#include <linux/workqueue.h>
#include <linux/hyperv.h>
+#include "hyperv_vmbus.h"
+#include "hv_utils_transport.h"
+
#define VSS_MAJOR 5
#define VSS_MINOR 0
#define VSS_VERSION (VSS_MAJOR << 16 | VSS_MINOR)
#define VSS_USERSPACE_TIMEOUT (msecs_to_jiffies(10 * 1000))
/*
- * Global state maintained for transaction that is being processed.
- * Note that only one transaction can be active at any point in time.
+ * Global state maintained for transaction that is being processed. For a class
+ * of integration services, including the "VSS service", the specified protocol
+ * is a "request/response" protocol which means that there can only be single
+ * outstanding transaction from the host at any given point in time. We use
+ * this to simplify memory management in this driver - we cache and process
+ * only one message at a time.
*
- * This state is set when we receive a request from the host; we
- * cleanup this state when the transaction is completed - when we respond
- * to the host with the key value.
+ * While the request/response protocol is guaranteed by the host, we further
+ * ensure this by serializing packet processing in this driver - we do not
+ * read additional packets from the VMBUs until the current packet is fully
+ * handled.
*/
static struct {
- bool active; /* transaction status - active or not */
+ int state; /* hvutil_device_state */
int recv_len; /* number of bytes received. */
struct vmbus_channel *recv_channel; /* chn we got the request */
u64 recv_req_id; /* request ID. */
struct hv_vss_msg *msg; /* current message */
+ void *vss_context; /* for the channel callback */
} vss_transaction;
static void vss_respond_to_host(int error);
-static struct cb_id vss_id = { CN_VSS_IDX, CN_VSS_VAL };
-static const char vss_name[] = "vss_kernel_module";
+/*
+ * This state maintains the version number registered by the daemon.
+ */
+static int dm_reg_value;
+
+static const char vss_devname[] = "vmbus/hv_vss";
static __u8 *recv_buffer;
+static struct hvutil_transport *hvt;
static void vss_send_op(struct work_struct *dummy);
static void vss_timeout_func(struct work_struct *dummy);
*/
pr_warn("VSS: timeout waiting for daemon to reply\n");
vss_respond_to_host(HV_E_FAIL);
+
+ /* Transaction is finished, reset the state. */
+ if (vss_transaction.state > HVUTIL_READY)
+ vss_transaction.state = HVUTIL_READY;
+
+ hv_poll_channel(vss_transaction.vss_context,
+ hv_vss_onchannelcallback);
}
-static void
-vss_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
+static int vss_handle_handshake(struct hv_vss_msg *vss_msg)
{
- struct hv_vss_msg *vss_msg;
+ u32 our_ver = VSS_OP_REGISTER1;
+
+ switch (vss_msg->vss_hdr.operation) {
+ case VSS_OP_REGISTER:
+ /* Daemon doesn't expect us to reply */
+ dm_reg_value = VSS_OP_REGISTER;
+ break;
+ case VSS_OP_REGISTER1:
+ /* Daemon expects us to reply with our own version*/
+ if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver)))
+ return -EFAULT;
+ dm_reg_value = VSS_OP_REGISTER1;
+ break;
+ default:
+ return -EINVAL;
+ }
+ vss_transaction.state = HVUTIL_READY;
+ pr_debug("VSS: userspace daemon ver. %d registered\n", dm_reg_value);
+ return 0;
+}
- vss_msg = (struct hv_vss_msg *)msg->data;
+static int vss_on_msg(void *msg, int len)
+{
+ struct hv_vss_msg *vss_msg = (struct hv_vss_msg *)msg;
- if (vss_msg->vss_hdr.operation == VSS_OP_REGISTER) {
- pr_info("VSS daemon registered\n");
- vss_transaction.active = false;
- if (vss_transaction.recv_channel != NULL)
- hv_vss_onchannelcallback(vss_transaction.recv_channel);
- return;
+ if (len != sizeof(*vss_msg))
+ return -EINVAL;
+ if (vss_msg->vss_hdr.operation == VSS_OP_REGISTER ||
+ vss_msg->vss_hdr.operation == VSS_OP_REGISTER1) {
+ /*
+ * Don't process registration messages if we're in the middle
+ * of a transaction processing.
+ */
+ if (vss_transaction.state > HVUTIL_READY)
+ return -EINVAL;
+ return vss_handle_handshake(vss_msg);
+ } else if (vss_transaction.state == HVUTIL_USERSPACE_REQ) {
+ vss_transaction.state = HVUTIL_USERSPACE_RECV;
+ if (cancel_delayed_work_sync(&vss_timeout_work)) {
+ vss_respond_to_host(vss_msg->error);
+ /* Transaction is finished, reset the state. */
+ vss_transaction.state = HVUTIL_READY;
+ hv_poll_channel(vss_transaction.vss_context,
+ hv_vss_onchannelcallback);
+ }
+ } else {
+ /* This is a spurious call! */
+ pr_warn("VSS: Transaction not active\n");
+ return -EINVAL;
}
- if (cancel_delayed_work_sync(&vss_timeout_work))
- vss_respond_to_host(vss_msg->error);
+ return 0;
}
{
int op = vss_transaction.msg->vss_hdr.operation;
int rc;
- struct cn_msg *msg;
struct hv_vss_msg *vss_msg;
- msg = kzalloc(sizeof(*msg) + sizeof(*vss_msg), GFP_ATOMIC);
- if (!msg)
+ /* The transaction state is wrong. */
+ if (vss_transaction.state != HVUTIL_HOSTMSG_RECEIVED)
return;
- vss_msg = (struct hv_vss_msg *)msg->data;
-
- msg->id.idx = CN_VSS_IDX;
- msg->id.val = CN_VSS_VAL;
+ vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL);
+ if (!vss_msg)
+ return;
vss_msg->vss_hdr.operation = op;
- msg->len = sizeof(struct hv_vss_msg);
- rc = cn_netlink_send(msg, 0, 0, GFP_ATOMIC);
+ vss_transaction.state = HVUTIL_USERSPACE_REQ;
+ rc = hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg));
if (rc) {
pr_warn("VSS: failed to communicate to the daemon: %d\n", rc);
- if (cancel_delayed_work_sync(&vss_timeout_work))
+ if (cancel_delayed_work_sync(&vss_timeout_work)) {
vss_respond_to_host(HV_E_FAIL);
+ vss_transaction.state = HVUTIL_READY;
+ }
}
- kfree(msg);
+
+ kfree(vss_msg);
return;
}
struct vmbus_channel *channel;
u64 req_id;
- /*
- * If a transaction is not active; log and return.
- */
-
- if (!vss_transaction.active) {
- /*
- * This is a spurious call!
- */
- pr_warn("VSS: Transaction not active\n");
- return;
- }
/*
* Copy the global state for completing the transaction. Note that
* only one transaction can be active at a time.
buf_len = vss_transaction.recv_len;
channel = vss_transaction.recv_channel;
req_id = vss_transaction.recv_req_id;
- vss_transaction.active = false;
icmsghdrp = (struct icmsg_hdr *)
&recv_buffer[sizeof(struct vmbuspipe_hdr)];
struct icmsg_hdr *icmsghdrp;
struct icmsg_negotiate *negop = NULL;
- if (vss_transaction.active) {
+ if (vss_transaction.state > HVUTIL_READY) {
/*
* We will defer processing this callback once
* the current transaction is complete.
*/
- vss_transaction.recv_channel = channel;
+ vss_transaction.vss_context = context;
return;
}
+ vss_transaction.vss_context = NULL;
vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
&requestid);
vss_transaction.recv_len = recvlen;
vss_transaction.recv_channel = channel;
vss_transaction.recv_req_id = requestid;
- vss_transaction.active = true;
vss_transaction.msg = (struct hv_vss_msg *)vss_msg;
switch (vss_msg->vss_hdr.operation) {
*/
case VSS_OP_FREEZE:
case VSS_OP_THAW:
+ if (vss_transaction.state < HVUTIL_READY) {
+ /* Userspace is not registered yet */
+ vss_respond_to_host(HV_E_FAIL);
+ return;
+ }
+ vss_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
schedule_work(&vss_send_op_work);
schedule_delayed_work(&vss_timeout_work,
VSS_USERSPACE_TIMEOUT);
}
+static void vss_on_reset(void)
+{
+ if (cancel_delayed_work_sync(&vss_timeout_work))
+ vss_respond_to_host(HV_E_FAIL);
+ vss_transaction.state = HVUTIL_DEVICE_INIT;
+}
+
int
hv_vss_init(struct hv_util_service *srv)
{
- int err;
-
- err = cn_add_callback(&vss_id, vss_name, vss_cn_callback);
- if (err)
- return err;
recv_buffer = srv->recv_buffer;
/*
* Defer processing channel callbacks until the daemon
* has registered.
*/
- vss_transaction.active = true;
+ vss_transaction.state = HVUTIL_DEVICE_INIT;
+
+ hvt = hvutil_transport_init(vss_devname, CN_VSS_IDX, CN_VSS_VAL,
+ vss_on_msg, vss_on_reset);
+ if (!hvt)
+ return -EFAULT;
+
return 0;
}
void hv_vss_deinit(void)
{
- cn_del_callback(&vss_id);
+ vss_transaction.state = HVUTIL_DEVICE_DYING;
cancel_delayed_work_sync(&vss_timeout_work);
cancel_work_sync(&vss_send_op_work);
+ hvutil_transport_destroy(hvt);
}
Code Review / kvmfornfv.git / blobdiff