On 2025/11/09 14:33, Vivek Kasireddy wrote:
Add a helper to check whether the addresses in an iovec array
belong to the same memory region or not. This is useful to verify
before trying to create a dmabuf from an iovec array.
Cc: Marc-André Lureau <[email protected]>
Cc: Alex Bennée <[email protected]>
Cc: Akihiko Odaki <[email protected]>
Cc: Dmitry Osipenko <[email protected]>
Cc: Alex Williamson <[email protected]>
Cc: Cédric Le Goater <[email protected]>
Signed-off-by: Vivek Kasireddy <[email protected]>
---
hw/display/virtio-gpu-dmabuf.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/hw/display/virtio-gpu-dmabuf.c b/hw/display/virtio-gpu-dmabuf.c
index c34d4c85bc..80143034d4 100644
--- a/hw/display/virtio-gpu-dmabuf.c
+++ b/hw/display/virtio-gpu-dmabuf.c
@@ -27,6 +27,31 @@
#include "standard-headers/linux/udmabuf.h"
#include "standard-headers/drm/drm_fourcc.h"
+static bool qemu_iovec_same_memory_regions(const struct iovec *iov, int iov_cnt)
+{
+ RAMBlock *rb, *curr_rb;
+ ram_addr_t offset;
+ int i;
+
+ rb = qemu_ram_block_from_host(iov[0].iov_base, false, &offset);
+ if (!rb) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "%s: Could not find ramblock/memory region\n", __func__);
+ return false;
+ }
+
+ for (i = 1; i < iov_cnt; i++) {
+ curr_rb = qemu_ram_block_from_host(iov[i].iov_base, false, &offset);
+ if (curr_rb != rb) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "%s: memory regions not same for iov entries\n",
+ __func__);
+ return false;
+ }
+ }
+ return true;
+}
+
static void virtio_gpu_create_udmabuf(struct virtio_gpu_simple_resource *res)
{
struct udmabuf_create_list *list;
@@ -137,6 +162,10 @@ void virtio_gpu_init_dmabuf(struct
virtio_gpu_simple_resource *res)
res->iov[0].iov_len < 4096) {
pdata = res->iov[0].iov_base;
} else {
+ if (!qemu_iovec_same_memory_regions(res->iov, res->iov_cnt)) {
+ return;
+ }
+
This check is unnecessary. Perhaps rejecting iov with different memory
regions may be fine if that simplifies the code, but this actually adds
some code.
virtio_gpu_create_udmabuf(res);
if (res->dmabuf_fd < 0) {
return;
Regards,
Akihiko Odaki
