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

[Igor Mammedov]

On Wed, 19 Jul 2017 16:48:23 +0800 (CST)
<wang.yi59 at zte.com.cn> wrote:

> >* wang.yi59 at zte.com.cn (wang.yi59 at zte.com.cn) wrote:  
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> >> Hi Eduardo,  
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> >>   
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> >> Thank you for your reply!  
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> >>   
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> >> >On Mon, Jul 17, 2017 at 09:49:37PM -0400, Yi Wang wrote:  
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> >>   
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> >> >> Add [vcpu] index support for hmp command "info lapic", which is  
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> >>   
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> >> >> useful when debugging ipi and so on. Current behavior is not  
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> >>   
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> >> >> changed when the parameter isn't specified.  
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> >>   
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> >> >>   
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> >>   
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> >> >> Signed-off-by: Yi Wang <wang.yi59 at zte.com.cn>  
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> >>   
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> >> >> Signed-off-by: Yun Liu <liu.yunh at zte.com.cn>  
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> >>   
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> >> >  
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> >>   
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> >> >We have 8 monitor commands (see below) that use the CPU set by  
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> >> >the "cpu" command (mon_get_cpu()) as input.  Why is "info lapic"  
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> >> >special?  
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> >>   
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> >> When we debugging a problem of ipi, we wanted to verify lapic info  
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> >> on each vCPU, but we found that we could only get vCPU 0's lapic  
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> >> through "info lapic", so we supposed this patch could help those  
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> >> who have the same problem as us.  
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> >  
> 
> >I think Eduardo's point is that you can already do:  
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> >    cpu 0  
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> >    info lapic  
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> >    cpu 1  
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> >    info lapic  
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> Yes, I get it, thank you.
> 
> The reason of the problem we met is that we use "virsh qemu-monitor-command",
> 
> so the 'cpu' command didn't work.
you can try to use qmp interface directly which supports specifying cpu for monitor commands:

qemu supports:

 -- Command: human-monitor-command

     Execute a command on the human monitor and return the output.

     Arguments:
     'command-line: string'
          the command to execute in the human monitor
     'cpu-index: int' (optional)
          The CPU to use for commands that require an implicit CPU

maybe "virsh qemu-monitor-command" can also do it, CCing libvirt list

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> ---
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> Best wishes
> 
> Yi Wang