An architecture may restrict host access to guest memory,
e.g. IBM s390 Secure Execution or AMD SEV.
Provide a new Kconfig entry the architecture can select,
CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS, when it provides
the arch_has_restricted_virtio_memory_access callback to advertise
to VIRTIO common code when the architecture restricts memory access
from the host.
The common code can then fail the probe for any device where
VIRTIO_F_IOMMU_PLATFORM is required, but not set.
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
---
drivers/virtio/Kconfig | 6 ++++++
drivers/virtio/virtio.c | 15 +++++++++++++++
include/linux/virtio_config.h | 9 +++++++++
3 files changed, 30 insertions(+)
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index 5809e5f5b157..9cd1c267c143 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -6,6 +6,12 @@ config VIRTIO
bus, such as CONFIG_VIRTIO_PCI, CONFIG_VIRTIO_MMIO, CONFIG_RPMSG
or CONFIG_S390_GUEST.
+config ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
+ bool
+ help
+ This option is selected if the architecture may need to enforce
+ VIRTIO_F_IOMMU_PLATFORM.
+
menuconfig VIRTIO_MENU
bool "Virtio drivers"
default y
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index a977e32a88f2..57ca41d77b09 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -176,6 +176,21 @@ int virtio_finalize_features(struct virtio_device *dev)
if (ret)
return ret;
+ ret = arch_has_restricted_virtio_memory_access();
+ if (ret) {
+ 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;
+ }
+ }
+
if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
return 0;
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index bb4cc4910750..e380664642b4 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -459,4 +459,13 @@ static inline void virtio_cwrite64(struct virtio_device *vdev,
_r; \
})
+#ifdef CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
+int arch_has_restricted_virtio_memory_access(void);
+#else
+static inline int arch_has_restricted_virtio_memory_access(void)
+{
+ return 0;
+}
+#endif /* CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS */
+
#endif /* _LINUX_VIRTIO_CONFIG_H */
--
2.25.1
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