[PATCH v7 14/15] KVM: x86/vmx: Flip Arch LBREn bit on guest state change

From: Yang Weijiang
Date: Fri Aug 06 2021 - 03:30:36 EST


Clear Arch LBREn bit on #SMI and restore it on RSM per ISA spec.,
also clear the bit when guest does warm reset.

Signed-off-by: Yang Weijiang <weijiang.yang@xxxxxxxxx>
---
arch/x86/kvm/vmx/vmx.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 31b9c06c9b3b..31969221db8c 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -4513,8 +4513,10 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
vmx_update_exception_bitmap(vcpu);

vpid_sync_context(vmx->vpid);
- if (init_event)
+ if (init_event) {
vmx_clear_hlt(vcpu);
+ flip_arch_lbr_ctl(vcpu, false);
+ }
}

static void vmx_enable_irq_window(struct kvm_vcpu *vcpu)
@@ -7513,6 +7515,7 @@ static int vmx_enter_smm(struct kvm_vcpu *vcpu, char *smstate)
vmx->nested.smm.vmxon = vmx->nested.vmxon;
vmx->nested.vmxon = false;
vmx_clear_hlt(vcpu);
+ flip_arch_lbr_ctl(vcpu, false);
return 0;
}

@@ -7533,6 +7536,7 @@ static int vmx_leave_smm(struct kvm_vcpu *vcpu, const char *smstate)

vmx->nested.smm.guest_mode = false;
}
+ flip_arch_lbr_ctl(vcpu, true);
return 0;
}

--
2.25.1