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Subject: Re: system hung up when offlining CPUs
To: Christoph Hellwig <hch@lst.de>
Cc: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>, tglx@linutronix.de,
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From: Marc Zyngier <marc.zyngier@arm.com>
Organization: ARM Ltd
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Date: Mon, 21 Aug 2017 14:37:57 +0100
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On 21/08/17 14:18, Christoph Hellwig wrote:
> Can you try the patch below please?
> 
> ---
> From d5f59cb7a629de8439b318e1384660e6b56e7dd8 Mon Sep 17 00:00:00 2001
> From: Christoph Hellwig <hch@lst.de>
> Date: Mon, 21 Aug 2017 14:24:11 +0200
> Subject: virtio_pci: fix cpu affinity support
> 
> Commit 0b0f9dc5 ("Revert "virtio_pci: use shared interrupts for
> virtqueues"") removed the adjustment of the pre_vectors for the virtio
> MSI-X vector allocation which was added in commit fb5e31d9 ("virtio:
> allow drivers to request IRQ affinity when creating VQs"). This will
> lead to an incorrect assignment of MSI-X vectors, and potential
> deadlocks when offlining cpus.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Fixes: 0b0f9dc5 ("Revert "virtio_pci: use shared interrupts for virtqueues")
> Reported-by: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>

Just gave it a go on an arm64 VM, and the behaviour seems much saner
(the virtio queue affinity now spans the whole system).

Tested-by: Marc Zyngier <marc.zyngier@arm.com>

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...