[PATCH v8 0/4] virtio-gpu: Add userptr support for compute workloads

[PATCH v8 0/4] virtio-gpu: Add userptr support for compute workloads

[Honglei Huang]

Hello,

This series adds virtio-gpu userptr support for ROCm native compute
contexts. The guest kernel pins an existing userspace mapping with
FOLL_LONGTERM and exposes it to the host as ordinary CREATE_BLOB
backing entries, avoiding a second shmem allocation and memcpy.

HINT_USERPTR and HINT_USERPTR_RDONLY live in blob_hints. They are
guest-only DRM ioctl selectors, not virtio CREATE_BLOB wire flags.
The device does not need a new wire flag. CREATE_BLOB only carries
the documented wire blob_flags (MAPPABLE / SHAREABLE / CROSS_DEVICE).

Patches overview:
1. Add VIRTIO_GPU_CAPSET_ROCM capability for compute workloads
2. Extend DRM UAPI with guest-only userptr hints and a userptr
   address field
3. Implement core userptr functionality with page management
4. Wire blob ioctl creation to userptr objects

Tests:
- Full OPENCL CTS tests passed on ROCm 5.7.0 in V2000 platform.
- Near 70% percentage of OPENCL CTS tests passed on ROCm 7.0 W7900 platform.
- most HIP catch tests passed on ROCm 7.0 W7900 platform.
- Some AI applications enabled on ROCm 7.0 W7900 platform.
- latest ROCm 7.14 and ROCm 10 testing is ongoing.

V8 changes:
- Move USE_USERPTR / USERPTR_RDONLY from blob_flags into blob_hints
  (HINT_USERPTR / HINT_USERPTR_RDONLY) so they do not occupy virtio
  wire bits
- Drop the CREATE_BLOB blob_flags mask; hints never go on the wire

V7 changes:
- Mask guest-only DRM flags out of CREATE_BLOB wire blob_flags
- Clear userptr->pages after pin failure to avoid double-free
- DMA-map userptr SG only when virtio_gpu_use_dma_api() is required
- Use DMA_TO_DEVICE for USERPTR_RDONLY
- Sync userptr SG for the device on TRANSFER_TO_HOST
- Mark writable pages dirty when unpinning
- Reject USERPTR unless blob_mem is VIRTGPU_BLOB_MEM_GUEST
- Disallow PRIME export of userptr objects
- Note that CAPSET_ROCM uses ID 8 because ID 7 is taken by VIRCL

V6 changes:
- Rebase onto drm-misc-next
- Keep USE_USERPTR / USERPTR_RDONLY as guest-only DRM flags; drop the
  virtio wire-header patch (5 patches down to 4)
- Fix userptr lifetime, DMA mapping, memlock accounting, alignment
  checks, and PRIME SG export
- Updated corresponding cover letter and commit messages

V5 changes:
    - Add VIRTIO_GPU_BLOB_FLAG_USERPTR_RDONLY definition to patch 2
    - Dropped unused VIRTIO_GPU_F_RESOURCE_USERPTR feature bit in patch 2
    - Included VIRTIO_GPU_BLOB_FLAG_USERPTR_RDONLY in VIRTGPU_BLOB_FLAG_USE_MASK in patch 5
    - Add check for userptr feature in patch 5 before creating userptr blob resource
    - Updated corresponding cover letter and commit messages

V4 changes:
    - Renamed VIRTIO_GPU_CAPSET_HSAKMT to VIRTIO_GPU_CAPSET_ROCM
    - Remove userptr feature probing cause it can reuse the guest
      blob resource code path, reduce patch count from 6 to 5
    - Updated corresponding commit messages
    - Consolidated userptr feature detection in final patch
    - Update corresponding cover letter content

V3 changes:
    - Split into focused patches for easier review
    - Removed complex interval tree userptr management
    - Simplified resource creation without deduplication
    - Added VIRTGPU_PARAM_RESOURCE_USERPTR for feature detection
    - Improved UAPI documentation and error handling
    - Enhanced code quality with proper cleanup paths
    - Removed MMU notifier dependencies for simplicity
    - Fixed resource lifecycle management issues

V2: - Split add HSAKMT context and blob userptr resource to two patches.
    - Remove MMU notifier related patches, cause use not moveable user space
      memory with MMU notifier is not a good idea.
    - Remove HSAKMT context check when create context, let all the context
      support the userptr feature.
    - Remove MMU notifier related content in cover letter.
    - Add more comments  for patch 6 in cover letter.

Previous version:
https://lore.kernel.org/dri-devel/20260917102540.1312102-1-honghuan@amd.com/

Honglei Huang (4):
  drm/virtio-gpu: Add VIRTIO_GPU_CAPSET_ROCM capability
  drm/virtgpu api: add blob userptr resource
  drm/virtio: implement userptr support for zero-copy memory access
  drm/virtio: wire blob ioctl creation to userptr objects

 drivers/gpu/drm/virtio/Makefile          |   3 +-
 drivers/gpu/drm/virtio/virtgpu_drv.h     |  38 +++
 drivers/gpu/drm/virtio/virtgpu_ioctl.c   |  29 +-
 drivers/gpu/drm/virtio/virtgpu_object.c  |  10 +
 drivers/gpu/drm/virtio/virtgpu_userptr.c | 330 +++++++++++++++++++++++
 drivers/gpu/drm/virtio/virtgpu_vq.c      |  33 ++-
 include/uapi/drm/virtgpu_drm.h           |   9 +
 include/uapi/linux/virtio_gpu.h          |   1 +
 8 files changed, 442 insertions(+), 11 deletions(-)
 create mode 100644 drivers/gpu/drm/virtio/virtgpu_userptr.c


base-commit: 766bfba0f3bae329f99b42dcabc3ef11fa368f0b
-- 
2.34.1

[PATCH v8 1/4] drm/virtio-gpu: Add VIRTIO_GPU_CAPSET_ROCM capability

[Honglei Huang]

Add a new GPU capability set VIRTIO_GPU_CAPSET_ROCM to support
ROCm compute workloads in virtualized environments.

ROCm (Radeon Open Compute) is AMD's open-source software platform
for GPU compute and HPC workloads.

ID 7 is already used by VIRCL in the virgl/virtio-gpu stack, so
ROCm uses ID 8. A matching virtio-gpu specification change is in
progress to register this assignment.

Signed-off-by: Honglei Huang <honghuan@amd.com>
---
 include/uapi/linux/virtio_gpu.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/uapi/linux/virtio_gpu.h b/include/uapi/linux/virtio_gpu.h
index 4f530d9005..3d4dfadc9d 100644
--- a/include/uapi/linux/virtio_gpu.h
+++ b/include/uapi/linux/virtio_gpu.h
@@ -321,6 +321,7 @@ struct virtio_gpu_cmd_submit {
 #define VIRTIO_GPU_CAPSET_VENUS 4
 #define VIRTIO_GPU_CAPSET_CROSS_DOMAIN 5
 #define VIRTIO_GPU_CAPSET_DRM 6
+#define VIRTIO_GPU_CAPSET_ROCM 8
 
 /* VIRTIO_GPU_CMD_GET_CAPSET_INFO */
 struct virtio_gpu_get_capset_info {
-- 
2.34.1

[PATCH v8 2/4] drm/virtgpu api: add blob userptr resource

[Honglei Huang]

Add DRM ioctl hints and a userptr address field so userspace can
request a blob backed by an existing process mapping.

UAPI changes:
- Add guest-only DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR and
  DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR_RDONLY to blob_hints
- Add a userptr field to drm_virtgpu_resource_create_blob

These hints select guest pin behavior in the ioctl. They are not
part of the virtio CREATE_BLOB wire ABI.

Signed-off-by: Honglei Huang <honghuan@amd.com>
---
 include/uapi/drm/virtgpu_drm.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/uapi/drm/virtgpu_drm.h b/include/uapi/drm/virtgpu_drm.h
index 95587e12ae..aa8abef8f9 100644
--- a/include/uapi/drm/virtgpu_drm.h
+++ b/include/uapi/drm/virtgpu_drm.h
@@ -203,8 +203,17 @@ struct drm_virtgpu_resource_create_blob {
 	__u64 blob_id;
 
 #define DRM_VIRTGPU_BLOB_FLAG_HINT_DEFER_MAPPING        0x0001
+/* Guest-only: pin an existing process mapping as blob backing. */
+#define DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR              0x0002
+#define DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR_RDONLY       0x0004
 	__u32 blob_hints;
 	__u32 pad2;
+
+	/*
+	 * userptr: guest userspace memory address for
+	 * DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR. Must be 0 if that hint is not set.
+	 */
+	__u64 userptr;
 };
 
 #define VIRTGPU_CONTEXT_PARAM_CAPSET_ID       0x0001
-- 
2.34.1

[PATCH v8 3/4] drm/virtio: implement userptr support for zero-copy memory access

[Honglei Huang]

Add userptr blob objects so the guest kernel can pin an existing
userspace mapping and advertise it as CREATE_BLOB backing entries.

- New virtio_gpu_object_userptr type for userptr resources
- Pin pages with pin_user_pages_fast() and FOLL_LONGTERM
- Charge FOLL_LONGTERM pins against RLIMIT_MEMLOCK
- DMA-map the scatterlist only when virtio_gpu_use_dma_api() is
  required; use DMA_TO_DEVICE for HINT_USERPTR_RDONLY
- Sync userptr SG for the device on TRANSFER_TO_HOST
- Mark writable pages dirty when unpinning
- Keep pages pinned until RESOURCE_UNREF is queued; drop them from
  cleanup_object() on the unref response or on create failure
- Clear userptr->pages on pin failure to avoid double-free on cleanup
- Reject unaligned or overflowing userptr ranges at create time
- Disallow PRIME export of userptr objects

Signed-off-by: Honglei Huang <honghuan@amd.com>
---
 drivers/gpu/drm/virtio/Makefile          |   3 +-
 drivers/gpu/drm/virtio/virtgpu_drv.h     |  38 +++
 drivers/gpu/drm/virtio/virtgpu_object.c  |  10 +
 drivers/gpu/drm/virtio/virtgpu_userptr.c | 330 +++++++++++++++++++++++
 drivers/gpu/drm/virtio/virtgpu_vq.c      |  33 ++-
 5 files changed, 404 insertions(+), 10 deletions(-)
 create mode 100644 drivers/gpu/drm/virtio/virtgpu_userptr.c

diff --git a/drivers/gpu/drm/virtio/Makefile b/drivers/gpu/drm/virtio/Makefile
index d2e1788a82..fe7332a621 100644
--- a/drivers/gpu/drm/virtio/Makefile
+++ b/drivers/gpu/drm/virtio/Makefile
@@ -6,6 +6,7 @@
 virtio-gpu-y := virtgpu_drv.o virtgpu_kms.o virtgpu_gem.o virtgpu_vram.o \
 	virtgpu_display.o virtgpu_vq.o \
 	virtgpu_fence.o virtgpu_object.o virtgpu_debugfs.o virtgpu_plane.o \
-	virtgpu_ioctl.o virtgpu_prime.o virtgpu_trace_points.o virtgpu_submit.o
+	virtgpu_ioctl.o virtgpu_prime.o virtgpu_trace_points.o virtgpu_submit.o \
+	virtgpu_userptr.o
 
 obj-$(CONFIG_DRM_VIRTIO_GPU) += virtio-gpu.o
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 9df4c71173..e59750fc30 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -105,6 +105,7 @@ struct virtio_gpu_object_params {
 	uint32_t blob_flags;
 	uint64_t blob_id;
 	uint32_t blob_hints;
+	uint64_t userptr;
 };
 
 struct virtio_gpu_object {
@@ -138,12 +139,42 @@ struct virtio_gpu_object_vram {
 	struct drm_mm_node vram_node;
 };
 
+struct virtio_gpu_object_userptr;
+
+struct virtio_gpu_object_userptr_ops {
+	int (*get_pages)(struct virtio_gpu_object_userptr *userptr);
+	void (*put_pages)(struct virtio_gpu_object_userptr *userptr);
+};
+
+struct virtio_gpu_object_userptr {
+	struct virtio_gpu_object base;
+	const struct virtio_gpu_object_userptr_ops *ops;
+	/* Protects pages and sgt. */
+	struct mutex lock;
+
+	uint64_t start;
+	uint32_t npages;
+	uint32_t bo_handle;
+	uint32_t flags;
+
+	struct virtio_gpu_device *vgdev;
+	struct drm_file *file;
+	struct page **pages;
+	struct sg_table *sgt;
+	bool dma_mapped;
+	enum dma_data_direction dma_dir;
+	struct mm_struct *mm;
+};
+
 #define to_virtio_gpu_shmem(virtio_gpu_object) \
 	container_of((virtio_gpu_object), struct virtio_gpu_object_shmem, base)
 
 #define to_virtio_gpu_vram(virtio_gpu_object) \
 	container_of((virtio_gpu_object), struct virtio_gpu_object_vram, base)
 
+#define to_virtio_gpu_userptr(virtio_gpu_object) \
+	container_of((virtio_gpu_object), struct virtio_gpu_object_userptr, base)
+
 struct virtio_gpu_object_array {
 	struct ww_acquire_ctx ticket;
 	struct list_head next;
@@ -562,4 +593,11 @@ void virtio_gpu_vram_map_deferred(struct virtio_gpu_object_vram *vram);
 int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
 				struct drm_file *file);
 
+/* virtgpu_userptr.c */
+int virtio_gpu_userptr_create(struct virtio_gpu_device *vgdev,
+			      struct drm_file *file,
+			      struct virtio_gpu_object_params *params,
+			      struct virtio_gpu_object **bo_ptr);
+bool virtio_gpu_is_userptr(struct virtio_gpu_object *bo);
+void virtio_gpu_userptr_dma_sync_for_device(struct virtio_gpu_object *bo);
 #endif
diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
index 49899485be..5c40f5a034 100644
--- a/drivers/gpu/drm/virtio/virtgpu_object.c
+++ b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -91,6 +91,16 @@ void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo)
 		drm_gem_free_mmap_offset(&vram->base.base.base);
 		drm_gem_object_release(&vram->base.base.base);
 		kfree(vram);
+	} else if (virtio_gpu_is_userptr(bo)) {
+		struct virtio_gpu_object_userptr *userptr =
+			to_virtio_gpu_userptr(bo);
+
+		mutex_lock(&userptr->lock);
+		userptr->ops->put_pages(userptr);
+		mutex_unlock(&userptr->lock);
+		mutex_destroy(&userptr->lock);
+		drm_gem_object_release(&userptr->base.base.base);
+		kfree(userptr);
 	} else {
 		drm_gem_object_release(&bo->base.base);
 		kfree(bo);
diff --git a/drivers/gpu/drm/virtio/virtgpu_userptr.c b/drivers/gpu/drm/virtio/virtgpu_userptr.c
new file mode 100644
index 0000000000..7a5870816d
--- /dev/null
+++ b/drivers/gpu/drm/virtio/virtgpu_userptr.c
@@ -0,0 +1,330 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/dma-mapping.h>
+#include <linux/limits.h>
+#include <linux/mm.h>
+#include <linux/overflow.h>
+#include <linux/pid.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/signal.h>
+#include <linux/vmalloc.h>
+
+#include "virtgpu_drv.h"
+#include <drm/drm_gem.h>
+
+static void virtio_gpu_userptr_free(struct drm_gem_object *obj)
+{
+	struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
+	struct virtio_gpu_device *vgdev = obj->dev->dev_private;
+
+	/*
+	 * Keep pages pinned until RESOURCE_UNREF completes. The response
+	 * callback calls virtio_gpu_cleanup_object(), which drops them.
+	 */
+	if (bo->created) {
+		virtio_gpu_remove_from_restore_list(bo);
+		virtio_gpu_cmd_unref_resource(vgdev, bo, false);
+		virtio_gpu_notify(vgdev);
+		return;
+	}
+
+	virtio_gpu_cleanup_object(bo);
+}
+
+static struct dma_buf *
+virtio_gpu_userptr_prime_export(struct drm_gem_object *obj, int flags)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static const struct drm_gem_object_funcs virtio_gpu_userptr_funcs = {
+	.open = virtio_gpu_gem_object_open,
+	.close = virtio_gpu_gem_object_close,
+	.free = virtio_gpu_userptr_free,
+	.export = virtio_gpu_userptr_prime_export,
+};
+
+bool virtio_gpu_is_userptr(struct virtio_gpu_object *bo)
+{
+	return bo->base.base.funcs == &virtio_gpu_userptr_funcs;
+}
+
+void virtio_gpu_userptr_dma_sync_for_device(struct virtio_gpu_object *bo)
+{
+	struct virtio_gpu_object_userptr *userptr = to_virtio_gpu_userptr(bo);
+	struct device *dev;
+
+	if (!userptr->dma_mapped)
+		return;
+
+	dev = drm_dev_dma_dev(userptr->base.base.base.dev);
+	dma_sync_sgtable_for_device(dev, userptr->sgt, DMA_TO_DEVICE);
+}
+
+static int
+virtio_gpu_userptr_get_pages(struct virtio_gpu_object_userptr *userptr)
+{
+	unsigned int flag = FOLL_LONGTERM;
+	unsigned int num_pages, pinned = 0;
+	int ret = 0;
+
+	if (userptr->pages)
+		return 0;
+
+	userptr->pages = kvmalloc_array(userptr->npages, sizeof(struct page *),
+					GFP_KERNEL);
+	if (!userptr->pages)
+		return -ENOMEM;
+
+	if (!(userptr->flags & DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR_RDONLY))
+		flag |= FOLL_WRITE;
+
+	do {
+		num_pages = userptr->npages - pinned;
+
+		ret = pin_user_pages_fast(userptr->start + pinned * PAGE_SIZE,
+					  num_pages, flag,
+					  userptr->pages + pinned);
+
+		if (ret < 0) {
+			if (pinned)
+				unpin_user_pages(userptr->pages, pinned);
+			kvfree(userptr->pages);
+			userptr->pages = NULL;
+			return ret;
+		}
+
+		pinned += ret;
+
+	} while (pinned < userptr->npages);
+
+	return 0;
+}
+
+static void
+virtio_gpu_userptr_unaccount(struct virtio_gpu_object_userptr *userptr)
+{
+	if (!userptr->mm)
+		return;
+
+	atomic64_sub(userptr->npages, &userptr->mm->pinned_vm);
+	mmdrop(userptr->mm);
+	userptr->mm = NULL;
+}
+
+static void
+virtio_gpu_userptr_put_pages(struct virtio_gpu_object_userptr *userptr)
+{
+	struct drm_device *dev = userptr->base.base.base.dev;
+
+	if (userptr->sgt) {
+		if (userptr->dma_mapped)
+			dma_unmap_sgtable(drm_dev_dma_dev(dev), userptr->sgt,
+					  userptr->dma_dir, 0);
+		userptr->dma_mapped = false;
+		sg_free_table(userptr->sgt);
+		kfree(userptr->sgt);
+		userptr->sgt = NULL;
+	}
+
+	if (userptr->pages) {
+		bool dirty = !(userptr->flags & DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR_RDONLY);
+
+		unpin_user_pages_dirty_lock(userptr->pages, userptr->npages,
+					    dirty);
+		kvfree(userptr->pages);
+		userptr->pages = NULL;
+	}
+
+	virtio_gpu_userptr_unaccount(userptr);
+}
+
+static int
+virtio_gpu_userptr_get_entries(struct virtio_gpu_device *vgdev,
+			       struct virtio_gpu_object_userptr *userptr,
+			       struct virtio_gpu_mem_entry **ents,
+			       unsigned int *nents)
+{
+	bool use_dma_api = virtio_gpu_use_dma_api(vgdev->vdev);
+	struct scatterlist *sg;
+	unsigned int count;
+	int si;
+
+	count = use_dma_api ? userptr->sgt->nents : userptr->sgt->orig_nents;
+	if (!count)
+		return -EINVAL;
+
+	*ents = kvmalloc_array(count, sizeof(**ents), GFP_KERNEL);
+	if (!*ents)
+		return -ENOMEM;
+
+	if (use_dma_api) {
+		for_each_sgtable_dma_sg(userptr->sgt, sg, si) {
+			(*ents)[si].addr = cpu_to_le64(sg_dma_address(sg));
+			(*ents)[si].length = cpu_to_le32(sg_dma_len(sg));
+			(*ents)[si].padding = 0;
+		}
+	} else {
+		for_each_sgtable_sg(userptr->sgt, sg, si) {
+			(*ents)[si].addr = cpu_to_le64(sg_phys(sg));
+			(*ents)[si].length = cpu_to_le32(sg->length);
+			(*ents)[si].padding = 0;
+		}
+	}
+
+	*nents = count;
+	return 0;
+}
+
+static int
+virtio_gpu_userptr_init(struct drm_device *dev, struct drm_file *file,
+			struct virtio_gpu_object_userptr *userptr,
+			struct virtio_gpu_object_params *params,
+			const struct virtio_gpu_object_userptr_ops *ops)
+{
+	struct drm_gem_object *obj;
+	int ret;
+
+	userptr->start = params->userptr;
+	userptr->npages = params->size >> PAGE_SHIFT;
+	userptr->flags = params->blob_hints;
+
+	mutex_init(&userptr->lock);
+	userptr->vgdev = dev->dev_private;
+	userptr->file = file;
+	userptr->ops = ops;
+
+	/*
+	 * Allocate the resource id before GEM init so a failure here can
+	 * unwind with a plain kfree and does not need a special id=0 guard
+	 * in the shared resource_id_put helper.
+	 */
+	ret = virtio_gpu_resource_id_get(userptr->vgdev,
+					 &userptr->base.hw_res_handle);
+	if (ret) {
+		mutex_destroy(&userptr->lock);
+		return ret;
+	}
+
+	obj = &userptr->base.base.base;
+	obj->funcs = &virtio_gpu_userptr_funcs;
+
+	drm_gem_private_object_init(dev, obj, params->size);
+	INIT_LIST_HEAD(&userptr->base.restore_node);
+
+	return 0;
+}
+
+static const struct virtio_gpu_object_userptr_ops virtio_gpu_userptr_ops = {
+	.get_pages = virtio_gpu_userptr_get_pages,
+	.put_pages = virtio_gpu_userptr_put_pages,
+};
+
+int virtio_gpu_userptr_create(struct virtio_gpu_device *vgdev,
+			      struct drm_file *file,
+			      struct virtio_gpu_object_params *params,
+			      struct virtio_gpu_object **bo_ptr)
+{
+	struct virtio_gpu_object_userptr *userptr;
+	struct virtio_gpu_mem_entry *ents = NULL;
+	struct sg_table *sgt;
+	struct mm_struct *mm;
+	unsigned long lock_limit;
+	unsigned long start;
+	unsigned long end;
+	s64 new_pinned;
+	unsigned int nents;
+	int ret;
+
+	*bo_ptr = NULL;
+
+	if (!params->size || !IS_ALIGNED(params->size, PAGE_SIZE) ||
+	    params->userptr != (unsigned long)params->userptr)
+		return -EINVAL;
+
+	start = params->userptr;
+	if (!IS_ALIGNED(start, PAGE_SIZE) ||
+	    check_add_overflow(start, (unsigned long)params->size, &end))
+		return -EINVAL;
+
+	if (!can_do_mlock())
+		return -EPERM;
+
+	if (params->size >> PAGE_SHIFT > INT_MAX)
+		return -E2BIG;
+
+	if (!access_ok((void __user *)start, params->size))
+		return -EFAULT;
+
+	userptr = kzalloc_obj(*userptr);
+	if (!userptr)
+		return -ENOMEM;
+
+	ret = virtio_gpu_userptr_init(vgdev->ddev, file, userptr, params,
+				      &virtio_gpu_userptr_ops);
+	if (ret) {
+		kfree(userptr);
+		return ret;
+	}
+
+	mm = current->mm;
+	mmgrab(mm);
+	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+	new_pinned = atomic64_add_return(userptr->npages, &mm->pinned_vm);
+	if (new_pinned < 0 ||
+	    (new_pinned > lock_limit && !capable(CAP_IPC_LOCK))) {
+		atomic64_sub(userptr->npages, &mm->pinned_vm);
+		mmdrop(mm);
+		ret = new_pinned < 0 ? -EOVERFLOW : -ENOMEM;
+		goto err_cleanup;
+	}
+	userptr->mm = mm;
+
+	mutex_lock(&userptr->lock);
+	ret = userptr->ops->get_pages(userptr);
+	mutex_unlock(&userptr->lock);
+	if (ret)
+		goto err_cleanup;
+
+	sgt = drm_prime_pages_to_sg(vgdev->ddev, userptr->pages,
+				    userptr->npages);
+	if (IS_ERR(sgt)) {
+		ret = PTR_ERR(sgt);
+		goto err_cleanup;
+	}
+
+	userptr->sgt = sgt;
+
+	/*
+	 * Match shmem blobs: only DMA-map when the virtio DMA API is in
+	 * use. Mapping unconditionally can create SWIOTLB bounce buffers
+	 * that get copied back over guest pages on unmap even though the
+	 * host was given sg_phys() addresses.
+	 */
+	if (virtio_gpu_use_dma_api(vgdev->vdev)) {
+		enum dma_data_direction dir =
+			(userptr->flags & DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR_RDONLY) ?
+			DMA_TO_DEVICE : DMA_BIDIRECTIONAL;
+
+		ret = dma_map_sgtable(drm_dev_dma_dev(vgdev->ddev), sgt,
+				      dir, 0);
+		if (ret)
+			goto err_cleanup;
+
+		userptr->dma_dir = dir;
+		userptr->dma_mapped = true;
+	}
+
+	ret = virtio_gpu_userptr_get_entries(vgdev, userptr, &ents, &nents);
+	if (ret)
+		goto err_cleanup;
+
+	virtio_gpu_cmd_resource_create_blob(vgdev, &userptr->base, params, ents,
+					    nents);
+
+	*bo_ptr = &userptr->base;
+	return 0;
+
+err_cleanup:
+	virtio_gpu_cleanup_object(&userptr->base);
+	return ret;
+}
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index c02c03c10d..dcbd7bb7a6 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -781,9 +781,14 @@ int virtio_gpu_panic_cmd_transfer_to_host_2d(struct virtio_gpu_device *vgdev,
 	struct virtio_gpu_vbuffer *vbuf;
 	bool use_dma_api = virtio_gpu_use_dma_api(vgdev->vdev);
 
-	if (virtio_gpu_is_shmem(bo) && use_dma_api)
-		dma_sync_sgtable_for_device(vgdev->vdev->dev.parent,
-					    bo->base.sgt, DMA_TO_DEVICE);
+	if (use_dma_api) {
+		if (virtio_gpu_is_shmem(bo))
+			dma_sync_sgtable_for_device(vgdev->vdev->dev.parent,
+						    bo->base.sgt,
+						    DMA_TO_DEVICE);
+		else if (virtio_gpu_is_userptr(bo))
+			virtio_gpu_userptr_dma_sync_for_device(bo);
+	}
 
 	cmd_p = virtio_gpu_panic_alloc_cmd_resp(vgdev, &vbuf, sizeof(*cmd_p));
 	memset(cmd_p, 0, sizeof(*cmd_p));
@@ -812,9 +817,14 @@ void virtio_gpu_cmd_transfer_to_host_2d(struct virtio_gpu_device *vgdev,
 	struct virtio_gpu_vbuffer *vbuf;
 	bool use_dma_api = virtio_gpu_use_dma_api(vgdev->vdev);
 
-	if (virtio_gpu_is_shmem(bo) && use_dma_api)
-		dma_sync_sgtable_for_device(vgdev->vdev->dev.parent,
-					    bo->base.sgt, DMA_TO_DEVICE);
+	if (use_dma_api) {
+		if (virtio_gpu_is_shmem(bo))
+			dma_sync_sgtable_for_device(vgdev->vdev->dev.parent,
+						    bo->base.sgt,
+						    DMA_TO_DEVICE);
+		else if (virtio_gpu_is_userptr(bo))
+			virtio_gpu_userptr_dma_sync_for_device(bo);
+	}
 
 	cmd_p = virtio_gpu_alloc_cmd(vgdev, &vbuf, sizeof(*cmd_p));
 	memset(cmd_p, 0, sizeof(*cmd_p));
@@ -1245,9 +1255,14 @@ void virtio_gpu_cmd_transfer_to_host_3d(struct virtio_gpu_device *vgdev,
 	struct virtio_gpu_vbuffer *vbuf;
 	bool use_dma_api = virtio_gpu_use_dma_api(vgdev->vdev);
 
-	if (virtio_gpu_is_shmem(bo) && use_dma_api)
-		dma_sync_sgtable_for_device(vgdev->vdev->dev.parent,
-					    bo->base.sgt, DMA_TO_DEVICE);
+	if (use_dma_api) {
+		if (virtio_gpu_is_shmem(bo))
+			dma_sync_sgtable_for_device(vgdev->vdev->dev.parent,
+						    bo->base.sgt,
+						    DMA_TO_DEVICE);
+		else if (virtio_gpu_is_userptr(bo))
+			virtio_gpu_userptr_dma_sync_for_device(bo);
+	}
 
 	cmd_p = virtio_gpu_alloc_cmd(vgdev, &vbuf, sizeof(*cmd_p));
 	memset(cmd_p, 0, sizeof(*cmd_p));
-- 
2.34.1

[PATCH v8 4/4] drm/virtio: wire blob ioctl creation to userptr objects

[Honglei Huang]

Integrate userptr into the blob resource creation ioctl.

- Accept DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR and
  HINT_USERPTR_RDONLY in VIRTGPU_BLOB_HINT_MASK
- Require userptr if and only if HINT_USERPTR is set
- Reject HINT_USERPTR unless blob_mem is VIRTGPU_BLOB_MEM_GUEST
- Pass the userspace address into the internal create params
- Call virtio_gpu_userptr_create() for userptr blob requests

Signed-off-by: Honglei Huang <honghuan@amd.com>
---
 drivers/gpu/drm/virtio/virtgpu_ioctl.c | 29 +++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 3d8e4ccdb7..225a550be0 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -38,6 +38,10 @@
 				    VIRTGPU_BLOB_FLAG_USE_SHAREABLE | \
 				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE)
 
+#define VIRTGPU_BLOB_HINT_MASK (DRM_VIRTGPU_BLOB_FLAG_HINT_DEFER_MAPPING | \
+				DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR | \
+				DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR_RDONLY)
+
 /* Must be called with &virtio_gpu_fpriv.struct_mutex held. */
 static void virtio_gpu_create_context_locked(struct virtio_gpu_device *vgdev,
 					     struct virtio_gpu_fpriv *vfpriv)
@@ -453,11 +457,25 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
 	if (rc_blob->blob_flags & ~VIRTGPU_BLOB_FLAG_USE_MASK)
 		return -EINVAL;
 
+	if (rc_blob->blob_hints & ~VIRTGPU_BLOB_HINT_MASK)
+		return -EINVAL;
+
 	if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE) {
 		if (!vgdev->has_resource_assign_uuid)
 			return -EINVAL;
 	}
 
+	if (rc_blob->blob_hints & DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR) {
+		if (!rc_blob->userptr)
+			return -EINVAL;
+	} else {
+		if (rc_blob->userptr)
+			return -EINVAL;
+
+		if (rc_blob->blob_hints & DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR_RDONLY)
+			return -EINVAL;
+	}
+
 	switch (rc_blob->blob_mem) {
 	case VIRTGPU_BLOB_MEM_GUEST:
 		*guest_blob = true;
@@ -472,6 +490,11 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
 		return -EINVAL;
 	}
 
+	/* Userptr is only defined for pure guest backing. */
+	if ((rc_blob->blob_hints & DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR) &&
+	    rc_blob->blob_mem != VIRTGPU_BLOB_MEM_GUEST)
+		return -EINVAL;
+
 	if (*host3d_blob) {
 		if (!vgdev->has_virgl_3d)
 			return -EINVAL;
@@ -495,6 +518,7 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
 	params->blob = true;
 	params->blob_flags = rc_blob->blob_flags;
 	params->blob_hints = rc_blob->blob_hints;
+	params->userptr = rc_blob->userptr;
 
 	if (vgdev->has_blob_alignment &&
 	    !IS_ALIGNED(params->size, vgdev->blob_alignment))
@@ -538,7 +562,10 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
 				      vfpriv->ctx_id, NULL, NULL);
 	}
 
-	if (guest_blob)
+	if (guest_blob &&
+	    (params.blob_hints & DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR))
+		ret = virtio_gpu_userptr_create(vgdev, file, &params, &bo);
+	else if (guest_blob)
 		ret = virtio_gpu_object_create(vgdev, &params, &bo, NULL);
 	else if (!guest_blob && host3d_blob)
 		ret = virtio_gpu_vram_create(vgdev, &params, &bo);
-- 
2.34.1

Re: [PATCH v8 1/4] drm/virtio-gpu: Add VIRTIO_GPU_CAPSET_ROCM capability

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] virtio-gpu: premature UAPI addition of unassigned capability ID
--

commit 970261f0dfa422eb342665d66f5e54d6944eda73
Author: Honglei Huang <honghuan@amd.com>

drm/virtio-gpu: Add VIRTIO_GPU_CAPSET_ROCM capability

This commit adds a new GPU capability set VIRTIO_GPU_CAPSET_ROCM to support
ROCm compute workloads in virtualized environments. It assigns ID 8 to ROCm,
noting that a matching virtio-gpu specification change is in progress.

> diff --git a/include/uapi/linux/virtio_gpu.h b/include/uapi/linux/virtio_gpu.h
> --- a/include/uapi/linux/virtio_gpu.h
> +++ b/include/uapi/linux/virtio_gpu.h
> @@ -321,6 +321,7 @@ struct virtio_gpu_cmd_submit {
>  #define VIRTIO_GPU_CAPSET_VENUS 4
>  #define VIRTIO_GPU_CAPSET_CROSS_DOMAIN 5
>  #define VIRTIO_GPU_CAPSET_DRM 6
> +#define VIRTIO_GPU_CAPSET_ROCM 8

[Severity: Medium]
Is it safe to add VIRTIO_GPU_CAPSET_ROCM to the Linux UAPI before the virtio
specification has officially assigned it?

Adding an unassigned capability ID to the Linux UAPI creates a risk of a
permanent ABI collision. If the OASIS virtio technical committee assigns ID 8
to a different capability or chooses a different ID for ROCm, the Linux ABI
will conflict with the standard.

Since UAPI changes are immutable once released, could this lock the kernel
into a potentially non-compliant ABI if userspace software compiles against
this UAPI header and uses ID 8 to communicate with the virtio-gpu device?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260918055917.2133574-1-honghuan@amd.com?part=1

Re: [PATCH v8 4/4] drm/virtio: wire blob ioctl creation to userptr objects

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Critical] drm/virtio: host GPU can overwrite guest read-only memory via userptr
--

commit c5dbb2382bf8fa9c29656a9b3e8e517c49a15783
Author: Honglei Huang <honghuan@amd.com>
Subject: drm/virtio: wire blob ioctl creation to userptr objects

This commit integrates userptr into the blob resource creation ioctl. It
accepts the userptr hints, validates them against the blob memory type,
and delegates creation to virtio_gpu_userptr_create().

> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> index 3d8e4ccdb7c1f..225a550be00ca 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
[ ... ]
> @@ -538,7 +562,10 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
>  				      vfpriv->ctx_id, NULL, NULL);
>  	}
>  
> -	if (guest_blob)
> +	if (guest_blob &&
> +	    (params.blob_hints & DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR))
> +		ret = virtio_gpu_userptr_create(vgdev, file, &params, &bo);

[Severity: Critical]
Does this code path allow the host GPU to overwrite guest read-only memory?

When the DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR_RDONLY hint is used, the guest
pins read-only physical pages (like shared libraries) by omitting FOLL_WRITE
in virtio_gpu_userptr_get_pages().

However, when virtio_gpu_userptr_create() delegates to the host:

drivers/gpu/drm/virtio/virtgpu_vq.c:virtio_gpu_cmd_resource_create_blob() {
        ...
        cmd_p->blob_mem = cpu_to_le32(params->blob_mem);
        cmd_p->blob_flags = cpu_to_le32(params->blob_flags);
        ...
}

The blob_hints containing the RDONLY flag are never serialized to the host
in the virtio-gpu protocol. Since the host is unaware of the read-only
restriction, it treats the physical pages as writable. Can guest userspace
then submit 3D rendering commands to the host GPU to modify this read-only
memory, bypassing guest protections?

> +	else if (guest_blob)
>  		ret = virtio_gpu_object_create(vgdev, &params, &bo, NULL);
>  	else if (!guest_blob && host3d_blob)
>  		ret = virtio_gpu_vram_create(vgdev, &params, &bo);

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260918055917.2133574-1-honghuan@amd.com?part=4

Re: [PATCH v8 3/4] drm/virtio: implement userptr support for zero-copy memory access

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Critical] drm/virtio: privilege escalation via HINT_USERPTR_RDONLY
--

commit 20ea6ca5af258a43b1dc12cab535283738613d35
Author: Honglei Huang <honghuan@amd.com>
Subject: drm/virtio: implement userptr support for zero-copy memory access

This commit adds userptr blob object support to virtio-gpu, allowing the
guest kernel to pin existing userspace mappings and use them as CREATE_BLOB
backing entries. It handles page pinning, DMA mapping if required, and
syncing the scatterlist for the device.

> diff --git a/drivers/gpu/drm/virtio/virtgpu_userptr.c b/drivers/gpu/drm/virtio/virtgpu_userptr.c
> new file mode 100644
> --- /dev/null
> +++ b/drivers/gpu/drm/virtio/virtgpu_userptr.c
[ ... ]
> +static int
> +virtio_gpu_userptr_get_pages(struct virtio_gpu_object_userptr *userptr)
> +{
> +	unsigned int flag = FOLL_LONGTERM;
> +	unsigned int num_pages, pinned = 0;
> +	int ret = 0;
[ ... ]
> +	if (!(userptr->flags & DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR_RDONLY))
> +		flag |= FOLL_WRITE;
> +
> +	do {
> +		num_pages = userptr->npages - pinned;
> +
> +		ret = pin_user_pages_fast(userptr->start + pinned * PAGE_SIZE,
> +					  num_pages, flag,
> +					  userptr->pages + pinned);

[Severity: Critical]
Does this allow unprivileged userspace to bypass guest page protections?

If a malicious guest userspace maps read-only memory (such as executable
pages like libc.so) and passes it with
DRM_VIRTGPU_BLOB_FLAG_HINT_USERPTR_RDONLY, the code omits FOLL_WRITE when
calling pin_user_pages_fast. 

The pinned physical addresses are then sent to the host. If the guest has no
vIOMMU (where virtio_gpu_use_dma_api() is false), these addresses are passed
directly to the host without DMA_TO_DEVICE IOMMU protection. The userspace
process could then submit a command stream via VIRTGPU_EXECBUFFER instructing
the host GPU to write to this resource, causing the host hypervisor to write
directly into the guest's read-only physical memory.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260918055917.2133574-1-honghuan@amd.com?part=3

[PATCH v8 4/4] drm/virtio: wire blob ioctl creation to userptr objects

[Honglei Huang]

Integrate userptr into the blob resource creation ioctl.

- A non-zero userptr selects virtio_gpu_userptr_create()
- Reject userptr unless blob_mem is VIRTGPU_BLOB_MEM_GUEST
- Accept VIRTGPU_BLOB_FLAG_USE_READONLY and pass it through on
  the CREATE_BLOB wire
- Advertise VIRTGPU_PARAM_USERPTR

Signed-off-by: Honglei Huang <honghuan@amd.com>
---
 drivers/gpu/drm/virtio/virtgpu_ioctl.c | 27 +++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 3d8e4ccdb7..d42ca3898d 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -36,7 +36,10 @@
 
 #define VIRTGPU_BLOB_FLAG_USE_MASK (VIRTGPU_BLOB_FLAG_USE_MAPPABLE | \
 				    VIRTGPU_BLOB_FLAG_USE_SHAREABLE | \
-				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE)
+				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE | \
+				    VIRTGPU_BLOB_FLAG_USE_READONLY)
+
+#define VIRTGPU_BLOB_HINT_MASK DRM_VIRTGPU_BLOB_FLAG_HINT_DEFER_MAPPING
 
 /* Must be called with &virtio_gpu_fpriv.struct_mutex held. */
 static void virtio_gpu_create_context_locked(struct virtio_gpu_device *vgdev,
@@ -122,6 +125,9 @@ static int virtio_gpu_getparam_ioctl(struct drm_device *dev, void *data,
 			return -ENOENT;
 		value = vgdev->blob_alignment;
 		break;
+	case VIRTGPU_PARAM_USERPTR:
+		value = 1;
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -453,11 +459,18 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
 	if (rc_blob->blob_flags & ~VIRTGPU_BLOB_FLAG_USE_MASK)
 		return -EINVAL;
 
+	if (rc_blob->blob_hints & ~VIRTGPU_BLOB_HINT_MASK)
+		return -EINVAL;
+
 	if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE) {
 		if (!vgdev->has_resource_assign_uuid)
 			return -EINVAL;
 	}
 
+	if (rc_blob->userptr &&
+	    rc_blob->blob_mem != VIRTGPU_BLOB_MEM_GUEST)
+		return -EINVAL;
+
 	switch (rc_blob->blob_mem) {
 	case VIRTGPU_BLOB_MEM_GUEST:
 		*guest_blob = true;
@@ -495,6 +508,7 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
 	params->blob = true;
 	params->blob_flags = rc_blob->blob_flags;
 	params->blob_hints = rc_blob->blob_hints;
+	params->userptr = rc_blob->userptr;
 
 	if (vgdev->has_blob_alignment &&
 	    !IS_ALIGNED(params->size, vgdev->blob_alignment))
@@ -518,9 +532,10 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
 	struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
 	struct drm_virtgpu_resource_create_blob *rc_blob = data;
 
-	if (verify_blob(vgdev, vfpriv, &params, rc_blob,
-			&guest_blob, &host3d_blob))
-		return -EINVAL;
+	ret = verify_blob(vgdev, vfpriv, &params, rc_blob,
+			  &guest_blob, &host3d_blob);
+	if (ret)
+		return ret;
 
 	if (vgdev->has_virgl_3d)
 		virtio_gpu_create_context(dev, file);
@@ -538,7 +553,9 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
 				      vfpriv->ctx_id, NULL, NULL);
 	}
 
-	if (guest_blob)
+	if (guest_blob && params.userptr)
+		ret = virtio_gpu_userptr_create(vgdev, file, &params, &bo);
+	else if (guest_blob)
 		ret = virtio_gpu_object_create(vgdev, &params, &bo, NULL);
 	else if (!guest_blob && host3d_blob)
 		ret = virtio_gpu_vram_create(vgdev, &params, &bo);
-- 
2.34.1

Re: [PATCH v8 4/4] drm/virtio: wire blob ioctl creation to userptr objects

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Critical] drm/virtio: privilege escalation via unnegotiated VIRTGPU_BLOB_FLAG_USE_READONLY
--

commit b371f8bf32b2c925d61457787ca19851334b0963
Author: Honglei Huang <honghuan@amd.com>
drm/virtio: wire blob ioctl creation to userptr objects

This commit integrates userptr into the blob resource creation ioctl.
It selects virtio_gpu_userptr_create for non-zero userptrs and
accepts the VIRTGPU_BLOB_FLAG_USE_READONLY flag.

> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> index 3d8e4ccdb7c1f..d42ca3898d4ed 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> @@ -36,7 +36,10 @@
>  
>  #define VIRTGPU_BLOB_FLAG_USE_MASK (VIRTGPU_BLOB_FLAG_USE_MAPPABLE | \
>  				    VIRTGPU_BLOB_FLAG_USE_SHAREABLE | \
> -				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE)
> +				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE | \
> +				    VIRTGPU_BLOB_FLAG_USE_READONLY)
> +
> +#define VIRTGPU_BLOB_HINT_MASK DRM_VIRTGPU_BLOB_FLAG_HINT_DEFER_MAPPING

[ ... ]

> @@ -453,11 +459,18 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
>  	if (rc_blob->blob_flags & ~VIRTGPU_BLOB_FLAG_USE_MASK)
>  		return -EINVAL;

[Severity: Critical]
Does verify_blob() unconditionally allow VIRTGPU_BLOB_FLAG_USE_READONLY 
without verifying if the host emulator actually supports enforcing it?

Other flags, such as VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE, have explicit host 
capability checks (such as vgdev->has_resource_assign_uuid) further down in 
this function. 

If a guest userspace calls DRM_IOCTL_VIRTGPU_RESOURCE_CREATE_BLOB with 
VIRTGPU_BLOB_FLAG_USE_READONLY set and a user pointer to read-only memory, 
the guest pins the memory without FOLL_WRITE. If the hypervisor does not 
understand the READONLY flag, it might ignore it and map the memory as 
read-write. 

Could this allow unprivileged guest users to submit virtio-gpu rendering 
commands that write to the buffer, bypassing the guest's page protections 
and modifying arbitrary read-only memory in the guest?

> +	if (rc_blob->blob_hints & ~VIRTGPU_BLOB_HINT_MASK)
> +		return -EINVAL;
> +
>  	if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE) {
>  		if (!vgdev->has_resource_assign_uuid)
>  			return -EINVAL;
>  	}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260918065653.2170828-1-honghuan@amd.com?part=4

[PATCH v8 4/4] drm/virtio: wire blob ioctl creation to userptr objects

[Honglei Huang]

Integrate userptr into the blob resource creation ioctl.

- A non-zero userptr selects virtio_gpu_userptr_create()
- Reject userptr unless blob_mem is VIRTGPU_BLOB_MEM_GUEST
- Reject VIRTGPU_BLOB_FLAG_USE_READONLY unless the device
  advertised VIRTIO_GPU_F_BLOB_READONLY
- Advertise VIRTGPU_PARAM_USERPTR and VIRTGPU_PARAM_BLOB_READONLY

Signed-off-by: Honglei Huang <honghuan@amd.com>
---
 drivers/gpu/drm/virtio/virtgpu_debugfs.c |  1 +
 drivers/gpu/drm/virtio/virtgpu_ioctl.c   | 35 ++++++++++++++++++++----
 drivers/gpu/drm/virtio/virtgpu_kms.c     |  8 ++++--
 3 files changed, 37 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_debugfs.c b/drivers/gpu/drm/virtio/virtgpu_debugfs.c
index 3a68a16b58..b8b9b40584 100644
--- a/drivers/gpu/drm/virtio/virtgpu_debugfs.c
+++ b/drivers/gpu/drm/virtio/virtgpu_debugfs.c
@@ -55,6 +55,7 @@ static int virtio_gpu_features(struct seq_file *m, void *data)
 			    vgdev->has_resource_assign_uuid);
 
 	virtio_gpu_add_bool(m, "blob resources", vgdev->has_resource_blob);
+	virtio_gpu_add_bool(m, "blob readonly", vgdev->has_blob_readonly);
 	virtio_gpu_add_bool(m, "context init", vgdev->has_context_init);
 	virtio_gpu_add_int(m, "cap sets", vgdev->num_capsets);
 	virtio_gpu_add_int(m, "scanouts", vgdev->num_scanouts);
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 3d8e4ccdb7..3dc058e50e 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -36,7 +36,10 @@
 
 #define VIRTGPU_BLOB_FLAG_USE_MASK (VIRTGPU_BLOB_FLAG_USE_MAPPABLE | \
 				    VIRTGPU_BLOB_FLAG_USE_SHAREABLE | \
-				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE)
+				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE | \
+				    VIRTGPU_BLOB_FLAG_USE_READONLY)
+
+#define VIRTGPU_BLOB_HINT_MASK DRM_VIRTGPU_BLOB_FLAG_HINT_DEFER_MAPPING
 
 /* Must be called with &virtio_gpu_fpriv.struct_mutex held. */
 static void virtio_gpu_create_context_locked(struct virtio_gpu_device *vgdev,
@@ -122,6 +125,12 @@ static int virtio_gpu_getparam_ioctl(struct drm_device *dev, void *data,
 			return -ENOENT;
 		value = vgdev->blob_alignment;
 		break;
+	case VIRTGPU_PARAM_USERPTR:
+		value = 1;
+		break;
+	case VIRTGPU_PARAM_BLOB_READONLY:
+		value = vgdev->has_blob_readonly ? 1 : 0;
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -453,11 +462,23 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
 	if (rc_blob->blob_flags & ~VIRTGPU_BLOB_FLAG_USE_MASK)
 		return -EINVAL;
 
+	if (rc_blob->blob_hints & ~VIRTGPU_BLOB_HINT_MASK)
+		return -EINVAL;
+
 	if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE) {
 		if (!vgdev->has_resource_assign_uuid)
 			return -EINVAL;
 	}
 
+	if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_READONLY) {
+		if (!vgdev->has_blob_readonly)
+			return -EINVAL;
+	}
+
+	if (rc_blob->userptr &&
+	    rc_blob->blob_mem != VIRTGPU_BLOB_MEM_GUEST)
+		return -EINVAL;
+
 	switch (rc_blob->blob_mem) {
 	case VIRTGPU_BLOB_MEM_GUEST:
 		*guest_blob = true;
@@ -495,6 +516,7 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
 	params->blob = true;
 	params->blob_flags = rc_blob->blob_flags;
 	params->blob_hints = rc_blob->blob_hints;
+	params->userptr = rc_blob->userptr;
 
 	if (vgdev->has_blob_alignment &&
 	    !IS_ALIGNED(params->size, vgdev->blob_alignment))
@@ -518,9 +540,10 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
 	struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
 	struct drm_virtgpu_resource_create_blob *rc_blob = data;
 
-	if (verify_blob(vgdev, vfpriv, &params, rc_blob,
-			&guest_blob, &host3d_blob))
-		return -EINVAL;
+	ret = verify_blob(vgdev, vfpriv, &params, rc_blob,
+			  &guest_blob, &host3d_blob);
+	if (ret)
+		return ret;
 
 	if (vgdev->has_virgl_3d)
 		virtio_gpu_create_context(dev, file);
@@ -538,7 +561,9 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
 				      vfpriv->ctx_id, NULL, NULL);
 	}
 
-	if (guest_blob)
+	if (guest_blob && params.userptr)
+		ret = virtio_gpu_userptr_create(vgdev, file, &params, &bo);
+	else if (guest_blob)
 		ret = virtio_gpu_object_create(vgdev, &params, &bo, NULL);
 	else if (!guest_blob && host3d_blob)
 		ret = virtio_gpu_vram_create(vgdev, &params, &bo);
diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 1d4d3bf46a..06c2bded49 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -249,15 +249,19 @@ int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
 		vgdev->blob_alignment = blob_alignment;
 	}
 
+	if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_BLOB_READONLY))
+		vgdev->has_blob_readonly = true;
+
 	DRM_INFO("features: %cvirgl %cedid %cresource_blob %chost_visible",
 		 vgdev->has_virgl_3d    ? '+' : '-',
 		 vgdev->has_edid        ? '+' : '-',
 		 vgdev->has_resource_blob ? '+' : '-',
 		 vgdev->has_host_visible ? '+' : '-');
 
-	DRM_INFO("features: %ccontext_init %cblob_alignment\n",
+	DRM_INFO("features: %ccontext_init %cblob_alignment %cblob_readonly\n",
 		 vgdev->has_context_init ? '+' : '-',
-		 vgdev->has_blob_alignment ? '+' : '-');
+		 vgdev->has_blob_alignment ? '+' : '-',
+		 vgdev->has_blob_readonly ? '+' : '-');
 
 	ret = virtio_gpu_find_vqs(vgdev);
 	if (ret) {
-- 
2.34.1

Re: [PATCH v8 4/4] drm/virtio: wire blob ioctl creation to userptr objects

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] drm/virtio: resource loss on resume for userptr blobs
--

commit 260e023045965d09441bfc27b3e47cf7b409d5b4
Author: Honglei Huang <honghuan@amd.com>

drm/virtio: wire blob ioctl creation to userptr objects

This commit integrates userptr into the blob resource creation ioctl.
It adds validation and wires up virtio_gpu_userptr_create() for guest
blob allocations.

> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
[ ... ]
> @@ -538,7 +561,9 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
>  				      vfpriv->ctx_id, NULL, NULL);
>  	}
>  
> -	if (guest_blob)
> +	if (guest_blob && params.userptr)
> +		ret = virtio_gpu_userptr_create(vgdev, file, &params, &bo);

[Severity: High]
Does this code handle system hibernation properly for userptr objects?

When virtio_gpu_userptr_create() in drivers/gpu/drm/virtio/virtgpu_userptr.c
successfully allocates the object, it returns without saving bo->params or
calling virtio_gpu_add_object_to_restore_list():

	virtio_gpu_cmd_resource_create_blob(vgdev, &userptr->base, params, ents,
					    nents);

	*bo_ptr = &userptr->base;
	return 0;

Consequently, these objects are permanently lost when the system resumes from
hibernation because their host-side resources are not re-created. Subsequent
GPU commands referencing these resources will fail.

Additionally, if these userptr objects were added to the obj_restore_list, it
seems virtio_gpu_object_restore_all() in drivers/gpu/drm/virtio/virtgpu_object.c
would crash:

	if (bo->params.blob || bo->attached) {
		ret = virtio_gpu_object_shmem_init(vgdev, bo, &ents,
						   &nents);
		if (ret)
			break;
	}

This logic assumes all non-imported blobs are backed by drm_gem_shmem_object,
but userptr blobs are not.

> +	else if (guest_blob)
>  		ret = virtio_gpu_object_create(vgdev, &params, &bo, NULL);
>  	else if (!guest_blob && host3d_blob)
>  		ret = virtio_gpu_vram_create(vgdev, &params, &bo);

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260918075600.2197253-1-honghuan@amd.com?part=4

[PATCH v8 4/4] drm/virtio: wire blob ioctl creation to userptr objects

[Honglei Huang]

Integrate userptr into the blob resource creation ioctl.

- A non-zero userptr selects virtio_gpu_userptr_create()
- Reject userptr unless blob_mem is VIRTGPU_BLOB_MEM_GUEST
- Reject VIRTGPU_BLOB_FLAG_USE_READONLY unless the device
  advertised VIRTIO_GPU_F_BLOB_READONLY
- Advertise VIRTGPU_PARAM_USERPTR and VIRTGPU_PARAM_BLOB_READONLY

Signed-off-by: Honglei Huang <honghuan@amd.com>
---
 drivers/gpu/drm/virtio/virtgpu_debugfs.c |  1 +
 drivers/gpu/drm/virtio/virtgpu_ioctl.c   | 35 ++++++++++++++++++++----
 drivers/gpu/drm/virtio/virtgpu_kms.c     |  8 ++++--
 3 files changed, 37 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_debugfs.c b/drivers/gpu/drm/virtio/virtgpu_debugfs.c
index 3a68a16b58..b8b9b40584 100644
--- a/drivers/gpu/drm/virtio/virtgpu_debugfs.c
+++ b/drivers/gpu/drm/virtio/virtgpu_debugfs.c
@@ -55,6 +55,7 @@ static int virtio_gpu_features(struct seq_file *m, void *data)
 			    vgdev->has_resource_assign_uuid);
 
 	virtio_gpu_add_bool(m, "blob resources", vgdev->has_resource_blob);
+	virtio_gpu_add_bool(m, "blob readonly", vgdev->has_blob_readonly);
 	virtio_gpu_add_bool(m, "context init", vgdev->has_context_init);
 	virtio_gpu_add_int(m, "cap sets", vgdev->num_capsets);
 	virtio_gpu_add_int(m, "scanouts", vgdev->num_scanouts);
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 3d8e4ccdb7..3dc058e50e 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -36,7 +36,10 @@
 
 #define VIRTGPU_BLOB_FLAG_USE_MASK (VIRTGPU_BLOB_FLAG_USE_MAPPABLE | \
 				    VIRTGPU_BLOB_FLAG_USE_SHAREABLE | \
-				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE)
+				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE | \
+				    VIRTGPU_BLOB_FLAG_USE_READONLY)
+
+#define VIRTGPU_BLOB_HINT_MASK DRM_VIRTGPU_BLOB_FLAG_HINT_DEFER_MAPPING
 
 /* Must be called with &virtio_gpu_fpriv.struct_mutex held. */
 static void virtio_gpu_create_context_locked(struct virtio_gpu_device *vgdev,
@@ -122,6 +125,12 @@ static int virtio_gpu_getparam_ioctl(struct drm_device *dev, void *data,
 			return -ENOENT;
 		value = vgdev->blob_alignment;
 		break;
+	case VIRTGPU_PARAM_USERPTR:
+		value = 1;
+		break;
+	case VIRTGPU_PARAM_BLOB_READONLY:
+		value = vgdev->has_blob_readonly ? 1 : 0;
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -453,11 +462,23 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
 	if (rc_blob->blob_flags & ~VIRTGPU_BLOB_FLAG_USE_MASK)
 		return -EINVAL;
 
+	if (rc_blob->blob_hints & ~VIRTGPU_BLOB_HINT_MASK)
+		return -EINVAL;
+
 	if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE) {
 		if (!vgdev->has_resource_assign_uuid)
 			return -EINVAL;
 	}
 
+	if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_READONLY) {
+		if (!vgdev->has_blob_readonly)
+			return -EINVAL;
+	}
+
+	if (rc_blob->userptr &&
+	    rc_blob->blob_mem != VIRTGPU_BLOB_MEM_GUEST)
+		return -EINVAL;
+
 	switch (rc_blob->blob_mem) {
 	case VIRTGPU_BLOB_MEM_GUEST:
 		*guest_blob = true;
@@ -495,6 +516,7 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
 	params->blob = true;
 	params->blob_flags = rc_blob->blob_flags;
 	params->blob_hints = rc_blob->blob_hints;
+	params->userptr = rc_blob->userptr;
 
 	if (vgdev->has_blob_alignment &&
 	    !IS_ALIGNED(params->size, vgdev->blob_alignment))
@@ -518,9 +540,10 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
 	struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
 	struct drm_virtgpu_resource_create_blob *rc_blob = data;
 
-	if (verify_blob(vgdev, vfpriv, &params, rc_blob,
-			&guest_blob, &host3d_blob))
-		return -EINVAL;
+	ret = verify_blob(vgdev, vfpriv, &params, rc_blob,
+			  &guest_blob, &host3d_blob);
+	if (ret)
+		return ret;
 
 	if (vgdev->has_virgl_3d)
 		virtio_gpu_create_context(dev, file);
@@ -538,7 +561,9 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
 				      vfpriv->ctx_id, NULL, NULL);
 	}
 
-	if (guest_blob)
+	if (guest_blob && params.userptr)
+		ret = virtio_gpu_userptr_create(vgdev, file, &params, &bo);
+	else if (guest_blob)
 		ret = virtio_gpu_object_create(vgdev, &params, &bo, NULL);
 	else if (!guest_blob && host3d_blob)
 		ret = virtio_gpu_vram_create(vgdev, &params, &bo);
diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 1d4d3bf46a..06c2bded49 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -249,15 +249,19 @@ int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
 		vgdev->blob_alignment = blob_alignment;
 	}
 
+	if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_BLOB_READONLY))
+		vgdev->has_blob_readonly = true;
+
 	DRM_INFO("features: %cvirgl %cedid %cresource_blob %chost_visible",
 		 vgdev->has_virgl_3d    ? '+' : '-',
 		 vgdev->has_edid        ? '+' : '-',
 		 vgdev->has_resource_blob ? '+' : '-',
 		 vgdev->has_host_visible ? '+' : '-');
 
-	DRM_INFO("features: %ccontext_init %cblob_alignment\n",
+	DRM_INFO("features: %ccontext_init %cblob_alignment %cblob_readonly\n",
 		 vgdev->has_context_init ? '+' : '-',
-		 vgdev->has_blob_alignment ? '+' : '-');
+		 vgdev->has_blob_alignment ? '+' : '-',
+		 vgdev->has_blob_readonly ? '+' : '-');
 
 	ret = virtio_gpu_find_vqs(vgdev);
 	if (ret) {
-- 
2.34.1

[PATCH v8 4/4] drm/virtio: wire blob ioctl creation to userptr objects

[Honglei Huang]

Integrate userptr into the blob resource creation ioctl.

- A non-zero userptr selects virtio_gpu_userptr_create()
- Reject userptr unless blob_mem is VIRTGPU_BLOB_MEM_GUEST
- Reject VIRTGPU_BLOB_FLAG_USE_READONLY unless the device
  advertised VIRTIO_GPU_F_BLOB_READONLY
- Advertise VIRTGPU_PARAM_USERPTR and VIRTGPU_PARAM_BLOB_READONLY

Signed-off-by: Honglei Huang <honghuan@amd.com>
---
 drivers/gpu/drm/virtio/virtgpu_debugfs.c |  1 +
 drivers/gpu/drm/virtio/virtgpu_ioctl.c   | 35 ++++++++++++++++++++----
 drivers/gpu/drm/virtio/virtgpu_kms.c     |  8 ++++--
 3 files changed, 37 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_debugfs.c b/drivers/gpu/drm/virtio/virtgpu_debugfs.c
index 3a68a16b58..b8b9b40584 100644
--- a/drivers/gpu/drm/virtio/virtgpu_debugfs.c
+++ b/drivers/gpu/drm/virtio/virtgpu_debugfs.c
@@ -55,6 +55,7 @@ static int virtio_gpu_features(struct seq_file *m, void *data)
 			    vgdev->has_resource_assign_uuid);
 
 	virtio_gpu_add_bool(m, "blob resources", vgdev->has_resource_blob);
+	virtio_gpu_add_bool(m, "blob readonly", vgdev->has_blob_readonly);
 	virtio_gpu_add_bool(m, "context init", vgdev->has_context_init);
 	virtio_gpu_add_int(m, "cap sets", vgdev->num_capsets);
 	virtio_gpu_add_int(m, "scanouts", vgdev->num_scanouts);
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 3d8e4ccdb7..3dc058e50e 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -36,7 +36,10 @@
 
 #define VIRTGPU_BLOB_FLAG_USE_MASK (VIRTGPU_BLOB_FLAG_USE_MAPPABLE | \
 				    VIRTGPU_BLOB_FLAG_USE_SHAREABLE | \
-				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE)
+				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE | \
+				    VIRTGPU_BLOB_FLAG_USE_READONLY)
+
+#define VIRTGPU_BLOB_HINT_MASK DRM_VIRTGPU_BLOB_FLAG_HINT_DEFER_MAPPING
 
 /* Must be called with &virtio_gpu_fpriv.struct_mutex held. */
 static void virtio_gpu_create_context_locked(struct virtio_gpu_device *vgdev,
@@ -122,6 +125,12 @@ static int virtio_gpu_getparam_ioctl(struct drm_device *dev, void *data,
 			return -ENOENT;
 		value = vgdev->blob_alignment;
 		break;
+	case VIRTGPU_PARAM_USERPTR:
+		value = 1;
+		break;
+	case VIRTGPU_PARAM_BLOB_READONLY:
+		value = vgdev->has_blob_readonly ? 1 : 0;
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -453,11 +462,23 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
 	if (rc_blob->blob_flags & ~VIRTGPU_BLOB_FLAG_USE_MASK)
 		return -EINVAL;
 
+	if (rc_blob->blob_hints & ~VIRTGPU_BLOB_HINT_MASK)
+		return -EINVAL;
+
 	if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE) {
 		if (!vgdev->has_resource_assign_uuid)
 			return -EINVAL;
 	}
 
+	if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_READONLY) {
+		if (!vgdev->has_blob_readonly)
+			return -EINVAL;
+	}
+
+	if (rc_blob->userptr &&
+	    rc_blob->blob_mem != VIRTGPU_BLOB_MEM_GUEST)
+		return -EINVAL;
+
 	switch (rc_blob->blob_mem) {
 	case VIRTGPU_BLOB_MEM_GUEST:
 		*guest_blob = true;
@@ -495,6 +516,7 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
 	params->blob = true;
 	params->blob_flags = rc_blob->blob_flags;
 	params->blob_hints = rc_blob->blob_hints;
+	params->userptr = rc_blob->userptr;
 
 	if (vgdev->has_blob_alignment &&
 	    !IS_ALIGNED(params->size, vgdev->blob_alignment))
@@ -518,9 +540,10 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
 	struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
 	struct drm_virtgpu_resource_create_blob *rc_blob = data;
 
-	if (verify_blob(vgdev, vfpriv, &params, rc_blob,
-			&guest_blob, &host3d_blob))
-		return -EINVAL;
+	ret = verify_blob(vgdev, vfpriv, &params, rc_blob,
+			  &guest_blob, &host3d_blob);
+	if (ret)
+		return ret;
 
 	if (vgdev->has_virgl_3d)
 		virtio_gpu_create_context(dev, file);
@@ -538,7 +561,9 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
 				      vfpriv->ctx_id, NULL, NULL);
 	}
 
-	if (guest_blob)
+	if (guest_blob && params.userptr)
+		ret = virtio_gpu_userptr_create(vgdev, file, &params, &bo);
+	else if (guest_blob)
 		ret = virtio_gpu_object_create(vgdev, &params, &bo, NULL);
 	else if (!guest_blob && host3d_blob)
 		ret = virtio_gpu_vram_create(vgdev, &params, &bo);
diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 1d4d3bf46a..06c2bded49 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -249,15 +249,19 @@ int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
 		vgdev->blob_alignment = blob_alignment;
 	}
 
+	if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_BLOB_READONLY))
+		vgdev->has_blob_readonly = true;
+
 	DRM_INFO("features: %cvirgl %cedid %cresource_blob %chost_visible",
 		 vgdev->has_virgl_3d    ? '+' : '-',
 		 vgdev->has_edid        ? '+' : '-',
 		 vgdev->has_resource_blob ? '+' : '-',
 		 vgdev->has_host_visible ? '+' : '-');
 
-	DRM_INFO("features: %ccontext_init %cblob_alignment\n",
+	DRM_INFO("features: %ccontext_init %cblob_alignment %cblob_readonly\n",
 		 vgdev->has_context_init ? '+' : '-',
-		 vgdev->has_blob_alignment ? '+' : '-');
+		 vgdev->has_blob_alignment ? '+' : '-',
+		 vgdev->has_blob_readonly ? '+' : '-');
 
 	ret = virtio_gpu_find_vqs(vgdev);
 	if (ret) {
-- 
2.34.1

Re: [PATCH v8 4/4] drm/virtio: wire blob ioctl creation to userptr objects

[sashiko-bot]

> Integrate userptr into the blob resource creation ioctl.
> 
> - A non-zero userptr selects virtio_gpu_userptr_create()
> - Reject userptr unless blob_mem is VIRTGPU_BLOB_MEM_GUEST
> - Reject VIRTGPU_BLOB_FLAG_USE_READONLY unless the device
>   advertised VIRTIO_GPU_F_BLOB_READONLY
> - Advertise VIRTGPU_PARAM_USERPTR and VIRTGPU_PARAM_BLOB_READONLY
> 
> Signed-off-by: Honglei Huang <honghuan@amd.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260918095940.2253018-1-honghuan@amd.com?part=4

Re: [PATCH v8 4/4] drm/virtio: wire blob ioctl creation to userptr objects

[Akihiko Odaki]

On 2026/09/18 18:59, Honglei Huang wrote:
> Integrate userptr into the blob resource creation ioctl.
> 
> - A non-zero userptr selects virtio_gpu_userptr_create()
> - Reject userptr unless blob_mem is VIRTGPU_BLOB_MEM_GUEST
> - Reject VIRTGPU_BLOB_FLAG_USE_READONLY unless the device
>    advertised VIRTIO_GPU_F_BLOB_READONLY
> - Advertise VIRTGPU_PARAM_USERPTR and VIRTGPU_PARAM_BLOB_READONLY
> 
> Signed-off-by: Honglei Huang <honghuan@amd.com>
> ---
>   drivers/gpu/drm/virtio/virtgpu_debugfs.c |  1 +
>   drivers/gpu/drm/virtio/virtgpu_ioctl.c   | 35 ++++++++++++++++++++----
>   drivers/gpu/drm/virtio/virtgpu_kms.c     |  8 ++++--
>   3 files changed, 37 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/virtio/virtgpu_debugfs.c b/drivers/gpu/drm/virtio/virtgpu_debugfs.c
> index 3a68a16b58..b8b9b40584 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_debugfs.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_debugfs.c
> @@ -55,6 +55,7 @@ static int virtio_gpu_features(struct seq_file *m, void *data)
>   			    vgdev->has_resource_assign_uuid);
>   
>   	virtio_gpu_add_bool(m, "blob resources", vgdev->has_resource_blob);
> +	virtio_gpu_add_bool(m, "blob readonly", vgdev->has_blob_readonly);
>   	virtio_gpu_add_bool(m, "context init", vgdev->has_context_init);
>   	virtio_gpu_add_int(m, "cap sets", vgdev->num_capsets);
>   	virtio_gpu_add_int(m, "scanouts", vgdev->num_scanouts);
> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> index 3d8e4ccdb7..3dc058e50e 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> @@ -36,7 +36,10 @@
>   
>   #define VIRTGPU_BLOB_FLAG_USE_MASK (VIRTGPU_BLOB_FLAG_USE_MAPPABLE | \
>   				    VIRTGPU_BLOB_FLAG_USE_SHAREABLE | \
> -				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE)
> +				    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE | \
> +				    VIRTGPU_BLOB_FLAG_USE_READONLY)
> +
> +#define VIRTGPU_BLOB_HINT_MASK DRM_VIRTGPU_BLOB_FLAG_HINT_DEFER_MAPPING
>   
>   /* Must be called with &virtio_gpu_fpriv.struct_mutex held. */
>   static void virtio_gpu_create_context_locked(struct virtio_gpu_device *vgdev,
> @@ -122,6 +125,12 @@ static int virtio_gpu_getparam_ioctl(struct drm_device *dev, void *data,
>   			return -ENOENT;
>   		value = vgdev->blob_alignment;
>   		break;
> +	case VIRTGPU_PARAM_USERPTR:
> +		value = 1;
> +		break;
> +	case VIRTGPU_PARAM_BLOB_READONLY:
> +		value = vgdev->has_blob_readonly ? 1 : 0;
> +		break;
>   	default:
>   		return -EINVAL;
>   	}
> @@ -453,11 +462,23 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
>   	if (rc_blob->blob_flags & ~VIRTGPU_BLOB_FLAG_USE_MASK)
>   		return -EINVAL;
>   
> +	if (rc_blob->blob_hints & ~VIRTGPU_BLOB_HINT_MASK)
> +		return -EINVAL;
> +
>   	if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE) {
>   		if (!vgdev->has_resource_assign_uuid)
>   			return -EINVAL;
>   	}
>   
> +	if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_READONLY) {
> +		if (!vgdev->has_blob_readonly)
> +			return -EINVAL;
> +	}
> +
> +	if (rc_blob->userptr &&
> +	    rc_blob->blob_mem != VIRTGPU_BLOB_MEM_GUEST)
> +		return -EINVAL;
> +
>   	switch (rc_blob->blob_mem) {
>   	case VIRTGPU_BLOB_MEM_GUEST:
>   		*guest_blob = true;
> @@ -495,6 +516,7 @@ static int verify_blob(struct virtio_gpu_device *vgdev,
>   	params->blob = true;
>   	params->blob_flags = rc_blob->blob_flags;
>   	params->blob_hints = rc_blob->blob_hints;
> +	params->userptr = rc_blob->userptr;
>   
>   	if (vgdev->has_blob_alignment &&
>   	    !IS_ALIGNED(params->size, vgdev->blob_alignment))
> @@ -518,9 +540,10 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
>   	struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
>   	struct drm_virtgpu_resource_create_blob *rc_blob = data;
>   
> -	if (verify_blob(vgdev, vfpriv, &params, rc_blob,
> -			&guest_blob, &host3d_blob))
> -		return -EINVAL;
> +	ret = verify_blob(vgdev, vfpriv, &params, rc_blob,
> +			  &guest_blob, &host3d_blob);
> +	if (ret)
> +		return ret;
>   
>   	if (vgdev->has_virgl_3d)
>   		virtio_gpu_create_context(dev, file);
> @@ -538,7 +561,9 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
>   				      vfpriv->ctx_id, NULL, NULL);
>   	}
>   
> -	if (guest_blob)
> +	if (guest_blob && params.userptr)
> +		ret = virtio_gpu_userptr_create(vgdev, file, &params, &bo);
> +	else if (guest_blob)
>   		ret = virtio_gpu_object_create(vgdev, &params, &bo, NULL);
>   	else if (!guest_blob && host3d_blob)
>   		ret = virtio_gpu_vram_create(vgdev, &params, &bo);
> diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
> index 1d4d3bf46a..06c2bded49 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_kms.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
> @@ -249,15 +249,19 @@ int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
>   		vgdev->blob_alignment = blob_alignment;
>   	}
>   
> +	if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_BLOB_READONLY))

This hits BUG(). It queries queries VIRTIO_GPU_F_BLOB_READONLY, but the 
feature is absent from the driver’s features[]. virtio_has_feature() 
validates device-specific queries through 
virtio_check_driver_offered_feature(), which executes BUG() for an 
unregistered feature. This affects ordinary probe regardless of host 
support.

Please add the feature to the array and ensure that the patch is 
properly tested before submission.

Regards,
Akihiko Odaki

> +		vgdev->has_blob_readonly = true;
> +
>   	DRM_INFO("features: %cvirgl %cedid %cresource_blob %chost_visible",
>   		 vgdev->has_virgl_3d    ? '+' : '-',
>   		 vgdev->has_edid        ? '+' : '-',
>   		 vgdev->has_resource_blob ? '+' : '-',
>   		 vgdev->has_host_visible ? '+' : '-');
>   
> -	DRM_INFO("features: %ccontext_init %cblob_alignment\n",
> +	DRM_INFO("features: %ccontext_init %cblob_alignment %cblob_readonly\n",
>   		 vgdev->has_context_init ? '+' : '-',
> -		 vgdev->has_blob_alignment ? '+' : '-');
> +		 vgdev->has_blob_alignment ? '+' : '-',
> +		 vgdev->has_blob_readonly ? '+' : '-');
>   
>   	ret = virtio_gpu_find_vqs(vgdev);
>   	if (ret) {

Re: [PATCH v8 4/4] drm/virtio: wire blob ioctl creation to userptr objects

[Huang, Honglei]

On 9/19/2026 10:28 PM, Akihiko Odaki wrote:
> On 2026/09/18 18:59, Honglei Huang wrote:
>> Integrate userptr into the blob resource creation ioctl.
>>
>> - A non-zero userptr selects virtio_gpu_userptr_create()
>> - Reject userptr unless blob_mem is VIRTGPU_BLOB_MEM_GUEST
>> - Reject VIRTGPU_BLOB_FLAG_USE_READONLY unless the device
>>    advertised VIRTIO_GPU_F_BLOB_READONLY
>> - Advertise VIRTGPU_PARAM_USERPTR and VIRTGPU_PARAM_BLOB_READONLY
>>
>> Signed-off-by: Honglei Huang <honghuan@amd.com>
>> ---
>>   drivers/gpu/drm/virtio/virtgpu_debugfs.c |  1 +
>>   drivers/gpu/drm/virtio/virtgpu_ioctl.c   | 35 ++++++++++++++++++++----
>>   drivers/gpu/drm/virtio/virtgpu_kms.c     |  8 ++++--
>>   3 files changed, 37 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/virtio/virtgpu_debugfs.c b/drivers/gpu/ 
>> drm/virtio/virtgpu_debugfs.c
>> index 3a68a16b58..b8b9b40584 100644
>> --- a/drivers/gpu/drm/virtio/virtgpu_debugfs.c
>> +++ b/drivers/gpu/drm/virtio/virtgpu_debugfs.c
>> @@ -55,6 +55,7 @@ static int virtio_gpu_features(struct seq_file *m, 
>> void *data)
>>                   vgdev->has_resource_assign_uuid);
>>       virtio_gpu_add_bool(m, "blob resources", vgdev->has_resource_blob);
>> +    virtio_gpu_add_bool(m, "blob readonly", vgdev->has_blob_readonly);
>>       virtio_gpu_add_bool(m, "context init", vgdev->has_context_init);
>>       virtio_gpu_add_int(m, "cap sets", vgdev->num_capsets);
>>       virtio_gpu_add_int(m, "scanouts", vgdev->num_scanouts);
>> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/ 
>> virtio/virtgpu_ioctl.c
>> index 3d8e4ccdb7..3dc058e50e 100644
>> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
>> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
>> @@ -36,7 +36,10 @@
>>   #define VIRTGPU_BLOB_FLAG_USE_MASK (VIRTGPU_BLOB_FLAG_USE_MAPPABLE | \
>>                       VIRTGPU_BLOB_FLAG_USE_SHAREABLE | \
>> -                    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE)
>> +                    VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE | \
>> +                    VIRTGPU_BLOB_FLAG_USE_READONLY)
>> +
>> +#define VIRTGPU_BLOB_HINT_MASK DRM_VIRTGPU_BLOB_FLAG_HINT_DEFER_MAPPING
>>   /* Must be called with &virtio_gpu_fpriv.struct_mutex held. */
>>   static void virtio_gpu_create_context_locked(struct 
>> virtio_gpu_device *vgdev,
>> @@ -122,6 +125,12 @@ static int virtio_gpu_getparam_ioctl(struct 
>> drm_device *dev, void *data,
>>               return -ENOENT;
>>           value = vgdev->blob_alignment;
>>           break;
>> +    case VIRTGPU_PARAM_USERPTR:
>> +        value = 1;
>> +        break;
>> +    case VIRTGPU_PARAM_BLOB_READONLY:
>> +        value = vgdev->has_blob_readonly ? 1 : 0;
>> +        break;
>>       default:
>>           return -EINVAL;
>>       }
>> @@ -453,11 +462,23 @@ static int verify_blob(struct virtio_gpu_device 
>> *vgdev,
>>       if (rc_blob->blob_flags & ~VIRTGPU_BLOB_FLAG_USE_MASK)
>>           return -EINVAL;
>> +    if (rc_blob->blob_hints & ~VIRTGPU_BLOB_HINT_MASK)
>> +        return -EINVAL;
>> +
>>       if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_CROSS_DEVICE) {
>>           if (!vgdev->has_resource_assign_uuid)
>>               return -EINVAL;
>>       }
>> +    if (rc_blob->blob_flags & VIRTGPU_BLOB_FLAG_USE_READONLY) {
>> +        if (!vgdev->has_blob_readonly)
>> +            return -EINVAL;
>> +    }
>> +
>> +    if (rc_blob->userptr &&
>> +        rc_blob->blob_mem != VIRTGPU_BLOB_MEM_GUEST)
>> +        return -EINVAL;
>> +
>>       switch (rc_blob->blob_mem) {
>>       case VIRTGPU_BLOB_MEM_GUEST:
>>           *guest_blob = true;
>> @@ -495,6 +516,7 @@ static int verify_blob(struct virtio_gpu_device 
>> *vgdev,
>>       params->blob = true;
>>       params->blob_flags = rc_blob->blob_flags;
>>       params->blob_hints = rc_blob->blob_hints;
>> +    params->userptr = rc_blob->userptr;
>>       if (vgdev->has_blob_alignment &&
>>           !IS_ALIGNED(params->size, vgdev->blob_alignment))
>> @@ -518,9 +540,10 @@ static int 
>> virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
>>       struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
>>       struct drm_virtgpu_resource_create_blob *rc_blob = data;
>> -    if (verify_blob(vgdev, vfpriv, &params, rc_blob,
>> -            &guest_blob, &host3d_blob))
>> -        return -EINVAL;
>> +    ret = verify_blob(vgdev, vfpriv, &params, rc_blob,
>> +              &guest_blob, &host3d_blob);
>> +    if (ret)
>> +        return ret;
>>       if (vgdev->has_virgl_3d)
>>           virtio_gpu_create_context(dev, file);
>> @@ -538,7 +561,9 @@ static int 
>> virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
>>                         vfpriv->ctx_id, NULL, NULL);
>>       }
>> -    if (guest_blob)
>> +    if (guest_blob && params.userptr)
>> +        ret = virtio_gpu_userptr_create(vgdev, file, &params, &bo);
>> +    else if (guest_blob)
>>           ret = virtio_gpu_object_create(vgdev, &params, &bo, NULL);
>>       else if (!guest_blob && host3d_blob)
>>           ret = virtio_gpu_vram_create(vgdev, &params, &bo);
>> diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/ 
>> virtio/virtgpu_kms.c
>> index 1d4d3bf46a..06c2bded49 100644
>> --- a/drivers/gpu/drm/virtio/virtgpu_kms.c
>> +++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
>> @@ -249,15 +249,19 @@ int virtio_gpu_init(struct virtio_device *vdev, 
>> struct drm_device *dev)
>>           vgdev->blob_alignment = blob_alignment;
>>       }
>> +    if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_BLOB_READONLY))
> 
> This hits BUG(). It queries queries VIRTIO_GPU_F_BLOB_READONLY, but the 
> feature is absent from the driver’s features[]. virtio_has_feature() 
> validates device-specific queries through 
> virtio_check_driver_offered_feature(), which executes BUG() for an 
> unregistered feature. This affects ordinary probe regardless of host 
> support.
> 
> Please add the feature to the array and ensure that the patch is 
> properly tested before submission.

Really thanks for the point out, we did test in previous version patch,
but for passing AI review I have to added the VIRTIO_GPU_F_BLOB_READONLY 
before send out, the AI review are so many, to address it I made many 
changes, resulted in this issue being overlooked. And I have tested the 
V9, the guest boot is OK, basic function is ok.

And due to the changing for virtio gpu, many other components need to be 
changed, need some times to give qemu/virglrender... code. We have a
lot of parallel tasks here. But I will keep changing code until you are 
satisfied.

Regards,
Honglei


> 
> Regards,
> Akihiko Odaki
> 
>> +        vgdev->has_blob_readonly = true;
>> +
>>       DRM_INFO("features: %cvirgl %cedid %cresource_blob %chost_visible",
>>            vgdev->has_virgl_3d    ? '+' : '-',
>>            vgdev->has_edid        ? '+' : '-',
>>            vgdev->has_resource_blob ? '+' : '-',
>>            vgdev->has_host_visible ? '+' : '-');
>> -    DRM_INFO("features: %ccontext_init %cblob_alignment\n",
>> +    DRM_INFO("features: %ccontext_init %cblob_alignment 
>> %cblob_readonly\n",
>>            vgdev->has_context_init ? '+' : '-',
>> -         vgdev->has_blob_alignment ? '+' : '-');
>> +         vgdev->has_blob_alignment ? '+' : '-',
>> +         vgdev->has_blob_readonly ? '+' : '-');
>>       ret = virtio_gpu_find_vqs(vgdev);
>>       if (ret) {
>