[hyperv] Ignore unsolicited VMBus messages

In some high-end Azure instances (e.g. NC6) we may receive an
unsolicited VMBUS_OFFER_CHANNEL message for a PCIe pass-through device
some time after completing the bus enumeration.  This currently causes
apparently random failures due to unexpected VMBus message types.

Fix by ignoring any unsolicited VMBus messages.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/interface/hyperv/vmbus.c b/src/interface/hyperv/vmbus.c
index e269aee29d46a1f29aa7fddcc9581604fa785d23..286572ce024474716e391ae2c1b4c7256c0a0f15 100644 (file)
--- a/src/interface/hyperv/vmbus.c
+++ b/src/interface/hyperv/vmbus.c
@@ -90,12 +90,12 @@ static int vmbus_post_empty_message ( struct hv_hypervisor *hv,
 }
 
 /**
- * Wait for received message
+ * Wait for received message of any type
  *
  * @v hv               Hyper-V hypervisor
  * @ret rc             Return status code
  */
-static int vmbus_wait_for_message ( struct hv_hypervisor *hv ) {
+static int vmbus_wait_for_any_message ( struct hv_hypervisor *hv ) {
        struct vmbus *vmbus = hv->vmbus;
        int rc;
 
@@ -116,6 +116,38 @@ static int vmbus_wait_for_message ( struct hv_hypervisor *hv ) {
        return 0;
 }
 
+/**
+ * Wait for received message of a specified type, ignoring any others
+ *
+ * @v hv               Hyper-V hypervisor
+ * @v type             Message type
+ * @ret rc             Return status code
+ */
+static int vmbus_wait_for_message ( struct hv_hypervisor *hv,
+                                   unsigned int type ) {
+       struct vmbus *vmbus = hv->vmbus;
+       const struct vmbus_message_header *header = &vmbus->message->header;
+       int rc;
+
+       /* Loop until specified message arrives, or until an error occurs */
+       while ( 1 ) {
+
+               /* Wait for message */
+               if ( ( rc = vmbus_wait_for_any_message ( hv ) ) != 0 )
+                       return rc;
+
+               /* Check for requested message type */
+               if ( header->type == cpu_to_le32 ( type ) )
+                       return 0;
+
+               /* Ignore any other messages (e.g. due to additional
+                * channels being offered at runtime).
+                */
+               DBGC ( vmbus, "VMBUS %p ignoring message type %d (expecting "
+                      "%d)\n", vmbus, le32_to_cpu ( header->type ), type );
+       }
+}
+
 /**
  * Initiate contact
  *
@@ -144,15 +176,10 @@ static int vmbus_initiate_contact ( struct hv_hypervisor *hv,
                return rc;
 
        /* Wait for response */
-       if ( ( rc = vmbus_wait_for_message ( hv ) ) != 0 )
+       if ( ( rc = vmbus_wait_for_message ( hv, VMBUS_VERSION_RESPONSE ) ) !=0)
                return rc;
 
        /* Check response */
-       if ( version->header.type != cpu_to_le32 ( VMBUS_VERSION_RESPONSE ) ) {
-               DBGC ( vmbus, "VMBUS %p unexpected version response type %d\n",
-                      vmbus, le32_to_cpu ( version->header.type ) );
-               return -EPROTO;
-       }
        if ( ! version->supported ) {
                DBGC ( vmbus, "VMBUS %p requested version not supported\n",
                       vmbus );
@@ -178,8 +205,6 @@ static int vmbus_initiate_contact ( struct hv_hypervisor *hv,
  * @ret rc             Return status code
  */
 static int vmbus_unload ( struct hv_hypervisor *hv ) {
-       struct vmbus *vmbus = hv->vmbus;
-       const struct vmbus_message_header *header = &vmbus->message->header;
        int rc;
 
        /* Post message */
@@ -187,16 +212,9 @@ static int vmbus_unload ( struct hv_hypervisor *hv ) {
                return rc;
 
        /* Wait for response */
-       if ( ( rc = vmbus_wait_for_message ( hv ) ) != 0 )
+       if ( ( rc = vmbus_wait_for_message ( hv, VMBUS_UNLOAD_RESPONSE ) ) != 0)
                return rc;
 
-       /* Check response */
-       if ( header->type != cpu_to_le32 ( VMBUS_UNLOAD_RESPONSE ) ) {
-               DBGC ( vmbus, "VMBUS %p unexpected unload response type %d\n",
-                      vmbus, le32_to_cpu ( header->type ) );
-               return -EPROTO;
-       }
-
        return 0;
 }
 
@@ -290,15 +308,10 @@ int vmbus_establish_gpadl ( struct vmbus_device *vmdev, userptr_t data,
                return rc;
 
        /* Wait for response */
-       if ( ( rc = vmbus_wait_for_message ( hv ) ) != 0 )
+       if ( ( rc = vmbus_wait_for_message ( hv, VMBUS_GPADL_CREATED ) ) != 0 )
                return rc;
 
        /* Check response */
-       if ( created->header.type != cpu_to_le32 ( VMBUS_GPADL_CREATED ) ) {
-               DBGC ( vmdev, "VMBUS %s unexpected GPADL response type %d\n",
-                      vmdev->dev.name, le32_to_cpu ( created->header.type ) );
-               return -EPROTO;
-       }
        if ( created->channel != cpu_to_le32 ( vmdev->channel ) ) {
                DBGC ( vmdev, "VMBUS %s unexpected GPADL channel %d\n",
                       vmdev->dev.name, le32_to_cpu ( created->channel ) );
@@ -346,15 +359,10 @@ int vmbus_gpadl_teardown ( struct vmbus_device *vmdev, unsigned int gpadl ) {
                return rc;
 
        /* Wait for response */
-       if ( ( rc = vmbus_wait_for_message ( hv ) ) != 0 )
+       if ( ( rc = vmbus_wait_for_message ( hv, VMBUS_GPADL_TORNDOWN ) ) != 0 )
                return rc;
 
        /* Check response */
-       if ( torndown->header.type != cpu_to_le32 ( VMBUS_GPADL_TORNDOWN ) ) {
-               DBGC ( vmdev, "VMBUS %s unexpected GPADL response type %d\n",
-                      vmdev->dev.name, le32_to_cpu ( torndown->header.type ) );
-               return -EPROTO;
-       }
        if ( torndown->gpadl != cpu_to_le32 ( gpadl ) ) {
                DBGC ( vmdev, "VMBUS %s unexpected GPADL ID %#08x\n",
                       vmdev->dev.name, le32_to_cpu ( torndown->gpadl ) );
@@ -443,15 +451,11 @@ int vmbus_open ( struct vmbus_device *vmdev,
                return rc;
 
        /* Wait for response */
-       if ( ( rc = vmbus_wait_for_message ( hv ) ) != 0 )
+       if ( ( rc = vmbus_wait_for_message ( hv,
+                                            VMBUS_OPEN_CHANNEL_RESULT ) ) != 0)
                return rc;
 
        /* Check response */
-       if ( opened->header.type != cpu_to_le32 ( VMBUS_OPEN_CHANNEL_RESULT ) ){
-               DBGC ( vmdev, "VMBUS %s unexpected open response type %d\n",
-                      vmdev->dev.name, le32_to_cpu ( opened->header.type ) );
-               return -EPROTO;
-       }
        if ( opened->channel != cpu_to_le32 ( vmdev->channel ) ) {
                DBGC ( vmdev, "VMBUS %s unexpected opened channel %#08x\n",
                       vmdev->dev.name, le32_to_cpu ( opened->channel ) );
@@ -1136,8 +1140,8 @@ static int vmbus_probe_channels ( struct hv_hypervisor *hv,
        while ( 1 ) {
 
                /* Wait for response */
-               if ( ( rc = vmbus_wait_for_message ( hv ) ) != 0 )
-                       goto err_wait_for_message;
+               if ( ( rc = vmbus_wait_for_any_message ( hv ) ) != 0 )
+                       goto err_wait_for_any_message;
 
                /* Handle response */
                if ( header->type == cpu_to_le32 ( VMBUS_OFFER_CHANNEL ) ) {
@@ -1223,7 +1227,7 @@ static int vmbus_probe_channels ( struct hv_hypervisor *hv,
        }
  err_unexpected_offer:
  err_alloc_vmdev:
- err_wait_for_message:
+ err_wait_for_any_message:
        /* Free any devices allocated (but potentially not yet probed) */
        list_for_each_entry_safe ( vmdev, tmp, &parent->children,
                                   dev.siblings ) {