Re: [Xen-devel] [PATCH RFC 05/14] xen: vmx: Disable the 2M/1G superpage when SPP enabled

[Yi Zhang <yi.z.zhang@xxxxxxxxxxxxxxx>]

On 2017-10-19 at 12:17:12 -0600, Tamas K Lengyel wrote:
> On Thu, Oct 19, 2017 at 2:11 AM, Zhang Yi <yi.z.zhang@xxxxxxxxxxxxxxx> wrote:
> > From: Zhang Yi Z <yi.z.zhang@xxxxxxxxxxxxxxx>
> >
> > Current we only support Sub-page Protection on the 4k
> > page table.
> >
> > Signed-off-by: Zhang Yi Z <yi.z.zhang@xxxxxxxxxxxxxxx>
> > ---
> >  xen/arch/x86/hvm/vmx/vmx.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
> > index 04ae0d6..a4c24bb 100644
> > --- a/xen/arch/x86/hvm/vmx/vmx.c
> > +++ b/xen/arch/x86/hvm/vmx/vmx.c
> > @@ -2497,6 +2497,12 @@ const struct hvm_function_table * __init 
> > start_vmx(void)
> >          vmx_function_table.get_guest_bndcfgs = vmx_get_guest_bndcfgs;
> >      }
> >
> > +    if ( cpu_has_vmx_ept_spp )
> 
> I think this really only ought to happen if the command-line option
> has also been enabled.

Sorry, didn't catch your point, the command line option opt_hap_2m and
opt_hap_1G was enable by default, I need to  disable the supper page
when spp feature enabled. Did you mean that if we enable 2M/1G by
command-line we couldn't disable it here? yes, it is, I will improve
this logic. Thank you Tamas.

> 
> > +    {
> > +        vmx_function_table.hap_capabilities &= ~HVM_HAP_SUPERPAGE_2MB;
> > +        vmx_function_table.hap_capabilities &= ~HVM_HAP_SUPERPAGE_1GB;
> > +    }
> > +
> >      setup_vmcs_dump();
> >
> >      lbr_tsx_fixup_check();
> > --
> > 2.7.4

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