Re: [PATCH] KVM: x86: Virtualize AMD CPUID faulting

[Sean Christopherson]

On Tue, Feb 10, 2026, Jamie Liu wrote:
> CPUID faulting via MSR_MISC_FEATURES_ENABLES_CPUID_FAULT is only used on
> Intel CPUs. The mechanism virtualized by this change is used on AMD
> CPUs. See arch/x86/kernel/cpu/amd.c:bsp_init_amd(),
> arch/x86/kernel/process.c:set_cpuid_faulting().

Please rewrite this to state what is being changed, e.g. how KVM is virtualizing
the feature, and most importantly why it is "safe" to do so.  Specifically, this
needs to call out that CPUID_USER_DIS is documented in the APM as an architectural
MSR, which for me at least, is mandatory for virtualizing/emulating any of the
MSR_K7_HWCR.

The fact that Intel uses some other mechanism is irrelevant, and the kernel source
code is not authoritative for things like this.