From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: Re: [PATCH v3 1/1] s390: virtio: let arch accept devices without IOMMU feature Date: Thu, 2 Jul 2020 15:03:51 +0200 Message-ID: <26ecd4c6-837b-1ce6-170b-a0155e4dd4d4@linux.ibm.com> References: <1592390637-17441-1-git-send-email-pmorel@linux.ibm.com> <1592390637-17441-2-git-send-email-pmorel@linux.ibm.com> <20200629115651-mutt-send-email-mst@kernel.org> <20200629180526.41d0732b.cohuck@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20200629180526.41d0732b.cohuck@redhat.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Cornelia Huck , "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, pasic@linux.ibm.com, borntraeger@de.ibm.com, frankja@linux.ibm.com, jasowang@redhat.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org, virtualization@lists.linux-foundation.org, thomas.lendacky@amd.com, david@gibson.dropbear.id.au, linuxram@us.ibm.com, heiko.carstens@de.ibm.com, gor@linux.ibm.com List-Id: virtualization@lists.linuxfoundation.org On 2020-06-29 18:05, Cornelia Huck wrote: > On Mon, 29 Jun 2020 11:57:14 -0400 > "Michael S. Tsirkin" 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 >>> Acked-by: Jason Wang >>> Acked-by: Christian Borntraeger >>> --- >>> 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. > Yes, clearly, I will add this. Thanks, Pierre -- Pierre Morel IBM Lab Boeblingen