Re: [PATCH v6 2/2] s390: virtio: PV needs VIRTIO I/O device protection
From: Christian Borntraeger <hidden>
Date: 2020-07-14 11:43:03
Also in:
kvm, linux-s390, lkml
On 14.07.20 13:38, Pierre Morel wrote:
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 <redacted> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Acked-by: Halil Pasic <pasic@linux.ibm.com>
We will probably move this (and other related code) into a new file, but we can do that later. As for now: Acked-by: Christian Borntraeger <redacted>
quoted hunk ↗ jump to hunk
--- 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..26efb663bac2 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c@@ -45,6 +45,7 @@ #include <asm/kasan.h> #include <asm/dma-mapping.h> #include <asm/uv.h> +#include <linux/virtio_config.h> 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 virtualizatio\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) {