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From: Laurent Vivier <lvivier@redhat.com>
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Date: Fri, 14 Aug 2015 09:16:08 +0200
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Subject: Re: [Qemu-devel] [PATCH RFC] pseries: define coldplugged devices as
 "configured"
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To: bharata@linux.vnet.ibm.com
Cc: Michael Roth <mdroth@linux.vnet.ibm.com>, dgibson@redhat.com, qemu-ppc@nongnu.org, Alexander Graf <agraf@suse.de>, qemu-devel@nongnu.org



On 14/08/2015 07:20, Bharata B Rao wrote:
> On Thu, Aug 13, 2015 at 02:53:02PM +0200, Laurent Vivier wrote:
>> When a device is hotplugged, attach() sets "configured" to
>> false, waiting an action from the OS to configure it and then
>> to call ibm,configure-connector. On ibm,configure-connector,
>> the hypervisor sets "configured" to true.
>>
>> In case of coldplugged device, attach() sets "configured" to
>> false, but firmware and OS never call the ibm,configure-connector
>> in this case, so it remains set to false.
>>
>> It could be harmless, but when we unplug a device, hypervisor
>> waits the device becomes configured because for it, a not configured
>> device is a device being configured, so it waits the end of configuration
>> to unplug it... and it never happens, so it is never unplugged.
> 
> Not true for at least logical DR device like CPU. I am able to cleanly
> unplug a cold plugged CPU in the patchset I posted at:
> 
> https://lists.gnu.org/archive/html/qemu-ppc/2015-08/msg00041.html
> 
> And this is how the state transitions work for cold plugged CPU devices:

Could you try with a PCI card ?

Thanks,
Laurent