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, 10 insertions, 1 deletions

diff --git a/arch/powerpc/kvm/44x_emulate.c b/arch/powerpc/kvm/44x_emulate.c
index 9ef79c78ede9..69f88d53c428 100644
--- a/arch/powerpc/kvm/44x_emulate.c
+++ b/arch/powerpc/kvm/44x_emulate.c
@@ -22,6 +22,7 @@
 #include <asm/dcr-regs.h>
 #include <asm/disassemble.h>
 #include <asm/kvm_44x.h>
+#include "timing.h"
 
 #include "booke.h"
 #include "44x_tlb.h"
@@ -58,11 +59,11 @@ int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
         int ws;
 
         switch (get_op(inst)) {
-
         case OP_RFI:
                 switch (get_xop(inst)) {
                 case XOP_RFI:
                         kvmppc_emul_rfi(vcpu);
+                        kvmppc_set_exit_type(vcpu, EMULATED_RFI_EXITS);
                         *advance = 0;
                         break;
 
@@ -78,10 +79,12 @@ int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
                 case XOP_MFMSR:
                         rt = get_rt(inst);
                         vcpu->arch.gpr[rt] = vcpu->arch.msr;
+                        kvmppc_set_exit_type(vcpu, EMULATED_MFMSR_EXITS);
                         break;
 
                 case XOP_MTMSR:
                         rs = get_rs(inst);
+                        kvmppc_set_exit_type(vcpu, EMULATED_MTMSR_EXITS);
                         kvmppc_set_msr(vcpu, vcpu->arch.gpr[rs]);
                         break;
 
@@ -89,11 +92,13 @@ int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
                         rs = get_rs(inst);
                         vcpu->arch.msr = (vcpu->arch.msr & ~MSR_EE)
                                                          | (vcpu->arch.gpr[rs] & MSR_EE);
+                        kvmppc_set_exit_type(vcpu, EMULATED_WRTEE_EXITS);
                         break;
 
                 case XOP_WRTEEI:
                         vcpu->arch.msr = (vcpu->arch.msr & ~MSR_EE)
                                                          | (inst & MSR_EE);
+                        kvmppc_set_exit_type(vcpu, EMULATED_WRTEE_EXITS);
                         break;
 
                 case XOP_MFDCR:
@@ -127,6 +132,7 @@ int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
                                 run->dcr.is_write = 0;
                                 vcpu->arch.io_gpr = rt;
                                 vcpu->arch.dcr_needed = 1;
+                                account_exit(vcpu, DCR_EXITS);
                                 emulated = EMULATE_DO_DCR;
                         }
 
@@ -146,6 +152,7 @@ int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
                                 run->dcr.data = vcpu->arch.gpr[rs];
                                 run->dcr.is_write = 1;
                                 vcpu->arch.dcr_needed = 1;
+                                account_exit(vcpu, DCR_EXITS);
                                 emulated = EMULATE_DO_DCR;
                         }
 
@@ -276,6 +283,7 @@ int kvmppc_core_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, int rs)
                 return EMULATE_FAIL;
         }
 
+        kvmppc_set_exit_type(vcpu, EMULATED_MTSPR_EXITS);
         return EMULATE_DONE;
 }
 
@@ -357,6 +365,7 @@ int kvmppc_core_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, int rt)
                 return EMULATE_FAIL;
         }
 
+        kvmppc_set_exit_type(vcpu, EMULATED_MFSPR_EXITS);
         return EMULATE_DONE;
 }