If L1 and L2 share VPID (because L1 don't use VPID or we haven't allocated
a vpid02), we need to flush TLB on L1<->L2 transitions.
Before this patch, this TLB flushing was done by vmx_flush_tlb().
If L0 use EPT, this will translate into INVEPT(active_eptp);
However, if L1 use EPT, in L1->L2 VMEntry, active EPTP is EPTP01 but
TLB entries populated by L2 are tagged with EPTP02.
Therefore we should delay vmx_flush_tlb() until active_eptp is EPTP02.
To achieve this, instead of directly calling vmx_flush_tlb() we request
it to be called by KVM_REQ_TLB_FLUSH which is evaluated after
KVM_REQ_LOAD_CR3 which sets the active_eptp to EPTP02 as required.
Similarly, on L2->L1 VMExit, active EPTP is EPTP02 but TLB entries
populated by L1 are tagged with EPTP01 and therefore we should delay
vmx_flush_tlb() until active_eptp is EPTP01.
Reviewed-by: Mihai Carabas <mihai.carabas@xxxxxxxxxx>
Reviewed-by: Darren Kenny <darren.kenny@xxxxxxxxxx>
Reviewed-by: Nikita Leshenko <nikita.leshchenko@xxxxxxxxxx>
Signed-off-by: Liran Alon <liran.alon@xxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index bed75118111c..a56845972722 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -12245,7 +12245,15 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
__vmx_flush_tlb(vcpu, vmx->nested.vpid02, true);
}
} else {
- vmx_flush_tlb(vcpu, true);
+ /*
+ * If L1 use EPT, then L0 needs to execute INVEPT on
+ * EPTP02 instead of EPTP01. Therefore, delay TLB
+ * flush until vmcs02->eptp is fully updated by
+ * KVM_REQ_LOAD_CR3. Note that this assumes
+ * KVM_REQ_TLB_FLUSH is evaluated after
+ * KVM_REQ_LOAD_CR3 in vcpu_enter_guest().
+ */
+ kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
}
}
@@ -13131,10 +13139,14 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu,
* Therefore, flush TLB only in case vmcs01 uses VPID and
* vmcs12 don't use VPID as in this case L1 & L2 TLB entries
* are both tagged with vmx->vpid.
+ *
+ * If vmcs12 uses EPT, we need to execute this flush on EPTP01
+ * and therefore we request the TLB flush to happen only after VMCS EPTP
+ * has been set by KVM_REQ_LOAD_CR3.
*/
if (enable_vpid &&
!(nested_cpu_has_vpid(vmcs12) && to_vmx(vcpu)->nested.vpid02)) {
- vmx_flush_tlb(vcpu, true);
+ kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
}
vmcs_write32(GUEST_SYSENTER_CS, vmcs12->host_ia32_sysenter_cs);
--
2.16.1
