When emulating exit from long mode, EFER_LMA is cleared which lead to
efer writing emulation, which will unset VM_ENTRY_IA32E_MODE control
bit as requested by SDM. So no need to unset VM_ENTRY_IA32E_MODE again
in exit_lmode() explicitly.
In fact benefited from shadow controls mechanism, this change doesn't
eliminate vmread or vmwrite.
Opportunistically remove unnecessory assignment to uret MSR data field
as vmx_setup_uret_msrs() will do the same thing.
In case EFER isn't supported by hardware, long mode isn't supported,
so this will no break.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxx>
---
arch/x86/kvm/vmx/vmx.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index b730d799c26e..b04588dc7faa 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2878,14 +2878,11 @@ int vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer)
return 0;
vcpu->arch.efer = efer;
- if (efer & EFER_LMA) {
+ if (efer & EFER_LMA)
vm_entry_controls_setbit(to_vmx(vcpu), VM_ENTRY_IA32E_MODE);
- msr->data = efer;
- } else {
+ else
vm_entry_controls_clearbit(to_vmx(vcpu), VM_ENTRY_IA32E_MODE);
- msr->data = efer & ~EFER_LME;
- }
vmx_setup_uret_msrs(vmx);
return 0;
}
@@ -2911,7 +2908,6 @@ static void enter_lmode(struct kvm_vcpu *vcpu)
static void exit_lmode(struct kvm_vcpu *vcpu)
{
- vm_entry_controls_clearbit(to_vmx(vcpu), VM_ENTRY_IA32E_MODE);
vmx_set_efer(vcpu, vcpu->arch.efer & ~EFER_LMA);
}
--
2.25.1
