The QemuGraphicConsole holds a strong QOM link back to the device via its "device" property (OBJ_PROP_LINK_STRONG). When graphic_console_close() is only called from vfio_display_finalize() during object finalize, this creates a ref-cycle deadlock: the device can't reach refcount 0 because the console holds a strong ref, but the console's ref is only dropped by graphic_console_close() which runs inside finalize.
Split the display teardown into two phases: - vfio_display_exit(): called during unrealize (vfio_exitfn), closes the graphic console to break the ref cycle, and removes display region subregions while the parent memory regions are still alive. - vfio_display_finalize(): remains in finalize (vfio_pci_put_device), frees display region memory, dmabuf, and edid resources. The region memory contains QOM child objects (MemoryRegions) that must stay alive until QOM finalization has processed them. Signed-off-by: Marc-André Lureau <[email protected]> --- hw/vfio/pci.h | 1 + hw/vfio/display.c | 30 +++++++++++++++++++----------- hw/vfio/pci.c | 1 + 3 files changed, 21 insertions(+), 11 deletions(-) diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h index c3a1f53d350..cf567115870 100644 --- a/hw/vfio/pci.h +++ b/hw/vfio/pci.h @@ -270,6 +270,7 @@ bool vfio_populate_vga(VFIOPCIDevice *vdev, Error **errp); void vfio_display_reset(VFIOPCIDevice *vdev); bool vfio_display_probe(VFIOPCIDevice *vdev, Error **errp); +void vfio_display_exit(VFIOPCIDevice *vdev); void vfio_display_finalize(VFIOPCIDevice *vdev); extern const VMStateDescription vfio_display_vmstate; diff --git a/hw/vfio/display.c b/hw/vfio/display.c index 8f91e83da88..34cc25ee0e0 100644 --- a/hw/vfio/display.c +++ b/hw/vfio/display.c @@ -505,15 +505,6 @@ static bool vfio_display_region_init(VFIOPCIDevice *vdev, Error **errp) return true; } -static void vfio_display_region_exit(VFIODisplay *dpy) -{ - if (!dpy->region.buffer.size) { - return; - } - - vfio_region_exit(&dpy->region.buffer); - vfio_region_finalize(&dpy->region.buffer); -} /* ---------------------------------------------------------------------- */ @@ -547,17 +538,34 @@ bool vfio_display_probe(VFIOPCIDevice *vdev, Error **errp) return false; } -void vfio_display_finalize(VFIOPCIDevice *vdev) +void vfio_display_exit(VFIOPCIDevice *vdev) { if (!vdev->dpy) { return; } + if (display_opengl) { + qemu_console_set_display_gl_ctx(vdev->dpy->con, NULL); + } qemu_graphic_console_close(vdev->dpy->con); + if (vdev->dpy->region.buffer.size) { + vfio_region_exit(&vdev->dpy->region.buffer); + } +} + +void vfio_display_finalize(VFIOPCIDevice *vdev) +{ + if (!vdev->dpy) { + return; + } + vfio_display_dmabuf_exit(vdev->dpy); - vfio_display_region_exit(vdev->dpy); + if (vdev->dpy->region.buffer.size) { + vfio_region_finalize(&vdev->dpy->region.buffer); + } vfio_display_edid_exit(vdev->dpy); g_free(vdev->dpy); + vdev->dpy = NULL; } static bool migrate_needed(void *opaque) diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index 9c06b25e637..78beacd24e1 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -3624,6 +3624,7 @@ static void vfio_exitfn(PCIDevice *pdev) VFIOPCIDevice *vdev = VFIO_PCI_DEVICE(pdev); VFIODevice *vbasedev = &vdev->vbasedev; + vfio_display_exit(vdev); vfio_unregister_req_notifier(vdev); vfio_unregister_err_notifier(vdev); pci_device_set_intx_routing_notifier(pdev, NULL); -- 2.54.0
