Re: [PATCH 22/25] KVM: TDX: Use guest physical address to configure EPT level and GPAW

Tony Lindgren
2024-10-10T10:36:19Z

On Thu, Oct 10, 2024 at 05:13:43PM +0800, Xiaoyao Li wrote:
> On 8/13/2024 6:48 AM, Rick Edgecombe wrote:
> > From: Xiaoyao Li <xiaoyao.li@intel.com>
> >
> > KVM reports guest physical address in CPUID.0x800000008.EAX[23:16],
> > which is similar to TDX's GPAW. Use this field as the interface for
> > userspace to configure the GPAW and EPT level for TDs.
> >
> > Note,
> >
> > 1. only value 48 and 52 are supported. 52 means GPAW-52 and EPT level
> > 5, and 48 means GPAW-48 and EPT level 4.
> > 2. value 48, i.e., GPAW-48 is always supported. value 52 is only
> > supported when the platform supports 5 level EPT.
> >
> > Current TDX module doesn't support max_gpa configuration. However
> > current implementation relies on max_gpa to configure EPT level and
> > GPAW. Hack KVM to make it work.
>
> This patch needs to be squashed into patch 14.

Yes agreed that makes sense.

Regards,

Tony