Messages in this thread | | | Date | Mon, 10 Jul 2023 08:59:04 -0500 | Subject | Re: [PATCHv3 0/3] x86/tdx: Fix one more load_unaligned_zeropad() issue | From | Tom Lendacky <> |
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On 7/9/23 01:09, Kirill A. Shutemov wrote: > On Sat, Jul 08, 2023 at 11:53:08PM +0000, Michael Kelley (LINUX) wrote: >> From: Kirill A. Shutemov <kirill@shutemov.name> Sent: Friday, July 7, 2023 7:07 AM >>> >>> On Thu, Jul 06, 2023 at 04:48:32PM +0000, Michael Kelley (LINUX) wrote: >>>> From: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Sent: Tuesday, June 6, 2023 2:56 AM >> >> [snip] >> >>> >>> It only addresses the problem that happens on transition, but >>> load_unaligned_zeropad() is still a problem for the shared mappings in >>> general, after transition is complete. Like if load_unaligned_zeropad() >>> steps from private to shared mapping and shared mapping triggers #VE, >>> kernel should be able to handle it. >> >> I'm showing my ignorance of TDX architectural details, but what's the >> situation where shared mappings in general can trigger a #VE? How >> do such situations get handled for references that aren't from >> load_unaligned_zeropad()? >> > > Shared mappings are under host/VMM control. It can just not map the page > in shared-ept and trigger ept-violation #VE. > >>> Any comments? >> >> This looks good to me. I applied the diff to a TDX VM running on >> Hyper-V. When a load_unaligned_zeropad() occurs on a page that is >> transitioning between private and shared, the zeropad fixup is now >> done correctly via the #VE handler. (This is *without* my RFC patch to >> mark the pages invalid during a transition.) > > Great. > > I am at vacation for the next two weeks. I will prepare a proper patch > when I am back. Feel free to make patch yourself if you feel it is urgent. >
Michael,
Are you still pursuing the RFC patch, then? Just trying to decide whether a patch will be needed for SNP...
Thanks, Tom
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