq = QLIST_FIRST(&blkdev->finished);
+ send_notify += blk_send_response_one(ioreq);
+ ioreq_release(ioreq, true);
+ }
+ if (send_notify) {
+ xen_be_send_notify(&blkdev->xendev);
+ }
+}
+
+static int blk_get_request(struct XenBlkDev *blkdev, struct ioreq *ioreq, RING_IDX rc)
+{
+ switch (blkdev->protocol) {
+ case BLKIF_PROTOCOL_NATIVE:
+ memcpy(&ioreq->req, RING_GET_REQUEST(&blkdev->rings.native, rc),
+ sizeof(ioreq->req));
+ break;
+ case BLKIF_PROTOCOL_X86_32:
+ blkif_get_x86_32_req(&ioreq->req,
+ RING_GET_REQUEST(&blkdev->rings.x86_32_part, rc));
+ break;
+ case BLKIF_PROTOCOL_X86_64:
+ blkif_get_x86_64_req(&ioreq->req,
+ RING_GET_REQUEST(&blkdev->rings.x86_64_part, rc));
+ break;
+ }
+ return 0;
+}
+
+static void blk_handle_requests(struct XenBlkDev *blkdev)
+{
+ RING_IDX rc, rp;
+ struct ioreq *ioreq;
+
+ blkdev->more_work = 0;
+
+ rc = blkdev->rings.common.req_cons;
+ rp = blkdev->rings.common.sring->req_prod;
+ xen_rmb(); /* Ensure we see queued requests up to 'rp'. */
+
+ blk_send_response_all(blkdev);
+ while (rc != rp) {
+ /* pull request from ring */
+ if (RING_REQUEST_CONS_OVERFLOW(&blkdev->rings.common, rc)) {
+ break;
+ }
+ ioreq = ioreq_start(blkdev);
+ if (ioreq == NULL) {
+ blkdev->more_work++;
+ break;
+ }
+ blk_get_request(blkdev, ioreq, rc);
+ blkdev->rings.common.req_cons = ++rc;
+
+ /* parse them */
+ if (ioreq_parse(ioreq) != 0) {
+ if (blk_send_response_one(ioreq)) {
+ xen_be_send_notify(&blkdev->xendev);
+ }
+ ioreq_release(ioreq, false);
+ continue;
+ }
+
+ ioreq_runio_qemu_aio(ioreq);
+ }
+
+ if (blkdev->more_work && blkdev->requests_inflight < max_requests) {
+ qemu_bh_schedule(blkdev->bh);
+ }
+}
+
+/* ------------------------------------------------------------- */
+
+static void blk_bh(void *opaque)
+{
+ struct XenBlkDev *blkdev = opaque;
+ blk_handle_requests(blkdev);
+}
+
+/*
+ * We need to account for the grant allocations requiring contiguous
+ * chunks; the worst case number would be
+ * max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1,
+ * but in order to keep things simple just use
+ * 2 * max_req * max_seg.
+ */
+#define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg))
+
+static void blk_alloc(struct XenDevice *xendev)
+{
+ struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+
+ QLIST_INIT(&blkdev->inflight);
+ QLIST_INIT(&blkdev->finished);
+ QLIST_INIT(&blkdev->freelist);
+ blkdev->bh = qemu_bh_new(blk_bh, blkdev);
+ if (xen_mode != XEN_EMULATE) {
+ batch_maps = 1;
+ }
+ if (xc_gnttab_set_max_grants(xendev->gnttabdev,
+ MAX_GRANTS(max_requests, BLKIF_MAX_SEGMENTS_PER_REQUEST)) < 0) {
+ xen_be_printf(xendev, 0, "xc_gnttab_set_max_grants failed: %s\n",
+ strerror(errno));
+ }
+}
+
+static void blk_parse_discard(struct XenBlkDev *blkdev)
+{
+ int enable;
+
+ blkdev->feature_discard = true;
+
+ if (xenstore_read_be_int(&blkdev->xendev, "discard-enable", &enable) == 0) {
+ blkdev->feature_discard = !!enable;
+ }
+
+ if (blkdev->feature_discard) {
+ xenstore_write_be_int(&blkdev->xendev, "feature-discard", 1);
+ }
+}
+
+static int blk_init(struct XenDevice *xendev)
+{
+ struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+ int info = 0;
+ char *directiosafe = NULL;
+
+ /* read xenstore entries */
+ if (blkdev->params == NULL) {
+ char *h = NULL;
+ blkdev->params = xenstore_read_be_str(&blkdev->xendev, "params");
+ if (blkdev->params != NULL) {
+ h = strchr(blkdev->params, ':');
+ }
+ if (h != NULL) {
+ blkdev->fileproto = blkdev->params;
+ blkdev->filename = h+1;
+ *h = 0;
+ } else {
+ blkdev->fileproto = "<unset>";
+ blkdev->filename = blkdev->params;
+ }
+ }
+ if (!strcmp("aio", blkdev->fileproto)) {
+ blkdev->fileproto = "raw";
+ }
+ if (blkdev->mode == NULL) {
+ blkdev->mode = xenstore_read_be_str(&blkdev->xendev, "mode");
+ }
+ if (blkdev->type == NULL) {
+ blkdev->type = xenstore_read_be_str(&blkdev->xendev, "type");
+ }
+ if (blkdev->dev == NULL) {
+ blkdev->dev = xenstore_read_be_str(&blkdev->xendev, "dev");
+ }
+ if (blkdev->devtype == NULL) {
+ blkdev->devtype = xenstore_read_be_str(&blkdev->xendev, "device-type");
+ }
+ directiosafe = xenstore_read_be_str(&blkdev->xendev, "direct-io-safe");
+ blkdev->directiosafe = (directiosafe && atoi(directiosafe));
+
+ /* do we have all we need? */
+ if (blkdev->params == NULL ||
+ blkdev->mode == NULL ||
+ blkdev->type == NULL ||
+ blkdev->dev == NULL) {
+ goto out_error;
+ }
+
+ /* read-only ? */
+ if (strcmp(blkdev->mode, "w")) {
+ info |= VDISK_READONLY;
+ }
+
+ /* cdrom ? */
+ if (blkdev->devtype && !strcmp(blkdev->devtype, "cdrom")) {
+ info |= VDISK_CDROM;
+ }
+
+ blkdev->file_blk = BLOCK_SIZE;
+
+ /* fill info
+ * blk_connect supplies sector-size and sectors
+ */
+ xenstore_write_be_int(&blkdev->xendev, "feature-flush-cache", 1);
+ xenstore_write_be_int(&blkdev->xendev, "feature-persistent", 1);
+ xenstore_write_be_int(&blkdev->xendev, "info", info);
+
+ blk_parse_discard(blkdev);
+
+ g_free(directiosafe);
+ return 0;
+
+out_error:
+ g_free(blkdev->params);
+ blkdev->params = NULL;
+ g_free(blkdev->mode);
+ blkdev->mode = NULL;
+ g_free(blkdev->type);
+ blkdev->type = NULL;
+ g_free(blkdev->dev);
+ blkdev->dev = NULL;
+ g_free(blkdev->devtype);
+ blkdev->devtype = NULL;
+ g_free(directiosafe);
+ blkdev->directiosafe = false;
+ return -1;
+}
+
+static int blk_connect(struct XenDevice *xendev)
+{
+ struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+ int pers, index, qflags;
+ bool readonly = true;
+
+ /* read-only ? */
+ if (blkdev->directiosafe) {
+ qflags = BDRV_O_NOCACHE | BDRV_O_NATIVE_AIO;
+ } else {
+ qflags = BDRV_O_CACHE_WB;
+ }
+ if (strcmp(blkdev->mode, "w") == 0) {
+ qflags |= BDRV_O_RDWR;
+ readonly = false;
+ }
+ if (blkdev->feature_discard) {
+ qflags |= BDRV_O_UNMAP;
+ }
+
+ /* init qemu block driver */
+ index = (blkdev->xendev.dev - 202 * 256) / 16;
+ blkdev->dinfo = drive_get(IF_XEN, 0, index);
+ if (!blkdev->dinfo) {
+ Error *local_err = NULL;
+ QDict *options = NULL;
+
+ if (strcmp(blkdev->fileproto, "<unset>")) {
+ options = qdict_new();
+ qdict_put(options, "driver", qstring_from_str(blkdev->fileproto));
+ }
+
+ /* setup via xenbus -> create new block driver instance */
+ xen_be_printf(&blkdev->xendev, 2, "create new bdrv (xenbus setup)\n");
+ blkdev->blk = blk_new_open(blkdev->dev, blkdev->filename, NULL, options,
+ qflags, &local_err);
+ if (!blkdev->blk) {
+ xen_be_printf(&blkdev->xendev, 0, "error: %s\n",
+ error_get_pretty(local_err));
+ error_free(local_err);
+ return -1;
+ }
+ } else {
+ /* setup via qemu cmdline -> already setup for us */
+ xen_be_printf(&blkdev->xendev, 2, "get configured bdrv (cmdline setup)\n");
+ blkdev->blk = blk_by_legacy_dinfo(blkdev->dinfo);
+ if (blk_is_read_only(blkdev->blk) && !readonly) {
+ xen_be_printf(&blkdev->xendev, 0, "Unexpected read-only drive");
+ blkdev->blk = NULL;
+ return -1;
+ }
+ /* blkdev->blk is not create by us, we get a reference
+ * so we can blk_unref() unconditionally */
+ blk_ref(blkdev->blk);
+ }
+ blk_attach_dev_nofail(blkdev->blk, blkdev);
+ blkdev->file_size = blk_getlength(blkdev->blk);
+ if (blkdev->file_size < 0) {
+ xen_be_printf(&blkdev->xendev, 1, "blk_getlength: %d (%s) | drv %s\n",
+ (int)blkdev->file_size, strerror(-blkdev->file_size),
+ bdrv_get_format_name(blk_bs(blkdev->blk)) ?: "-");
+ blkdev->file_size = 0;
+ }
+
+ xen_be_printf(xendev, 1, "type \"%s\", fileproto \"%s\", filename \"%s\","
+ " size %" PRId64 " (%" PRId64 " MB)\n",
+ blkdev->type, blkdev->fileproto, blkdev->filename,
+ blkdev->file_size, blkdev->file_size >> 20);
+
+ /* Fill in number of sector size and number of sectors */
+ xenstore_write_be_int(&blkdev->xendev, "sector-size", blkdev->file_blk);
+ xenstore_write_be_int64(&blkdev->xendev, "sectors",
+ blkdev->file_size / blkdev->file_blk);
+
+ if (xenstore_read_fe_int(&blkdev->xendev, "ring-ref", &blkdev->ring_ref) == -1) {
+ return -1;
+ }
+ if (xenstore_read_fe_int(&blkdev->xendev, "event-channel",
+ &blkdev->xendev.remote_port) == -1) {
+ return -1;
+ }
+ if (xenstore_read_fe_int(&blkdev->xendev, "feature-persistent", &pers)) {
+ blkdev->feature_persistent = FALSE;
+ } else {
+ blkdev->feature_persistent = !!pers;
+ }
+
+ blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
+ if (blkdev->xendev.protocol) {
+ if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_32) == 0) {
+ blkdev->protocol = BLKIF_PROTOCOL_X86_32;
+ }
+ if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_64) == 0) {
+ blkdev->protocol = BLKIF_PROTOCOL_X86_64;
+ }
+ }
+
+ blkdev->sring = xc_gnttab_map_grant_ref(blkdev->xendev.gnttabdev,
+ blkdev->xendev.dom,
+ blkdev->ring_ref,
+ PROT_READ | PROT_WRITE);
+ if (!blkdev->sring) {
+ return -1;
+ }
+ blkdev->cnt_map++;
+
+ switch (blkdev->protocol) {
+ case BLKIF_PROTOCOL_NATIVE:
+ {
+ blkif_sring_t *sring_native = blkdev->sring;
+ BACK_RING_INIT(&blkdev->rings.native, sring_native, XC_PAGE_SIZE);
+ break;
+ }
+ case BLKIF_PROTOCOL_X86_32:
+ {
+ blkif_x86_32_sring_t *sring_x86_32 = blkdev->sring;
+
+ BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, XC_PAGE_SIZE);
+ break;
+ }
+ case BLKIF_PROTOCOL_X86_64:
+ {
+ blkif_x86_64_sring_t *sring_x86_64 = blkdev->sring;
+
+ BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, XC_PAGE_SIZE);
+ break;
+ }
+ }
+
+ if (blkdev->feature_persistent) {
+ /* Init persistent grants */
+ blkdev->max_grants = max_requests * BLKIF_MAX_SEGMENTS_PER_REQUEST;
+ blkdev->persistent_gnts = g_tree_new_full((GCompareDataFunc)int_cmp,
+ NULL, NULL,
+ batch_maps ?
+ (GDestroyNotify)g_free :
+ (GDestroyNotify)destroy_grant);
+ blkdev->persistent_regions = NULL;
+ blkdev->persistent_gnt_count = 0;
+ }
+
+ xen_be_bind_evtchn(&blkdev->xendev);
+
+ xen_be_printf(&blkdev->xendev, 1, "ok: proto %s, ring-ref %d, "
+ "remote port %d, local port %d\n",
+ blkdev->xendev.protocol, blkdev->ring_ref,
+ blkdev->xendev.remote_port, blkdev->xendev.local_port);
+ return 0;
+}
+
+static void blk_disconnect(struct XenDevice *xendev)
+{
+ struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+
+ if (blkdev->blk) {
+ blk_detach_dev(blkdev->blk, blkdev);
+ blk_unref(blkdev->blk);
+ blkdev->blk = NULL;
+ }
+ xen_be_unbind_evtchn(&blkdev->xendev);
+
+ if (blkdev->sring) {
+ xc_gnttab_munmap(blkdev->xendev.gnttabdev, blkdev->sring, 1);
+ blkdev->cnt_map--;
+ blkdev->sring = NULL;
+ }
+
+ /*
+ * Unmap persistent grants before switching to the closed state
+ * so the frontend can free them.
+ *
+ * In the !batch_maps case g_tree_destroy will take care of unmapping
+ * the grant, but in the batch_maps case we need to iterate over every
+ * region in persistent_regions and unmap it.
+ */
+ if (blkdev->feature_persistent) {
+ g_tree_destroy(blkdev->persistent_gnts);
+ assert(batch_maps || blkdev->persistent_gnt_count == 0);
+ if (batch_maps) {
+ blkdev->persistent_gnt_count = 0;
+ g_slist_foreach(blkdev->persistent_regions,
+ (GFunc)remove_persistent_region, blkdev);
+ g_slist_free(blkdev->persistent_regions);
+ }
+ blkdev->feature_persistent = false;
+ }
+}
+
+static int blk_free(struct XenDevice *xendev)
+{
+ struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+ struct ioreq *ioreq;
+
+ if (blkdev->blk || blkdev->sring) {
+ blk_disconnect(xendev);
+ }
+
+ while (!QLIST_EMPTY(&blkdev->freelist)) {
+ ioreq = QLIST_FIRST(&blkdev->freelist);
+ QLIST_REMOVE(ioreq, list);
+ qemu_iovec_destroy(&ioreq->v);
+ g_free(ioreq);
+ }
+
+ g_free(blkdev->params);
+ g_free(blkdev->mode);
+ g_free(blkdev->type);
+ g_free(blkdev->dev);
+ g_free(blkdev->devtype);
+ qemu_bh_delete(blkdev->bh);
+ return 0;
+}
+
+static void blk_event(struct XenDevice *xendev)
+{
+ struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+
+ qemu_bh_schedule(blkdev->bh);
+}
+
+struct XenDevOps xen_blkdev_ops = {
+ .size = sizeof(struct XenBlkDev),
+ .flags = DEVOPS_FLAG_NEED_GNTDEV,
+ .alloc = blk_alloc,
+ .init = blk_init,
+ .initialise = blk_connect,
+ .disconnect = blk_disconnect,
+ .event = blk_event,
+ .free = blk_free,
+};
Code Review / kvmfornfv.git / blobdiff