From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cornelia Huck Subject: Re: [PATCH] s390: protvirt: virtio: Refuse device without IOMMU Date: Wed, 10 Jun 2020 15:24:31 +0200 Message-ID: <20200610152431.358fded7.cohuck@redhat.com> References: <1591794711-5915-1-git-send-email-pmorel@linux.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1591794711-5915-1-git-send-email-pmorel@linux.ibm.com> Sender: kvm-owner@vger.kernel.org To: Pierre Morel Cc: linux-kernel@vger.kernel.org, pasic@linux.ibm.com, borntraeger@de.ibm.com, frankja@linux.ibm.com, mst@redhat.com, jasowang@redhat.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org, virtualization@lists.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org On Wed, 10 Jun 2020 15:11:51 +0200 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 > --- > 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? > /* Write the status to the host. */ > vcdev->dma_area->status = status; > ccw->cmd_code = CCW_CMD_WRITE_STATUS;