[PATCH v4 4/5] vhost_user: Function defs for add/rem mem regions

[Pravin M Bathija]

These changes cover the function definition for add/remove memory
region calls which are invoked on receiving vhost user message from
vhost user front-end (e.g. Qemu). In our case, in addition to testing
with qemu front-end, the testing has also been performed with libblkio
front-end and spdk/dpdk back-end. We did I/O using libblkio based device
driver, to spdk based drives. There are also changes for set_mem_table
and new definition for get memory slots. Our changes optimize the set
memory table call to use common support functions. Message get memory
slots is how the vhost-user front-end queries the vhost-user back-end
about the number of memory slots available to be registered by the
back-end. In addition support function to invalidate vring is also
defined which is used in add/remove memory region functions.

Signed-off-by: Pravin M Bathija <pravin.bathija at dell.com>
---
 lib/vhost/vhost_user.c | 249 +++++++++++++++++++++++++++++++++++------
 1 file changed, 217 insertions(+), 32 deletions(-)

diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index 7dc21fe42a..d9cf967ba2 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -71,6 +71,9 @@ VHOST_MESSAGE_HANDLER(VHOST_USER_SET_FEATURES, vhost_user_set_features, false, t
 VHOST_MESSAGE_HANDLER(VHOST_USER_SET_OWNER, vhost_user_set_owner, false, true) \
 VHOST_MESSAGE_HANDLER(VHOST_USER_RESET_OWNER, vhost_user_reset_owner, false, false) \
 VHOST_MESSAGE_HANDLER(VHOST_USER_SET_MEM_TABLE, vhost_user_set_mem_table, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_MAX_MEM_SLOTS, vhost_user_get_max_mem_slots, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_ADD_MEM_REG, vhost_user_add_mem_reg, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_REM_MEM_REG, vhost_user_rem_mem_reg, false, true) \
 VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_BASE, vhost_user_set_log_base, true, true) \
 VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_FD, vhost_user_set_log_fd, true, true) \
 VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_NUM, vhost_user_set_vring_num, false, true) \
@@ -1520,7 +1523,6 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
 	struct virtio_net *dev = *pdev;
 	struct VhostUserMemory *memory = &ctx->msg.payload.memory;
 	struct rte_vhost_mem_region *reg;
-	int numa_node = SOCKET_ID_ANY;
 	uint64_t mmap_offset;
 	uint32_t i;
 	bool async_notify = false;
@@ -1565,39 +1567,13 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
 		if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 			vhost_user_iotlb_flush_all(dev);
 
-		free_mem_region(dev);
+		free_all_mem_regions(dev);
 		rte_free(dev->mem);
 		dev->mem = NULL;
 	}
 
-	/*
-	 * If VQ 0 has already been allocated, try to allocate on the same
-	 * NUMA node. It can be reallocated later in numa_realloc().
-	 */
-	if (dev->nr_vring > 0)
-		numa_node = dev->virtqueue[0]->numa_node;
-
-	dev->nr_guest_pages = 0;
-	if (dev->guest_pages == NULL) {
-		dev->max_guest_pages = 8;
-		dev->guest_pages = rte_zmalloc_socket(NULL,
-					dev->max_guest_pages *
-					sizeof(struct guest_page),
-					RTE_CACHE_LINE_SIZE,
-					numa_node);
-		if (dev->guest_pages == NULL) {
-			VHOST_CONFIG_LOG(dev->ifname, ERR,
-				"failed to allocate memory for dev->guest_pages");
-			goto close_msg_fds;
-		}
-	}
-
-	dev->mem = rte_zmalloc_socket("vhost-mem-table", sizeof(struct rte_vhost_memory) +
-		sizeof(struct rte_vhost_mem_region) * memory->nregions, 0, numa_node);
-	if (dev->mem == NULL) {
-		VHOST_CONFIG_LOG(dev->ifname, ERR, "failed to allocate memory for dev->mem");
-		goto free_guest_pages;
-	}
+	if (vhost_user_initialize_memory(pdev) < 0)
+		goto close_msg_fds;
 
 	for (i = 0; i < memory->nregions; i++) {
 		reg = &dev->mem->regions[i];
@@ -1661,11 +1637,182 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
 	return RTE_VHOST_MSG_RESULT_OK;
 
 free_mem_table:
-	free_mem_region(dev);
+	free_all_mem_regions(dev);
 	rte_free(dev->mem);
 	dev->mem = NULL;
+	rte_free(dev->guest_pages);
+	dev->guest_pages = NULL;
+close_msg_fds:
+	close_msg_fds(ctx);
+	return RTE_VHOST_MSG_RESULT_ERR;
+}
+
 
-free_guest_pages:
+static int
+vhost_user_get_max_mem_slots(struct virtio_net **pdev __rte_unused,
+			struct vhu_msg_context *ctx,
+			int main_fd __rte_unused)
+{
+	uint32_t max_mem_slots = VHOST_MEMORY_MAX_NREGIONS;
+
+	ctx->msg.payload.u64 = (uint64_t)max_mem_slots;
+	ctx->msg.size = sizeof(ctx->msg.payload.u64);
+	ctx->fd_num = 0;
+
+	return RTE_VHOST_MSG_RESULT_REPLY;
+}
+
+static void
+dev_invalidate_vrings(struct virtio_net *dev)
+{
+	uint32_t i;
+
+	for (i = 0; i < dev->nr_vring; i++) {
+		struct vhost_virtqueue *vq = dev->virtqueue[i];
+
+		if (!vq)
+			continue;
+
+		if (vq->desc || vq->avail || vq->used) {
+			/* vhost_user_lock_all_queue_pairs locked all qps */
+			VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_ADD_MEM_REG);
+
+			/*
+			 * If the memory table got updated, the ring addresses
+			 * need to be translated again as virtual addresses have
+			 * changed.
+			 */
+			vring_invalidate(dev, vq);
+
+			translate_ring_addresses(&dev, &vq);
+		}
+	}
+}
+
+static int
+vhost_user_add_mem_reg(struct virtio_net **pdev,
+			struct vhu_msg_context *ctx,
+			int main_fd __rte_unused)
+{
+	uint32_t i;
+	struct virtio_net *dev = *pdev;
+	struct VhostUserMemoryRegion *region = &ctx->msg.payload.memory_single.region;
+
+	/* convert first region add to normal memory table set */
+	if (dev->mem == NULL) {
+		if (vhost_user_initialize_memory(pdev) < 0)
+			goto close_msg_fds;
+	}
+
+	/* make sure new region will fit */
+	if (dev->mem->nregions >= VHOST_MEMORY_MAX_NREGIONS) {
+		VHOST_CONFIG_LOG(dev->ifname, ERR, "too many memory regions already (%u)",
+									dev->mem->nregions);
+		goto close_msg_fds;
+	}
+
+	/* make sure supplied memory fd present */
+	if (ctx->fd_num != 1) {
+		VHOST_CONFIG_LOG(dev->ifname, ERR, "fd count makes no sense (%u)", ctx->fd_num);
+		goto close_msg_fds;
+	}
+
+	/* Make sure no overlap in guest virtual address space */
+	if (dev->mem != NULL && dev->mem->nregions > 0)	{
+		for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) {
+			struct rte_vhost_mem_region *current_region = &dev->mem->regions[i];
+
+			if (current_region->mmap_size == 0)
+				continue;
+
+			uint64_t current_region_guest_start = current_region->guest_user_addr;
+			uint64_t current_region_guest_end = current_region_guest_start
+								+ current_region->mmap_size - 1;
+			uint64_t proposed_region_guest_start = region->userspace_addr;
+			uint64_t proposed_region_guest_end = proposed_region_guest_start
+								+ region->memory_size - 1;
+			bool overlap = false;
+
+			bool curent_region_guest_start_overlap =
+				current_region_guest_start >= proposed_region_guest_start &&
+				current_region_guest_start <= proposed_region_guest_end;
+			bool curent_region_guest_end_overlap =
+				current_region_guest_end >= proposed_region_guest_start &&
+				current_region_guest_end <= proposed_region_guest_end;
+			bool proposed_region_guest_start_overlap =
+				proposed_region_guest_start >= current_region_guest_start &&
+				proposed_region_guest_start <= current_region_guest_end;
+			bool proposed_region_guest_end_overlap =
+				proposed_region_guest_end >= current_region_guest_start &&
+				proposed_region_guest_end <= current_region_guest_end;
+
+			overlap = curent_region_guest_start_overlap
+				|| curent_region_guest_end_overlap
+				|| proposed_region_guest_start_overlap
+				|| proposed_region_guest_end_overlap;
+
+			if (overlap) {
+				VHOST_CONFIG_LOG(dev->ifname, ERR,
+					"requested memory region overlaps with another region");
+				VHOST_CONFIG_LOG(dev->ifname, ERR,
+					"\tRequested region address:0x%" PRIx64,
+					region->userspace_addr);
+				VHOST_CONFIG_LOG(dev->ifname, ERR,
+					"\tRequested region size:0x%" PRIx64,
+					region->memory_size);
+				VHOST_CONFIG_LOG(dev->ifname, ERR,
+					"\tOverlapping region address:0x%" PRIx64,
+					current_region->guest_user_addr);
+				VHOST_CONFIG_LOG(dev->ifname, ERR,
+					"\tOverlapping region size:0x%" PRIx64,
+					current_region->mmap_size);
+				goto close_msg_fds;
+			}
+
+		}
+	}
+
+	/* find a new region and set it like memory table set does */
+	struct rte_vhost_mem_region *reg = NULL;
+
+	for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) {
+		if (dev->mem->regions[i].guest_user_addr == 0) {
+			reg = &dev->mem->regions[i];
+			break;
+		}
+	}
+	if (reg == NULL) {
+		VHOST_CONFIG_LOG(dev->ifname, ERR, "no free memory region");
+		goto close_msg_fds;
+	}
+
+	reg->guest_phys_addr = region->guest_phys_addr;
+	reg->guest_user_addr = region->userspace_addr;
+	reg->size            = region->memory_size;
+	reg->fd              = ctx->fds[0];
+
+	if (vhost_user_mmap_region(dev, reg, region->mmap_offset) < 0) {
+		VHOST_CONFIG_LOG(dev->ifname, ERR, "failed to mmap region");
+		goto close_msg_fds;
+	}
+
+	dev->mem->nregions++;
+
+	if (dev->async_copy && rte_vfio_is_enabled("vfio"))
+		async_dma_map_region(dev, reg, true);
+
+	if (vhost_user_postcopy_register(dev, main_fd, ctx) < 0)
+		goto free_mem_table;
+
+	dev_invalidate_vrings(dev);
+	dump_guest_pages(dev);
+
+	return RTE_VHOST_MSG_RESULT_OK;
+
+free_mem_table:
+	free_all_mem_regions(dev);
+	rte_free(dev->mem);
+	dev->mem = NULL;
 	rte_free(dev->guest_pages);
 	dev->guest_pages = NULL;
 close_msg_fds:
@@ -1673,6 +1820,44 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
 	return RTE_VHOST_MSG_RESULT_ERR;
 }
 
+static int
+vhost_user_rem_mem_reg(struct virtio_net **pdev __rte_unused,
+			struct vhu_msg_context *ctx __rte_unused,
+			int main_fd __rte_unused)
+{
+	uint32_t i;
+	struct virtio_net *dev = *pdev;
+	struct VhostUserMemoryRegion *region = &ctx->msg.payload.memory_single.region;
+
+	if (dev->mem != NULL && dev->mem->nregions > 0) {
+		for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) {
+			struct rte_vhost_mem_region *current_region = &dev->mem->regions[i];
+
+			if (current_region->guest_user_addr == 0)
+				continue;
+
+			/*
+			 * According to the vhost-user specification:
+			 * The memory region to be removed is identified by its guest address,
+			 * user address and size. The mmap offset is ignored.
+			 */
+			if (region->userspace_addr == current_region->guest_user_addr
+				&& region->guest_phys_addr == current_region->guest_phys_addr
+				&& region->memory_size == current_region->size) {
+				if (dev->async_copy && rte_vfio_is_enabled("vfio"))
+					async_dma_map_region(dev, current_region, false);
+				dev_invalidate_vrings(dev);
+				free_mem_region(current_region);
+				dev->mem->nregions--;
+				return RTE_VHOST_MSG_RESULT_OK;
+			}
+		}
+	}
+
+	VHOST_CONFIG_LOG(dev->ifname, ERR, "failed to find region");
+	return RTE_VHOST_MSG_RESULT_ERR;
+}
+
 static bool
 vq_is_ready(struct virtio_net *dev, struct vhost_virtqueue *vq)
 {
-- 
2.43.0