[Qemu-devel] [PATCH] provide cpu_index to env mapping

[Qemu-devel] [PATCH] provide cpu_index to env mapping

[Glauber Costa]

There are some people interested in, given a cpu number,
pick its CPUState. KVM is an example, although not yet in tree.
This patch provides a way of doing that.

Signed-off-by: Glauber Costa <glommer@redhat.com>
---
 cpu-all.h |    1 +
 exec.c    |   13 +++++++++++++
 2 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/cpu-all.h b/cpu-all.h
index dc9b034..8990be3 100644
--- a/cpu-all.h
+++ b/cpu-all.h
@@ -741,6 +741,7 @@ int page_check_range(target_ulong start, target_ulong len, int flags);
 
 void cpu_exec_init_all(unsigned long tb_size);
 CPUState *cpu_copy(CPUState *env);
+CPUState *qemu_get_cpu(int cpu);
 
 void cpu_dump_state(CPUState *env, FILE *f,
                     int (*cpu_fprintf)(FILE *f, const char *fmt, ...),
diff --git a/exec.c b/exec.c
index 52f4e89..6c26cb6 100644
--- a/exec.c
+++ b/exec.c
@@ -541,6 +541,19 @@ static int cpu_common_load(QEMUFile *f, void *opaque, int version_id)
 }
 #endif
 
+CPUState *qemu_get_cpu(int cpu)
+{
+    CPUState *env = first_cpu;
+
+    while (env) {
+        if (env->cpu_index == cpu)
+            break;
+        env = env->next_cpu;
+    }
+
+    return env;
+}
+
 void cpu_exec_init(CPUState *env)
 {
     CPUState **penv;
-- 
1.5.6.6

Re: [Qemu-devel] [PATCH] provide cpu_index to env mapping

[Avi Kivity]

Glauber Costa wrote:
> There are some people interested in, given a cpu number,
> pick its CPUState. KVM is an example, although not yet in tree.
> This patch provides a way of doing that.
>
>   

I think it's better to migrate kvm towards using env as the handle 
instead of the cpu index.

kvm will soon address lose its cpu numbering in favor of apic ids; and 
apic ids will not start from zero on large guests.

-- 
error compiling committee.c: too many arguments to function

Re: [Qemu-devel] [PATCH] provide cpu_index to env mapping

[Glauber Costa]

On Tue, Jun 09, 2009 at 07:25:02PM +0300, Avi Kivity wrote:
> Glauber Costa wrote:
>> There are some people interested in, given a cpu number,
>> pick its CPUState. KVM is an example, although not yet in tree.
>> This patch provides a way of doing that.
>>
>>   
>
> I think it's better to migrate kvm towards using env as the handle  
> instead of the cpu index.
btw: the particular user of this is cpu hotplug.

Re: [Qemu-devel] [PATCH] provide cpu_index to env mapping

[Avi Kivity]

Glauber Costa wrote:
> On Tue, Jun 09, 2009 at 07:25:02PM +0300, Avi Kivity wrote:
>   
>> Glauber Costa wrote:
>>     
>>> There are some people interested in, given a cpu number,
>>> pick its CPUState. KVM is an example, although not yet in tree.
>>> This patch provides a way of doing that.
>>>
>>>   
>>>       
>> I think it's better to migrate kvm towards using env as the handle  
>> instead of the cpu index.
>>     
> btw: the particular user of this is cpu hotplug.
>   

Well, cpu hotplug should definitely use the apic id.

-- 
error compiling committee.c: too many arguments to function

Re: [Qemu-devel] [PATCH] provide cpu_index to env mapping

[Gleb Natapov]

On Tue, Jun 09, 2009 at 07:25:02PM +0300, Avi Kivity wrote:
> Glauber Costa wrote:
>> There are some people interested in, given a cpu number,
>> pick its CPUState. KVM is an example, although not yet in tree.
>> This patch provides a way of doing that.
>>
>>   
>
> I think it's better to migrate kvm towards using env as the handle  
> instead of the cpu index.
>
> kvm will soon address lose its cpu numbering in favor of apic ids; and  
> apic ids will not start from zero on large guests.
>
The work is almost done.

--
			Gleb.

Re: [Qemu-devel] [PATCH] provide cpu_index to env mapping

[Gleb Natapov]

On Tue, Jun 09, 2009 at 01:40:09PM -0300, Glauber Costa wrote:
> On Tue, Jun 09, 2009 at 07:25:02PM +0300, Avi Kivity wrote:
> > Glauber Costa wrote:
> >> There are some people interested in, given a cpu number,
> >> pick its CPUState. KVM is an example, although not yet in tree.
> >> This patch provides a way of doing that.
> >>
> >>   
> >
> > I think it's better to migrate kvm towards using env as the handle  
> > instead of the cpu index.
> btw: the particular user of this is cpu hotplug.
> 
cpu hotplug can use apic ids too.

--
			Gleb.

Re: [Qemu-devel] [PATCH] provide cpu_index to env mapping

[Glauber Costa]

On Tue, Jun 09, 2009 at 07:42:42PM +0300, Avi Kivity wrote:
> Glauber Costa wrote:
>> On Tue, Jun 09, 2009 at 07:25:02PM +0300, Avi Kivity wrote:
>>   
>>> Glauber Costa wrote:
>>>     
>>>> There are some people interested in, given a cpu number,
>>>> pick its CPUState. KVM is an example, although not yet in tree.
>>>> This patch provides a way of doing that.
>>>>
>>>>         
>>> I think it's better to migrate kvm towards using env as the handle   
>>> instead of the cpu index.
>>>     
>> btw: the particular user of this is cpu hotplug.
>>   
>
> Well, cpu hotplug should definitely use the apic id.
yes.