Use prot flags sent by client to map dma regions (#227)

* Use prot flags sent by client to map dma regions

Signed-off-by: Swapnil Ingle <swapnil.ingle@nutanix.com>
Reviewed-by: Thanos Makatos <thanos.makatos@nutanix.com>

3 files changed, 19 insertions, 8 deletions

diff --git a/lib/dma.c b/lib/dma.c
index 69b3fe5..59d85eb 100644
--- a/lib/dma.c
+++ b/lib/dma.c
@@ -215,7 +215,7 @@ dma_controller_destroy(dma_controller_t *dma)
 int
 dma_controller_add_region(dma_controller_t *dma,
                           dma_addr_t dma_addr, size_t size,
-                          int fd, off_t offset)
+                          int fd, off_t offset, uint32_t prot)
 {
     int idx;
     dma_memory_region_t *region;
@@ -243,7 +243,13 @@ dma_controller_add_region(dma_controller_t *dma,
                  */
                 vfu_log(dma->vfu_ctx, LOG_ERR,
                        "bad fd=%d for new DMA region %#lx-%#lx, existing fd=%d\n",
-                       fd, offset, offset + size, region->fd);
+                       fd, offset, offset + size - 1, region->fd);
+                goto err;
+            }
+            if (region->prot != prot) {
+                vfu_log(dma->vfu_ctx, LOG_ERR, "bad prot=%#x "
+                        "for new DMA region %#lx-%#lx, existing prot=%#x\n",
+                        prot, offset, offset + size - 1, region->prot);
                 goto err;
             }
             return idx;
@@ -284,12 +290,13 @@ dma_controller_add_region(dma_controller_t *dma,
     region->size = size;
     region->page_size = page_size;
     region->offset = offset;
+    region->prot = prot;
     region->fd = fd;
     region->refcnt = 0;
 
     if (fd != -1) {
-        region->virt_addr = dma_map_region(region, PROT_READ | PROT_WRITE,
-                                           0, region->size);
+        region->virt_addr = dma_map_region(region, region->prot, 0,
+                                           region->size);
         if (region->virt_addr == MAP_FAILED) {
             vfu_log(dma->vfu_ctx, LOG_ERR,
                    "failed to memory map DMA region %#lx-%#lx: %s\n",
diff --git a/lib/dma.h b/lib/dma.h
index 7bab3da..d8ff38c 100644
--- a/lib/dma.h
+++ b/lib/dma.h
@@ -83,6 +83,9 @@ struct vfu_ctx;
 
 typedef struct {
     dma_addr_t dma_addr;        // DMA address of this region
+    uint32_t prot;              // memory protection of the mapping
+                                // defined in sys/mman.h
+
     size_t size;                // Size of this region
     int fd;                     // File descriptor to mmap
     int page_size;              // Page size of this fd
@@ -116,7 +119,7 @@ dma_controller_destroy(dma_controller_t *dma);
 int
 dma_controller_add_region(dma_controller_t *dma,
                           dma_addr_t dma_addr, size_t size,
-                          int fd, off_t offset);
+                          int fd, off_t offset, uint32_t prot);
 
 int
 dma_controller_remove_region(dma_controller_t *dma,
diff --git a/lib/libvfio-user.c b/lib/libvfio-user.c
index c0503ff..2b95b43 100644
--- a/lib/libvfio-user.c
+++ b/lib/libvfio-user.c
@@ -519,7 +519,8 @@ handle_dma_map_or_unmap(vfu_ctx_t *vfu_ctx, uint32_t size, bool map,
                                             dma_regions[i].addr,
                                             dma_regions[i].size,
                                             fd,
-                                            dma_regions[i].offset);
+                                            dma_regions[i].offset,
+                                            dma_regions[i].prot);
             if (ret < 0) {
                 if (fd != -1) {
                     close(fd);
@@ -534,10 +535,10 @@ handle_dma_map_or_unmap(vfu_ctx_t *vfu_ctx, uint32_t size, bool map,
             }
             ret = 0;
             vfu_log(vfu_ctx, LOG_DEBUG,
-                    "added DMA region %#lx-%#lx offset=%#lx fd=%d",
+                    "added DMA region %#lx-%#lx offset=%#lx fd=%d prot=%#x",
                     dma_regions[i].addr,
                     dma_regions[i].addr + dma_regions[i].size - 1,
-                    dma_regions[i].offset, fd);
+                    dma_regions[i].offset, fd, dma_regions[i].prot);
         } else {
             ret = dma_controller_remove_region(vfu_ctx->dma,
                                                dma_regions[i].addr,