[PATCH v2 1/2] KVM: x86: Remove unnecessory assignment to uret->data

From: Zhenzhong Duan
Date: Fri Mar 11 2022 - 05:32:11 EST


While update_transition_efer() doesn't unconditionally set uret->data,
which on the surface makes this look suspect, but it's safe because
uret->data is consumed if and only if uret->load_into_hardware is
true, and it's (a) set to false if uret->data isn't updated and
(b) uret->data is guaranteed to be updated before it's set to true.

Drop the local "msr" and use "vmx" directly instead of redoing to_vmx().

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxx>
---
arch/x86/kvm/vmx/vmx.c | 14 +++++---------
1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index b730d799c26e..cadb3769031c 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2871,21 +2871,17 @@ static void enter_rmode(struct kvm_vcpu *vcpu)
int vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
- struct vmx_uret_msr *msr = vmx_find_uret_msr(vmx, MSR_EFER);

/* Nothing to do if hardware doesn't support EFER. */
- if (!msr)
+ if (!vmx_find_uret_msr(vmx, MSR_EFER))
return 0;

vcpu->arch.efer = efer;
- if (efer & EFER_LMA) {
- vm_entry_controls_setbit(to_vmx(vcpu), VM_ENTRY_IA32E_MODE);
- msr->data = efer;
- } else {
- vm_entry_controls_clearbit(to_vmx(vcpu), VM_ENTRY_IA32E_MODE);
+ if (efer & EFER_LMA)
+ vm_entry_controls_setbit(vmx, VM_ENTRY_IA32E_MODE);
+ else
+ vm_entry_controls_clearbit(vmx, VM_ENTRY_IA32E_MODE);

- msr->data = efer & ~EFER_LME;
- }
vmx_setup_uret_msrs(vmx);
return 0;
}
--
2.25.1