KVM: vmx: write HOST_IA32_EFER in vmx_set_constant_host_state()
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Message ID 20180731134243.24436-1-sean.j.christopherson@intel.com
State New
Headers show
Series
  • KVM: vmx: write HOST_IA32_EFER in vmx_set_constant_host_state()
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Commit Message

Sean Christopherson July 31, 2018, 1:42 p.m. UTC
EFER is constant in the host and writing it once during setup means
we can skip writing the host value in add_atomic_switch_msr_special().

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/vmx.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Patch
diff mbox series

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 1689f433f3a0..5bd42d144049 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2420,7 +2420,8 @@  static void add_atomic_switch_msr_special(struct vcpu_vmx *vmx,
 		u64 guest_val, u64 host_val)
 {
 	vmcs_write64(guest_val_vmcs, guest_val);
-	vmcs_write64(host_val_vmcs, host_val);
+	if (host_val_vmcs != HOST_IA32_EFER)
+		vmcs_write64(host_val_vmcs, host_val);
 	vm_entry_controls_setbit(vmx, entry);
 	vm_exit_controls_setbit(vmx, exit);
 }
@@ -5949,6 +5950,9 @@  static void vmx_set_constant_host_state(struct vcpu_vmx *vmx)
 		rdmsr(MSR_IA32_CR_PAT, low32, high32);
 		vmcs_write64(HOST_IA32_PAT, low32 | ((u64) high32 << 32));
 	}
+
+	if (cpu_has_load_ia32_efer)
+		vmcs_write64(HOST_IA32_EFER, host_efer);
 }
 
 static void set_cr4_guest_host_mask(struct vcpu_vmx *vmx)