Merge tag 'hyperv-next-signed-20210629' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv updates from Wei Liu:
 "Just a few minor enhancement patches and bug fixes"

* tag 'hyperv-next-signed-20210629' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  PCI: hv: Add check for hyperv_initialized in init_hv_pci_drv()
  Drivers: hv: Move Hyper-V extended capability check to arch neutral code
  drivers: hv: Fix missing error code in vmbus_connect()
  x86/hyperv: fix logical processor creation
  hv_utils: Fix passing zero to 'PTR_ERR' warning
  scsi: storvsc: Use blk_mq_unique_tag() to generate requestIDs
  Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer
  hv_balloon: Remove redundant assignment to region_start

10 files changed, 168 insertions, 32 deletions

diff --git a/drivers/hv/Makefile b/drivers/hv/Makefile
index 94daf8240c95..d76df5c8c2a9 100644
--- a/drivers/hv/Makefile
+++ b/drivers/hv/Makefile
@@ -11,3 +11,6 @@ hv_vmbus-y := vmbus_drv.o \
 		 channel_mgmt.o ring_buffer.o hv_trace.o
 hv_vmbus-$(CONFIG_HYPERV_TESTING)	+= hv_debugfs.o
 hv_utils-y := hv_util.o hv_kvp.o hv_snapshot.o hv_fcopy.o hv_utils_transport.o
+
+# Code that must be built-in
+obj-$(subst m,y,$(CONFIG_HYPERV)) += hv_common.o
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index c2635e913a92..f3761c73b074 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -662,12 +662,15 @@ static int __vmbus_open(struct vmbus_channel *newchannel,
 	newchannel->onchannel_callback = onchannelcallback;
 	newchannel->channel_callback_context = context;
 
-	err = hv_ringbuffer_init(&newchannel->outbound, page, send_pages);
+	if (!newchannel->max_pkt_size)
+		newchannel->max_pkt_size = VMBUS_DEFAULT_MAX_PKT_SIZE;
+
+	err = hv_ringbuffer_init(&newchannel->outbound, page, send_pages, 0);
 	if (err)
 		goto error_clean_ring;
 
-	err = hv_ringbuffer_init(&newchannel->inbound,
-				 &page[send_pages], recv_pages);
+	err = hv_ringbuffer_init(&newchannel->inbound, &page[send_pages],
+				 recv_pages, newchannel->max_pkt_size);
 	if (err)
 		goto error_clean_ring;
 
@@ -1186,15 +1189,14 @@ EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);
  * vmbus_next_request_id - Returns a new request id. It is also
  * the index at which the guest memory address is stored.
  * Uses a spin lock to avoid race conditions.
- * @rqstor: Pointer to the requestor struct
+ * @channel: Pointer to the VMbus channel struct
  * @rqst_add: Guest memory address to be stored in the array
  */
-u64 vmbus_next_request_id(struct vmbus_requestor *rqstor, u64 rqst_addr)
+u64 vmbus_next_request_id(struct vmbus_channel *channel, u64 rqst_addr)
 {
+	struct vmbus_requestor *rqstor = &channel->requestor;
 	unsigned long flags;
 	u64 current_id;
-	const struct vmbus_channel *channel =
-		container_of(rqstor, const struct vmbus_channel, requestor);
 
 	/* Check rqstor has been initialized */
 	if (!channel->rqstor_size)
@@ -1228,16 +1230,15 @@ EXPORT_SYMBOL_GPL(vmbus_next_request_id);
 /*
  * vmbus_request_addr - Returns the memory address stored at @trans_id
  * in @rqstor. Uses a spin lock to avoid race conditions.
- * @rqstor: Pointer to the requestor struct
+ * @channel: Pointer to the VMbus channel struct
  * @trans_id: Request id sent back from Hyper-V. Becomes the requestor's
  * next request id.
  */
-u64 vmbus_request_addr(struct vmbus_requestor *rqstor, u64 trans_id)
+u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id)
 {
+	struct vmbus_requestor *rqstor = &channel->requestor;
 	unsigned long flags;
 	u64 req_addr;
-	const struct vmbus_channel *channel =
-		container_of(rqstor, const struct vmbus_channel, requestor);
 
 	/* Check rqstor has been initialized */
 	if (!channel->rqstor_size)
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 311cd005b3be..5e479d54918c 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -232,8 +232,10 @@ int vmbus_connect(void)
 	 */
 
 	for (i = 0; ; i++) {
-		if (i == ARRAY_SIZE(vmbus_versions))
+		if (i == ARRAY_SIZE(vmbus_versions)) {
+			ret = -EDOM;
 			goto cleanup;
+		}
 
 		version = vmbus_versions[i];
 		if (version > max_version)
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index 58af84e30144..7f11ea07d698 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -1010,7 +1010,6 @@ static void hot_add_req(struct work_struct *dummy)
 		 * that need to be hot-added while ensuring the alignment
 		 * and size requirements of Linux as it relates to hot-add.
 		 */
-		region_start = pg_start;
 		region_size = (pfn_cnt / HA_CHUNK) * HA_CHUNK;
 		if (pfn_cnt % HA_CHUNK)
 			region_size += HA_CHUNK;
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
new file mode 100644
index 000000000000..7f42da98d377
--- /dev/null
+++ b/drivers/hv/hv_common.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Architecture neutral utility routines for interacting with
+ * Hyper-V. This file is specifically for code that must be
+ * built-in to the kernel image when CONFIG_HYPERV is set
+ * (vs. being in a module) because it is called from architecture
+ * specific code under arch/.
+ *
+ * Copyright (C) 2021, Microsoft, Inc.
+ *
+ * Author : Michael Kelley <mikelley@microsoft.com>
+ */
+
+#include <linux/types.h>
+#include <linux/export.h>
+#include <linux/bitfield.h>
+#include <asm/hyperv-tlfs.h>
+#include <asm/mshyperv.h>
+
+
+/* Bit mask of the extended capability to query: see HV_EXT_CAPABILITY_xxx */
+bool hv_query_ext_cap(u64 cap_query)
+{
+	/*
+	 * The address of the 'hv_extended_cap' variable will be used as an
+	 * output parameter to the hypercall below and so it should be
+	 * compatible with 'virt_to_phys'. Which means, it's address should be
+	 * directly mapped. Use 'static' to keep it compatible; stack variables
+	 * can be virtually mapped, making them incompatible with
+	 * 'virt_to_phys'.
+	 * Hypercall input/output addresses should also be 8-byte aligned.
+	 */
+	static u64 hv_extended_cap __aligned(8);
+	static bool hv_extended_cap_queried;
+	u64 status;
+
+	/*
+	 * Querying extended capabilities is an extended hypercall. Check if the
+	 * partition supports extended hypercall, first.
+	 */
+	if (!(ms_hyperv.priv_high & HV_ENABLE_EXTENDED_HYPERCALLS))
+		return false;
+
+	/* Extended capabilities do not change at runtime. */
+	if (hv_extended_cap_queried)
+		return hv_extended_cap & cap_query;
+
+	status = hv_do_hypercall(HV_EXT_CALL_QUERY_CAPABILITIES, NULL,
+				 &hv_extended_cap);
+
+	/*
+	 * The query extended capabilities hypercall should not fail under
+	 * any normal circumstances. Avoid repeatedly making the hypercall, on
+	 * error.
+	 */
+	hv_extended_cap_queried = true;
+	if (!hv_result_success(status)) {
+		pr_err("Hyper-V: Extended query capabilities hypercall failed 0x%llx\n",
+		       status);
+		return false;
+	}
+
+	return hv_extended_cap & cap_query;
+}
+EXPORT_SYMBOL_GPL(hv_query_ext_cap);
diff --git a/drivers/hv/hv_fcopy.c b/drivers/hv/hv_fcopy.c
index 59ce85e00a02..660036da7449 100644
--- a/drivers/hv/hv_fcopy.c
+++ b/drivers/hv/hv_fcopy.c
@@ -349,6 +349,7 @@ int hv_fcopy_init(struct hv_util_service *srv)
 {
 	recv_buffer = srv->recv_buffer;
 	fcopy_transaction.recv_channel = srv->channel;
+	fcopy_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2;
 
 	/*
 	 * When this driver loads, the user level daemon that
diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
index b49962d312ce..c698592b83e4 100644
--- a/drivers/hv/hv_kvp.c
+++ b/drivers/hv/hv_kvp.c
@@ -757,6 +757,7 @@ hv_kvp_init(struct hv_util_service *srv)
 {
 	recv_buffer = srv->recv_buffer;
 	kvp_transaction.recv_channel = srv->channel;
+	kvp_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 4;
 
 	/*
 	 * When this driver loads, the user level daemon that
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index e4aefeb330da..136576cba26f 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -750,8 +750,8 @@ static int hv_timesync_init(struct hv_util_service *srv)
 	 */
 	hv_ptp_clock = ptp_clock_register(&ptp_hyperv_info, NULL);
 	if (IS_ERR_OR_NULL(hv_ptp_clock)) {
-		pr_err("cannot register PTP clock: %ld\n",
-		       PTR_ERR(hv_ptp_clock));
+		pr_err("cannot register PTP clock: %d\n",
+		       PTR_ERR_OR_ZERO(hv_ptp_clock));
 		hv_ptp_clock = NULL;
 	}
 
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 9416e09ebd58..42f3d9d123a1 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -174,7 +174,7 @@ extern int hv_synic_cleanup(unsigned int cpu);
 void hv_ringbuffer_pre_init(struct vmbus_channel *channel);
 
 int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
-		       struct page *pages, u32 pagecnt);
+		       struct page *pages, u32 pagecnt, u32 max_pkt_size);
 
 void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info);
 
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 374f8afbf8a5..2aee356840a2 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -181,7 +181,7 @@ void hv_ringbuffer_pre_init(struct vmbus_channel *channel)
 
 /* Initialize the ring buffer. */
 int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
-		       struct page *pages, u32 page_cnt)
+		       struct page *pages, u32 page_cnt, u32 max_pkt_size)
 {
 	int i;
 	struct page **pages_wraparound;
@@ -223,6 +223,14 @@ int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
 		sizeof(struct hv_ring_buffer);
 	ring_info->priv_read_index = 0;
 
+	/* Initialize buffer that holds copies of incoming packets */
+	if (max_pkt_size) {
+		ring_info->pkt_buffer = kzalloc(max_pkt_size, GFP_KERNEL);
+		if (!ring_info->pkt_buffer)
+			return -ENOMEM;
+		ring_info->pkt_buffer_size = max_pkt_size;
+	}
+
 	spin_lock_init(&ring_info->ring_lock);
 
 	return 0;
@@ -235,6 +243,9 @@ void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info)
 	vunmap(ring_info->ring_buffer);
 	ring_info->ring_buffer = NULL;
 	mutex_unlock(&ring_info->ring_buffer_mutex);
+
+	kfree(ring_info->pkt_buffer);
+	ring_info->pkt_buffer_size = 0;
 }
 
 /* Write to the ring buffer. */
@@ -301,10 +312,12 @@ int hv_ringbuffer_write(struct vmbus_channel *channel,
 	 */
 
 	if (desc->flags == VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED) {
-		rqst_id = vmbus_next_request_id(&channel->requestor, requestid);
-		if (rqst_id == VMBUS_RQST_ERROR) {
-			spin_unlock_irqrestore(&outring_info->ring_lock, flags);
-			return -EAGAIN;
+		if (channel->next_request_id_callback != NULL) {
+			rqst_id = channel->next_request_id_callback(channel, requestid);
+			if (rqst_id == VMBUS_RQST_ERROR) {
+				spin_unlock_irqrestore(&outring_info->ring_lock, flags);
+				return -EAGAIN;
+			}
 		}
 	}
 	desc = hv_get_ring_buffer(outring_info) + old_write;
@@ -332,7 +345,8 @@ int hv_ringbuffer_write(struct vmbus_channel *channel,
 	if (channel->rescind) {
 		if (rqst_id != VMBUS_NO_RQSTOR) {
 			/* Reclaim request ID to avoid leak of IDs */
-			vmbus_request_addr(&channel->requestor, rqst_id);
+			if (channel->request_addr_callback != NULL)
+				channel->request_addr_callback(channel, rqst_id);
 		}
 		return -ENODEV;
 	}
@@ -375,7 +389,7 @@ int hv_ringbuffer_read(struct vmbus_channel *channel,
 	memcpy(buffer, (const char *)desc + offset, packetlen);
 
 	/* Advance ring index to next packet descriptor */
-	__hv_pkt_iter_next(channel, desc);
+	__hv_pkt_iter_next(channel, desc, true);
 
 	/* Notify host of update */
 	hv_pkt_iter_close(channel);
@@ -402,6 +416,22 @@ static u32 hv_pkt_iter_avail(const struct hv_ring_buffer_info *rbi)
 }
 
 /*
+ * Get first vmbus packet without copying it out of the ring buffer
+ */
+struct vmpacket_descriptor *hv_pkt_iter_first_raw(struct vmbus_channel *channel)
+{
+	struct hv_ring_buffer_info *rbi = &channel->inbound;
+
+	hv_debug_delay_test(channel, MESSAGE_DELAY);
+
+	if (hv_pkt_iter_avail(rbi) < sizeof(struct vmpacket_descriptor))
+		return NULL;
+
+	return (struct vmpacket_descriptor *)(hv_get_ring_buffer(rbi) + rbi->priv_read_index);
+}
+EXPORT_SYMBOL_GPL(hv_pkt_iter_first_raw);
+
+/*
  * Get first vmbus packet from ring buffer after read_index
  *
  * If ring buffer is empty, returns NULL and no other action needed.
@@ -409,17 +439,49 @@ static u32 hv_pkt_iter_avail(const struct hv_ring_buffer_info *rbi)
 struct vmpacket_descriptor *hv_pkt_iter_first(struct vmbus_channel *channel)
 {
 	struct hv_ring_buffer_info *rbi = &channel->inbound;
-	struct vmpacket_descriptor *desc;
+	struct vmpacket_descriptor *desc, *desc_copy;
+	u32 bytes_avail, pkt_len, pkt_offset;
 
-	hv_debug_delay_test(channel, MESSAGE_DELAY);
-	if (hv_pkt_iter_avail(rbi) < sizeof(struct vmpacket_descriptor))
+	desc = hv_pkt_iter_first_raw(channel);
+	if (!desc)
 		return NULL;
 
-	desc = hv_get_ring_buffer(rbi) + rbi->priv_read_index;
-	if (desc)
-		prefetch((char *)desc + (desc->len8 << 3));
+	bytes_avail = min(rbi->pkt_buffer_size, hv_pkt_iter_avail(rbi));
+
+	/*
+	 * Ensure the compiler does not use references to incoming Hyper-V values (which
+	 * could change at any moment) when reading local variables later in the code
+	 */
+	pkt_len = READ_ONCE(desc->len8) << 3;
+	pkt_offset = READ_ONCE(desc->offset8) << 3;
+
+	/*
+	 * If pkt_len is invalid, set it to the smaller of hv_pkt_iter_avail() and
+	 * rbi->pkt_buffer_size
+	 */
+	if (pkt_len < sizeof(struct vmpacket_descriptor) || pkt_len > bytes_avail)
+		pkt_len = bytes_avail;
+
+	/*
+	 * If pkt_offset is invalid, arbitrarily set it to
+	 * the size of vmpacket_descriptor
+	 */
+	if (pkt_offset < sizeof(struct vmpacket_descriptor) || pkt_offset > pkt_len)
+		pkt_offset = sizeof(struct vmpacket_descriptor);
+
+	/* Copy the Hyper-V packet out of the ring buffer */
+	desc_copy = (struct vmpacket_descriptor *)rbi->pkt_buffer;
+	memcpy(desc_copy, desc, pkt_len);
+
+	/*
+	 * Hyper-V could still change len8 and offset8 after the earlier read.
+	 * Ensure that desc_copy has legal values for len8 and offset8 that
+	 * are consistent with the copy we just made
+	 */
+	desc_copy->len8 = pkt_len >> 3;
+	desc_copy->offset8 = pkt_offset >> 3;
 
-	return desc;
+	return desc_copy;
 }
 EXPORT_SYMBOL_GPL(hv_pkt_iter_first);
 
@@ -431,7 +493,8 @@ EXPORT_SYMBOL_GPL(hv_pkt_iter_first);
  */
 struct vmpacket_descriptor *
 __hv_pkt_iter_next(struct vmbus_channel *channel,
-		   const struct vmpacket_descriptor *desc)
+		   const struct vmpacket_descriptor *desc,
+		   bool copy)
 {
 	struct hv_ring_buffer_info *rbi = &channel->inbound;
 	u32 packetlen = desc->len8 << 3;
@@ -444,7 +507,7 @@ __hv_pkt_iter_next(struct vmbus_channel *channel,
 		rbi->priv_read_index -= dsize;
 
 	/* more data? */
-	return hv_pkt_iter_first(channel);
+	return copy ? hv_pkt_iter_first(channel) : hv_pkt_iter_first_raw(channel);
 }
 EXPORT_SYMBOL_GPL(__hv_pkt_iter_next);