lkml.org 
[lkml]   [2020]   [Jun]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
SubjectRe: [PATCH] s390: protvirt: virtio: Refuse device without IOMMU
From
Date


On 2020-06-10 15:24, Cornelia Huck wrote:
> On Wed, 10 Jun 2020 15:11:51 +0200
> Pierre Morel <pmorel@linux.ibm.com> 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@linux.ibm.com>
>> ---
>> 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

\
 
 \ /
  Last update: 2020-06-10 16:38    [W:0.878 / U:0.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site