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, 56 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index a4a7d5ef6cf8..2f5b49f2a98e 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -71,6 +71,49 @@ struct kvmppc_44x_tlbe {
         u32 word2;
 };
 
+enum kvm_exit_types {
+        MMIO_EXITS,
+        DCR_EXITS,
+        SIGNAL_EXITS,
+        ITLB_REAL_MISS_EXITS,
+        ITLB_VIRT_MISS_EXITS,
+        DTLB_REAL_MISS_EXITS,
+        DTLB_VIRT_MISS_EXITS,
+        SYSCALL_EXITS,
+        ISI_EXITS,
+        DSI_EXITS,
+        EMULATED_INST_EXITS,
+        EMULATED_MTMSRWE_EXITS,
+        EMULATED_WRTEE_EXITS,
+        EMULATED_MTSPR_EXITS,
+        EMULATED_MFSPR_EXITS,
+        EMULATED_MTMSR_EXITS,
+        EMULATED_MFMSR_EXITS,
+        EMULATED_TLBSX_EXITS,
+        EMULATED_TLBWE_EXITS,
+        EMULATED_RFI_EXITS,
+        DEC_EXITS,
+        EXT_INTR_EXITS,
+        HALT_WAKEUP,
+        USR_PR_INST,
+        FP_UNAVAIL,
+        DEBUG_EXITS,
+        TIMEINGUEST,
+        __NUMBER_OF_KVM_EXIT_TYPES
+};
+
+#ifdef CONFIG_KVM_EXIT_TIMING
+/* allow access to big endian 32bit upper/lower parts and 64bit var */
+struct exit_timing {
+        union {
+                u64 tv64;
+                struct {
+                        u32 tbu, tbl;
+                } tv32;
+        };
+};
+#endif
+
 struct kvm_arch {
 };
 
@@ -130,6 +173,19 @@ struct kvm_vcpu_arch {
         u32 dbcr0;
         u32 dbcr1;
 
+#ifdef CONFIG_KVM_EXIT_TIMING
+        struct exit_timing timing_exit;
+        struct exit_timing timing_last_enter;
+        u32 last_exit_type;
+        u32 timing_count_type[__NUMBER_OF_KVM_EXIT_TYPES];
+        u64 timing_sum_duration[__NUMBER_OF_KVM_EXIT_TYPES];
+        u64 timing_sum_quad_duration[__NUMBER_OF_KVM_EXIT_TYPES];
+        u64 timing_min_duration[__NUMBER_OF_KVM_EXIT_TYPES];
+        u64 timing_max_duration[__NUMBER_OF_KVM_EXIT_TYPES];
+        u64 timing_last_exit;
+        struct dentry *debugfs_exit_timing;
+#endif
+
         u32 last_inst;
         ulong fault_dear;
         ulong fault_esr;