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Date: Thu, 11 Apr 2013 12:15:27 +0200
From: Stefan Hajnoczi <stefanha@gmail.com>
Message-ID: <20130411101527.GD9165@stefanha-thinkpad.redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 3/5] vring: use hostmem's RAM safe api
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To: Liu Ping Fan <qemulist@gmail.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, Anthony Liguori <aliguori@us.ibm.com>, Jan Kiszka <jan.kiszka@siemens.com>, Marcelo Tosatti <mtosatti@redhat.com>, qemu-devel@nongnu.org, Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>, Paolo Bonzini <pbonzini@redhat.com>

On Mon, Apr 01, 2013 at 04:20:32PM +0800, Liu Ping Fan wrote:
> @@ -51,7 +50,7 @@ bool vring_setup(Vring *vring, VirtIODevice *vdev, int n)
>  
>  void vring_teardown(Vring *vring)
>  {
> -    hostmem_finalize(&vring->hostmem);
> +    memory_region_unref(vring->vring_mr);
>  }

dataplane keeps a reference to the vring.  This prevents memory hot
unplug while the device is up.  If this is a problem we'll have to
reduce the lifespan of the vring mapping.

Stefan