[PATCH v13 3/5] vhost_user: support function defines for back-end

[<pravin.bathija@dell.com>]

From: Pravin M Bathija <pravin.bathija@dell.com>

Here we define support functions which are called from the various
vhost-user back-end message functions like set memory table, get
memory slots, add memory region, remove memory region.  These are
essentially common functions to unmap a set of memory regions,
perform register copy, align memory addresses and dma map/unmap a
single memory region.

Signed-off-by: Pravin M Bathija <pravin.bathija@dell.com>
---
 lib/vhost/vhost_user.c | 89 ++++++++++++++++++++++++++++--------------
 1 file changed, 60 insertions(+), 29 deletions(-)

diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index 4bfb13fb98..0ee3fe7a5e 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -171,20 +171,27 @@ get_blk_size(int fd)
 	return ret == -1 ? (uint64_t)-1 : (uint64_t)stat.st_blksize;
 }
 
-static void
-async_dma_map(struct virtio_net *dev, bool do_map)
+static int
+async_dma_map_region(struct virtio_net *dev, struct rte_vhost_mem_region *reg, bool do_map)
 {
-	int ret = 0;
 	uint32_t i;
-	struct guest_page *page;
+	int ret;
+	uint64_t reg_start = reg->host_user_addr;
+	uint64_t reg_end = reg_start + reg->size;
+
+	for (i = 0; i < dev->nr_guest_pages; i++) {
+		struct guest_page *page = &dev->guest_pages[i];
+
+		/* Only process pages belonging to this region */
+		if (page->host_user_addr < reg_start ||
+		    page->host_user_addr >= reg_end)
+			continue;
 
-	if (do_map) {
-		for (i = 0; i < dev->nr_guest_pages; i++) {
-			page = &dev->guest_pages[i];
+		if (do_map) {
 			ret = rte_vfio_container_dma_map(RTE_VFIO_DEFAULT_CONTAINER_FD,
-							 page->host_user_addr,
-							 page->host_iova,
-							 page->size);
+					page->host_user_addr,
+					page->host_iova,
+					page->size);
 			if (ret) {
 				/*
 				 * DMA device may bind with kernel driver, in this case,
@@ -199,33 +206,57 @@ async_dma_map(struct virtio_net *dev, bool do_map)
 				 * normal case in async path. This is a workaround.
 				 */
 				if (rte_errno == ENODEV)
-					return;
+					return 0;
 
 				/* DMA mapping errors won't stop VHOST_USER_SET_MEM_TABLE. */
 				VHOST_CONFIG_LOG(dev->ifname, ERR, "DMA engine map failed");
+				return -1;
 			}
-		}
-
-	} else {
-		for (i = 0; i < dev->nr_guest_pages; i++) {
-			page = &dev->guest_pages[i];
+		} else {
 			ret = rte_vfio_container_dma_unmap(RTE_VFIO_DEFAULT_CONTAINER_FD,
-							   page->host_user_addr,
-							   page->host_iova,
-							   page->size);
+					page->host_user_addr,
+					page->host_iova,
+					page->size);
 			if (ret) {
 				/* like DMA map, ignore the kernel driver case when unmap. */
 				if (rte_errno == EINVAL)
-					return;
+					return 0;
 
 				VHOST_CONFIG_LOG(dev->ifname, ERR, "DMA engine unmap failed");
+				return -1;
 			}
 		}
 	}
+
+	return 0;
+}
+
+static void
+async_dma_map(struct virtio_net *dev, bool do_map)
+{
+	uint32_t i;
+	struct rte_vhost_mem_region *reg;
+
+	for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) {
+		reg = &dev->mem->regions[i];
+		if (reg->host_user_addr == 0)
+			continue;
+		async_dma_map_region(dev, reg, do_map);
+	}
 }
 
 static void
-free_mem_region(struct virtio_net *dev)
+free_mem_region(struct rte_vhost_mem_region *reg)
+{
+	if (reg != NULL && reg->mmap_addr) {
+		munmap(reg->mmap_addr, reg->mmap_size);
+		close(reg->fd);
+		memset(reg, 0, sizeof(struct rte_vhost_mem_region));
+	}
+}
+
+static void
+free_all_mem_regions(struct virtio_net *dev)
 {
 	uint32_t i;
 	struct rte_vhost_mem_region *reg;
@@ -236,12 +267,10 @@ free_mem_region(struct virtio_net *dev)
 	if (dev->async_copy && rte_vfio_is_enabled("vfio"))
 		async_dma_map(dev, false);
 
-	for (i = 0; i < dev->mem->nregions; i++) {
+	for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) {
 		reg = &dev->mem->regions[i];
-		if (reg->host_user_addr) {
-			munmap(reg->mmap_addr, reg->mmap_size);
-			close(reg->fd);
-		}
+		if (reg->mmap_addr)
+			free_mem_region(reg);
 	}
 }
 
@@ -255,7 +284,7 @@ vhost_backend_cleanup(struct virtio_net *dev)
 		vdpa_dev->ops->dev_cleanup(dev->vid);
 
 	if (dev->mem) {
-		free_mem_region(dev);
+		free_all_mem_regions(dev);
 		rte_free(dev->mem);
 		dev->mem = NULL;
 	}
@@ -704,7 +733,7 @@ numa_realloc(struct virtio_net **pdev, struct vhost_virtqueue **pvq)
 	vhost_devices[dev->vid] = dev;
 
 	mem_size = sizeof(struct rte_vhost_memory) +
-		sizeof(struct rte_vhost_mem_region) * dev->mem->nregions;
+		sizeof(struct rte_vhost_mem_region) * VHOST_MEMORY_MAX_NREGIONS;
 	mem = rte_realloc_socket(dev->mem, mem_size, 0, node);
 	if (!mem) {
 		VHOST_CONFIG_LOG(dev->ifname, ERR,
@@ -808,8 +837,10 @@ hua_to_alignment(struct rte_vhost_memory *mem, void *ptr)
 	uint32_t i;
 	uintptr_t hua = (uintptr_t)ptr;
 
-	for (i = 0; i < mem->nregions; i++) {
+	for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) {
 		r = &mem->regions[i];
+		if (r->host_user_addr == 0)
+			continue;
 		if (hua >= r->host_user_addr &&
 			hua < r->host_user_addr + r->size) {
 			return get_blk_size(r->fd);
-- 
2.43.0