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OvmfPkg: Add AmdSevDxe driver

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When SEV is enabled, the MMIO memory range must be mapped as unencrypted
(i.e C-bit cleared).

We need to clear the C-bit for MMIO GCD entries in order to cover the
ranges that were added during the PEI phase (through memory resource
descriptor HOBs). Additionally, the NonExistent ranges are processed
in order to cover, in advance, MMIO ranges added later in the DXE phase
by various device drivers, via the appropriate DXE memory space services.

The approach is not transparent for later addition of system memory ranges
to the GCD memory space map. (Such ranges should be encrypted.) OVMF does
not do such a thing at the moment, so this approach should be OK.

The driver is being added to the APRIORI DXE file so that, we clear the
C-bit from MMIO regions before any driver accesses it.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Leo Duran <leo.duran@amd.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Suggested-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Acked-by: Jordan Justen <jordan.l.justen@intel.com>
This commit is contained in:
Brijesh Singh
2017-07-06 09:26:45 -04:00
committed by Jordan Justen
parent 13b5d743c8
commit 24e4ad7554
6 changed files with 124 additions and 0 deletions
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OvmfPkg/OvmfPkgX64.dsc
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@@ -823,6 +823,7 @@
!endif
OvmfPkg/PlatformDxe/Platform.inf
OvmfPkg/AmdSevDxe/AmdSevDxe.inf
!if $(SMM_REQUIRE) == TRUE
OvmfPkg/SmmAccess/SmmAccess2Dxe.inf