KVM: VMX: Add support for guest/host-only profiling

Support guest/host-only profiling by switch perf msrs on
a guest entry if needed.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 55e849b52d9e..98f4b0bcc660 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -39,6 +39,7 @@
 #include <asm/mce.h>
 #include <asm/i387.h>
 #include <asm/xcr.h>
+#include <asm/perf_event.h>
 
 #include "trace.h"
 
@@ -6050,6 +6051,24 @@ static void vmx_cancel_injection(struct kvm_vcpu *vcpu)
         vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, 0);
 }
 
+static void atomic_switch_perf_msrs(struct vcpu_vmx *vmx)
+{
+        int i, nr_msrs;
+        struct perf_guest_switch_msr *msrs;
+
+        msrs = perf_guest_get_msrs(&nr_msrs);
+
+        if (!msrs)
+                return;
+
+        for (i = 0; i < nr_msrs; i++)
+                if (msrs[i].host == msrs[i].guest)
+                        clear_atomic_switch_msr(vmx, msrs[i].msr);
+                else
+                        add_atomic_switch_msr(vmx, msrs[i].msr, msrs[i].guest,
+                                        msrs[i].host);
+}
+
 #ifdef CONFIG_X86_64
 #define R "r"
 #define Q "q"
@@ -6099,6 +6118,8 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
         if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
                 vmx_set_interrupt_shadow(vcpu, 0);
 
+        atomic_switch_perf_msrs(vmx);
+
         vmx->__launched = vmx->loaded_vmcs->launched;
         asm(
                 /* Store host registers */