| Message ID | 20191120122452.57462-1-liran.alon@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: nVMX: Assume TLB entries of L1 and L2 are tagged differently if L0 use EPT | expand |
On 20/11/19 13:24, Liran Alon wrote: > Since commit 1313cc2bd8f6 ("kvm: mmu: Add guest_mode to kvm_mmu_page_role"), > guest_mode was added to mmu-role and therefore if L0 use EPT, it will > always run L1 and L2 with different EPTP. i.e. EPTP01!=EPTP02. > > Because TLB entries are tagged with EP4TA, KVM can assume > TLB entries populated while running L2 are tagged differently > than TLB entries populated while running L1. > > Therefore, update nested_has_guest_tlb_tag() to consider if > L0 use EPT instead of if L1 use EPT. > > Reviewed-by: Joao Martins <joao.m.martins@oracle.com> > Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com> > Signed-off-by: Liran Alon <liran.alon@oracle.com> > --- > arch/x86/kvm/vmx/nested.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c > index 229ca7164318..fdcead2d4dd6 100644 > --- a/arch/x86/kvm/vmx/nested.c > +++ b/arch/x86/kvm/vmx/nested.c > @@ -1024,7 +1024,9 @@ static int nested_vmx_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, bool ne > * populated by L2 differently than TLB entries populated > * by L1. > * > - * If L1 uses EPT, then TLB entries are tagged with different EPTP. > + * If L0 uses EPT, L1 and L2 run with different EPTP because > + * guest_mode is part of kvm_mmu_page_role. Thus, TLB entries > + * are tagged with different EPTP. > * > * If L1 uses VPID and we allocated a vpid02, TLB entries are tagged > * with different VPID (L1 entries are tagged with vmx->vpid > @@ -1034,7 +1036,7 @@ static bool nested_has_guest_tlb_tag(struct kvm_vcpu *vcpu) > { > struct vmcs12 *vmcs12 = get_vmcs12(vcpu); > > - return nested_cpu_has_ept(vmcs12) || > + return enable_ept || > (nested_cpu_has_vpid(vmcs12) && to_vmx(vcpu)->nested.vpid02); > } > > Queued, thanks. Paolo
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 229ca7164318..fdcead2d4dd6 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -1024,7 +1024,9 @@ static int nested_vmx_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, bool ne * populated by L2 differently than TLB entries populated * by L1. * - * If L1 uses EPT, then TLB entries are tagged with different EPTP. + * If L0 uses EPT, L1 and L2 run with different EPTP because + * guest_mode is part of kvm_mmu_page_role. Thus, TLB entries + * are tagged with different EPTP. * * If L1 uses VPID and we allocated a vpid02, TLB entries are tagged * with different VPID (L1 entries are tagged with vmx->vpid @@ -1034,7 +1036,7 @@ static bool nested_has_guest_tlb_tag(struct kvm_vcpu *vcpu) { struct vmcs12 *vmcs12 = get_vmcs12(vcpu); - return nested_cpu_has_ept(vmcs12) || + return enable_ept || (nested_cpu_has_vpid(vmcs12) && to_vmx(vcpu)->nested.vpid02); }
Since commit 1313cc2bd8f6 ("kvm: mmu: Add guest_mode to kvm_mmu_page_role"), guest_mode was added to mmu-role and therefore if L0 use EPT, it will always run L1 and L2 with different EPTP. i.e. EPTP01!=EPTP02. Because TLB entries are tagged with EP4TA, KVM can assume TLB entries populated while running L2 are tagged differently than TLB entries populated while running L1. Therefore, update nested_has_guest_tlb_tag() to consider if L0 use EPT instead of if L1 use EPT. Reviewed-by: Joao Martins <joao.m.martins@oracle.com> Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com> Signed-off-by: Liran Alon <liran.alon@oracle.com> --- arch/x86/kvm/vmx/nested.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)