virtio: let arch advertise guest's memory access restrictions
authorPierre Morel <pmorel@linux.ibm.com>
Thu, 10 Sep 2020 08:53:49 +0000 (10:53 +0200)
committerMichael S. Tsirkin <mst@redhat.com>
Wed, 21 Oct 2020 14:34:12 +0000 (10:34 -0400)
commit0afa15e1a5294754066343cad24af5ec8edae96d
tree64e15eeb034e2bfb937aaf6def594750032712b8
parentb9747fdf0c1dad088eb21d5191295999ae7b4b40
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>
drivers/virtio/Kconfig
drivers/virtio/virtio.c
include/linux/virtio_config.h