Messages in this thread | | | Date | Wed, 17 May 2023 16:35:55 +0800 | Subject | Re: Re: [PATCH v2 1/2] virtio: abstract virtqueue related methods | From | zhenwei pi <> |
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On 5/17/23 15:46, Christoph Hellwig wrote: > On Wed, May 17, 2023 at 03:43:03PM +0800, zhenwei pi wrote: >> I have a plan to introduce 'Virtio Over Fabrics'(TCP&RDMA) as Virtio >> transport, as mentioned in cover letter of this series: >> 3 weeks ago, I posted a proposal 'Virtio Over Fabrics': >> https://lists.oasis-open.org/archives/virtio-comment/202304/msg00442.html > > Just don't do it. Please define your own protocols over RDMA or TCP > for exactly the operations you need (for many they will already exist) > instead of piggyg backing on virtio and making everyone else pay the > price. >
Hi
1, `virtqueue_add_inbuf` in current version: static inline int virtqueue_add_inbuf(struct virtqueue *vq, struct scatterlist *sg, unsigned int num, void *data, gfp_t gfp) { if (likely(!vq->abstract)) return vring_virtqueue_add_sgs(vq, &sg, num, 0, 1, data, NULL, gfp);
return vq->add_sgs(vq, &sg, num, 0, 1, data, NULL, gfp); }
And disassemble 'virtinput_queue_evtbuf': static void virtinput_queue_evtbuf(struct virtio_input *vi, struct virtio_input_event *evtbuf) { struct scatterlist sg[1];
sg_init_one(sg, evtbuf, sizeof(*evtbuf)); virtqueue_add_inbuf(vi->evt, sg, 1, evtbuf, GFP_ATOMIC); }
I notice that two instructions are newly added for vring like: 24d: 80 78 35 00 cmpb $0x0,0x35(%rax) 251: 75 3f jne 292
Is it an expensive price...
2, Storage/FS specific remote protocol is quite popular, otherwise I'm not familiar with other device protocols. For example, I need a remote crypto device to accelerate HTTPS ... With Virtio Over Fabrics, I have a chance to attach a virtio-crypto device to do this work.
-- zhenwei pi
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