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SubjectRe: [PATCH] x86/mm/cpa: Warn if set_memory_XXcrypted() fails
Date
On Wed, 2023-10-25 at 13:03 -0500, Tom Lendacky wrote:
>
> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>

Thanks!
> >
>
> Under SEV, when making a page private/encrypted and the hypervisor
> does
> not assign the page to the guest (encrypted), but says it did, then
> when
> SEV tries to perform the PVALIDATE in the enc_status_change_finish()
> call,
> a nested page fault (#NPF) will be generated and exit to the
> hypervisor.
> Until the hypervisor assigns the page to the guest, the guest will
> not be
> able to make forward progress in regards to updating or using that
> page.

Yea, mismatches between guest page tables and EPT/NPT can be trouble
for TDX as well.

>
> And if the hypervisor returns an error when changing the page state,
> then,
> yes, the guest will terminate.

I guess those callbacks could be changed to return an error after all
these fixes then, if you want.
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