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))
+ return -EIO;
+
/* Give virtio_ring a chance to accept features. */
vring_transport_features(vdev);
Thanks,
Regards,
Pierre
--
Pierre Morel
IBM Lab Boeblingen
