On Tue, Sep 23, 2014 at 09:06:03AM -0700, Eric Northup wrote:
> On Tue, Sep 23, 2014 at 3:32 AM, Michael S. Tsirkin <mst@xxxxxxxxxx> wrote:
> > On restore, virtio pci does the following:
> > + set features
> > + init vqs etc - device can be used at this point!
> > + set ACKNOWLEDGE,DRIVER and DRIVER_OK status bits
> >
> > This is in violation of the virtio spec, which
> > requires the following order:
> > - ACKNOWLEDGE
> > - DRIVER
> > - init vqs
> > - DRIVER_OK
> >
> > Cc: stable@xxxxxxxxxxxxxxx
> > Cc: Amit Shah <amit.shah@xxxxxxxxxx>
> > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> > ---
> >
> > Lightly tested.
> > Will repost as non-RFC once testing is done, sending
> > out now for early flames/comments.
> >
> > Thanks!
> >
> > drivers/virtio/virtio_pci.c | 36 ++++++++++++++++++++++++++++++++----
> > 1 file changed, 32 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
> > index 58f7e45..58cbf6e 100644
> > --- a/drivers/virtio/virtio_pci.c
> > +++ b/drivers/virtio/virtio_pci.c
> > @@ -785,6 +785,7 @@ static int virtio_pci_restore(struct device *dev)
> > struct pci_dev *pci_dev = to_pci_dev(dev);
> > struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
> > struct virtio_driver *drv;
> > + unsigned status = 0;
> > int ret;
> >
> > drv = container_of(vp_dev->vdev.dev.driver,
> > @@ -795,14 +796,41 @@ static int virtio_pci_restore(struct device *dev)
> > return ret;
> >
> > pci_set_master(pci_dev);
> > + /* We always start by resetting the device, in case a previous
> > + * driver messed it up. */
> > + vp_reset(&vp_dev->vdev);
>
> This should happen before enabling PCI bus mastering.
this is the order of events in initialization,
it seems better to be consistent.
> > +
> > + /* Acknowledge that we've seen the device. */
> > + status |= VIRTIO_CONFIG_S_ACKNOWLEDGE;
> > + vp_set_status(&vp_dev->vdev, status);
> > +
> > + /* Maybe driver failed before freeze.
> > + * Restore the failed status, for debugging. */
> > + status |= vp_dev->saved_status & VIRTIO_CONFIG_S_FAILED;
> > + vp_set_status(&vp_dev->vdev, status);
> > +
> > + if (!drv)
> > + return 0;
> > +
> > + /* We have a driver! */
> > + status |= VIRTIO_CONFIG_S_DRIVER;
> > + vp_set_status(&vp_dev->vdev, status);
> > +
> > vp_finalize_features(&vp_dev->vdev);
> >
> > - if (drv && drv->restore)
> > - ret = drv->restore(&vp_dev->vdev);
> > + if (!drv->restore)
> > + return 0;
> > +
> > + ret = drv->restore(&vp_dev->vdev);
> > + if (ret) {
> > + status |= VIRTIO_CONFIG_S_FAILED;
> > + vp_set_status(&vp_dev->vdev, status);
> > + return ret;
> > + }
> >
> > /* Finally, tell the device we're all set */
> > - if (!ret)
> > - vp_set_status(&vp_dev->vdev, vp_dev->saved_status);
> > + status |= VIRTIO_CONFIG_S_DRIVER_OK;
> > + vp_set_status(&vp_dev->vdev, status);
> >
> > return ret;
> > }
> > --
> > MST
> > _______________________________________________
> > Virtualization mailing list
> > Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
> > https://lists.linuxfoundation.org/mailman/listinfo/virtualization
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