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Hi, This is the first attempt to add a new qemu nvme backend using in-kernel nvme target. Most code are ported from qemu-nvme and also borrow code from Hannes Reinecke's rts-megasas. It's similar as vhost-scsi, but doesn't use virtio. The advantage is guest can run unmodified NVMe driver. So guest can be any OS that has a NVMe driver. The goal is to get as good performance as

Hi, This is the first attempt to add a new qemu nvme backend using in-kernel nvme target. Most code are ported from qemu-nvme and also borrow code from Hannes Reinecke's rts-megasas. It's similar as vhost-scsi, but doesn't use virtio. The advantage is guest can run unmodified NVMe driver. So guest can be any OS that has a NVMe driver. The goal is to get as good performance as

On 18/11/2015 06:47, Ming Lin wrote: > @@ -726,7 +798,11 @@ static void nvme_process_db(NvmeCtrl *n, hwaddr addr, int val) > } > > start_sqs = nvme_cq_full(cq) ? 1 : 0; > - cq->head = new_head; > + /* When the mapped pointer memory area is setup, we don't rely on > + * the MMIO written values to update the head pointer. */ >

On 18/11/2015 06:47, Ming Lin wrote: > @@ -726,7 +798,11 @@ static void nvme_process_db(NvmeCtrl *n, hwaddr addr, int val) > } > > start_sqs = nvme_cq_full(cq) ? 1 : 0; > - cq->head = new_head; > + /* When the mapped pointer memory area is setup, we don't rely on > + * the MMIO written values to update the head pointer. */ >

...ifier(EventNotifier *e) > +{ > + NvmeCQueue *cq = > + container_of(e, NvmeCQueue, notifier); > + > + nvme_post_cqes(cq); > +} > + > +static void nvme_init_cq_eventfd(NvmeCQueue *cq) > +{ > + NvmeCtrl *n = cq->ctrl; > + uint16_t offset = (cq->cqid*2+1) * NVME_CAP_DSTRD(n->bar.cap); > + > + event_notifier_init(&cq->notifier, 0); > + event_notifier_set_handler(&cq->notifier, nvme_cq_notifier); > + memory_region_add_eventfd(&n->iomem, > + 0x1000 + offset, 4, true, cq->cqid*2+1, &cq-&...

...ifier(EventNotifier *e) > +{ > + NvmeCQueue *cq = > + container_of(e, NvmeCQueue, notifier); > + > + nvme_post_cqes(cq); > +} > + > +static void nvme_init_cq_eventfd(NvmeCQueue *cq) > +{ > + NvmeCtrl *n = cq->ctrl; > + uint16_t offset = (cq->cqid*2+1) * NVME_CAP_DSTRD(n->bar.cap); > + > + event_notifier_init(&cq->notifier, 0); > + event_notifier_set_handler(&cq->notifier, nvme_cq_notifier); > + memory_region_add_eventfd(&n->iomem, > + 0x1000 + offset, 4, true, cq->cqid*2+1, &cq-&...

...init_sq(NvmeSQueue *sq, NvmeCtrl *n, uint64_t dma_addr, QTAILQ_INSERT_TAIL(&(sq->req_list), &sq->io_req[i], entry); } sq->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, nvme_process_sq, sq); + sq->db_addr = 0; + sq->eventidx_addr = 0; assert(n->cq[cqid]); cq = n->cq[cqid]; @@ -430,6 +443,8 @@ static void nvme_init_cq(NvmeCQueue *cq, NvmeCtrl *n, uint64_t dma_addr, cq->head = cq->tail = 0; QTAILQ_INIT(&cq->req_list); QTAILQ_INIT(&cq->sq_list); + cq->db_addr = 0; + cq->eventidx_addr = 0; m...

...return NVME_SUCCESS; } +static void nvme_cq_notifier(EventNotifier *e) +{ + NvmeCQueue *cq = + container_of(e, NvmeCQueue, notifier); + + nvme_post_cqes(cq); +} + +static void nvme_init_cq_eventfd(NvmeCQueue *cq) +{ + NvmeCtrl *n = cq->ctrl; + uint16_t offset = (cq->cqid*2+1) * NVME_CAP_DSTRD(n->bar.cap); + + event_notifier_init(&cq->notifier, 0); + event_notifier_set_handler(&cq->notifier, nvme_cq_notifier); + memory_region_add_eventfd(&n->iomem, + 0x1000 + offset, 4, true, cq->cqid*2+1, &cq->notifier); +} + +stati...

...eCQueue *cq = > > + container_of(e, NvmeCQueue, notifier); > > + > > + nvme_post_cqes(cq); > > +} > > + > > +static void nvme_init_cq_eventfd(NvmeCQueue *cq) > > +{ > > + NvmeCtrl *n = cq->ctrl; > > + uint16_t offset = (cq->cqid*2+1) * NVME_CAP_DSTRD(n->bar.cap); > > + > > + event_notifier_init(&cq->notifier, 0); > > + event_notifier_set_handler(&cq->notifier, nvme_cq_notifier); > > + memory_region_add_eventfd(&n->iomem, > > + 0x1000 + offset, 4, true, c...

Hi Rob & Mihai, I wrote vhost-nvme patches on top of Christoph's NVMe target. vhost-nvme still uses mmio. So the guest OS can run unmodified NVMe driver. But the tests I have done didn't show competitive performance compared to virtio-blk/virtio-scsi. The bottleneck is in mmio. Your nvme vendor extension patches reduces greatly the number of MMIO writes. So I'd like to push it

Hi Rob & Mihai, I wrote vhost-nvme patches on top of Christoph's NVMe target. vhost-nvme still uses mmio. So the guest OS can run unmodified NVMe driver. But the tests I have done didn't show competitive performance compared to virtio-blk/virtio-scsi. The bottleneck is in mmio. Your nvme vendor extension patches reduces greatly the number of MMIO writes. So I'd like to push it