[PATCH] drm/virtio: Don't detach GEM from a non-created context

[PATCH] drm/virtio: Don't detach GEM from a non-created context

[Jason Macnak]

Applies the same treatment as commit 7cf6dd467e87 ("drm/virtio:
Don't attach GEM to a non-created context in gem_object_open()")
to virtio_gpu_gem_object_close() to avoid trying to detach
a resource that was never attached due to a context
never being created when context_init is supported.

Fixes: 086b9f27f0ab ("drm/virtio: Don't create a context with default param if context_init is supported")
Cc: <stable@vger.kernel.org> # v6.14+
Signed-off-by: Jason Macnak <natsu@google.com>
---
 drivers/gpu/drm/virtio/virtgpu_gem.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c
index 435d37d36034..66c3f6f74e9c 100644
--- a/drivers/gpu/drm/virtio/virtgpu_gem.c
+++ b/drivers/gpu/drm/virtio/virtgpu_gem.c
@@ -139,13 +139,15 @@ void virtio_gpu_gem_object_close(struct drm_gem_object *obj,
 	if (!vgdev->has_virgl_3d)
 		return;
 
-	objs = virtio_gpu_array_alloc(1);
-	if (!objs)
-		return;
-	virtio_gpu_array_add_obj(objs, obj);
+	if (vfpriv->context_created) {
+		objs = virtio_gpu_array_alloc(1);
+		if (!objs)
+			return;
+		virtio_gpu_array_add_obj(objs, obj);
 
-	virtio_gpu_cmd_context_detach_resource(vgdev, vfpriv->ctx_id,
-					       objs);
+		virtio_gpu_cmd_context_detach_resource(vgdev, vfpriv->ctx_id,
+						       objs);
+	}
 	virtio_gpu_notify(vgdev);
 }
 
-- 
2.55.0.rc0.799.gd6f94ed593-goog

Re: [PATCH] drm/virtio: Don't detach GEM from a non-created context

[Dmitry Osipenko]

Hi,

On 6/25/26 20:08, Jason Macnak wrote:
> Applies the same treatment as commit 7cf6dd467e87 ("drm/virtio:
> Don't attach GEM to a non-created context in gem_object_open()")
> to virtio_gpu_gem_object_close() to avoid trying to detach
> a resource that was never attached due to a context
> never being created when context_init is supported.
> 
> Fixes: 086b9f27f0ab ("drm/virtio: Don't create a context with default param if context_init is supported")
> Cc: <stable@vger.kernel.org> # v6.14+
> Signed-off-by: Jason Macnak <natsu@google.com>
> ---
>  drivers/gpu/drm/virtio/virtgpu_gem.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c
> index 435d37d36034..66c3f6f74e9c 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_gem.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_gem.c
> @@ -139,13 +139,15 @@ void virtio_gpu_gem_object_close(struct drm_gem_object *obj,
>  	if (!vgdev->has_virgl_3d)
>  		return;
>  
> -	objs = virtio_gpu_array_alloc(1);
> -	if (!objs)
> -		return;
> -	virtio_gpu_array_add_obj(objs, obj);
> +	if (vfpriv->context_created) {
> +		objs = virtio_gpu_array_alloc(1);
> +		if (!objs)
> +			return;
> +		virtio_gpu_array_add_obj(objs, obj);
>  
> -	virtio_gpu_cmd_context_detach_resource(vgdev, vfpriv->ctx_id,
> -					       objs);
> +		virtio_gpu_cmd_context_detach_resource(vgdev, vfpriv->ctx_id,
> +						       objs);
> +	}
>  	virtio_gpu_notify(vgdev);
>  }

The following scenario still will be troubling:

1. vgdev->has_context_init = true
2. virtio_gpu_gem_object_open() invoked, GEM created and not attached to ctx
3. virtio_gpu_context_init_ioctl() invoked, now vfpriv->context_created
= true
4. virtio_gpu_gem_object_close() will detach resource that wasn't attached

Add obj->ctx_attached member to struct virtio_gpu_object. See
virtio_gpu_object_attach() that uses obj->attached, do the same for
virtio_gpu_cmd_context_attach_resource().

-- 
Best regards,
Dmitry

Re: [PATCH] drm/virtio: Don't detach GEM from a non-created context

[Yiwei Zhang]

On Mon, Jun 29, 2026 at 2:39 PM Dmitry Osipenko
<dmitry.osipenko@collabora.com> wrote:
>
> Hi,
>
> On 6/25/26 20:08, Jason Macnak wrote:
> > Applies the same treatment as commit 7cf6dd467e87 ("drm/virtio:
> > Don't attach GEM to a non-created context in gem_object_open()")
> > to virtio_gpu_gem_object_close() to avoid trying to detach
> > a resource that was never attached due to a context
> > never being created when context_init is supported.
> >
> > Fixes: 086b9f27f0ab ("drm/virtio: Don't create a context with default param if context_init is supported")
> > Cc: <stable@vger.kernel.org> # v6.14+
> > Signed-off-by: Jason Macnak <natsu@google.com>
> > ---
> >  drivers/gpu/drm/virtio/virtgpu_gem.c | 14 ++++++++------
> >  1 file changed, 8 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c
> > index 435d37d36034..66c3f6f74e9c 100644
> > --- a/drivers/gpu/drm/virtio/virtgpu_gem.c
> > +++ b/drivers/gpu/drm/virtio/virtgpu_gem.c
> > @@ -139,13 +139,15 @@ void virtio_gpu_gem_object_close(struct drm_gem_object *obj,
> >       if (!vgdev->has_virgl_3d)
> >               return;
> >
> > -     objs = virtio_gpu_array_alloc(1);
> > -     if (!objs)
> > -             return;
> > -     virtio_gpu_array_add_obj(objs, obj);
> > +     if (vfpriv->context_created) {
> > +             objs = virtio_gpu_array_alloc(1);
> > +             if (!objs)
> > +                     return;
> > +             virtio_gpu_array_add_obj(objs, obj);
> >
> > -     virtio_gpu_cmd_context_detach_resource(vgdev, vfpriv->ctx_id,
> > -                                            objs);
> > +             virtio_gpu_cmd_context_detach_resource(vgdev, vfpriv->ctx_id,
> > +                                                    objs);
> > +     }
> >       virtio_gpu_notify(vgdev);
> >  }
>
> The following scenario still will be troubling:
>
> 1. vgdev->has_context_init = true
> 2. virtio_gpu_gem_object_open() invoked, GEM created and not attached to ctx
> 3. virtio_gpu_context_init_ioctl() invoked, now vfpriv->context_created
> = true
> 4. virtio_gpu_gem_object_close() will detach resource that wasn't attached
>
> Add obj->ctx_attached member to struct virtio_gpu_object. See
> virtio_gpu_object_attach() that uses obj->attached, do the same for
> virtio_gpu_cmd_context_attach_resource().
>
> --
> Best regards,
> Dmitry

Hi Dmitry,

WIth context_init, resource attach/detach is per-context based. So a
simple obj->ctx_attached won't work. One would have to track in the
guest context_init ctx for whether a bo has been attached or not.

Another option is to accept this patch and live with the case you
mentioned. We can consider that "invalid" user behavior.

Best,
Yiwei

Re: [PATCH] drm/virtio: Don't detach GEM from a non-created context

[Dmitry Osipenko]

On 7/7/26 22:01, Yiwei Zhang wrote:
> On Mon, Jun 29, 2026 at 2:39 PM Dmitry Osipenko
> <dmitry.osipenko@collabora.com> wrote:
>>
>> Hi,
>>
>> On 6/25/26 20:08, Jason Macnak wrote:
>>> Applies the same treatment as commit 7cf6dd467e87 ("drm/virtio:
>>> Don't attach GEM to a non-created context in gem_object_open()")
>>> to virtio_gpu_gem_object_close() to avoid trying to detach
>>> a resource that was never attached due to a context
>>> never being created when context_init is supported.
>>>
>>> Fixes: 086b9f27f0ab ("drm/virtio: Don't create a context with default param if context_init is supported")
>>> Cc: <stable@vger.kernel.org> # v6.14+
>>> Signed-off-by: Jason Macnak <natsu@google.com>
>>> ---
>>>  drivers/gpu/drm/virtio/virtgpu_gem.c | 14 ++++++++------
>>>  1 file changed, 8 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c
>>> index 435d37d36034..66c3f6f74e9c 100644
>>> --- a/drivers/gpu/drm/virtio/virtgpu_gem.c
>>> +++ b/drivers/gpu/drm/virtio/virtgpu_gem.c
>>> @@ -139,13 +139,15 @@ void virtio_gpu_gem_object_close(struct drm_gem_object *obj,
>>>       if (!vgdev->has_virgl_3d)
>>>               return;
>>>
>>> -     objs = virtio_gpu_array_alloc(1);
>>> -     if (!objs)
>>> -             return;
>>> -     virtio_gpu_array_add_obj(objs, obj);
>>> +     if (vfpriv->context_created) {
>>> +             objs = virtio_gpu_array_alloc(1);
>>> +             if (!objs)
>>> +                     return;
>>> +             virtio_gpu_array_add_obj(objs, obj);
>>>
>>> -     virtio_gpu_cmd_context_detach_resource(vgdev, vfpriv->ctx_id,
>>> -                                            objs);
>>> +             virtio_gpu_cmd_context_detach_resource(vgdev, vfpriv->ctx_id,
>>> +                                                    objs);
>>> +     }
>>>       virtio_gpu_notify(vgdev);
>>>  }
>>
>> The following scenario still will be troubling:
>>
>> 1. vgdev->has_context_init = true
>> 2. virtio_gpu_gem_object_open() invoked, GEM created and not attached to ctx
>> 3. virtio_gpu_context_init_ioctl() invoked, now vfpriv->context_created
>> = true
>> 4. virtio_gpu_gem_object_close() will detach resource that wasn't attached
>>
>> Add obj->ctx_attached member to struct virtio_gpu_object. See
>> virtio_gpu_object_attach() that uses obj->attached, do the same for
>> virtio_gpu_cmd_context_attach_resource().
>>
>> --
>> Best regards,
>> Dmitry
> 
> Hi Dmitry,
> 
> WIth context_init, resource attach/detach is per-context based. So a
> simple obj->ctx_attached won't work. One would have to track in the
> guest context_init ctx for whether a bo has been attached or not.
> 
> Another option is to accept this patch and live with the case you
> mentioned. We can consider that "invalid" user behavior.

Indeed, obj->ctx_attached shouldn't work for a shared/exported BO. Will
think on it for a couple days more and then merge this version if no
better ideas will appear.

-- 
Best regards,
Dmitry

Re: [PATCH] drm/virtio: Don't detach GEM from a non-created context

[Dmitry Osipenko]

On 6/25/26 20:08, Jason Macnak wrote:
> Applies the same treatment as commit 7cf6dd467e87 ("drm/virtio:
> Don't attach GEM to a non-created context in gem_object_open()")
> to virtio_gpu_gem_object_close() to avoid trying to detach
> a resource that was never attached due to a context
> never being created when context_init is supported.
> 
> Fixes: 086b9f27f0ab ("drm/virtio: Don't create a context with default param if context_init is supported")
> Cc: <stable@vger.kernel.org> # v6.14+
> Signed-off-by: Jason Macnak <natsu@google.com>
> ---
>  drivers/gpu/drm/virtio/virtgpu_gem.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c
> index 435d37d36034..66c3f6f74e9c 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_gem.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_gem.c
> @@ -139,13 +139,15 @@ void virtio_gpu_gem_object_close(struct drm_gem_object *obj,
>  	if (!vgdev->has_virgl_3d)
>  		return;
>  
> -	objs = virtio_gpu_array_alloc(1);
> -	if (!objs)
> -		return;
> -	virtio_gpu_array_add_obj(objs, obj);
> +	if (vfpriv->context_created) {
> +		objs = virtio_gpu_array_alloc(1);
> +		if (!objs)
> +			return;
> +		virtio_gpu_array_add_obj(objs, obj);
>  
> -	virtio_gpu_cmd_context_detach_resource(vgdev, vfpriv->ctx_id,
> -					       objs);
> +		virtio_gpu_cmd_context_detach_resource(vgdev, vfpriv->ctx_id,
> +						       objs);
> +	}
>  	virtio_gpu_notify(vgdev);
>  }
>  

Applied to misc-fixes, thanks!

-- 
Best regards,
Dmitry