x86/sev-es: Do not support MMIO to/from encrypted memory

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MMIO memory is usually not mapped encrypted, so there is no reason to
support emulated MMIO when it is mapped encrypted.

Prevent a possible hypervisor attack where a RAM page is mapped as
an MMIO page in the nested page-table, so that any guest access to it
will trigger a #VC exception and leak the data on that page to the
hypervisor via the GHCB (like with valid MMIO). On the read side this
attack would allow the HV to inject data into the guest.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lkml.kernel.org/r/20201028164659.27002-6-joro@8bytes.org

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Joerg Roedel 2020-10-28 17:46:59 +01:00 • committed by Borislav Petkov

parent c9f09539e1

commit 2411cd8211

1 changed files with 13 additions and 7 deletions

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arch/x86/kernel/sev-es.c

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