KVM: ppc: Implement in-kernel exit timing statistics

Existing KVM statistics are either just counters (kvm_stat) reported for
KVM generally or trace based aproaches like kvm_trace.
For KVM on powerpc we had the need to track the timings of the different exit
types. While this could be achieved parsing data created with a kvm_trace
extension this adds too much overhead (at least on embedded PowerPC) slowing
down the workloads we wanted to measure.

Therefore this patch adds a in-kernel exit timing statistic to the powerpc kvm
code. These statistic is available per vm&vcpu under the kvm debugfs directory.
As this statistic is low, but still some overhead it can be enabled via a
.config entry and should be off by default.

Since this patch touched all powerpc kvm_stat code anyway this code is now
merged and simplified together with the exit timing statistic code (still
working with exit timing disabled in .config).

Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 7ad150e0fbbf..1deda37cb771 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -28,9 +28,9 @@
 #include <asm/uaccess.h>
 #include <asm/kvm_ppc.h>
 #include <asm/tlbflush.h>
+#include "timing.h"
 #include "../mm/mmu_decl.h"
 
-
 gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
 {
         return gfn;
@@ -171,11 +171,15 @@ void kvm_arch_flush_shadow(struct kvm *kvm)
 
 struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
 {
-        return kvmppc_core_vcpu_create(kvm, id);
+        struct kvm_vcpu *vcpu;
+        vcpu = kvmppc_core_vcpu_create(kvm, id);
+        kvmppc_create_vcpu_debugfs(vcpu, id);
+        return vcpu;
 }
 
 void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
 {
+        kvmppc_remove_vcpu_debugfs(vcpu);
         kvmppc_core_vcpu_free(vcpu);
 }