[Qemu-devel] [PATCH v2] hmp: allow cpu index for "info lapic"

Yi Wang posted 1 patch 6 years, 8 months ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/1500342577-12486-1-git-send-email-wang.yi59@zte.com.cn
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hmp-commands-info.hx  | 6 +++---
target/i386/monitor.c | 8 +++++++-
2 files changed, 10 insertions(+), 4 deletions(-)
[Qemu-devel] [PATCH v2] hmp: allow cpu index for "info lapic"
Posted by Yi Wang 6 years, 8 months ago
Add [vcpu] index support for hmp command "info lapic", which is
useful when debugging ipi and so on. Current behavior is not
changed when the parameter isn't specified.

Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Signed-off-by: Yun Liu <liu.yunh@zte.com.cn>
---
 hmp-commands-info.hx  | 6 +++---
 target/i386/monitor.c | 8 +++++++-
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
index d9df238..c534b03 100644
--- a/hmp-commands-info.hx
+++ b/hmp-commands-info.hx
@@ -115,9 +115,9 @@ ETEXI
 #if defined(TARGET_I386)
     {
         .name       = "lapic",
-        .args_type  = "",
-        .params     = "",
-        .help       = "show local apic state",
+        .args_type  = "vcpu:i?",
+        .params     = "[vcpu]",
+        .help       = "show local apic state (vcpu: vCPU to read, default is 0)",
         .cmd        = hmp_info_local_apic,
     },
 #endif
diff --git a/target/i386/monitor.c b/target/i386/monitor.c
index 77ead60..813005e 100644
--- a/target/i386/monitor.c
+++ b/target/i386/monitor.c
@@ -632,8 +632,14 @@ const MonitorDef *target_monitor_defs(void)
 
 void hmp_info_local_apic(Monitor *mon, const QDict *qdict)
 {
-    CPUState *cs = mon_get_cpu();
+    CPUState *cs;
 
+    if (qdict_haskey(qdict, "vcpu")) {
+        int index = qdict_get_try_int(qdict, "vcpu", 0);
+        cs = qemu_get_cpu(index);
+    } else {
+        cs = mon_get_cpu();
+    }
     if (!cs) {
         monitor_printf(mon, "No CPU available\n");
         return;
-- 
1.8.3.1



Re: [Qemu-devel] [PATCH v2] hmp: allow cpu index for "info lapic"
Posted by Igor Mammedov 6 years, 8 months ago
On Mon, 17 Jul 2017 21:49:37 -0400
Yi Wang <wang.yi59@zte.com.cn> wrote:

> Add [vcpu] index support for hmp command "info lapic", which is
> useful when debugging ipi and so on. Current behavior is not
> changed when the parameter isn't specified.
we shouldn't expose cpu_index to users anymore,

I would suggest using to use real APIC ID here but we don't
have monitor command that returns APIC IDs for present cpus.

"info hotpluggable-cpus" gives you a list of available CPUs
it also gives you qom_path to cpu so potentially you could
read apic-id property of cpu.

But we have only QMP variant of qom-get so monitor needs
addition of qom-get command that will be a wrapper around
QMP command.

It could be solved in 2 ways:
 * use socket-id/core-id/thread-id to specify desired cpu
   /possible values in 'info hotpluggable-cpus'/

 * use apic-id value to specify interrupt controller
   - apic-id could be retrieved with new qom-get
     (qom-get would also be useful to read other properties)
   - extend 'info registers' with apic id value
    for example instead of current:
    
     CPU#1
     EAX=00000c06 EBX=00000000 ECX=000002ff EDX=00000000
     ....

    it would look like:

     CPU#1 (socket-id: a, core-id: b, thread-id: c, apic-id: d)
     ...


> 
> Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
> Signed-off-by: Yun Liu <liu.yunh@zte.com.cn>
> ---
>  hmp-commands-info.hx  | 6 +++---
>  target/i386/monitor.c | 8 +++++++-
>  2 files changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
> index d9df238..c534b03 100644
> --- a/hmp-commands-info.hx
> +++ b/hmp-commands-info.hx
> @@ -115,9 +115,9 @@ ETEXI
>  #if defined(TARGET_I386)
>      {
>          .name       = "lapic",
> -        .args_type  = "",
> -        .params     = "",
> -        .help       = "show local apic state",
> +        .args_type  = "vcpu:i?",
> +        .params     = "[vcpu]",
> +        .help       = "show local apic state (vcpu: vCPU to read, default is 0)",
>          .cmd        = hmp_info_local_apic,
>      },
>  #endif
> diff --git a/target/i386/monitor.c b/target/i386/monitor.c
> index 77ead60..813005e 100644
> --- a/target/i386/monitor.c
> +++ b/target/i386/monitor.c
> @@ -632,8 +632,14 @@ const MonitorDef *target_monitor_defs(void)
>  
>  void hmp_info_local_apic(Monitor *mon, const QDict *qdict)
>  {
> -    CPUState *cs = mon_get_cpu();
> +    CPUState *cs;
>  
> +    if (qdict_haskey(qdict, "vcpu")) {
> +        int index = qdict_get_try_int(qdict, "vcpu", 0);
> +        cs = qemu_get_cpu(index);
> +    } else {
> +        cs = mon_get_cpu();
> +    }
>      if (!cs) {
>          monitor_printf(mon, "No CPU available\n");
>          return;


Re: [Qemu-devel] [PATCH v2] hmp: allow cpu index for "info lapic"
Posted by Eduardo Habkost 6 years, 8 months ago
On Tue, Jul 18, 2017 at 04:54:17PM +0200, Igor Mammedov wrote:
> On Mon, 17 Jul 2017 21:49:37 -0400
> Yi Wang <wang.yi59@zte.com.cn> wrote:
> 
> > Add [vcpu] index support for hmp command "info lapic", which is
> > useful when debugging ipi and so on. Current behavior is not
> > changed when the parameter isn't specified.
> we shouldn't expose cpu_index to users anymore,
> 
> I would suggest using to use real APIC ID here but we don't
> have monitor command that returns APIC IDs for present cpus.
> 
> "info hotpluggable-cpus" gives you a list of available CPUs
> it also gives you qom_path to cpu so potentially you could
> read apic-id property of cpu.
> 
> But we have only QMP variant of qom-get so monitor needs
> addition of qom-get command that will be a wrapper around
> QMP command.
> 
> It could be solved in 2 ways:
>  * use socket-id/core-id/thread-id to specify desired cpu
>    /possible values in 'info hotpluggable-cpus'/
> 
>  * use apic-id value to specify interrupt controller
>    - apic-id could be retrieved with new qom-get
>      (qom-get would also be useful to read other properties)
>    - extend 'info registers' with apic id value
>     for example instead of current:
>     
>      CPU#1
>      EAX=00000c06 EBX=00000000 ECX=000002ff EDX=00000000
>      ....
> 
>     it would look like:
> 
>      CPU#1 (socket-id: a, core-id: b, thread-id: c, apic-id: d)
>      ...

We already print "CPU #<n>" on "info cpus", so <n> is already a
perfectly good identifier for a human interface.  I think HMP
should not require any identifier that isn't a simple number that
is shown very prominently on "info cpus".

If we don't want to use cpu_index as an identifier anymore, we
can start printing arch ID instead of cpu_index on commands that
print "CPU #<n>", and change mon_get_cpu() and monitor_set_cpu()
accordingly.

-- 
Eduardo

Re: [Qemu-devel] [PATCH v2] hmp: allow cpu index for "info lapic"
Posted by Igor Mammedov 6 years, 8 months ago
On Tue, 18 Jul 2017 20:26:50 -0300
Eduardo Habkost <ehabkost@redhat.com> wrote:

> On Tue, Jul 18, 2017 at 04:54:17PM +0200, Igor Mammedov wrote:
> > On Mon, 17 Jul 2017 21:49:37 -0400
> > Yi Wang <wang.yi59@zte.com.cn> wrote:
> > 
> > > Add [vcpu] index support for hmp command "info lapic", which is
> > > useful when debugging ipi and so on. Current behavior is not
> > > changed when the parameter isn't specified.
> > we shouldn't expose cpu_index to users anymore,
> > 
> > I would suggest using to use real APIC ID here but we don't
> > have monitor command that returns APIC IDs for present cpus.
> > 
> > "info hotpluggable-cpus" gives you a list of available CPUs
> > it also gives you qom_path to cpu so potentially you could
> > read apic-id property of cpu.
> > 
> > But we have only QMP variant of qom-get so monitor needs
> > addition of qom-get command that will be a wrapper around
> > QMP command.
> > 
> > It could be solved in 2 ways:
> >  * use socket-id/core-id/thread-id to specify desired cpu
> >    /possible values in 'info hotpluggable-cpus'/
> > 
> >  * use apic-id value to specify interrupt controller
> >    - apic-id could be retrieved with new qom-get
> >      (qom-get would also be useful to read other properties)
> >    - extend 'info registers' with apic id value
> >     for example instead of current:
> >     
> >      CPU#1
> >      EAX=00000c06 EBX=00000000 ECX=000002ff EDX=00000000
> >      ....
> > 
> >     it would look like:
> > 
> >      CPU#1 (socket-id: a, core-id: b, thread-id: c, apic-id: d)
> >      ...
> 
> We already print "CPU #<n>" on "info cpus", so <n> is already a
> perfectly good identifier for a human interface.  I think HMP
> should not require any identifier that isn't a simple number that
> is shown very prominently on "info cpus".
> 
> If we don't want to use cpu_index as an identifier anymore, we
> can start printing arch ID instead of cpu_index on commands that
> print "CPU #<n>", and change mon_get_cpu() and monitor_set_cpu()
> accordingly.
Looks like a good plan, but it probably should touch all commands
that use cpu_index, also I'd leave cpu_index in 'info cpus' where
it is till we faze it out from CLI.



Re: [Qemu-devel] [PATCH v2] hmp: allow cpu index for "info lapic"
Posted by Eduardo Habkost 6 years, 8 months ago
On Mon, Jul 17, 2017 at 09:49:37PM -0400, Yi Wang wrote:
> Add [vcpu] index support for hmp command "info lapic", which is
> useful when debugging ipi and so on. Current behavior is not
> changed when the parameter isn't specified.
> 
> Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
> Signed-off-by: Yun Liu <liu.yunh@zte.com.cn>

We have 8 monitor commands (see below) that use the CPU set by
the "cpu" command (mon_get_cpu()) as input.  Why is "info lapic"
special?

* info cpustats
* info lapic
* info mem
* info registers
* info tlb
* x
* memsave
* inject-nmi (QMP)

-- 
Eduardo