perf: Enhance perf to allow for guest statistic collection from host

Below patch introduces perf_guest_info_callbacks and related
register/unregister functions. Add more PERF_RECORD_MISC_XXX bits
meaning guest kernel and guest user space.

Signed-off-by: Zhang Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 626154a9f535..2ea78abf69d9 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1720,6 +1720,11 @@ struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
 {
         struct perf_callchain_entry *entry;
 
+        if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
+                /* TODO: We don't support guest os callchain now */
+                return NULL;
+        }
+
         if (in_nmi())
                 entry = &__get_cpu_var(pmc_nmi_entry);
         else
@@ -1743,3 +1748,29 @@ void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int ski
         regs->cs = __KERNEL_CS;
         local_save_flags(regs->flags);
 }
+
+unsigned long perf_instruction_pointer(struct pt_regs *regs)
+{
+        unsigned long ip;
+        if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
+                ip = perf_guest_cbs->get_guest_ip();
+        else
+                ip = instruction_pointer(regs);
+        return ip;
+}
+
+unsigned long perf_misc_flags(struct pt_regs *regs)
+{
+        int misc = 0;
+        if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
+                misc |= perf_guest_cbs->is_user_mode() ?
+                        PERF_RECORD_MISC_GUEST_USER :
+                        PERF_RECORD_MISC_GUEST_KERNEL;
+        } else
+                misc |= user_mode(regs) ? PERF_RECORD_MISC_USER :
+                        PERF_RECORD_MISC_KERNEL;
+        if (regs->flags & PERF_EFLAGS_EXACT)
+                misc |= PERF_RECORD_MISC_EXACT;
+
+        return misc;
+}