Re: [PATCH v3 2/5] x86/boot/compressed/64: Add CPUID sanity check to early #VC handler

2020-10-28 Thread Joerg Roedel
On Tue, Oct 27, 2020 at 11:38:46AM +0100, Borislav Petkov wrote: > So why are we doing those checks here at all then? I mean, the HV > can tell us whatever it wants, i.e., make sure those checks pass but > still report the C-bit at the wrong position. Which means that those > checks are simply

Re: [PATCH v3 2/5] x86/boot/compressed/64: Add CPUID sanity check to early #VC handler

2020-10-27 Thread Borislav Petkov
On Wed, Oct 21, 2020 at 02:39:35PM +0200, Joerg Roedel wrote: > From: Joerg Roedel > > The early #VC handler which doesn't have a GHCB can only handle CPUID > exit codes. It is needed by the early boot code to handle #VC > exceptions raised in verify_cpu() and to get the position of the C > bit.

[PATCH v3 2/5] x86/boot/compressed/64: Add CPUID sanity check to early #VC handler

2020-10-21 Thread Joerg Roedel
From: Joerg Roedel The early #VC handler which doesn't have a GHCB can only handle CPUID exit codes. It is needed by the early boot code to handle #VC exceptions raised in verify_cpu() and to get the position of the C bit. But the CPUID information comes from the hypervisor, which is untrusted