On 04/03/2016 08:26 PM, Michael S. Tsirkin wrote: > The spec says: after writing 0 to device_status, the driver MUST wait > for a read of device_status to return 0 before reinitializing the > device. > > Cc: sta...@vger.kernel.org > Signed-off-by: Michael S. Tsirkin <m...@redhat.com> > --- > drivers/virtio/virtio_pci_modern.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/virtio/virtio_pci_modern.c > b/drivers/virtio/virtio_pci_modern.c > index f6f28cc..e76bd91 100644 > --- a/drivers/virtio/virtio_pci_modern.c > +++ b/drivers/virtio/virtio_pci_modern.c > @@ -17,6 +17,7 @@ > * > */ > > +#include <linux/delay.h> > #define VIRTIO_PCI_NO_LEGACY > #include "virtio_pci_common.h" > > @@ -271,9 +272,13 @@ static void vp_reset(struct virtio_device *vdev) > struct virtio_pci_device *vp_dev = to_vp_device(vdev); > /* 0 status means a reset. */ > vp_iowrite8(0, &vp_dev->common->device_status); > - /* Flush out the status write, and flush in device writes, > - * including MSI-X interrupts, if any. */ > - vp_ioread8(&vp_dev->common->device_status); > + /* After writing 0 to device_status, the driver MUST wait for a read of > + * device_status to return 0 before reinitializing the device. > + * This will flush out the status write, and flush in device writes, > + * including MSI-X interrupts, if any. > + */ > + while (vp_ioread8(&vp_dev->common->device_status)) > + msleep(1); > /* Flush pending VQ/configuration callbacks. */ > vp_synchronize_vectors(vdev); > }
Acked-by: Jason Wang <jasow...@redhat.com>
