On Tue, Aug 02, 2022 at 08:41:47PM +0000, Sean Christopherson wrote:
> On Fri, Jul 15, 2022, Yu Zhang wrote:
> > Although currently vmx_pf_exception_test can succeed, its
> > success is actually because we are using identical mappings
> > in the page tables and EB.PF is not set by L1. In practice,
> > the #PFs shall be expected by L1, if it is using shadowing
> > for L2.
>
> I'm a bit lost. Is there an actual failure somewhere? AFAICT, this passes when
> run as L1 or L2, with or without EPT enabled.
Thanks for your reply, Sean.
There's no failure. But IMHO, there should have been(for the
vmx_pf_exception_test, not the access test) - L1 shall expect
#PF induced VM exits, when it is using shadow for L2.
B.R.
Yu
> > So just set up the EPT, and clear the EB.PT, then L1 has the
> > right to claim a failure if a #PF is encountered.
> >
> > Signed-off-by: Yu Zhang <yu.c.zhang@xxxxxxxxxxxxxxx>
> > ---
> > x86/vmx_tests.c | 11 +++++++++++
> > 1 file changed, 11 insertions(+)
> >
> > diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c > > index
4d581e7..cc90611 100644
> > --- a/x86/vmx_tests.c
> > +++ b/x86/vmx_tests.c
> > @@ -10639,6 +10639,17 @@ static void __vmx_pf_exception_test(invalidate_tlb_t inv_fn, void *data)
> >
> > static void vmx_pf_exception_test(void)
> > {
> > + u32 eb;
> > +
> > + if (setup_ept(false)) {
> > + printf("EPT not supported.\n");
> > + return;
> > + }
> > +
> > + eb = vmcs_read(EXC_BITMAP);
> > + eb &= ~(1 << PF_VECTOR);
> > + vmcs_write(EXC_BITMAP, eb);
> > +
> > __vmx_pf_exception_test(NULL, NULL);
> > }
> >
> > --
> > 2.25.1
> >
