Re: [PATCH Part2 v6 14/49] crypto: ccp: Handle the legacy TMR allocation when SNP is enabled

Borislav Petkov
2022-11-16T18:39:46Z

On Wed, Nov 16, 2022 at 12:01:11PM -0600, Kalra, Ashish wrote:
> Ok, so i will work on implementing this leaked pages list and put it on a
> sev/snp associated structure.

See __sgx_sanitize_pages() and the poison list there, for an example.

> Also to add here, we will actually get a not-present #PF instead of the RMP
> violation #PF on writing to these leaked pages, as these pages would have
> been removed from the kernel direct map.

So if you do the list and still have the kernel raise a RMP fault for
those pages, traversing that list in the RMP handler to check whether
the page is there on it, should be a lot faster operation than doing the
#PF thing and removing them from the direct map.

And sorry for misleading you about UPM - we were thinking wrong
yesterday.

Thx.

--
Regards/Gruss,
Boris.