From: Laurent Vivier <lvivier@redhat.com>
To: Greg Kurz <groug@kaod.org>, qemu-devel@nongnu.org
Cc: David Gibson <david@gibson.dropbear.id.au>,
qemu-ppc@nongnu.org, Cedric Le Goater <clg@kaod.org>,
Bharata B Rao <bharata@linux.vnet.ibm.com>
Subject: Re: [Qemu-devel] [PATCH] xics_kvm: cache already enabled vCPU ids
Date: Wed, 17 May 2017 17:24:23 +0200 [thread overview]
Message-ID: <a464cc50-650a-9aa9-ffe6-aa96582b1e3e@redhat.com> (raw)
In-Reply-To: <b1400dd4-ee4a-fa5e-a7b3-d2c5185d58ca@redhat.com>
On 17/05/2017 17:18, Laurent Vivier wrote:
> On 17/05/2017 16:38, Greg Kurz wrote:
>> Since commit a45863bda90d ("xics_kvm: Don't enable KVM_CAP_IRQ_XICS if
>> already enabled"), we were able to re-hotplug a vCPU that had been hot-
>> unplugged ealier, thanks to a boolean flag in ICPState that we set when
>> enabling KVM_CAP_IRQ_XICS.
>>
>> This could work because the lifecycle of all ICPState objects was the
>> same as the machine. Commit 5bc8d26de20c ("spapr: allocate the ICPState
>> object from under sPAPRCPUCore") broke this assumption and now we always
>> pass a freshly allocated ICPState object (ie, with the flag unset) to
>> icp_kvm_cpu_setup().
>>
>> This cause re-hotplug to fail with:
>>
>> Unable to connect CPU8 to kernel XICS: Device or resource busy
>>
>> Let's fix this by caching all the vCPU ids for which KVM_CAP_IRQ_XICS was
>> enabled. This also drops the now useless boolean flag from ICPState.
>>
>> Reported-by: Laurent Vivier <lvivier@redhat.com>
>> Signed-off-by: Greg Kurz <groug@kaod.org>
>
> Tested-by: Laurent Vivier <lvivier@redhat.com>
and:
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
next prev parent reply other threads:[~2017-05-17 15:24 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-17 14:38 [Qemu-devel] [PATCH] xics_kvm: cache already enabled vCPU ids Greg Kurz
2017-05-17 15:18 ` Laurent Vivier
2017-05-17 15:24 ` Laurent Vivier [this message]
2017-05-17 15:36 ` Cédric Le Goater
2017-05-18 5:56 ` David Gibson
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