Re: [Xen-devel] [XTF PATCH 07/16] vvmx: test vmxon in CPL=3 and out of VMX operation

[Haozhong Zhang <haozhong.zhang@xxxxxxxxx>]

On 12/16/16 20:33 +0000, Andrew Cooper wrote:
> On 16/12/16 13:43, Haozhong Zhang wrote:
> > diff --git a/tests/vvmx/vmxon.c b/tests/vvmx/vmxon.c
> > index 31f074c..ca33b3c 100644
> > --- a/tests/vvmx/vmxon.c
> > +++ b/tests/vvmx/vmxon.c
> > @@ -28,11 +28,42 @@ static bool test_vmxon_novmxe(void)
> >                                VMXERR_FAULT, EXINFO_SYM(UD, 0), 0);
> >  }
> >
> > +static unsigned long vmxon_in_user(void)
> I'd name this user_vmxon() as it is slightly shorter, but I'm not
> terribly fussed.
>
> > +{
> > +    exinfo_t fault;
> > +    unsigned long ret = vmxon((uint64_t)vmxon_region, &fault);
> > +
> > +    return (ret << 32) | fault;
> > +}
> > +
> > +/**
> > + * vmxon in CPL=3 and out of VMX operation
> > + *
> > + * Expect: #GP(0)
> > + */
> > +static bool test_vmxon_in_user(void)
> Similarly, test_user_vmxon()
I'll turn to shorter names.

> > +{
> > +    clear_vmcs(vmxon_region, get_vmcs_revid());
> > +
> > +    unsigned long ret = exec_user(vmxon_in_user);
> > +    uint8_t err = (ret >> 32) & 0xff;
> > +    exinfo_t fault = ret & 0xFFFFFFFF;
> > +
> > +    return handle_vmxinsn_err(__func__, err, fault,
> > +                              VMXERR_FAULT, EXINFO_SYM(GP, 0), 0);
> > +}
> > +
> >  bool test_vmxon(void)
> >  {
> >      if ( !test_vmxon_novmxe() )
> >          return false;
> Your subject says out of VMX operation, but the implementation is inside
> VMX operation.
vmxon in test_vmxon_novmxe() fails if test_vmxon_novmxe() return true,
so here we are still out of VMX operation.

> It would be worth testing both scenarios, as they should be
> distinguished by #UD vs #GP[0].
Yes, patch 13 - 16 are for this purpose.

Thanks,
Haozhong

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