On 2020-07-06 16:33, Cornelia Huck wrote:
On Mon, 6 Jul 2020 15:37:37 +0200
Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:
On 2020-07-02 15:03, Pierre Morel wrote:
On 2020-06-29 18:05, Cornelia Huck wrote:
On Mon, 29 Jun 2020 11:57:14 -0400
"Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote:
On Wed, Jun 17, 2020 at 12:43:57PM +0200, Pierre Morel wrote:
An architecture protecting the guest memory against unauthorized host
access may want to enforce VIRTIO I/O device protection through the
use of VIRTIO_F_IOMMU_PLATFORM.
Let's give a chance to the architecture to accept or not devices
without VIRTIO_F_IOMMU_PLATFORM.
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Acked-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
arch/s390/mm/init.c | 6 ++++++
drivers/virtio/virtio.c | 22 ++++++++++++++++++++++
include/linux/virtio.h | 2 ++
3 files changed, 30 insertions(+)
@@ -179,6 +194,13 @@ int virtio_finalize_features(struct
virtio_device *dev)
if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
return 0;
+ if (arch_needs_virtio_iommu_platform(dev) &&
+ !virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) {
+ dev_warn(&dev->dev,
+ "virtio: device must provide VIRTIO_F_IOMMU_PLATFORM\n");
+ return -ENODEV;
+ }
+
virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
status = dev->config->get_status(dev);
if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
Well don't you need to check it *before* VIRTIO_F_VERSION_1, not after?
But it's only available with VERSION_1 anyway, isn't it? So it probably
also needs to fail when this feature is needed if VERSION_1 has not been
negotiated, I think.
would be something like:
- if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
- return 0;
+ if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
+ ret = arch_accept_virtio_features(dev);
+ if (ret)
+ dev_warn(&dev->dev,
+ "virtio: device must provide
VIRTIO_F_VERSION_1\n");
+ return ret;
+ }
That looks wrong; I think we want to validate in all cases. What about:
ret = arch_accept_virtio_features(dev); // this can include checking for
// older or newer features
if (ret)
// assume that the arch callback moaned already
return ret;
if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
return 0;
// do the virtio-1 only FEATURES_OK dance
hum, you are right, I was too focused on keeping my simple
arch_accept_virtio_features() function unchanged.
It must be more general.
just a thought on the function name:
It becomes more general than just IOMMU_PLATFORM related.
What do you think of:
arch_accept_virtio_features()
Or maybe arch_validate_virtio_features()?
OK validated.
Thanks,
Pierre
--
Pierre Morel
IBM Lab Boeblingen
