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

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

On Thu, Feb 01, 2024 at 05:44:30AM +0000, Xu, Min M wrote:
> On Wednesday, January 31, 2024 4:24 PM, Gerd Hoffmann wrote:
> > On Wed, Jan 31, 2024 at 06:19:38AM +0000, Xu, Min M wrote:
> > > On Tuesday, January 30, 2024 8:32 PM, 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?
> > > >
> > > We test the patch in TDX with PcdUse5LevelPageTable TRUE. It failed if the
> > td-guest is configured with multiple vCpus. We're investigating what
> > happened.
> > 
> > My first guess would be we need to somehow propagate to the APs that
> > cr4.la57 must be set.
> Yes, we make a quick poc that set the LA57 for APs. It works in multiple vCPUs scenario.

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 & take care,
  Gerd



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