Re: [PATCH v18 0/6] drm/i915/gvt: Dma-buf support for GVT-g

[Zhenyu Wang]

On 2017.11.15 11:49:00 +0100, Gerd Hoffmann wrote:
> On Wed, Nov 15, 2017 at 05:11:49PM +0800, Tina Zhang wrote:
> > v17->v18:
> > 1) unmap vgpu's opregion when destroying vgpu.
> > 2) update comments for VFIO_DEVICE_GET_GFX_DMABUF. (Alex)
> 
> > This patch set adds the dma-buf support for intel GVT-g.
> > 
> > dma-buf is an uniform mechanism to share DMA buffers across different
> > devices and subsystems. dma-buf for intel GVT-g is mainly used to share
> > the vgpu's framebuffer to userspace to leverage userspace graphics stacks
> > to render the framebuffer to the display monitor.
> > 
> > The main idea is that we create a gem object and set vgpu's framebuffer as
> > its backing storage. Then, export a dma-buf associated with this gem object.
> > With the fd of this dma-buf, userspace can directly handle this buffer.
> > 
> > This patch set can be tried with the following example:
> > 	git://git.kraxel.org/qemu  branch: work/intel-vgpu
> > 
> > A topic branch with the latest patch set is:
> >         https://github.com/intel/gvt-linux.git   branch: topic/dmabuf
> 
> Tested-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> 

After debugging with Tina on one left race that fixed by
https://lists.freedesktop.org/archives/intel-gvt-dev/2017-November/002505.html

I still need below qemu fix for proper cursor handling, otherwise qemu
just crashed when I click in my terminal program which hides cursor then.

diff --git a/hw/vfio/display.c b/hw/vfio/display.c
index e500ec2cb1..d9a044b080 100644
--- a/hw/vfio/display.c
+++ b/hw/vfio/display.c
@@ -169,8 +169,9 @@ static void vfio_display_dmabuf_update(void *opaque)
     cursor = vfio_display_get_dmabuf(vdev, DRM_PLANE_TYPE_CURSOR);
     if (vdev->cursor != cursor) {
         vdev->cursor = cursor;
-        dpy_gl_cursor_dmabuf(vdev->display_con,
-                             &cursor->buf);
+        if (cursor)
+            dpy_gl_cursor_dmabuf(vdev->display_con,
+                                 &cursor->buf);
         free_bufs = true;
     }
     if (cursor != NULL) {

And with these it seems pretty fine now that I'll queue them up for -next pull.

thanks

-- 
Open Source Technology Center, Intel ltd.

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