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[v8,12/12] KVM: x86: Disable Intel Processor Trace when VMXON in L1 guest

Message ID 1526295432-20640-13-git-send-email-luwei.kang@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Luwei Kang May 14, 2018, 10:57 a.m. UTC 
Currently, Intel Processor Trace do not support tracing in L1 guest
VMX operation(IA32_VMX_MISC[bit 14] is 0). As mentioned in SDM,
on these type of processors, execution of the VMXON instruction will
clears IA32_RTIT_CTL.TraceEn and any attempt to write IA32_RTIT_CTL
causes a general-protection exception (#GP).

Signed-off-by: Luwei Kang <luwei.kang@intel.com>
---
 arch/x86/kvm/vmx.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
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Patch

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 170cd48..7ace11a 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3996,7 +3996,8 @@  static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		break;
 	case MSR_IA32_RTIT_CTL:
 		if ((pt_mode != PT_MODE_HOST_GUEST) ||
-			vmx_rtit_ctl_check(vcpu, data))
+			vmx_rtit_ctl_check(vcpu, data) ||
+			vmx->nested.vmxon)
 			return 1;
 		vmcs_write64(GUEST_IA32_RTIT_CTL, data);
 		pt_set_intercept_for_msr(vmx, !(data & RTIT_CTL_TRACEEN));
@@ -8089,6 +8090,11 @@  static int handle_vmon(struct kvm_vcpu *vcpu)
 	if (ret)
 		return ret;
 
+	if (pt_mode == PT_MODE_HOST_GUEST) {
+		vmx->pt_desc.guest.ctl = 0;
+		pt_set_intercept_for_msr(vmx, 1);
+	}
+
 	nested_vmx_succeed(vcpu);
 	return kvm_skip_emulated_instruction(vcpu);
 }