On Tue, Jan 09, 2024 at 07:49:16PM +0100, Stefan Fritsch wrote:
> @bluhm: Does the attached patch fix the panic?
Yes. My test does not crash the patched guest anymore.
bluhm
> The fdt part is completely untested, testers welcome.
>
> diff --git a/sys/dev/fdt/virtio_mmio.c b/sys/dev/fdt/virtio_mmio.c
> index 4f1e9eba9b7..27fb17d6102 100644
> --- a/sys/dev/fdt/virtio_mmio.c
> +++ b/sys/dev/fdt/virtio_mmio.c
> @@ -200,11 +200,19 @@ virtio_mmio_set_status(struct virtio_softc *vsc, int
> status)
> struct virtio_mmio_softc *sc = (struct virtio_mmio_softc *)vsc;
> int old = 0;
>
> - if (status != 0)
> + if (status == 0) {
> + bus_space_write_4(sc->sc_iot, sc->sc_ioh, VIRTIO_MMIO_STATUS,
> + 0);
> + while (bus_space_read_4(sc->sc_iot, sc->sc_ioh,
> + VIRTIO_MMIO_STATUS) != 0) {
> + CPU_BUSY_CYCLE();
> + }
> + } else {
> old = bus_space_read_4(sc->sc_iot, sc->sc_ioh,
> - VIRTIO_MMIO_STATUS);
> - bus_space_write_4(sc->sc_iot, sc->sc_ioh, VIRTIO_MMIO_STATUS,
> - status|old);
> + VIRTIO_MMIO_STATUS);
> + bus_space_write_4(sc->sc_iot, sc->sc_ioh, VIRTIO_MMIO_STATUS,
> + status|old);
> + }
> }
>
> int
> diff --git a/sys/dev/pci/virtio_pci.c b/sys/dev/pci/virtio_pci.c
> index 398dc960f6d..ef95c834823 100644
> --- a/sys/dev/pci/virtio_pci.c
> +++ b/sys/dev/pci/virtio_pci.c
> @@ -282,15 +282,29 @@ virtio_pci_set_status(struct virtio_softc *vsc, int
> status)
> int old = 0;
>
> if (sc->sc_sc.sc_version_1) {
> - if (status != 0)
> + if (status == 0) {
> + CWRITE(sc, device_status, 0);
> + while (CREAD(sc, device_status) != 0) {
> + CPU_BUSY_CYCLE();
> + }
> + } else {
> old = CREAD(sc, device_status);
> - CWRITE(sc, device_status, status|old);
> + CWRITE(sc, device_status, status|old);
> + }
> } else {
> - if (status != 0)
> + if (status == 0) {
> + bus_space_write_1(sc->sc_iot, sc->sc_ioh,
> + VIRTIO_CONFIG_DEVICE_STATUS, status|old);
> + while (bus_space_read_1(sc->sc_iot, sc->sc_ioh,
> + VIRTIO_CONFIG_DEVICE_STATUS) != 0) {
> + CPU_BUSY_CYCLE();
> + }
> + } else {
> old = bus_space_read_1(sc->sc_iot, sc->sc_ioh,
> VIRTIO_CONFIG_DEVICE_STATUS);
> - bus_space_write_1(sc->sc_iot, sc->sc_ioh,
> - VIRTIO_CONFIG_DEVICE_STATUS, status|old);
> + bus_space_write_1(sc->sc_iot, sc->sc_ioh,
> + VIRTIO_CONFIG_DEVICE_STATUS, status|old);
> + }
> }
> }
>
