Merge tag 'hyperv-next-signed-20220528' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv updates from Wei Liu:

 - Harden hv_sock driver (Andrea Parri)

 - Harden Hyper-V PCI driver (Andrea Parri)

 - Fix multi-MSI for Hyper-V PCI driver (Jeffrey Hugo)

 - Fix Hyper-V PCI to reduce boot time (Dexuan Cui)

 - Remove code for long EOL'ed Hyper-V versions (Michael Kelley, Saurabh
   Sengar)

 - Fix balloon driver error handling (Shradha Gupta)

 - Fix a typo in vmbus driver (Julia Lawall)

 - Ignore vmbus IMC device (Michael Kelley)

 - Add a new error message to Hyper-V DRM driver (Saurabh Sengar)

* tag 'hyperv-next-signed-20220528' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (28 commits)
  hv_balloon: Fix balloon_probe() and balloon_remove() error handling
  scsi: storvsc: Removing Pre Win8 related logic
  Drivers: hv: vmbus: fix typo in comment
  PCI: hv: Fix synchronization between channel callback and hv_pci_bus_exit()
  PCI: hv: Add validation for untrusted Hyper-V values
  PCI: hv: Fix interrupt mapping for multi-MSI
  PCI: hv: Reuse existing IRTE allocation in compose_msi_msg()
  drm/hyperv: Remove support for Hyper-V 2008 and 2008R2/Win7
  video: hyperv_fb: Remove support for Hyper-V 2008 and 2008R2/Win7
  scsi: storvsc: Remove support for Hyper-V 2008 and 2008R2/Win7
  Drivers: hv: vmbus: Remove support for Hyper-V 2008 and Hyper-V 2008R2/Win7
  x86/hyperv: Disable hardlockup detector by default in Hyper-V guests
  drm/hyperv: Add error message for fb size greater than allocated
  PCI: hv: Do not set PCI_COMMAND_MEMORY to reduce VM boot time
  PCI: hv: Fix hv_arch_irq_unmask() for multi-MSI
  Drivers: hv: vmbus: Refactor the ring-buffer iterator functions
  Drivers: hv: vmbus: Accept hv_sock offers in isolated guests
  hv_sock: Add validation for untrusted Hyper-V values
  hv_sock: Copy packets sent by Hyper-V out of the ring buffer
  hv_sock: Check hv_pkt_iter_first_raw()'s return value
  ...

1 files changed, 181 insertions, 62 deletions

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index d270a204324e..db814f7b93ba 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -92,6 +92,13 @@ static enum pci_protocol_version_t pci_protocol_versions[] = {
 #define SLOT_NAME_SIZE 11
 
 /*
+ * Size of requestor for VMbus; the value is based on the observation
+ * that having more than one request outstanding is 'rare', and so 64
+ * should be generous in ensuring that we don't ever run out.
+ */
+#define HV_PCI_RQSTOR_SIZE 64
+
+/*
  * Message Types
  */
 
@@ -604,17 +611,19 @@ static unsigned int hv_msi_get_int_vector(struct irq_data *data)
 	return cfg->vector;
 }
 
-static void hv_set_msi_entry_from_desc(union hv_msi_entry *msi_entry,
-				       struct msi_desc *msi_desc)
-{
-	msi_entry->address.as_uint32 = msi_desc->msg.address_lo;
-	msi_entry->data.as_uint32 = msi_desc->msg.data;
-}
-
 static int hv_msi_prepare(struct irq_domain *domain, struct device *dev,
 			  int nvec, msi_alloc_info_t *info)
 {
-	return pci_msi_prepare(domain, dev, nvec, info);
+	int ret = pci_msi_prepare(domain, dev, nvec, info);
+
+	/*
+	 * By using the interrupt remapper in the hypervisor IOMMU, contiguous
+	 * CPU vectors is not needed for multi-MSI
+	 */
+	if (info->type == X86_IRQ_ALLOC_TYPE_PCI_MSI)
+		info->flags &= ~X86_IRQ_ALLOC_CONTIGUOUS_VECTORS;
+
+	return ret;
 }
 
 /**
@@ -631,6 +640,7 @@ static void hv_arch_irq_unmask(struct irq_data *data)
 {
 	struct msi_desc *msi_desc = irq_data_get_msi_desc(data);
 	struct hv_retarget_device_interrupt *params;
+	struct tran_int_desc *int_desc;
 	struct hv_pcibus_device *hbus;
 	struct cpumask *dest;
 	cpumask_var_t tmp;
@@ -645,6 +655,7 @@ static void hv_arch_irq_unmask(struct irq_data *data)
 	pdev = msi_desc_to_pci_dev(msi_desc);
 	pbus = pdev->bus;
 	hbus = container_of(pbus->sysdata, struct hv_pcibus_device, sysdata);
+	int_desc = data->chip_data;
 
 	spin_lock_irqsave(&hbus->retarget_msi_interrupt_lock, flags);
 
@@ -652,7 +663,8 @@ static void hv_arch_irq_unmask(struct irq_data *data)
 	memset(params, 0, sizeof(*params));
 	params->partition_id = HV_PARTITION_ID_SELF;
 	params->int_entry.source = HV_INTERRUPT_SOURCE_MSI;
-	hv_set_msi_entry_from_desc(&params->int_entry.msi_entry, msi_desc);
+	params->int_entry.msi_entry.address.as_uint32 = int_desc->address & 0xffffffff;
+	params->int_entry.msi_entry.data.as_uint32 = int_desc->data;
 	params->device_id = (hbus->hdev->dev_instance.b[5] << 24) |
 			   (hbus->hdev->dev_instance.b[4] << 16) |
 			   (hbus->hdev->dev_instance.b[7] << 8) |
@@ -969,11 +981,7 @@ static void hv_pci_generic_compl(void *context, struct pci_response *resp,
 {
 	struct hv_pci_compl *comp_pkt = context;
 
-	if (resp_packet_size >= offsetofend(struct pci_response, status))
-		comp_pkt->completion_status = resp->status;
-	else
-		comp_pkt->completion_status = -1;
-
+	comp_pkt->completion_status = resp->status;
 	complete(&comp_pkt->host_event);
 }
 
@@ -1513,6 +1521,10 @@ static void hv_int_desc_free(struct hv_pci_dev *hpdev,
 		u8 buffer[sizeof(struct pci_delete_interrupt)];
 	} ctxt;
 
+	if (!int_desc->vector_count) {
+		kfree(int_desc);
+		return;
+	}
 	memset(&ctxt, 0, sizeof(ctxt));
 	int_pkt = (struct pci_delete_interrupt *)&ctxt.pkt.message;
 	int_pkt->message_type.type =
@@ -1520,7 +1532,7 @@ static void hv_int_desc_free(struct hv_pci_dev *hpdev,
 	int_pkt->wslot.slot = hpdev->desc.win_slot.slot;
 	int_pkt->int_desc = *int_desc;
 	vmbus_sendpacket(hpdev->hbus->hdev->channel, int_pkt, sizeof(*int_pkt),
-			 (unsigned long)&ctxt.pkt, VM_PKT_DATA_INBAND, 0);
+			 0, VM_PKT_DATA_INBAND, 0);
 	kfree(int_desc);
 }
 
@@ -1590,19 +1602,24 @@ static void hv_pci_compose_compl(void *context, struct pci_response *resp,
 	struct pci_create_int_response *int_resp =
 		(struct pci_create_int_response *)resp;
 
+	if (resp_packet_size < sizeof(*int_resp)) {
+		comp_pkt->comp_pkt.completion_status = -1;
+		goto out;
+	}
 	comp_pkt->comp_pkt.completion_status = resp->status;
 	comp_pkt->int_desc = int_resp->int_desc;
+out:
 	complete(&comp_pkt->comp_pkt.host_event);
 }
 
 static u32 hv_compose_msi_req_v1(
 	struct pci_create_interrupt *int_pkt, struct cpumask *affinity,
-	u32 slot, u8 vector)
+	u32 slot, u8 vector, u8 vector_count)
 {
 	int_pkt->message_type.type = PCI_CREATE_INTERRUPT_MESSAGE;
 	int_pkt->wslot.slot = slot;
 	int_pkt->int_desc.vector = vector;
-	int_pkt->int_desc.vector_count = 1;
+	int_pkt->int_desc.vector_count = vector_count;
 	int_pkt->int_desc.delivery_mode = DELIVERY_MODE;
 
 	/*
@@ -1625,14 +1642,14 @@ static int hv_compose_msi_req_get_cpu(struct cpumask *affinity)
 
 static u32 hv_compose_msi_req_v2(
 	struct pci_create_interrupt2 *int_pkt, struct cpumask *affinity,
-	u32 slot, u8 vector)
+	u32 slot, u8 vector, u8 vector_count)
 {
 	int cpu;
 
 	int_pkt->message_type.type = PCI_CREATE_INTERRUPT_MESSAGE2;
 	int_pkt->wslot.slot = slot;
 	int_pkt->int_desc.vector = vector;
-	int_pkt->int_desc.vector_count = 1;
+	int_pkt->int_desc.vector_count = vector_count;
 	int_pkt->int_desc.delivery_mode = DELIVERY_MODE;
 	cpu = hv_compose_msi_req_get_cpu(affinity);
 	int_pkt->int_desc.processor_array[0] =
@@ -1644,7 +1661,7 @@ static u32 hv_compose_msi_req_v2(
 
 static u32 hv_compose_msi_req_v3(
 	struct pci_create_interrupt3 *int_pkt, struct cpumask *affinity,
-	u32 slot, u32 vector)
+	u32 slot, u32 vector, u8 vector_count)
 {
 	int cpu;
 
@@ -1652,7 +1669,7 @@ static u32 hv_compose_msi_req_v3(
 	int_pkt->wslot.slot = slot;
 	int_pkt->int_desc.vector = vector;
 	int_pkt->int_desc.reserved = 0;
-	int_pkt->int_desc.vector_count = 1;
+	int_pkt->int_desc.vector_count = vector_count;
 	int_pkt->int_desc.delivery_mode = DELIVERY_MODE;
 	cpu = hv_compose_msi_req_get_cpu(affinity);
 	int_pkt->int_desc.processor_array[0] =
@@ -1683,6 +1700,8 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 	struct cpumask *dest;
 	struct compose_comp_ctxt comp;
 	struct tran_int_desc *int_desc;
+	struct msi_desc *msi_desc;
+	u8 vector, vector_count;
 	struct {
 		struct pci_packet pci_pkt;
 		union {
@@ -1691,11 +1710,21 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 			struct pci_create_interrupt3 v3;
 		} int_pkts;
 	} __packed ctxt;
-
+	u64 trans_id;
 	u32 size;
 	int ret;
 
-	pdev = msi_desc_to_pci_dev(irq_data_get_msi_desc(data));
+	/* Reuse the previous allocation */
+	if (data->chip_data) {
+		int_desc = data->chip_data;
+		msg->address_hi = int_desc->address >> 32;
+		msg->address_lo = int_desc->address & 0xffffffff;
+		msg->data = int_desc->data;
+		return;
+	}
+
+	msi_desc  = irq_data_get_msi_desc(data);
+	pdev = msi_desc_to_pci_dev(msi_desc);
 	dest = irq_data_get_effective_affinity_mask(data);
 	pbus = pdev->bus;
 	hbus = container_of(pbus->sysdata, struct hv_pcibus_device, sysdata);
@@ -1704,17 +1733,40 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 	if (!hpdev)
 		goto return_null_message;
 
-	/* Free any previous message that might have already been composed. */
-	if (data->chip_data) {
-		int_desc = data->chip_data;
-		data->chip_data = NULL;
-		hv_int_desc_free(hpdev, int_desc);
-	}
-
 	int_desc = kzalloc(sizeof(*int_desc), GFP_ATOMIC);
 	if (!int_desc)
 		goto drop_reference;
 
+	if (!msi_desc->pci.msi_attrib.is_msix && msi_desc->nvec_used > 1) {
+		/*
+		 * If this is not the first MSI of Multi MSI, we already have
+		 * a mapping.  Can exit early.
+		 */
+		if (msi_desc->irq != data->irq) {
+			data->chip_data = int_desc;
+			int_desc->address = msi_desc->msg.address_lo |
+					    (u64)msi_desc->msg.address_hi << 32;
+			int_desc->data = msi_desc->msg.data +
+					 (data->irq - msi_desc->irq);
+			msg->address_hi = msi_desc->msg.address_hi;
+			msg->address_lo = msi_desc->msg.address_lo;
+			msg->data = int_desc->data;
+			put_pcichild(hpdev);
+			return;
+		}
+		/*
+		 * The vector we select here is a dummy value.  The correct
+		 * value gets sent to the hypervisor in unmask().  This needs
+		 * to be aligned with the count, and also not zero.  Multi-msi
+		 * is powers of 2 up to 32, so 32 will always work here.
+		 */
+		vector = 32;
+		vector_count = msi_desc->nvec_used;
+	} else {
+		vector = hv_msi_get_int_vector(data);
+		vector_count = 1;
+	}
+
 	memset(&ctxt, 0, sizeof(ctxt));
 	init_completion(&comp.comp_pkt.host_event);
 	ctxt.pci_pkt.completion_func = hv_pci_compose_compl;
@@ -1725,7 +1777,8 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 		size = hv_compose_msi_req_v1(&ctxt.int_pkts.v1,
 					dest,
 					hpdev->desc.win_slot.slot,
-					hv_msi_get_int_vector(data));
+					vector,
+					vector_count);
 		break;
 
 	case PCI_PROTOCOL_VERSION_1_2:
@@ -1733,14 +1786,16 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 		size = hv_compose_msi_req_v2(&ctxt.int_pkts.v2,
 					dest,
 					hpdev->desc.win_slot.slot,
-					hv_msi_get_int_vector(data));
+					vector,
+					vector_count);
 		break;
 
 	case PCI_PROTOCOL_VERSION_1_4:
 		size = hv_compose_msi_req_v3(&ctxt.int_pkts.v3,
 					dest,
 					hpdev->desc.win_slot.slot,
-					hv_msi_get_int_vector(data));
+					vector,
+					vector_count);
 		break;
 
 	default:
@@ -1753,10 +1808,10 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 		goto free_int_desc;
 	}
 
-	ret = vmbus_sendpacket(hpdev->hbus->hdev->channel, &ctxt.int_pkts,
-			       size, (unsigned long)&ctxt.pci_pkt,
-			       VM_PKT_DATA_INBAND,
-			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+	ret = vmbus_sendpacket_getid(hpdev->hbus->hdev->channel, &ctxt.int_pkts,
+				     size, (unsigned long)&ctxt.pci_pkt,
+				     &trans_id, VM_PKT_DATA_INBAND,
+				     VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 	if (ret) {
 		dev_err(&hbus->hdev->device,
 			"Sending request for interrupt failed: 0x%x",
@@ -1835,6 +1890,15 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 
 enable_tasklet:
 	tasklet_enable(&channel->callback_event);
+	/*
+	 * The completion packet on the stack becomes invalid after 'return';
+	 * remove the ID from the VMbus requestor if the identifier is still
+	 * mapped to/associated with the packet.  (The identifier could have
+	 * been 're-used', i.e., already removed and (re-)mapped.)
+	 *
+	 * Cf. hv_pci_onchannelcallback().
+	 */
+	vmbus_request_addr_match(channel, trans_id, (unsigned long)&ctxt.pci_pkt);
 free_int_desc:
 	kfree(int_desc);
 drop_reference:
@@ -2082,12 +2146,17 @@ static void prepopulate_bars(struct hv_pcibus_device *hbus)
 				}
 			}
 			if (high_size <= 1 && low_size <= 1) {
-				/* Set the memory enable bit. */
-				_hv_pcifront_read_config(hpdev, PCI_COMMAND, 2,
-							 &command);
-				command |= PCI_COMMAND_MEMORY;
-				_hv_pcifront_write_config(hpdev, PCI_COMMAND, 2,
-							  command);
+				/*
+				 * No need to set the PCI_COMMAND_MEMORY bit as
+				 * the core PCI driver doesn't require the bit
+				 * to be pre-set. Actually here we intentionally
+				 * keep the bit off so that the PCI BAR probing
+				 * in the core PCI driver doesn't cause Hyper-V
+				 * to unnecessarily unmap/map the virtual BARs
+				 * from/to the physical BARs multiple times.
+				 * This reduces the VM boot time significantly
+				 * if the BAR sizes are huge.
+				 */
 				break;
 			}
 		}
@@ -2223,12 +2292,14 @@ static void q_resource_requirements(void *context, struct pci_response *resp,
 	struct q_res_req_compl *completion = context;
 	struct pci_q_res_req_response *q_res_req =
 		(struct pci_q_res_req_response *)resp;
+	s32 status;
 	int i;
 
-	if (resp->status < 0) {
+	status = (resp_packet_size < sizeof(*q_res_req)) ? -1 : resp->status;
+	if (status < 0) {
 		dev_err(&completion->hpdev->hbus->hdev->device,
 			"query resource requirements failed: %x\n",
-			resp->status);
+			status);
 	} else {
 		for (i = 0; i < PCI_STD_NUM_BARS; i++) {
 			completion->hpdev->probed_bar[i] =
@@ -2652,7 +2723,7 @@ static void hv_eject_device_work(struct work_struct *work)
 	ejct_pkt->message_type.type = PCI_EJECTION_COMPLETE;
 	ejct_pkt->wslot.slot = hpdev->desc.win_slot.slot;
 	vmbus_sendpacket(hbus->hdev->channel, ejct_pkt,
-			 sizeof(*ejct_pkt), (unsigned long)&ctxt.pkt,
+			 sizeof(*ejct_pkt), 0,
 			 VM_PKT_DATA_INBAND, 0);
 
 	/* For the get_pcichild() in hv_pci_eject_device() */
@@ -2699,8 +2770,9 @@ static void hv_pci_onchannelcallback(void *context)
 	const int packet_size = 0x100;
 	int ret;
 	struct hv_pcibus_device *hbus = context;
+	struct vmbus_channel *chan = hbus->hdev->channel;
 	u32 bytes_recvd;
-	u64 req_id;
+	u64 req_id, req_addr;
 	struct vmpacket_descriptor *desc;
 	unsigned char *buffer;
 	int bufferlen = packet_size;
@@ -2712,14 +2784,15 @@ static void hv_pci_onchannelcallback(void *context)
 	struct pci_dev_inval_block *inval;
 	struct pci_dev_incoming *dev_message;
 	struct hv_pci_dev *hpdev;
+	unsigned long flags;
 
 	buffer = kmalloc(bufferlen, GFP_ATOMIC);
 	if (!buffer)
 		return;
 
 	while (1) {
-		ret = vmbus_recvpacket_raw(hbus->hdev->channel, buffer,
-					   bufferlen, &bytes_recvd, &req_id);
+		ret = vmbus_recvpacket_raw(chan, buffer, bufferlen,
+					   &bytes_recvd, &req_id);
 
 		if (ret == -ENOBUFS) {
 			kfree(buffer);
@@ -2746,15 +2819,29 @@ static void hv_pci_onchannelcallback(void *context)
 		switch (desc->type) {
 		case VM_PKT_COMP:
 
+			lock_requestor(chan, flags);
+			req_addr = __vmbus_request_addr_match(chan, req_id,
+							      VMBUS_RQST_ADDR_ANY);
+			if (req_addr == VMBUS_RQST_ERROR) {
+				unlock_requestor(chan, flags);
+				dev_err(&hbus->hdev->device,
+					"Invalid transaction ID %llx\n",
+					req_id);
+				break;
+			}
+			comp_packet = (struct pci_packet *)req_addr;
+			response = (struct pci_response *)buffer;
 			/*
-			 * The host is trusted, and thus it's safe to interpret
-			 * this transaction ID as a pointer.
+			 * Call ->completion_func() within the critical section to make
+			 * sure that the packet pointer is still valid during the call:
+			 * here 'valid' means that there's a task still waiting for the
+			 * completion, and that the packet data is still on the waiting
+			 * task's stack.  Cf. hv_compose_msi_msg().
 			 */
-			comp_packet = (struct pci_packet *)req_id;
-			response = (struct pci_response *)buffer;
 			comp_packet->completion_func(comp_packet->compl_ctxt,
 						     response,
 						     bytes_recvd);
+			unlock_requestor(chan, flags);
 			break;
 
 		case VM_PKT_DATA_INBAND:
@@ -2764,7 +2851,8 @@ static void hv_pci_onchannelcallback(void *context)
 			case PCI_BUS_RELATIONS:
 
 				bus_rel = (struct pci_bus_relations *)buffer;
-				if (bytes_recvd <
+				if (bytes_recvd < sizeof(*bus_rel) ||
+				    bytes_recvd <
 					struct_size(bus_rel, func,
 						    bus_rel->device_count)) {
 					dev_err(&hbus->hdev->device,
@@ -2778,7 +2866,8 @@ static void hv_pci_onchannelcallback(void *context)
 			case PCI_BUS_RELATIONS2:
 
 				bus_rel2 = (struct pci_bus_relations2 *)buffer;
-				if (bytes_recvd <
+				if (bytes_recvd < sizeof(*bus_rel2) ||
+				    bytes_recvd <
 					struct_size(bus_rel2, func,
 						    bus_rel2->device_count)) {
 					dev_err(&hbus->hdev->device,
@@ -2792,6 +2881,11 @@ static void hv_pci_onchannelcallback(void *context)
 			case PCI_EJECT:
 
 				dev_message = (struct pci_dev_incoming *)buffer;
+				if (bytes_recvd < sizeof(*dev_message)) {
+					dev_err(&hbus->hdev->device,
+						"eject message too small\n");
+					break;
+				}
 				hpdev = get_pcichild_wslot(hbus,
 						      dev_message->wslot.slot);
 				if (hpdev) {
@@ -2803,6 +2897,11 @@ static void hv_pci_onchannelcallback(void *context)
 			case PCI_INVALIDATE_BLOCK:
 
 				inval = (struct pci_dev_inval_block *)buffer;
+				if (bytes_recvd < sizeof(*inval)) {
+					dev_err(&hbus->hdev->device,
+						"invalidate message too small\n");
+					break;
+				}
 				hpdev = get_pcichild_wslot(hbus,
 							   inval->wslot.slot);
 				if (hpdev) {
@@ -3431,6 +3530,10 @@ static int hv_pci_probe(struct hv_device *hdev,
 		goto free_dom;
 	}
 
+	hdev->channel->next_request_id_callback = vmbus_next_request_id;
+	hdev->channel->request_addr_callback = vmbus_request_addr;
+	hdev->channel->rqstor_size = HV_PCI_RQSTOR_SIZE;
+
 	ret = vmbus_open(hdev->channel, pci_ring_size, pci_ring_size, NULL, 0,
 			 hv_pci_onchannelcallback, hbus);
 	if (ret)
@@ -3561,6 +3664,7 @@ free_bus:
 static int hv_pci_bus_exit(struct hv_device *hdev, bool keep_devs)
 {
 	struct hv_pcibus_device *hbus = hv_get_drvdata(hdev);
+	struct vmbus_channel *chan = hdev->channel;
 	struct {
 		struct pci_packet teardown_packet;
 		u8 buffer[sizeof(struct pci_message)];
@@ -3568,13 +3672,14 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool keep_devs)
 	struct hv_pci_compl comp_pkt;
 	struct hv_pci_dev *hpdev, *tmp;
 	unsigned long flags;
+	u64 trans_id;
 	int ret;
 
 	/*
 	 * After the host sends the RESCIND_CHANNEL message, it doesn't
 	 * access the per-channel ringbuffer any longer.
 	 */
-	if (hdev->channel->rescind)
+	if (chan->rescind)
 		return 0;
 
 	if (!keep_devs) {
@@ -3611,16 +3716,26 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool keep_devs)
 	pkt.teardown_packet.compl_ctxt = &comp_pkt;
 	pkt.teardown_packet.message[0].type = PCI_BUS_D0EXIT;
 
-	ret = vmbus_sendpacket(hdev->channel, &pkt.teardown_packet.message,
-			       sizeof(struct pci_message),
-			       (unsigned long)&pkt.teardown_packet,
-			       VM_PKT_DATA_INBAND,
-			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+	ret = vmbus_sendpacket_getid(chan, &pkt.teardown_packet.message,
+				     sizeof(struct pci_message),
+				     (unsigned long)&pkt.teardown_packet,
+				     &trans_id, VM_PKT_DATA_INBAND,
+				     VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 	if (ret)
 		return ret;
 
-	if (wait_for_completion_timeout(&comp_pkt.host_event, 10 * HZ) == 0)
+	if (wait_for_completion_timeout(&comp_pkt.host_event, 10 * HZ) == 0) {
+		/*
+		 * The completion packet on the stack becomes invalid after
+		 * 'return'; remove the ID from the VMbus requestor if the
+		 * identifier is still mapped to/associated with the packet.
+		 *
+		 * Cf. hv_pci_onchannelcallback().
+		 */
+		vmbus_request_addr_match(chan, trans_id,
+					 (unsigned long)&pkt.teardown_packet);
 		return -ETIMEDOUT;
+	}
 
 	return 0;
 }
@@ -3761,6 +3876,10 @@ static int hv_pci_resume(struct hv_device *hdev)
 
 	hbus->state = hv_pcibus_init;
 
+	hdev->channel->next_request_id_callback = vmbus_next_request_id;
+	hdev->channel->request_addr_callback = vmbus_request_addr;
+	hdev->channel->rqstor_size = HV_PCI_RQSTOR_SIZE;
+
 	ret = vmbus_open(hdev->channel, pci_ring_size, pci_ring_size, NULL, 0,
 			 hv_pci_onchannelcallback, hbus);
 	if (ret)