From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1L5P3p-0000Kz-Bj for qemu-devel@nongnu.org; Wed, 26 Nov 2008 13:24:25 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1L5P3n-0000KI-Oi for qemu-devel@nongnu.org; Wed, 26 Nov 2008 13:24:24 -0500 Received: from [199.232.76.173] (port=34625 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1L5P3n-0000KF-F4 for qemu-devel@nongnu.org; Wed, 26 Nov 2008 13:24:23 -0500 Received: from e32.co.us.ibm.com ([32.97.110.150]:49420) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1L5P3n-0006uA-31 for qemu-devel@nongnu.org; Wed, 26 Nov 2008 13:24:23 -0500 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by e32.co.us.ibm.com (8.13.1/8.13.1) with ESMTP id mAQIN3nw002607 for ; Wed, 26 Nov 2008 11:23:03 -0700 Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id mAQIOLqO096344 for ; Wed, 26 Nov 2008 11:24:21 -0700 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id mAQIOKnT016725 for ; Wed, 26 Nov 2008 11:24:20 -0700 Subject: Re: [Qemu-devel] [PATCH 2/2] Virtio block device support From: Hollis Blanchard In-Reply-To: <1227650239-14162-2-git-send-email-aliguori@us.ibm.com> References: <1227650239-14162-1-git-send-email-aliguori@us.ibm.com> <1227650239-14162-2-git-send-email-aliguori@us.ibm.com> Content-Type: text/plain Date: Wed, 26 Nov 2008 12:24:20 -0600 Message-Id: <1227723860.6562.5.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Anthony Liguori , Avi Kivity , kvm-devel On Tue, 2008-11-25 at 15:57 -0600, Anthony Liguori wrote: > This has been posted before but I believe it now has addressed all outstanding > concerns. I'd like to apply it if there are no objections. > > This patch adds virtio-blk support to QEMU. virtio-blk is a paravirtual disk > controller that can achieve good performance when using KVM. > > Since virtio is based on a scatter/gather API, we don't have a linear buffer > for each request. This forces us to allocate a linear buffer since the current > block driver API does not have a scatter/gather operation. This allocation > can never exceed the maximum data limit on the ring queue so it isn't > unbounded. > > posix-aio cannot support a scatter/gather asynchronous operation so we'll need > to introduce our own thread pool to eliminate this limitation. There is work > underway to do this. > > Signed-off-by: Anthony Liguori Tested and working (in conjunction with the virtio page size patch I just posted). -- Hollis Blanchard IBM Linux Technology Center