From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: [PATCH v2 1/1] s390: virtio: let arch accept devices without IOMMU feature Date: Mon, 15 Jun 2020 14:39:24 +0200 Message-ID: <1592224764-1258-2-git-send-email-pmorel@linux.ibm.com> References: <1592224764-1258-1-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: <1592224764-1258-1-git-send-email-pmorel@linux.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" To: linux-kernel@vger.kernel.org Cc: linux-s390@vger.kernel.org, frankja@linux.ibm.com, kvm@vger.kernel.org, mst@redhat.com, cohuck@redhat.com, virtualization@lists.linux-foundation.org, pasic@linux.ibm.com, borntraeger@de.ibm.com List-Id: virtualization@lists.linuxfoundation.org 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 --- arch/s390/mm/init.c | 6 ++++++ drivers/virtio/virtio.c | 9 +++++++++ include/linux/virtio.h | 2 ++ 3 files changed, 17 insertions(+) diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 87b2d024e75a..3f04ad09650f 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -46,6 +46,7 @@ #include #include #include +#include pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(.bss..swapper_pg_dir); @@ -162,6 +163,11 @@ bool force_dma_unencrypted(struct device *dev) return is_prot_virt_guest(); } +int arch_needs_iommu_platform(struct virtio_device *dev) +{ + return is_prot_virt_guest(); +} + /* protected virtualization */ static void pv_init(void) { diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index a977e32a88f2..30091089bee8 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -167,6 +167,11 @@ void virtio_add_status(struct virtio_device *dev, unsigned int status) } EXPORT_SYMBOL_GPL(virtio_add_status); +int __weak arch_needs_iommu_platform(struct virtio_device *dev) +{ + return 0; +} + int virtio_finalize_features(struct virtio_device *dev) { int ret = dev->config->finalize_features(dev); @@ -179,6 +184,10 @@ int virtio_finalize_features(struct virtio_device *dev) if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) return 0; + if (arch_needs_iommu_platform(dev) && + !virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) + return -EIO; + virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK); status = dev->config->get_status(dev); if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) { diff --git a/include/linux/virtio.h b/include/linux/virtio.h index a493eac08393..2c46b310c38c 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -195,4 +195,6 @@ void unregister_virtio_driver(struct virtio_driver *drv); #define module_virtio_driver(__virtio_driver) \ module_driver(__virtio_driver, register_virtio_driver, \ unregister_virtio_driver) + +int arch_needs_iommu_platform(struct virtio_device *dev); #endif /* _LINUX_VIRTIO_H */ -- 2.25.1