Re: [PATCH v4 24/25] KVM: VMX: Cache MSR_IA32_VMX_MISC in vmcs_config

Vitaly Kuznetsov
2022-08-02T16:14:14Z

Sean Christopherson <seanjc@google.com> writes:

> On Thu, Jul 14, 2022, Vitaly Kuznetsov wrote:
>> @@ -2613,6 +2614,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,
>> if (((vmx_msr_high >> 18) & 15) != 6)
>> return -EIO;
>>
>> + rdmsrl(MSR_IA32_VMX_MISC, misc_msr);
>
> Might make sense to sanitize fields that KVM doesn't use and that are not exposed
> to L1. Not sure it's worthwhile though as many of the bits fall into a grey area,
> e.g. all the SMM stuff isn't technically used by KVM, but that's largely because
> much of it just isn't relevant to virtualization.
>
> I'm totally ok leaving it as-is, though maybe name it "unsanitized_misc" or so
> to make that obvious?

I couldn't convince myself to add 'unsanitized_' prefix as I don't think
it significantly reduces possible confusion (the quiestion would be
'sanitized for what and in which way?') so a need for 'git grep' seems
imminent anyway. Hope I've addressed the rest of your comments in v5
though, thanks for your review!

--
Vitaly