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

["Gerd Hoffmann" <kraxel@redhat.com>]

On Fri, Feb 02, 2024 at 01:28:47PM -0600, Lendacky, Thomas via groups.io wrote:
> On 2/2/24 02:44, Gerd Hoffmann wrote:
> > On Fri, Feb 02, 2024 at 08:30:23AM +0000, Xu, Min M wrote:
> > > > Pushed branch with two experimental patches:
> > > >    https://github.com/kraxel/edk2/commits/devel/paging-5lvl/
> > > > 
> > > > One for tdx, writing different values into TDX_WORK_AREA_PGTBL_READY for
> > > > 4-level and 5-level paging modes.
> > > > 
> > > > One for sev, which adds a 2-level page directory for the first gigabyte and
> > > > places it at the same physical address it has in 4-level paging.
> > > > With that SevClearPageEncMaskForGhcbPage should work unmodified in 5-
> > > > level mode.
> > > > 
> > > > Test results are welcome.
> > > 
> > > Thanks Gerd, it works in TDX. One typo in the patch that pageTableEntriesLoopla57  and pageTableEntriesLoopLa57.
> > 
> > Thanks for testing.
> > 
> > Added a second sev patch to the branch, rearranging the #vc
> > handler uninstall to make the la57 cpuid checks work on sev.
> > 
> > @Tom: Would be great if you can give this a test
> 
> So this gets us past the ASM code CPUID instructions, however, the
> SEV support is still assuming 4-level paging and so:

Thanks for testing.  So, with the patch series the ResetVector is ready
for 5-level paging.  Good start.  I'll go over the series and will send
an update later (not urgent, it's post-freeze material anyway).

> SEV ASSERT:
>   AmdSevDxe:SetMemoryEncDec: bad PML4 for Physical=0x8000000000

As expected.

> FYI, this uncovered an SNP CPUID table processing bug in the ResetVector
> code and so I sent a fix to the mailing list.

I see the fix already merged.  Nice.

take care,
  Gerd



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