From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: [PATCH v7 2/2] s390: virtio: PV needs VIRTIO I/O device protection Date: Wed, 15 Jul 2020 10:31:09 +0200 Message-ID: <1594801869-13365-3-git-send-email-pmorel@linux.ibm.com> References: <1594801869-13365-1-git-send-email-pmorel@linux.ibm.com> Return-path: In-Reply-To: <1594801869-13365-1-git-send-email-pmorel@linux.ibm.com> Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: pasic@linux.ibm.com, borntraeger@de.ibm.com, frankja@linux.ibm.com, mst@redhat.com, jasowang@redhat.com, cohuck@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, hca@linux.ibm.com, gor@linux.ibm.com List-Id: virtualization@lists.linuxfoundation.org If protected virtualization is active on s390, the virtio queues are not accessible to the host, unless VIRTIO_F_IOMMU_PLATFORM has been negotiated. Use the new arch_validate_virtio_features() interface to fail probe if that's not the case, preventing a host error on access attempt. Signed-off-by: Pierre Morel Reviewed-by: Cornelia Huck Acked-by: Halil Pasic Acked-by: Christian Borntraeger --- arch/s390/mm/init.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 6dc7c3b60ef6..d39af6554d4f 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -45,6 +45,7 @@ #include #include #include +#include pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(.bss..swapper_pg_dir); @@ -161,6 +162,33 @@ bool force_dma_unencrypted(struct device *dev) return is_prot_virt_guest(); } +/* + * arch_validate_virtio_features + * @dev: the VIRTIO device being added + * + * Return an error if required features are missing on a guest running + * with protected virtualization. + */ +int arch_validate_virtio_features(struct virtio_device *dev) +{ + if (!is_prot_virt_guest()) + return 0; + + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) { + dev_warn(&dev->dev, + "legacy virtio not supported with protected virtualization\n"); + return -ENODEV; + } + + if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) { + dev_warn(&dev->dev, + "support for limited memory access required for protected virtualization\n"); + return -ENODEV; + } + + return 0; +} + /* protected virtualization */ static void pv_init(void) { -- 2.25.1