On Wed, May 30, 2018 at 11:55 AM Jim Mattson <jmattson@xxxxxxxxxx> wrote:
>
> Hi Konrad,
>
> I don't expect any hypervisor to do this, but I'll see if I can put
> together a unit test.
>
> On Wed, May 30, 2018 at 11:19 AM, Konrad Rzeszutek Wilk
> <konrad.wilk@xxxxxxxxxx> wrote:
> > On Wed, May 30, 2018 at 11:10:50AM -0700, Jim Mattson wrote:
> >> It is never correct for a VMX instruction to fail with "invalid VMCS"
> >> if there is, in fact, a current VMCS. Reads from unbacked addresses
> >> return all 1's, which means that an unbacked VMCS will not have the
> >> correct VMCS revision ID.
> >
> > Yikes.
> >
> > Is there a particular Hypervisor that does this? Would it make sense
> > to also have some kiund of test-cases?
> >
> >>
> >> Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
> >> ---
> >> arch/x86/kvm/vmx.c | 3 ++-
> >> 1 file changed, 2 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> >> index e50beb76d846..705a5afe5374 100644
> >> --- a/arch/x86/kvm/vmx.c
> >> +++ b/arch/x86/kvm/vmx.c
> >> @@ -8348,7 +8348,8 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
> >> struct page *page;
> >> page = kvm_vcpu_gpa_to_page(vcpu, vmptr);
> >> if (is_error_page(page)) {
> >> - nested_vmx_failInvalid(vcpu);
> >> + nested_vmx_failValid(vcpu,
> >> + VMXERR_VMPTRLD_INCORRECT_VMCS_REVISION_ID);
> >> return kvm_skip_emulated_instruction(vcpu);
> >> }
> >> new_vmcs12 = kmap(page);
> >> --
> >> 2.17.0.921.gf22659ad46-goog
> >>
Ping.
