On 2025/11/12 16:44, Akihiko Odaki wrote:
On 2025/11/12 16:54, Honglei Huang wrote:
Add support for the USE_USERPTR blob flag in virtio-gpu to enable
user pointer mapping for blob resources. This allows guest applications
to use user-allocated memory for GPU resources more efficiently.
Changes include:
- Add VIRTIO_GPU_BLOB_FLAG_USE_USERPTR flag definition
- Enhance blob resource creation to handle userptr flag properly
- Remove arbitrary nr_entries limit (16384) in mapping creation
- Add conditional handling for userptr vs regular blob mapping
- Support guest_blob_mapped parameter for virgl renderer
This enables more flexible memory management between guest and host
for GPU virtualization scenarios.
Signed-off-by: Honglei Huang <[email protected]>
---
hw/display/virtio-gpu-virgl.c | 21 +++++++++++++++------
hw/display/virtio-gpu.c | 7 -------
include/standard-headers/linux/virtio_gpu.h | 1 +
3 files changed, 16 insertions(+), 13 deletions(-)
diff --git a/hw/display/virtio-gpu-virgl.c b/hw/display/virtio-gpu-
virgl.c
index 07f6355ad6..9da64bf16f 100644
--- a/hw/display/virtio-gpu-virgl.c
+++ b/hw/display/virtio-gpu-virgl.c
@@ -702,12 +702,21 @@ static void
virgl_cmd_resource_create_blob(VirtIOGPU *g,
res->base.dmabuf_fd = -1;
if (cblob.blob_mem != VIRTIO_GPU_BLOB_MEM_HOST3D) {
- ret = virtio_gpu_create_mapping_iov(g, cblob.nr_entries,
sizeof(cblob),
- cmd, &res->base.addrs,
- &res->base.iov, &res-
>base.iov_cnt);
- if (!ret) {
- cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
- return;
+ if (cblob.blob_flags & VIRTIO_GPU_BLOB_FLAG_USE_USERPTR) {
+ ret = virtio_gpu_create_mapping_iov(g, cblob.nr_entries,
sizeof(cblob), cmd, &res->base.addrs,
+ &res->base.iov, &res-
>base.iov_cnt);
+ if (ret != 0) {
+ cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
+ return;
+ }
+ } else {
+ ret = virtio_gpu_create_mapping_iov(g, cblob.nr_entries,
sizeof(cblob),
+ cmd, &res->base.addrs,
+ &res->base.iov, &res-
>base.iov_cnt);
+ if (!ret) {
Why does this check !ret instead of ret != 0?
Regards,
Akihiko Odaki
+ cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
+ return;
+ }
}
}
diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
index 43e88a4daf..956dc811fa 100644
--- a/hw/display/virtio-gpu.c
+++ b/hw/display/virtio-gpu.c
@@ -808,13 +808,6 @@ int virtio_gpu_create_mapping_iov(VirtIOGPU *g,
size_t esize, s;
int e, v;
- if (nr_entries > 16384) {
- qemu_log_mask(LOG_GUEST_ERROR,
- "%s: nr_entries is too big (%d > 16384)\n",
- __func__, nr_entries);
- return -1;
- }
-
esize = sizeof(*ents) * nr_entries;
ents = g_malloc(esize);
s = iov_to_buf(cmd->elem.out_sg, cmd->elem.out_num,
diff --git a/include/standard-headers/linux/virtio_gpu.h b/include/
standard-headers/linux/virtio_gpu.h
index 00cd3f04af..b85e781a2d 100644
--- a/include/standard-headers/linux/virtio_gpu.h
+++ b/include/standard-headers/linux/virtio_gpu.h
@@ -405,6 +405,7 @@ struct virtio_gpu_resource_create_blob {
#define VIRTIO_GPU_BLOB_FLAG_USE_MAPPABLE 0x0001
#define VIRTIO_GPU_BLOB_FLAG_USE_SHAREABLE 0x0002
#define VIRTIO_GPU_BLOB_FLAG_USE_CROSS_DEVICE 0x0004
+#define VIRTIO_GPU_BLOB_FLAG_USE_USERPTR 0x0008
/* zero is invalid blob mem */
uint32_t blob_mem;
uint32_t blob_flags;
Hi Akihiko,
Thank you for the review!
You're absolutely right. I need to maintain a consistent code style.
I'll fix this in v2 along with making both check consistent.
Regards,
Honglei
