Messages in this thread | | | Subject | Re: [PATCH] s390: protvirt: virtio: Refuse device without IOMMU | From | Pierre Morel <> | Date | Mon, 15 Jun 2020 13:50:56 +0200 |
| |
On 2020-06-15 05:01, Jason Wang wrote: > > On 2020/6/12 下午7:38, Pierre Morel wrote: >> >> >> On 2020-06-12 11:21, Pierre Morel wrote: >>> >>> >>> On 2020-06-11 05:10, Jason Wang wrote: >>>> >>>> On 2020/6/10 下午9:11, Pierre Morel 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; >>>>> + >>>>> /* Write the status to the host. */ >>>>> vcdev->dma_area->status = status; >>>>> ccw->cmd_code = CCW_CMD_WRITE_STATUS; >>>> >>>> >>>> I wonder whether we need move it to virtio core instead of ccw. >>>> >>>> I think the other memory protection technologies may suffer from >>>> this as well. >>>> >>>> Thanks >>>> >>> >>> >>> What would you think of the following, also taking into account >>> Connie's comment on where the test should be done: >>> >>> - declare a weak function in virtio.c code, returning that memory >>> protection is not in use. >>> >>> - overwrite the function in the arch code >>> >>> - call this function inside core virtio_finalize_features() and if >>> required fail if the device don't have VIRTIO_F_IOMMU_PLATFORM. > > > I think this is fine. >
Thanks, I try this.
Regards, Pierre
-- Pierre Morel IBM Lab Boeblingen
| |