[PATCH v8 2/2] s390: virtio: PV needs VIRTIO I/O device protection
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STALE2246d
SUPERSEDED
From: Pierre Morel <hidden>
Date: 2020-08-18 14:58:58
Also in:
kvm, linux-s390, lkml
Subsystem:
s390 architecture, the rest · Maintainers:
Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Linus Torvalds
Revision v8 of 9 in this series.
Revisions (9)
If protected virtualization is active on s390, the virtio queues are not accessible to the host, unless VIRTIO_F_IOMMU_PLATFORM has been negotiated. Define CONFIG_ARCH_HAS_RESTRICTED_MEMORY_ACCESS and export arch_has_restricted_memory_access to fail probe if that's not the case, preventing a host error on access attempt. Signed-off-by: Pierre Morel <redacted> --- arch/s390/Kconfig | 1 + arch/s390/mm/init.c | 30 ++++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+)
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 9cfd8de907cb..d4a3ef4fa27b 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig@@ -820,6 +820,7 @@ menu "Virtualization" config PROTECTED_VIRTUALIZATION_GUEST def_bool n prompt "Protected virtualization guest support" + select ARCH_HAS_RESTRICTED_MEMORY_ACCESS help Select this option, if you want to be able to run this kernel as a protected virtualization KVM guest.
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 6dc7c3b60ef6..aec04d7dd089 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 +162,35 @@ bool force_dma_unencrypted(struct device *dev) return is_prot_virt_guest(); } +#ifdef CONFIG_ARCH_HAS_RESTRICTED_MEMORY_ACCESS +/* + * arch_has_restricted_memory_access + * @dev: the VIRTIO device being added + * + * Return an error if required features are missing on a guest running + * with protected virtualization. + */ +int arch_has_restricted_memory_access(struct virtio_device *dev) +{ + if (!is_prot_virt_guest()) + return 0; + + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) { + dev_warn(&dev->dev, "device must provide VIRTIO_F_VERSION_1\n"); + return -ENODEV; + } + + if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) { + dev_warn(&dev->dev, + "device must provide VIRTIO_F_IOMMU_PLATFORM\n"); + return -ENODEV; + } + + return 0; +} +EXPORT_SYMBOL(arch_has_restricted_memory_access); +#endif + /* protected virtualization */ static void pv_init(void) {
--
2.25.1
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