[PATCH 2/3] KVM: nVMX: colocate guest vmcs checks

["Radim Krčmář" <rkrcmar@redhat.com>]

Few guest checks were done before entering the guest, for which there is
no reason.  Having them all in one place will be simpler.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 arch/x86/kvm/vmx.c | 72 +++++++++++++++++++++++++++++-------------------------
 1 file changed, 39 insertions(+), 33 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index ab65b31ce58c..050899431b5e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10499,39 +10499,6 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 		}
 	}
 
-	if (!nested_guest_cr0_valid(vcpu, vmcs12->guest_cr0) ||
-	    !nested_guest_cr4_valid(vcpu, vmcs12->guest_cr4)) {
-		nested_vmx_entry_failure(vcpu, vmcs12,
-			EXIT_REASON_INVALID_STATE, ENTRY_FAIL_DEFAULT);
-		return 1;
-	}
-	if (vmcs12->vmcs_link_pointer != -1ull) {
-		nested_vmx_entry_failure(vcpu, vmcs12,
-			EXIT_REASON_INVALID_STATE, ENTRY_FAIL_VMCS_LINK_PTR);
-		return 1;
-	}
-
-	/*
-	 * If the load IA32_EFER VM-entry control is 1, the following checks
-	 * are performed on the field for the IA32_EFER MSR:
-	 * - Bits reserved in the IA32_EFER MSR must be 0.
-	 * - Bit 10 (corresponding to IA32_EFER.LMA) must equal the value of
-	 *   the IA-32e mode guest VM-exit control. It must also be identical
-	 *   to bit 8 (LME) if bit 31 in the CR0 field (corresponding to
-	 *   CR0.PG) is 1.
-	 */
-	if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_EFER) {
-		ia32e = (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) != 0;
-		if (!kvm_valid_efer(vcpu, vmcs12->guest_ia32_efer) ||
-		    ia32e != !!(vmcs12->guest_ia32_efer & EFER_LMA) ||
-		    ((vmcs12->guest_cr0 & X86_CR0_PG) &&
-		     ia32e != !!(vmcs12->guest_ia32_efer & EFER_LME))) {
-			nested_vmx_entry_failure(vcpu, vmcs12,
-				EXIT_REASON_INVALID_STATE, ENTRY_FAIL_DEFAULT);
-			return 1;
-		}
-	}
-
 	/*
 	 * We're finally done with prerequisite checking, and can start with
 	 * the nested entry.
@@ -10561,6 +10528,45 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 
 	vmx_segment_cache_clear(vmx);
 
+	if (!nested_guest_cr0_valid(vcpu, vmcs12->guest_cr0) ||
+	    !nested_guest_cr4_valid(vcpu, vmcs12->guest_cr4)) {
+		leave_guest_mode(vcpu);
+		vmx_load_vmcs01(vcpu);
+		nested_vmx_entry_failure(vcpu, vmcs12,
+			EXIT_REASON_INVALID_STATE, ENTRY_FAIL_DEFAULT);
+		return 1;
+	}
+	if (vmcs12->vmcs_link_pointer != -1ull) {
+		leave_guest_mode(vcpu);
+		vmx_load_vmcs01(vcpu);
+		nested_vmx_entry_failure(vcpu, vmcs12,
+			EXIT_REASON_INVALID_STATE, ENTRY_FAIL_VMCS_LINK_PTR);
+		return 1;
+	}
+
+	/*
+	 * If the load IA32_EFER VM-entry control is 1, the following checks
+	 * are performed on the field for the IA32_EFER MSR:
+	 * - Bits reserved in the IA32_EFER MSR must be 0.
+	 * - Bit 10 (corresponding to IA32_EFER.LMA) must equal the value of
+	 *   the IA-32e mode guest VM-exit control. It must also be identical
+	 *   to bit 8 (LME) if bit 31 in the CR0 field (corresponding to
+	 *   CR0.PG) is 1.
+	 */
+	if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_EFER) {
+		ia32e = (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) != 0;
+		if (!kvm_valid_efer(vcpu, vmcs12->guest_ia32_efer) ||
+		    ia32e != !!(vmcs12->guest_ia32_efer & EFER_LMA) ||
+		    ((vmcs12->guest_cr0 & X86_CR0_PG) &&
+		     ia32e != !!(vmcs12->guest_ia32_efer & EFER_LME))) {
+			leave_guest_mode(vcpu);
+			vmx_load_vmcs01(vcpu);
+			nested_vmx_entry_failure(vcpu, vmcs12,
+				EXIT_REASON_INVALID_STATE, ENTRY_FAIL_DEFAULT);
+			return 1;
+		}
+	}
+
 	if (prepare_vmcs02(vcpu, vmcs12, &exit_qualification)) {
 		leave_guest_mode(vcpu);
 		vmx_load_vmcs01(vcpu);
-- 
2.11.0