Re: [PATCH] KVM: x86: cleanup CR3 reserved bits checks

[Paolo Bonzini]

On 02/02/21 19:34, Sean Christopherson wrote:
> On Tue, Feb 02, 2021, Paolo Bonzini wrote:
> > If not in long mode, the low bits of CR3 are reserved but not enforced to
> > be zero, so remove those checks.  If in long mode, however, the MBZ bits
> > extend down to the highest physical address bit of the guest, excluding
> > the encryption bit.
> >
> > Make the checks consistent with the above, and match them between
> > nested_vmcb_checks and KVM_SET_SREGS.
> Fixes + Cc:stable@?

Difficult to say what it fixes, it's been there forever for KVM_SET_SREGS.

For the nSVM part I'll go with

Fixes: 761e41693465 ("KVM: nSVM: Check that MBZ bits in CR3 and CR4 are 
not set on vmrun of nested guests")

Paolo

> > Signed-off-by: Paolo Bonzini<pbonzini@xxxxxxxxxx>
> Reviewed-by: Sean Christopherson<seanjc@xxxxxxxxxx>