Messages in this thread | | | Date | Fri, 7 Jan 2022 14:46:41 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH 08/26] x86/tdx: Handle in-kernel MMIO |
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On Wed, Jan 05, 2022 at 06:43:11PM +0300, Kirill A. Shutemov wrote: > Not encrypted, saved/restored by TDX module. But yes, cannot be exposed > (without guest intend). > > I talk here about *why* the traditional way to handle MMIO -- on VMM side > -- doesn't work for TDX. It's not safe with untrusted VMM.
Lemme see if I understand this correctly: TDX module saves/restores guest registers so a malicious hypervisor cannot access them? And that's why you can't do the traditional way MMIO is done?
> readX()/writeX() helpers limit the range of instructions which can trigger > MMIO. It makes MMIO instruction emulation feasible. Raw access to MMIO > region allows compiler to generate whatever instruction it wants. > Supporting all possible instructions is a task of a different scope.
Yap, please add that to the commit message.
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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