Messages in this thread | | | Date | Fri, 7 Jan 2022 20:04:36 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH 08/26] x86/tdx: Handle in-kernel MMIO |
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On Fri, Jan 07, 2022 at 08:49:26PM +0300, Kirill A. Shutemov wrote: > To emulate an instruction the emulator needs two things: > > - R/W access to the register file to read/modify instruction arguments > and see RIP of the faulted instruction. > > - Read access to memory where instruction is placed to see what to > emualte. In this case it is guest kernel text. > > Both of them are not available to VMM in TDX environment: > > - Register file is never exposed to VMM. When a TD exits to the module, > it saves registers into the state-save area allocated for that TD. > The module then scrubs these registers before returning execution > control to the VMM, to help prevent leakage of TD state. > > - Memory is encrypted TD-private key. The CPU disallows software other > than the TDX module and TDs from making memory accesses using the > private key.
Thanks, that's very helpful info. It would be nice to have it in the commit message.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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