diff mbox

[v10,11/12] KVM: x86: Set intercept for Intel PT MSRs read/write

Message ID 1530612254-16642-12-git-send-email-luwei.kang@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Luwei Kang July 3, 2018, 10:04 a.m. UTC 
From: Chao Peng <chao.p.peng@linux.intel.com>

To save performance overhead, disable intercept Intel PT MSRs
read/write when Intel PT is enabled in guest.
MSR_IA32_RTIT_CTL is an exception that will always be intercepted.

Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Signed-off-by: Luwei Kang <luwei.kang@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
 arch/x86/kvm/vmx.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
diff mbox

Patch

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 0430cdb..ba2fa3d 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1115,6 +1115,7 @@  static bool nested_vmx_is_page_fault_vmexit(struct vmcs12 *vmcs12,
 static void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu);
 static void __always_inline vmx_disable_intercept_for_msr(unsigned long *msr_bitmap,
 							  u32 msr, int type);
+static void pt_set_intercept_for_msr(struct vcpu_vmx *vmx, bool flag);
 
 static DEFINE_PER_CPU(struct vmcs *, vmxarea);
 static DEFINE_PER_CPU(struct vmcs *, current_vmcs);
@@ -4207,6 +4208,7 @@  static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			vmx_rtit_ctl_check(vcpu, data))
 			return 1;
 		vmcs_write64(GUEST_IA32_RTIT_CTL, data);
+		pt_set_intercept_for_msr(vmx, !(data & RTIT_CTL_TRACEEN));
 		vmx->pt_desc.guest.ctl = data;
 		break;
 	case MSR_IA32_RTIT_STATUS:
@@ -6029,6 +6031,27 @@  static void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu)
 	vmx->msr_bitmap_mode = mode;
 }
 
+static void pt_set_intercept_for_msr(struct vcpu_vmx *vmx, bool flag)
+{
+	unsigned long *msr_bitmap = vmx->vmcs01.msr_bitmap;
+	u32 i;
+
+	vmx_set_intercept_for_msr(msr_bitmap, MSR_IA32_RTIT_STATUS,
+							MSR_TYPE_RW, flag);
+	vmx_set_intercept_for_msr(msr_bitmap, MSR_IA32_RTIT_OUTPUT_BASE,
+							MSR_TYPE_RW, flag);
+	vmx_set_intercept_for_msr(msr_bitmap, MSR_IA32_RTIT_OUTPUT_MASK,
+							MSR_TYPE_RW, flag);
+	vmx_set_intercept_for_msr(msr_bitmap, MSR_IA32_RTIT_CR3_MATCH,
+							MSR_TYPE_RW, flag);
+	for (i = 0; i < vmx->pt_desc.addr_range; i++) {
+		vmx_set_intercept_for_msr(msr_bitmap,
+			MSR_IA32_RTIT_ADDR0_A + i * 2, MSR_TYPE_RW, flag);
+		vmx_set_intercept_for_msr(msr_bitmap,
+			MSR_IA32_RTIT_ADDR0_B + i * 2, MSR_TYPE_RW, flag);
+	}
+}
+
 static bool vmx_get_enable_apicv(struct kvm_vcpu *vcpu)
 {
 	return enable_apicv;