Re: [RFC] Revert "kvm: nVMX: Restrict VMX capability MSR changes"

[Liran Alon]

> On 20 Jan 2020, at 17:41, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
> 
> On 20/01/20 16:11, Vitaly Kuznetsov wrote:
>> 
>> RFC. I think the check for vmx->nested.vmxon is legitimate for everything
>> but restore so removing it (what I do with the revert) is likely a no-go.
>> I'd like to gather opinions on the proper fix: should we somehow check
>> that the vCPU is in 'restore' start (has never being run) and make
>> KVM_SET_MSRS pass or should we actually mandate that KVM_SET_NESTED_STATE
>> is run after KVM_SET_MSRS by userspace?
>> 
>> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> 
> I think this should be fixed in QEMU, by doing KVM_SET_MSRS for feature
> MSRs way earlier.  

I agree.

> I'll do it since I'm currently working on a patch to
> add a KVM_SET_MSR for the microcode revision.

Please Cc me.

Thanks,
-Liran