Re: [PATCH v2 5/5] KVM: nVMX: expose VPID capability to L1

[Wanpeng Li]

On 10/13/15 10:44 PM, Paolo Bonzini wrote:
> On 08/10/2015 07:57, Wanpeng Li wrote:
> > Expose VPID capability to L1. For nested guests, we don't do anything
> > specific for single context invalidation. Hence, only advertise support
> > for global context invalidation. The major benefit of nested VPID comes
> > from having separate vpids when switching between L1 and L2, and also
> > when L2's vCPUs not sched in/out on L1.
> >
> > Reviewed-by: Wincy Van <fanwenyi0529@xxxxxxxxx>
> > Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
> > ---
> >   arch/x86/kvm/vmx.c | 36 ++++++++++++++++++++++++------------
> >   1 file changed, 24 insertions(+), 12 deletions(-)
> >
> > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> > index 31d272e..22b4dc7 100644
> > --- a/arch/x86/kvm/vmx.c
> > +++ b/arch/x86/kvm/vmx.c
> > @@ -442,7 +442,7 @@ struct nested_vmx {
> >   	u32 nested_vmx_true_entry_ctls_low;
> >   	u32 nested_vmx_misc_low;
> >   	u32 nested_vmx_misc_high;
> > -	u32 nested_vmx_ept_caps;
> > +	u64 nested_vmx_ept_vpid_caps;
> Considering that all VMX_VPID_ constants are off by 32, perhaps it's
> simpler to have separate variables for nested_vmx_ept_caps and
> nested_vmx_vpid_caps, and only rejoin them when reading the MSR.  It
> will make this patch smaller too.
>
> You can add the new field to struct nested_vmx in patch 3 (leaving it
> initialized to 0, of course).

Good point. I will do it after the new travel recently. :-)

Regards,
Wanpeng Li
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