[PATCH 1/3] virtio-gpu: Add support for VIRTIO_GPU_BLOB_FLAG_USE_USERPTR flag

[Honglei Huang <honghuan@amd.com>]

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 <honghuan@amd.com>
---
 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) {
+                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;
-- 
2.34.1