hw/vfio/display: add ramfb support

So we have a boot display when using a vgpu as primary display.

ramfb depends on a fw_cfg file.  fw_cfg files can not be added and
removed at runtime, therefore a ramfb-enabled vfio device can't be
hotplugged.

Add a nohotplug variant of the vfio-pci device (as child class).  Add
the ramfb property to the nohotplug variant only.  So to enable the vgpu
display with boot support use this:

  -device vfio-pci-nohotplug,display=on,ramfb=on,sysfsdev=...

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/hw/vfio/display.c b/hw/vfio/display.c
index 59c0e5d1d7..dead30e626 100644
--- a/hw/vfio/display.c
+++ b/hw/vfio/display.c
@@ -124,6 +124,9 @@ static void vfio_display_dmabuf_update(void *opaque)
 
     primary = vfio_display_get_dmabuf(vdev, DRM_PLANE_TYPE_PRIMARY);
     if (primary == NULL) {
+        if (dpy->ramfb) {
+            ramfb_display_update(dpy->con, dpy->ramfb);
+        }
         return;
     }
 
@@ -181,6 +184,9 @@ static int vfio_display_dmabuf_init(VFIOPCIDevice *vdev, Error **errp)
     vdev->dpy->con = graphic_console_init(DEVICE(vdev), 0,
                                           &vfio_display_dmabuf_ops,
                                           vdev);
+    if (vdev->enable_ramfb) {
+        vdev->dpy->ramfb = ramfb_setup(errp);
+    }
     return 0;
 }
 
@@ -228,6 +234,9 @@ static void vfio_display_region_update(void *opaque)
         return;
     }
     if (!plane.drm_format || !plane.size) {
+        if (dpy->ramfb) {
+            ramfb_display_update(dpy->con, dpy->ramfb);
+        }
         return;
     }
     format = qemu_drm_format_to_pixman(plane.drm_format);
@@ -300,6 +309,9 @@ static int vfio_display_region_init(VFIOPCIDevice *vdev, Error **errp)
     vdev->dpy->con = graphic_console_init(DEVICE(vdev), 0,
                                           &vfio_display_region_ops,
                                           vdev);
+    if (vdev->enable_ramfb) {
+        vdev->dpy->ramfb = ramfb_setup(errp);
+    }
     return 0;
 }