On Fri, 2015-09-11 at 08:48 +0100, Stefan Hajnoczi wrote: > On Thu, Sep 10, 2015 at 6:28 PM, Ming Lin <mlin@xxxxxxxxxx> wrote: > > On Thu, 2015-09-10 at 15:38 +0100, Stefan Hajnoczi wrote: > >> On Thu, Sep 10, 2015 at 6:48 AM, Ming Lin <mlin@xxxxxxxxxx> wrote: > >> > These 2 patches added virtio-nvme to kernel and qemu, > >> > basically modified from virtio-blk and nvme code. > >> > > >> > As title said, request for your comments. > >> > > >> > Play it in Qemu with: > >> > -drive file=disk.img,format=raw,if=none,id=D22 \ > >> > -device virtio-nvme-pci,drive=D22,serial=1234,num_queues=4 > >> > > >> > The goal is to have a full NVMe stack from VM guest(virtio-nvme) > >> > to host(vhost_nvme) to LIO NVMe-over-fabrics target. > >> > >> Why is a virtio-nvme guest device needed? I guess there must either > >> be NVMe-only features that you want to pass through, or you think the > >> performance will be significantly better than virtio-blk/virtio-scsi? > > > > It simply passes through NVMe commands. > > I understand that. My question is why the guest needs to send NVMe commands? > > If the virtio_nvme.ko guest driver only sends read/write/flush then > there's no advantage over virtio-blk. > > There must be something you are trying to achieve which is not > possible with virtio-blk or virtio-scsi. What is that? I actually learned from your virtio-scsi work. http://www.linux-kvm.org/images/f/f5/2011-forum-virtio-scsi.pdf Then I thought a full NVMe stack from guest to host to target seems reasonable. Trying to achieve similar things as virtio-scsi, but all NVMe protocol. - Effective NVMe passthrough - Multiple target choices: QEMU, LIO-NVMe(vhost_nvme) - Almost unlimited scalability. Thousands of namespaces per PCI device - True NVMe device - End-to-end Protection Information - .... _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
