Re: [edk2-devel] [PATCH v2 0/5] OvmfPkg: Add support for 5-level paging

["Lendacky, Thomas via groups.io" <thomas.lendacky=amd.com@groups.io>]

On 1/30/24 13:15, Laszlo Ersek wrote:
> On 1/30/24 13:31, Gerd Hoffmann wrote:
>> Patch #1 has been submitted separately last week.
>> Intewl raised concerns that removing or renaming
>> the PCD breaks platforms, so I'm just doing the
>> minimal fix here.
>>
>> Patch #2 + #3 update OvmfPkg ResetVector and
>> PlatformInitLib for 5-level paging support.
>>
>> Tom, Min: can you test this patch set with SEV / TDX?
> 
> I'll merge the series when those tests succeed. (Please keep me CC'd.)

I replied to the patch 4/5 with some comments.

As long as the PcdUse5LevelPageTable PCD is FALSE, this series doesn't 
appear to affect SEV.

When PcdUse5LevelPageTable is set to TRUE, the CPUID calls in 
OvmfPkg/ResetVector/Ia32/PageTables64.asm will cause an SEV-ES/SEV-SNP 
guest to crash because there is no #VC handler established.

When PcdUse5LevelPageTable is set to TRUE, an SEV guest will ASSERT:
   AmdSevDxe:SetMemoryEncDec: bad PML4 for Physical=0x8000000000
   ASSERT_EFI_ERROR (Status = No mapping)

The SEV code in BaseMemEncryptSevLib was written before the page table 
library support was developed, and as such, only supports 4-level paging. 
So the SEV page table support needs updating.

Thanks,
Tom

> 
> Thanks
> Laszlo
> 
>>
>> v2 changes:
>>   - fix sev/tdx handling with 5-level paging.
>>   - more comments for 5-level page table setup.
>>   - improve PAGE_* naming (new patch #3).
>>   - rename Page5LevelSupported to Page5LevelEnabled (new patch #2).
>>   - pick up some review tags.
>>
>> Gerd Hoffmann (5):
>>    MdeModulePkg/DxeIplPeim: fix PcdUse5LevelPageTable assert
>>    MdeModulePkg/DxeIplPeim: rename variable
>>    OvmfPkg/ResetVector: improve page table flag names
>>    OvmfPkg/ResetVector: add 5-level paging support
>>    OvmfPkg/PlatformInitLib: add 5-level paging support
>>
>>   OvmfPkg/ResetVector/ResetVector.inf           |   1 +
>>   .../Core/DxeIplPeim/X64/VirtualMemory.c       |  24 ++--
>>   OvmfPkg/Library/PlatformInitLib/MemDetect.c   |  57 ++++++---
>>   OvmfPkg/ResetVector/Ia32/PageTables64.asm     | 116 +++++++++++++++---
>>   OvmfPkg/ResetVector/ResetVector.nasmb         |   1 +
>>   5 files changed, 152 insertions(+), 47 deletions(-)
>>
> 


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