When choosing IOVA as PA mode, IOVA is likely to be discontinuous,
which requires page by page mapping for DMA devices. To be consistent,
this patch implements page by page mapping instead of mapping at the
region granularity for both IOVA as VA and PA mode.

Fixes: 7c61fa08b716 ("vhost: enable IOMMU for async vhost")

Signed-off-by: Xuan Ding <xuan.d...@intel.com>
---
v4:
* Remove unnessary ENOSUP check.
* Adjust return type.

v3:
* Fix commit title.

v2:
* Fix a format issue.
---
 lib/vhost/vhost.h      |   1 +
 lib/vhost/vhost_user.c | 111 ++++++++++++++++++++---------------------
 2 files changed, 54 insertions(+), 58 deletions(-)

diff --git a/lib/vhost/vhost.h b/lib/vhost/vhost.h
index 7085e0885c..d246538ca5 100644
--- a/lib/vhost/vhost.h
+++ b/lib/vhost/vhost.h
@@ -355,6 +355,7 @@ struct vring_packed_desc_event {
 struct guest_page {
        uint64_t guest_phys_addr;
        uint64_t host_phys_addr;
+       uint64_t host_user_addr;
        uint64_t size;
 };
 
diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index a781346c4d..0a9dc3350f 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -143,57 +143,56 @@ get_blk_size(int fd)
        return ret == -1 ? (uint64_t)-1 : (uint64_t)stat.st_blksize;
 }
 
-static int
-async_dma_map(struct rte_vhost_mem_region *region, bool do_map)
+static void
+async_dma_map(struct virtio_net *dev, bool do_map)
 {
-       uint64_t host_iova;
        int ret = 0;
-
-       host_iova = rte_mem_virt2iova((void 
*)(uintptr_t)region->host_user_addr);
+       uint32_t i;
+       struct guest_page *page;
        if (do_map) {
-               /* Add mapped region into the default container of DPDK. */
-               ret = rte_vfio_container_dma_map(RTE_VFIO_DEFAULT_CONTAINER_FD,
-                                                region->host_user_addr,
-                                                host_iova,
-                                                region->size);
-               if (ret) {
-                       /*
-                        * DMA device may bind with kernel driver, in this case,
-                        * we don't need to program IOMMU manually. However, if 
no
-                        * device is bound with vfio/uio in DPDK, and vfio 
kernel
-                        * module is loaded, the API will still be called and 
return
-                        * with ENODEV/ENOSUP.
-                        *
-                        * DPDK vfio only returns ENODEV/ENOSUP in very similar
-                        * situations(vfio either unsupported, or supported
-                        * but no devices found). Either way, no mappings could 
be
-                        * performed. We treat it as normal case in async path.
-                        */
-                       if (rte_errno == ENODEV || rte_errno == ENOTSUP)
-                               return 0;
-
-                       VHOST_LOG_CONFIG(ERR, "DMA engine map failed\n");
-                       /* DMA mapping errors won't stop 
VHST_USER_SET_MEM_TABLE. */
-                       return 0;
+               for (i = 0; i < dev->nr_guest_pages; i++) {
+                       page = &dev->guest_pages[i];
+                       ret = 
rte_vfio_container_dma_map(RTE_VFIO_DEFAULT_CONTAINER_FD,
+                                                        page->host_user_addr,
+                                                        page->host_phys_addr,
+                                                        page->size);
+                       if (ret) {
+                               /*
+                                * DMA device may bind with kernel driver, in 
this case,
+                                * we don't need to program IOMMU manually. 
However, if no
+                                * device is bound with vfio/uio in DPDK, and 
vfio kernel
+                                * module is loaded, the API will still be 
called and return
+                                * with ENODEV.
+                                *
+                                * DPDK vfio only returns ENODEV in very 
similar situations
+                                * (vfio either unsupported, or supported but 
no devices found).
+                                * Either way, no mappings could be performed. 
We treat it as
+                                * normal case in async path. This is a 
workaround.
+                                */
+                               if (rte_errno == ENODEV)
+                                       return;
+
+                               /* DMA mapping errors won't stop 
VHST_USER_SET_MEM_TABLE. */
+                               VHOST_LOG_CONFIG(ERR, "DMA engine map 
failed\n");
+                       }
                }
 
        } else {
-               /* Remove mapped region from the default container of DPDK. */
-               ret = 
rte_vfio_container_dma_unmap(RTE_VFIO_DEFAULT_CONTAINER_FD,
-                                                  region->host_user_addr,
-                                                  host_iova,
-                                                  region->size);
-               if (ret) {
-                       /* like DMA map, ignore the kernel driver case when 
unmap. */
-                       if (rte_errno == EINVAL)
-                               return 0;
-
-                       VHOST_LOG_CONFIG(ERR, "DMA engine unmap failed\n");
-                       return ret;
+               for (i = 0; i < dev->nr_guest_pages; i++) {
+                       page = &dev->guest_pages[i];
+                       ret = 
rte_vfio_container_dma_unmap(RTE_VFIO_DEFAULT_CONTAINER_FD,
+                                                          page->host_user_addr,
+                                                          page->host_phys_addr,
+                                                          page->size);
+                       if (ret) {
+                               /* like DMA map, ignore the kernel driver case 
when unmap. */
+                               if (rte_errno == EINVAL)
+                                       return;
+
+                               VHOST_LOG_CONFIG(ERR, "DMA engine unmap 
failed\n");
+                       }
                }
        }
-
-       return ret;
 }
 
 static void
@@ -205,12 +204,12 @@ free_mem_region(struct virtio_net *dev)
        if (!dev || !dev->mem)
                return;
 
+       if (dev->async_copy && rte_vfio_is_enabled("vfio"))
+               async_dma_map(dev, false);
+
        for (i = 0; i < dev->mem->nregions; i++) {
                reg = &dev->mem->regions[i];
                if (reg->host_user_addr) {
-                       if (dev->async_copy && rte_vfio_is_enabled("vfio"))
-                               async_dma_map(reg, false);
-
                        munmap(reg->mmap_addr, reg->mmap_size);
                        close(reg->fd);
                }
@@ -978,7 +977,7 @@ vhost_user_set_vring_base(struct virtio_net **pdev,
 
 static int
 add_one_guest_page(struct virtio_net *dev, uint64_t guest_phys_addr,
-                  uint64_t host_phys_addr, uint64_t size)
+                  uint64_t host_phys_addr, uint64_t host_user_addr, uint64_t 
size)
 {
        struct guest_page *page, *last_page;
        struct guest_page *old_pages;
@@ -1009,6 +1008,7 @@ add_one_guest_page(struct virtio_net *dev, uint64_t 
guest_phys_addr,
        page = &dev->guest_pages[dev->nr_guest_pages++];
        page->guest_phys_addr = guest_phys_addr;
        page->host_phys_addr  = host_phys_addr;
+       page->host_user_addr = host_user_addr;
        page->size = size;
 
        return 0;
@@ -1028,7 +1028,8 @@ add_guest_pages(struct virtio_net *dev, struct 
rte_vhost_mem_region *reg,
        size = page_size - (guest_phys_addr & (page_size - 1));
        size = RTE_MIN(size, reg_size);
 
-       if (add_one_guest_page(dev, guest_phys_addr, host_phys_addr, size) < 0)
+       if (add_one_guest_page(dev, guest_phys_addr, host_phys_addr,
+                              host_user_addr, size) < 0)
                return -1;
 
        host_user_addr  += size;
@@ -1040,7 +1041,7 @@ add_guest_pages(struct virtio_net *dev, struct 
rte_vhost_mem_region *reg,
                host_phys_addr = rte_mem_virt2iova((void *)(uintptr_t)
                                                  host_user_addr);
                if (add_one_guest_page(dev, guest_phys_addr, host_phys_addr,
-                               size) < 0)
+                                      host_user_addr, size) < 0)
                        return -1;
 
                host_user_addr  += size;
@@ -1215,7 +1216,6 @@ vhost_user_mmap_region(struct virtio_net *dev,
        uint64_t mmap_size;
        uint64_t alignment;
        int populate;
-       int ret;
 
        /* Check for memory_size + mmap_offset overflow */
        if (mmap_offset >= -region->size) {
@@ -1274,14 +1274,6 @@ vhost_user_mmap_region(struct virtio_net *dev,
                        VHOST_LOG_CONFIG(ERR, "adding guest pages to region 
failed.\n");
                        return -1;
                }
-
-               if (rte_vfio_is_enabled("vfio")) {
-                       ret = async_dma_map(region, true);
-                       if (ret) {
-                               VHOST_LOG_CONFIG(ERR, "Configure IOMMU for DMA 
engine failed\n");
-                               return -1;
-                       }
-               }
        }
 
        VHOST_LOG_CONFIG(INFO,
@@ -1420,6 +1412,9 @@ vhost_user_set_mem_table(struct virtio_net **pdev, struct 
VhostUserMsg *msg,
                dev->mem->nregions++;
        }
 
+       if (dev->async_copy && rte_vfio_is_enabled("vfio"))
+               async_dma_map(dev, true);
+
        if (vhost_user_postcopy_register(dev, main_fd, msg) < 0)
                goto free_mem_table;
 
-- 
2.17.1

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