Patchwork [1/4] kvm-all: add kvm_ioctl, kvm_vm_ioctl, kvm_vcpu_ioctl tracepoints

login
register
mail settings
Submitter Stefan Hajnoczi
Date May 3, 2013, 12:01 p.m.
Message ID <1367582485-15579-2-git-send-email-stefanha@redhat.com>
Download mbox | patch
Permalink /patch/241289/
State New
Headers show

Comments

Stefan Hajnoczi - May 3, 2013, 12:01 p.m.
From: Kazuya Saito <saito.kazuya@jp.fujitsu.com>

This patch adds tracepoints at ioctl to kvm. Tracing these ioctl is
useful for clarification whether the cause of troubles is qemu or kvm.

Signed-off-by: Kazuya Saito <saito.kazuya@jp.fujitsu.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 kvm-all.c    | 4 ++++
 trace-events | 5 +++++
 2 files changed, 9 insertions(+)
Andreas Färber - May 3, 2013, 12:12 p.m.
Am 03.05.2013 14:01, schrieb Stefan Hajnoczi:
> From: Kazuya Saito <saito.kazuya@jp.fujitsu.com>
> 
> This patch adds tracepoints at ioctl to kvm. Tracing these ioctl is
> useful for clarification whether the cause of troubles is qemu or kvm.
> 
> Signed-off-by: Kazuya Saito <saito.kazuya@jp.fujitsu.com>
> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  kvm-all.c    | 4 ++++
>  trace-events | 5 +++++
>  2 files changed, 9 insertions(+)
> 
> diff --git a/kvm-all.c b/kvm-all.c
> index f6c0f4a..4f73b98 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -33,6 +33,7 @@
>  #include "exec/memory.h"
>  #include "exec/address-spaces.h"
>  #include "qemu/event_notifier.h"
> +#include "trace.h"
>  
>  /* This check must be after config-host.h is included */
>  #ifdef CONFIG_EVENTFD
> @@ -1687,6 +1688,7 @@ int kvm_ioctl(KVMState *s, int type, ...)
>      arg = va_arg(ap, void *);
>      va_end(ap);
>  
> +    trace_kvm_ioctl(type, arg);
>      ret = ioctl(s->fd, type, arg);
>      if (ret == -1) {
>          ret = -errno;
> @@ -1704,6 +1706,7 @@ int kvm_vm_ioctl(KVMState *s, int type, ...)
>      arg = va_arg(ap, void *);
>      va_end(ap);
>  
> +    trace_kvm_vm_ioctl(type, arg);
>      ret = ioctl(s->vmfd, type, arg);
>      if (ret == -1) {
>          ret = -errno;
> @@ -1721,6 +1724,7 @@ int kvm_vcpu_ioctl(CPUState *cpu, int type, ...)
>      arg = va_arg(ap, void *);
>      va_end(ap);
>  
> +    trace_kvm_vcpu_ioctl(cpu->cpu_index, type, arg);
>      ret = ioctl(cpu->kvm_fd, type, arg);
>      if (ret == -1) {
>          ret = -errno;
> diff --git a/trace-events b/trace-events
> index 55e80be..d5bc7a5 100644
> --- a/trace-events
> +++ b/trace-events
> @@ -1153,3 +1153,8 @@ virtio_ccw_new_device(int cssid, int ssid, int schid, int devno, const char *dev
>  
>  # migration.c
>  migrate_set_state(int new_state) "new state %d"
> +
> +# kvm-all.c
> +kvm_ioctl(int type, void *arg) "type %d, arg %p"
> +kvm_vm_ioctl(int type, void *arg) "type %d, arg %p"
> +kvm_vcpu_ioctl(int cpu_index, int type, void *arg) "cpu_index %d, type %d, arg %p"

Sorry that I'm just seeing this patch now (wasn't CC'ed), but I wonder
whether cpu_index is the best thing to trace here? Can we still change
trace event API or would we have to nack/change now?

CC'ing Igor since he just introduced a cpu_get_arch_id() and there's
also a kvm_arch_vcpu_id() introduced earlier by Eduardo.

Regards,
Andreas
Eduardo Habkost - May 3, 2013, 1:31 p.m.
On Fri, May 03, 2013 at 02:12:14PM +0200, Andreas Färber wrote:
> Am 03.05.2013 14:01, schrieb Stefan Hajnoczi:
> > From: Kazuya Saito <saito.kazuya@jp.fujitsu.com>
> > 
> > This patch adds tracepoints at ioctl to kvm. Tracing these ioctl is
> > useful for clarification whether the cause of troubles is qemu or kvm.
> > 
> > Signed-off-by: Kazuya Saito <saito.kazuya@jp.fujitsu.com>
> > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> > ---
> >  kvm-all.c    | 4 ++++
> >  trace-events | 5 +++++
> >  2 files changed, 9 insertions(+)
> > 
> > diff --git a/kvm-all.c b/kvm-all.c
> > index f6c0f4a..4f73b98 100644
> > --- a/kvm-all.c
> > +++ b/kvm-all.c
> > @@ -33,6 +33,7 @@
> >  #include "exec/memory.h"
> >  #include "exec/address-spaces.h"
> >  #include "qemu/event_notifier.h"
> > +#include "trace.h"
> >  
> >  /* This check must be after config-host.h is included */
> >  #ifdef CONFIG_EVENTFD
> > @@ -1687,6 +1688,7 @@ int kvm_ioctl(KVMState *s, int type, ...)
> >      arg = va_arg(ap, void *);
> >      va_end(ap);
> >  
> > +    trace_kvm_ioctl(type, arg);
> >      ret = ioctl(s->fd, type, arg);
> >      if (ret == -1) {
> >          ret = -errno;
> > @@ -1704,6 +1706,7 @@ int kvm_vm_ioctl(KVMState *s, int type, ...)
> >      arg = va_arg(ap, void *);
> >      va_end(ap);
> >  
> > +    trace_kvm_vm_ioctl(type, arg);
> >      ret = ioctl(s->vmfd, type, arg);
> >      if (ret == -1) {
> >          ret = -errno;
> > @@ -1721,6 +1724,7 @@ int kvm_vcpu_ioctl(CPUState *cpu, int type, ...)
> >      arg = va_arg(ap, void *);
> >      va_end(ap);
> >  
> > +    trace_kvm_vcpu_ioctl(cpu->cpu_index, type, arg);
> >      ret = ioctl(cpu->kvm_fd, type, arg);
> >      if (ret == -1) {
> >          ret = -errno;
> > diff --git a/trace-events b/trace-events
> > index 55e80be..d5bc7a5 100644
> > --- a/trace-events
> > +++ b/trace-events
> > @@ -1153,3 +1153,8 @@ virtio_ccw_new_device(int cssid, int ssid, int schid, int devno, const char *dev
> >  
> >  # migration.c
> >  migrate_set_state(int new_state) "new state %d"
> > +
> > +# kvm-all.c
> > +kvm_ioctl(int type, void *arg) "type %d, arg %p"
> > +kvm_vm_ioctl(int type, void *arg) "type %d, arg %p"
> > +kvm_vcpu_ioctl(int cpu_index, int type, void *arg) "cpu_index %d, type %d, arg %p"
> 
> Sorry that I'm just seeing this patch now (wasn't CC'ed), but I wonder
> whether cpu_index is the best thing to trace here? Can we still change
> trace event API or would we have to nack/change now?
> 
> CC'ing Igor since he just introduced a cpu_get_arch_id() and there's
> also a kvm_arch_vcpu_id() introduced earlier by Eduardo.

Being kvm_vcpu_ioctl() a very low-level KVM function, I believe the KVM
VCPU "id" (the argument passed to KVM_CREATE_VCPU, that needs to be the
APIC ID on x86, and is returned by kvm_arch_vcpu_id()) is the best CPU
identifier to be included here.

cpu_index is the most ambiguous and least reliable CPU identifier we
have today. I wouldn't use it in any new code.
Stefan Hajnoczi - May 8, 2013, 8:48 a.m.
On Fri, May 03, 2013 at 02:12:14PM +0200, Andreas Färber wrote:
> > +# kvm-all.c
> > +kvm_ioctl(int type, void *arg) "type %d, arg %p"
> > +kvm_vm_ioctl(int type, void *arg) "type %d, arg %p"
> > +kvm_vcpu_ioctl(int cpu_index, int type, void *arg) "cpu_index %d, type %d, arg %p"
> 
> Sorry that I'm just seeing this patch now (wasn't CC'ed), but I wonder
> whether cpu_index is the best thing to trace here? Can we still change
> trace event API or would we have to nack/change now?

Trace events are not stable.  We can change them.

STefan

Patch

diff --git a/kvm-all.c b/kvm-all.c
index f6c0f4a..4f73b98 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -33,6 +33,7 @@ 
 #include "exec/memory.h"
 #include "exec/address-spaces.h"
 #include "qemu/event_notifier.h"
+#include "trace.h"
 
 /* This check must be after config-host.h is included */
 #ifdef CONFIG_EVENTFD
@@ -1687,6 +1688,7 @@  int kvm_ioctl(KVMState *s, int type, ...)
     arg = va_arg(ap, void *);
     va_end(ap);
 
+    trace_kvm_ioctl(type, arg);
     ret = ioctl(s->fd, type, arg);
     if (ret == -1) {
         ret = -errno;
@@ -1704,6 +1706,7 @@  int kvm_vm_ioctl(KVMState *s, int type, ...)
     arg = va_arg(ap, void *);
     va_end(ap);
 
+    trace_kvm_vm_ioctl(type, arg);
     ret = ioctl(s->vmfd, type, arg);
     if (ret == -1) {
         ret = -errno;
@@ -1721,6 +1724,7 @@  int kvm_vcpu_ioctl(CPUState *cpu, int type, ...)
     arg = va_arg(ap, void *);
     va_end(ap);
 
+    trace_kvm_vcpu_ioctl(cpu->cpu_index, type, arg);
     ret = ioctl(cpu->kvm_fd, type, arg);
     if (ret == -1) {
         ret = -errno;
diff --git a/trace-events b/trace-events
index 55e80be..d5bc7a5 100644
--- a/trace-events
+++ b/trace-events
@@ -1153,3 +1153,8 @@  virtio_ccw_new_device(int cssid, int ssid, int schid, int devno, const char *dev
 
 # migration.c
 migrate_set_state(int new_state) "new state %d"
+
+# kvm-all.c
+kvm_ioctl(int type, void *arg) "type %d, arg %p"
+kvm_vm_ioctl(int type, void *arg) "type %d, arg %p"
+kvm_vcpu_ioctl(int cpu_index, int type, void *arg) "cpu_index %d, type %d, arg %p"