1 files changed, 129 insertions, 4 deletions

diff --git a/src/interface/hyperv/vmbus.c b/src/interface/hyperv/vmbus.c
index 7915ddfe..45a7caec 100644
--- a/src/interface/hyperv/vmbus.c
+++ b/src/interface/hyperv/vmbus.c
@@ -50,6 +50,16 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  */
 #define VMBUS_GPADL_MAGIC 0x18ae0000
 
+/** Current (i.e. most recently issued) GPADL ID */
+static unsigned int vmbus_gpadl = VMBUS_GPADL_MAGIC;
+
+/** Obsolete GPADL ID threshold
+ *
+ * When the Hyper-V connection is reset, any previous GPADLs are
+ * automatically rendered obsolete.
+ */
+unsigned int vmbus_obsolete_gpadl;
+
 /**
  * Post message
  *
@@ -281,12 +291,12 @@ int vmbus_establish_gpadl ( struct vmbus_device *vmdev, userptr_t data,
 		uint64_t pfn[pfn_count];
 	} __attribute__ (( packed )) gpadlhdr;
 	const struct vmbus_gpadl_created *created = &vmbus->message->created;
-	static unsigned int gpadl = VMBUS_GPADL_MAGIC;
+	unsigned int gpadl;
 	unsigned int i;
 	int rc;
 
 	/* Allocate GPADL ID */
-	gpadl++;
+	gpadl = ++vmbus_gpadl;
 
 	/* Construct message */
 	memset ( &gpadlhdr, 0, sizeof ( gpadlhdr ) );
@@ -347,6 +357,15 @@ int vmbus_gpadl_teardown ( struct vmbus_device *vmdev, unsigned int gpadl ) {
 	const struct vmbus_gpadl_torndown *torndown = &vmbus->message->torndown;
 	int rc;
 
+	/* If GPADL is obsolete (i.e. was created before the most
+	 * recent Hyper-V reset), then we will never receive a
+	 * response to the teardown message.  Since the GPADL is
+	 * already destroyed as far as the hypervisor is concerned, no
+	 * further action is required.
+	 */
+	if ( vmbus_gpadl_is_obsolete ( gpadl ) )
+		return 0;
+
 	/* Construct message */
 	memset ( &teardown, 0, sizeof ( teardown ) );
 	teardown.header.type = cpu_to_le32 ( VMBUS_GPADL_TEARDOWN );
@@ -530,8 +549,7 @@ void vmbus_close ( struct vmbus_device *vmdev ) {
 	}
 
 	/* Tear down GPADL */
-	if ( ( rc = vmbus_gpadl_teardown ( vmdev,
-					   vmdev->gpadl ) ) != 0 ) {
+	if ( ( rc = vmbus_gpadl_teardown ( vmdev, vmdev->gpadl ) ) != 0 ) {
 		DBGC ( vmdev, "VMBUS %s failed to tear down channel GPADL: "
 		       "%s\n", vmdev->dev.name, strerror ( rc ) );
 		/* We can't prevent the remote VM from continuing to
@@ -1187,6 +1205,8 @@ static int vmbus_probe_channels ( struct hv_hypervisor *hv,
 					&parent->children );
 			vmdev->dev.parent = parent;
 			vmdev->hv = hv;
+			memcpy ( &vmdev->instance, &offer->instance,
+				 sizeof ( vmdev->instance ) );
 			vmdev->channel = channel;
 			vmdev->monitor = offer->monitor;
 			vmdev->signal = ( offer->monitored ?
@@ -1201,6 +1221,7 @@ static int vmbus_probe_channels ( struct hv_hypervisor *hv,
 		} else if ( header->type ==
 			    cpu_to_le32 ( VMBUS_ALL_OFFERS_DELIVERED ) ) {
 
+			/* End of offer list */
 			break;
 
 		} else {
@@ -1244,6 +1265,77 @@ static int vmbus_probe_channels ( struct hv_hypervisor *hv,
 	return rc;
 }
 
+
+/**
+ * Reset channels
+ *
+ * @v hv		Hyper-V hypervisor
+ * @v parent		Parent device
+ * @ret rc		Return status code
+ */
+static int vmbus_reset_channels ( struct hv_hypervisor *hv,
+				  struct device *parent ) {
+	struct vmbus *vmbus = hv->vmbus;
+	const struct vmbus_message_header *header = &vmbus->message->header;
+	const struct vmbus_offer_channel *offer = &vmbus->message->offer;
+	const union uuid *type;
+	struct vmbus_device *vmdev;
+	unsigned int channel;
+	int rc;
+
+	/* Post message */
+	if ( ( rc = vmbus_post_empty_message ( hv, VMBUS_REQUEST_OFFERS ) ) !=0)
+		return rc;
+
+	/* Collect responses */
+	while ( 1 ) {
+
+		/* Wait for response */
+		if ( ( rc = vmbus_wait_for_any_message ( hv ) ) != 0 )
+			return rc;
+
+		/* Handle response */
+		if ( header->type == cpu_to_le32 ( VMBUS_OFFER_CHANNEL ) ) {
+
+			/* Parse offer */
+			type = &offer->type;
+			channel = le32_to_cpu ( offer->channel );
+			DBGC2 ( vmbus, "VMBUS %p offer %d type %s",
+				vmbus, channel, uuid_ntoa ( type ) );
+			if ( offer->monitored )
+				DBGC2 ( vmbus, " monitor %d", offer->monitor );
+			DBGC2 ( vmbus, "\n" );
+
+			/* Do nothing with the offer; we already have all
+			 * of the relevant state from the initial probe.
+			 */
+
+		} else if ( header->type ==
+			    cpu_to_le32 ( VMBUS_ALL_OFFERS_DELIVERED ) ) {
+
+			/* End of offer list */
+			break;
+
+		} else {
+			DBGC ( vmbus, "VMBUS %p unexpected offer response type "
+			       "%d\n", vmbus, le32_to_cpu ( header->type ) );
+			return -EPROTO;
+		}
+	}
+
+	/* Reset all devices */
+	list_for_each_entry ( vmdev, &parent->children, dev.siblings ) {
+		if ( ( rc = vmdev->driver->reset ( vmdev ) ) != 0 ) {
+			DBGC ( vmdev, "VMBUS %s could not reset: %s\n",
+			       vmdev->dev.name, strerror ( rc ) );
+			/* Continue attempting to reset other devices */
+			continue;
+		}
+	}
+
+	return 0;
+}
+
 /**
  * Remove channels
  *
@@ -1331,6 +1423,39 @@ int vmbus_probe ( struct hv_hypervisor *hv, struct device *parent ) {
 }
 
 /**
+ * Reset Hyper-V virtual machine bus
+ *
+ * @v hv		Hyper-V hypervisor
+ * @v parent		Parent device
+ * @ret rc		Return status code
+ */
+int vmbus_reset ( struct hv_hypervisor *hv, struct device *parent ) {
+	struct vmbus *vmbus = hv->vmbus;
+	int rc;
+
+	/* Mark all existent GPADLs as obsolete */
+	vmbus_obsolete_gpadl = vmbus_gpadl;
+
+	/* Clear interrupt and monitor pages */
+	memset ( vmbus->intr, 0, PAGE_SIZE );
+	memset ( vmbus->monitor_in, 0, PAGE_SIZE );
+	memset ( vmbus->monitor_out, 0, PAGE_SIZE );
+
+	/* Enable message interrupt */
+	hv_enable_sint ( hv, VMBUS_MESSAGE_SINT );
+
+	/* Renegotiate protocol version */
+	if ( ( rc = vmbus_negotiate_version ( hv ) ) != 0 )
+		return rc;
+
+	/* Reenumerate channels */
+	if ( ( rc = vmbus_reset_channels ( hv, parent ) ) != 0 )
+		return rc;
+
+	return 0;
+}
+
+/**
  * Remove Hyper-V virtual machine bus
  *
  * @v hv		Hyper-V hypervisor