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Date: Tue, 07 May 2013 15:36:45 +0200
From: Gerd Hoffmann <kraxel@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] uhci: Use an intermediate buffer for usb
	packet data
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To: Hans de Goede <hdegoede@redhat.com>
Cc: qemu-devel@nongnu.org

On 05/06/13 10:48, Hans de Goede wrote:
> Due to various unfortunate reasons we cannot reliable detect a guest
> cancelling a packet as soon as it happens, instead we detect cancels
> with some delay.
> 
> When packets are handled async, and we directly pass the guest memory for
> the packet to the usb-device as iovec, this means that the usb-device can
> write to guest-memory which the guest has already re-used for other purposes
> -> not good!
> 
> This patch fixes this by adding an intermediate buffer and writing back not
> only the result, but also the data, of async completed packets when scanning
> the schedule.

Patch added to usb patch queue, pull req sent.

thanks,
  Gerd