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Re: [Qemu-devel] [PATCH v5 04/11] dataplane: add virtqueue vring code
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH v5 04/11] dataplane: add virtqueue vring code |
Date: |
Thu, 6 Dec 2012 13:53:41 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Thu, Dec 06, 2012 at 01:22:29PM +0200, Michael S. Tsirkin wrote:
> On Wed, Dec 05, 2012 at 09:47:03PM +0100, Stefan Hajnoczi wrote:
> > The virtio-blk-data-plane cannot access memory using the usual QEMU
> > functions since it executes outside the global mutex and the memory APIs
> > are this time are not thread-safe.
> >
> > This patch introduces a virtqueue module based on the kernel's vhost
> > vring code. The trick is that we map guest memory ahead of time and
> > access it cheaply outside the global mutex.
>
> Question: can virtio.c be reworked to use vring.c instead?
> The cost of keeping an extra memory listener around seems negligeable.
> The only issue I see is around dirty tracking for used ring writes.
> Maybe we could add a callback for this?
virtio.c and dataplane/vring.c will be unified but I think it's beyond
the scope of this series. This is the thread-safe memory API
refactoring we discussed.
Stefan
- [Qemu-devel] [PATCH v5 00/11] virtio: virtio-blk data plane, Stefan Hajnoczi, 2012/12/05
- [Qemu-devel] [PATCH v5 01/11] raw-posix: add raw_get_aio_fd() for virtio-blk-data-plane, Stefan Hajnoczi, 2012/12/05
- [Qemu-devel] [PATCH v5 02/11] configure: add CONFIG_VIRTIO_BLK_DATA_PLANE, Stefan Hajnoczi, 2012/12/05
- [Qemu-devel] [PATCH v5 03/11] dataplane: add host memory mapping code, Stefan Hajnoczi, 2012/12/05
- [Qemu-devel] [PATCH v5 04/11] dataplane: add virtqueue vring code, Stefan Hajnoczi, 2012/12/05
- [Qemu-devel] [PATCH v5 05/11] dataplane: add event loop, Stefan Hajnoczi, 2012/12/05
- [Qemu-devel] [PATCH v5 06/11] dataplane: add Linux AIO request queue, Stefan Hajnoczi, 2012/12/05
- [Qemu-devel] [PATCH v5 07/11] iov: add iov_discard() to remove data, Stefan Hajnoczi, 2012/12/05
- [Qemu-devel] [PATCH v5 11/11] virtio-blk: add x-data-plane=on|off performance feature, Stefan Hajnoczi, 2012/12/05