linux-kernel - [PATCH] KVM: nVMX: INVPCID support

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Date:   Thu, 27 Jul 2017 15:20:39 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     david@...hat.com
Subject: [PATCH] KVM: nVMX: INVPCID support

Expose the "Enable INVPCID" secondary execution control to the guest
and properly reflect the exit reason.

In addition, before this patch the guest was always running with
INVPCID enabled, causing pcid.flat's "Test on INVPCID when disabled"
test to fail.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/vmx.c | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index ed43fd824264..9c3c6c524430 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8189,6 +8189,10 @@ static bool nested_vmx_exit_reflected(struct kvm_vcpu *vcpu, u32 exit_reason)
 		 * table is L0's fault.
 		 */
 		return false;
+	case EXIT_REASON_INVPCID:
+		return
+			nested_cpu_has2(vmcs12, SECONDARY_EXEC_ENABLE_INVPCID) &&
+			nested_cpu_has(vmcs12, CPU_BASED_INVLPG_EXITING);
 	case EXIT_REASON_WBINVD:
 		return nested_cpu_has2(vmcs12, SECONDARY_EXEC_WBINVD_EXITING);
 	case EXIT_REASON_XSETBV:
@@ -9440,7 +9444,6 @@ static void nested_vmx_cr_fixed1_bits_update(struct kvm_vcpu *vcpu)
 
 static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 {
-	struct kvm_cpuid_entry2 *best;
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	u32 secondary_exec_ctl = vmx_secondary_exec_control(vmx);
 
@@ -9459,15 +9462,27 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 		}
 	}
 
-	/* Exposing INVPCID only when PCID is exposed */
-	best = kvm_find_cpuid_entry(vcpu, 0x7, 0);
-	if (vmx_invpcid_supported() &&
-	    (!best || !(best->ebx & bit(X86_FEATURE_INVPCID)) ||
-	    !guest_cpuid_has_pcid(vcpu))) {
-		secondary_exec_ctl &= ~SECONDARY_EXEC_ENABLE_INVPCID;
+	if (vmx_invpcid_supported()) {
+		/* Exposing INVPCID only when PCID is exposed */
+		struct kvm_cpuid_entry2 *best = kvm_find_cpuid_entry(vcpu, 0x7, 0);
+		bool invpcid_enabled =
+			best && best->ebx & bit(X86_FEATURE_INVPCID) &&
+			guest_cpuid_has_pcid(vcpu);
 
-		if (best)
-			best->ebx &= ~bit(X86_FEATURE_INVPCID);
+		if (!invpcid_enabled) {
+			secondary_exec_ctl &= ~SECONDARY_EXEC_ENABLE_INVPCID;
+			if (best)
+				best->ebx &= ~bit(X86_FEATURE_INVPCID);
+		}
+
+		if (nested) {
+			if (invpcid_enabled)
+				vmx->nested.nested_vmx_secondary_ctls_high |=
+					SECONDARY_EXEC_ENABLE_INVPCID;
+			else
+				vmx->nested.nested_vmx_secondary_ctls_high &=
+					~SECONDARY_EXEC_ENABLE_INVPCID;
+		}
 	}
 
 	if (cpu_has_secondary_exec_ctrls())
@@ -10175,6 +10190,7 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 
 		/* Take the following fields only from vmcs12 */
 		exec_control &= ~(SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
+				  SECONDARY_EXEC_ENABLE_INVPCID |
 				  SECONDARY_EXEC_RDTSCP |
 				  SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
 				  SECONDARY_EXEC_APIC_REGISTER_VIRT);
-- 
1.8.3.1