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authorPierre Morel <pmorel@linux.ibm.com>2020-09-10 10:53:49 +0200
committerMichael S. Tsirkin <mst@redhat.com>2020-10-21 10:34:12 -0400
commit0afa15e1a5294754066343cad24af5ec8edae96d (patch)
tree64e15eeb034e2bfb937aaf6def594750032712b8 /drivers/virtio
parentb9747fdf0c1dad088eb21d5191295999ae7b4b40 (diff)
virtio: let arch advertise guest's memory access restrictions
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_ACCESS_PLATFORM is required, but not set. Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Halil Pasic <pasic@linux.ibm.com> Link: https://lore.kernel.org/r/1599728030-17085-2-git-send-email-pmorel@linux.ibm.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'drivers/virtio')
-rw-r--r--drivers/virtio/Kconfig6
-rw-r--r--drivers/virtio/virtio.c15
2 files changed, 21 insertions, 0 deletions
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index 5c92e4a50882..ef2d49430800 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_ACCESS_PLATFORM
+
menuconfig VIRTIO_MENU
bool "Virtio drivers"
default y
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index a977e32a88f2..a2b3f12e10a2 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_ACCESS_PLATFORM)) {
+ dev_warn(&dev->dev,
+ "device must provide VIRTIO_F_ACCESS_PLATFORM\n");
+ return -ENODEV;
+ }
+ }
+
if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
return 0;