From e711121e3fcfeaf0a3a4fe9ef1007b01225f6c77 Mon Sep 17 00:00:00 2001
From: "wei@redhat.com" <wei@redhat.com>
Date: Tue, 3 Feb 2015 19:51:06 +0100
Subject: kvm_stat: Add RESET support for perf event ioctl

Message-id: <1422993066-11422-4-git-send-email-wei@redhat.com>
Patchwork-id: 63715
O-Subject: [qemu-kvm-rhev RHELSA PATCH V2 3/3] kvm_stat: Add RESET support for perf event ioctl
Bugzilla: 1184603
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Andrew Jones <drjones@redhat.com>

While running kvm_stat using tracepoint on ARM64 hardware (e.g. "kvm_stat
-1 -t"), the initial values of some kvm_userspace_exit counters were found
to be very suspecious. For instance the tracing tool showed that S390_TSCH
was called many times on ARM64 machine, which apparently was wrong. It
turned out the the perf event counters need to be reset before use.

This patch adds RESET ioctl support for perf monitoring. Before calling
ioctl to enable a perf event, this patch resets the counter first. With
this patch, the init counter values become correct on ARM64 hardware.

NOTE: This patch is slightly different from the upstream commit
(fc116efad). I extended the upstream commit with a fix to PPC RESET ioctl
number, which has been submitted to upstream & queued for QEMU by Paolo.

Example:

==== before patch ====
kvm_userspace_exit(S390_SIEIC)      1426         0
kvm_userspace_exit(S390_TSCH)       339         0

==== after patch ====
kvm_userspace_exit(S390_SIEIC)         0         0
kvm_userspace_exit(S390_TSCH)         0         0

Signed-off-by: Wei Huang <wei@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

diff --git a/scripts/kvm/kvm_stat b/scripts/kvm/kvm_stat
index 7e5d256..68ac19e 100755
--- a/scripts/kvm/kvm_stat
+++ b/scripts/kvm/kvm_stat
@@ -246,6 +246,7 @@ def ppc_init():
             'SET_FILTER' : 0x80002406 | (ctypes.sizeof(ctypes.c_char_p) << 16),
             'ENABLE'     : 0x20002400,
             'DISABLE'    : 0x20002401,
+            'RESET'      : 0x20002403,
         }
     })