On Wed, 10 Jun 2020 16:37:55 +0200 Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote: > On 2020-06-10 15:24, Cornelia Huck wrote: > > On Wed, 10 Jun 2020 15:11:51 +0200 > > Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote: > > > >> Protected Virtualisation protects the memory of the guest and > >> do not allow a the host to access all of its memory. > >> > >> Let's refuse a VIRTIO device which does not use IOMMU > >> protected access. > >> > >> Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx> > >> --- > >> drivers/s390/virtio/virtio_ccw.c | 5 +++++ > >> 1 file changed, 5 insertions(+) > >> > >> diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c > >> index 5730572b52cd..06ffbc96587a 100644 > >> --- a/drivers/s390/virtio/virtio_ccw.c > >> +++ b/drivers/s390/virtio/virtio_ccw.c > >> @@ -986,6 +986,11 @@ static void virtio_ccw_set_status(struct virtio_device *vdev, u8 status) > >> if (!ccw) > >> return; > >> > >> + /* Protected Virtualisation guest needs IOMMU */ > >> + if (is_prot_virt_guest() && > >> + !__virtio_test_bit(vdev, VIRTIO_F_IOMMU_PLATFORM)) > >> + status &= ~VIRTIO_CONFIG_S_FEATURES_OK; > >> + > > > > set_status seems like an odd place to look at features; shouldn't that > > rather be done in finalize_features? > > Right, looks better to me too. > What about: > > > > diff --git a/drivers/s390/virtio/virtio_ccw.c > b/drivers/s390/virtio/virtio_ccw.c > index 06ffbc96587a..227676297ea0 100644 > --- a/drivers/s390/virtio/virtio_ccw.c > +++ b/drivers/s390/virtio/virtio_ccw.c > @@ -833,6 +833,11 @@ static int virtio_ccw_finalize_features(struct > virtio_device *vdev) > ret = -ENOMEM; > goto out_free; > } > + > + if (is_prot_virt_guest() && > + !__virtio_test_bit(vdev, VIRTIO_F_IOMMU_PLATFORM)) Add a comment, and (maybe) a message? Otherwise, I think this is fine, as it should fail the probe, which is what we want. > + return -EIO; > + > /* Give virtio_ring a chance to accept features. */ > vring_transport_features(vdev); > > > > Thanks, > > Regards, > Pierre >
