x86/virtio: Have SEV guests enforce restricted virtio memory access

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An SEV guest requires that virtio devices use the DMA API to allow the
hypervisor to successfully access guest memory as needed.

The VIRTIO_F_VERSION_1 and VIRTIO_F_ACCESS_PLATFORM features tell virtio
to use the DMA API. Add arch_has_restricted_virtio_memory_access() for
x86, to fail the device probe if these features have not been set for the
device when running as an SEV guest.

 [ bp: Fix -Wmissing-prototypes warning
   Reported-by: kernel test robot <lkp@intel.com> ]

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/b46e0211f77ca1831f11132f969d470a6ffc9267.1614897610.git.thomas.lendacky@amd.com

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Tom Lendacky 2021-03-04 16:40:11 -06:00 • committed by Borislav Petkov

parent f3db3365c0

commit 229164175f

2 changed files with 7 additions and 0 deletions

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1

arch/x86/Kconfig

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6

arch/x86/mm/mem_encrypt.c

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