Messages in this thread | | | Subject | Re: [PATCH v3 1/1] s390: virtio: let arch accept devices without IOMMU feature | From | Pierre Morel <> | Date | Mon, 6 Jul 2020 15:37:37 +0200 |
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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@redhat.com> 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@linux.ibm.com> >>>> Acked-by: Jason Wang <jasowang@redhat.com> >>>> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> >>>> --- >>>> 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; + }
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()
?
Regards, Pierre
-- Pierre Morel IBM Lab Boeblingen
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