linux-kernel - [PATCH 1/3] KVM: nVMX: extract calculation of the L1's EFER

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Date:   Wed, 10 Nov 2021 12:00:16 +0200
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     kvm@...r.kernel.org
Cc:     Wanpeng Li <wanpengli@...cent.com>, Borislav Petkov <bp@...en8.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
        Sean Christopherson <seanjc@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Jim Mattson <jmattson@...gle.com>,
        Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH 1/3] KVM: nVMX: extract calculation of the L1's EFER

This will be useful in the next patch.

No functional change intended.

Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
---
 arch/x86/kvm/vmx/nested.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index b4ee5e9f9e201..49ae96c0cc4d1 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -4228,6 +4228,21 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 	kvm_clear_interrupt_queue(vcpu);
 }
 
+/*
+ * Given vmcs12, return the expected L1 value of IA32_EFER
+ * after VM exit from that vmcs12
+ */
+static inline u64 nested_vmx_get_vmcs12_host_efer(struct kvm_vcpu *vcpu,
+						  struct vmcs12 *vmcs12)
+{
+	if (vmcs12->vm_exit_controls & VM_EXIT_LOAD_IA32_EFER)
+		return vmcs12->host_ia32_efer;
+	else if (vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE)
+		return vcpu->arch.efer | (EFER_LMA | EFER_LME);
+	else
+		return vcpu->arch.efer & ~(EFER_LMA | EFER_LME);
+}
+
 /*
  * A part of what we need to when the nested L2 guest exits and we want to
  * run its L1 parent, is to reset L1's guest state to the host state specified
@@ -4243,12 +4258,7 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu,
 	enum vm_entry_failure_code ignored;
 	struct kvm_segment seg;
 
-	if (vmcs12->vm_exit_controls & VM_EXIT_LOAD_IA32_EFER)
-		vcpu->arch.efer = vmcs12->host_ia32_efer;
-	else if (vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE)
-		vcpu->arch.efer |= (EFER_LMA | EFER_LME);
-	else
-		vcpu->arch.efer &= ~(EFER_LMA | EFER_LME);
+	vcpu->arch.efer = nested_vmx_get_vmcs12_host_efer(vcpu, vmcs12);
 	vmx_set_efer(vcpu, vcpu->arch.efer);
 
 	kvm_rsp_write(vcpu, vmcs12->host_rsp);
-- 
2.26.3