> On 6 Sep 2018, at 19:06, Jim Mattson <jmattson@xxxxxxxxxx> wrote:
>
> On Thu, Sep 6, 2018 at 6:32 AM, Liran Alon <liran.alon@xxxxxxxxxx> wrote:
>> If CPU use both VPID and EPT, TLB entries populated by CPU are tagged
>> with both EPTP and VPID. Therefore, if L1 uses EPT, L2 TLB entries
>> are separated from L1 TLB entries by the EPTP tags as vmcs02 use
>> EPTP02 while vmcs01 use EPTP01.
>>
>> Thus, we don't need to make sure that vmcs02->vpid != vmcs01->vpid.
>> Therefore, we can just set vmcs02->vpid to vmcs12->vpid.
>>
>> Reviewed-by: Mihai Carabas <mihai.carabas@xxxxxxxxxx>
>> Reviewed-by: Darren Kenny <darren.kenny@xxxxxxxxxx>
>> Reviewed-by: Nikita Leshchenko <nikita.leshchenko@xxxxxxxxxx>
>> Signed-off-by: Liran Alon <liran.alon@xxxxxxxxxx>
>
> I suggested this back in July, but Paolo didn't like it. I still like it. :-)
>
> Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>
Yes, you are right this is based on your suggestion.
This is why I Cc you to this email thread. However, I forgot to:
Suggested-by: Jim Mattson <jmattson@xxxxxxxxxx>
Paolo/Radim, if you decide to apply this, please add this tag to the commit.
Thanks,
-Liran
>
>> ---
>> arch/x86/kvm/vmx.c | 18 ++++++++++++++----
>> 1 file changed, 14 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index b97e0c5ccb46..98faba65c24a 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -12018,10 +12018,20 @@ static void prepare_vmcs02_full(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
>> vmcs_write64(GUEST_BNDCFGS, vmcs12->guest_bndcfgs);
>>
>> if (enable_vpid) {
>> - if (nested_cpu_has_vpid(vmcs12) && vmx->nested.vpid02)
>> - vmcs_write16(VIRTUAL_PROCESSOR_ID, vmx->nested.vpid02);
>> - else
>> - vmcs_write16(VIRTUAL_PROCESSOR_ID, vmx->vpid);
>> + u16 vmcs02_vpid;
>
> You could simplify the logic below if you initialize vmcs02_vpid to vmx->vpid.
> BTW, when did we switch to compilation options that allow mid-block
> declarations? Woohoo!
>
>> + if (nested_cpu_has_vpid(vmcs12)) {
>> + if (nested_cpu_has_ept(vmcs12))
>> + vmcs02_vpid = vmcs12->virtual_processor_id;
>> + else if (vmx->nested.vpid02)
>> + vmcs02_vpid = vmx->nested.vpid02;
>> + else
>> + vmcs02_vpid = vmx->vpid;
>> + } else {
>> + vmcs02_vpid = vmx->vpid;
>> + }
>> +
>> + vmcs_write16(VIRTUAL_PROCESSOR_ID, vmcs02_vpid);
>> }
>>
>> /*
>> --
>> 2.16.1
>>
