Hi all,
The goal of the series is to give a chance to the architecture
to validate VIRTIO device features.
The tests are back to virtio_finalize_features.
No more argument for the architecture callback which only reports
if the architecture needs guest memory access restrictions for
VIRTIO.
I renamed the callback to arch_has_restricted_virtio_memory_access,
and the config option to ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS.
Regards,
Pierre
Pierre Morel (2):
virtio: let arch advertise guest's memory access restrictions
s390: virtio: PV needs VIRTIO I/O device protection
arch/s390/Kconfig | 1 +
arch/s390/mm/init.c | 10 ++++++++++
drivers/virtio/Kconfig | 6 ++++++
drivers/virtio/virtio.c | 15 +++++++++++++++
include/linux/virtio_config.h | 9 +++++++++
5 files changed, 41 insertions(+)
--
2.25.1
Changelog
to v10:
- removed virtio_config.h unnecessary include
- wording
(Connie)
to v9:
- move virtio tests back to virtio_finalize_features
(Connie)
- remove virtio device argument
to v8:
- refactoring by using an optional callback
(Connie)
to v7:
- typo in warning message
(Connie)
to v6:
- rewording warning messages
(Connie, Halil)
to v5:
- return directly from S390 arch_validate_virtio_features()
when the guest is not protected.
(Connie)
- Somme rewording
(Connie, Michael)
- moved back code from arch/s390/ ...kernel/uv.c to ...mm/init.c
(Christian)
to v4:
- separate virtio and arch code
(Pierre)
- moved code from arch/s390/mm/init.c to arch/s390/kernel/uv.c
(as interpreted from Heiko's comment)
- moved validation inside the arch code
(Connie)
- moved the call to arch validation before VIRTIO_F_1 test
(Michael)
to v3:
- add warning
(Connie, Christian)
- add comment
(Connie)
- change hook name
(Halil, Connie)
to v2:
- put the test in virtio_finalize_features()
(Connie)
- put the test inside VIRTIO core
(Jason)
- pass a virtio device as parameter
(Halil)
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 <[email protected]>
Reviewed-by: Cornelia Huck <[email protected]>
---
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