[PATCH v3] virtio-gpu: fix unmap the already mapped items

[Li Zhijian]

we go here either (!(*iov)[i].iov_base) or (len != l), so we need to consider
to unmap the 'i'th item as well when the 'i'th item is not nil

CC: Li Qiang <liq3ea@gmail.com>
Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
---
v2: address Gerd's comments
v3: leave (*iov)[i].iov_len as the real mapped len (Li Qiang)
---
 hw/display/virtio-gpu.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
index 5f0dd7c150..90be4e3ed7 100644
--- a/hw/display/virtio-gpu.c
+++ b/hw/display/virtio-gpu.c
@@ -646,9 +646,9 @@ int virtio_gpu_create_mapping_iov(VirtIOGPU *g,
         uint64_t a = le64_to_cpu(ents[i].addr);
         uint32_t l = le32_to_cpu(ents[i].length);
         hwaddr len = l;
-        (*iov)[i].iov_len = l;
         (*iov)[i].iov_base = dma_memory_map(VIRTIO_DEVICE(g)->dma_as,
                                             a, &len, DMA_DIRECTION_TO_DEVICE);
+        (*iov)[i].iov_len = len;
         if (addr) {
             (*addr)[i] = a;
         }
@@ -656,6 +656,9 @@ int virtio_gpu_create_mapping_iov(VirtIOGPU *g,
             qemu_log_mask(LOG_GUEST_ERROR, "%s: failed to map MMIO memory for"
                           " resource %d element %d\n",
                           __func__, ab->resource_id, i);
+            if ((*iov)[i].iov_base) {
+                i++; /* cleanup the 'i'th map */
+            }
             virtio_gpu_cleanup_mapping_iov(g, *iov, i);
             g_free(ents);
             *iov = NULL;
-- 
2.28.0