Re: [PATCH v3 06/27] x86/cea: Export per CPU variable cea_exception_stacks

[Dave Hansen]

On 10/1/24 10:51, Xin Li wrote:
...>> Also, what's the purpose of clearing GUEST_IA32_FRED_RSP[123] at
>> init_vmcs() time?  I would have thought that those values wouldn't
>> matter until the VMCS gets loaded at vmx_vcpu_load_vmcs() when they are
>> overwritten anyway.  Or, I could be just totally misunderstanding how
>> KVM consumes the VMCS. 🙂
> 
> I don't see any misunderstanding.  However we just do what the SDM
> claims, even it seems that it's not a must *logically*.
> 
> FRED spec says:
> The RESET state of each of the new MSRs is zero. INIT does not change
> the value of the new MSRs

Oh, sorry.  I was misreading the "HOST_" and "GUEST_" MSR prefixes.  I
thought the same VMCS field was being written at VMCS load *and* init
time (which it isn't).  Sorry for the noise.