From 09b13fa8c1a1093e9458549ac8bb203a7c65c62a Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Sun, 25 Jan 2015 21:14:58 -0800 Subject: [PATCH] vhost/scsi: Add ANY_LAYOUT support in vhost_scsi_handle_vq This patch adds ANY_LAYOUT compatible support within the existing vhost_scsi_handle_vq() ->handle_kick() callback. It calculates data_direction + exp_data_len for the new tcm_vhost_cmd descriptor by walking both outgoing + incoming iovecs using iov_iter, assuming the layout of outgoing request header + T10_PI + Data payload comes first. It also uses copy_from_iter() to copy leading virtio-scsi request header that may or may not include SCSI CDB, that returns a re-calculated iovec to start of T10_PI or Data SGL memory. Also, go ahead and drop the legacy pre virtio v1.0 !ANY_LAYOUT logic. Cc: Michael S. Tsirkin Cc: Paolo Bonzini Cc: Al Viro Signed-off-by: Nicholas Bellinger --- drivers/vhost/scsi.c | 306 ++++++++++++++++--------------------------- 1 file changed, 110 insertions(+), 196 deletions(-) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 5396b8a3028f..e53959f30c26 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -827,93 +827,6 @@ out: return ret; } -static int -vhost_scsi_map_iov_to_sgl(struct tcm_vhost_cmd *cmd, - struct iovec *iov, - int niov, - bool write) -{ - struct scatterlist *sg = cmd->tvc_sgl; - unsigned int sgl_count = 0; - int ret, i; - - for (i = 0; i < niov; i++) - sgl_count += iov_num_pages(iov[i].iov_base, iov[i].iov_len); - - if (sgl_count > TCM_VHOST_PREALLOC_SGLS) { - pr_err("vhost_scsi_map_iov_to_sgl() sgl_count: %u greater than" - " preallocated TCM_VHOST_PREALLOC_SGLS: %u\n", - sgl_count, TCM_VHOST_PREALLOC_SGLS); - return -ENOBUFS; - } - - pr_debug("%s sg %p sgl_count %u\n", __func__, sg, sgl_count); - sg_init_table(sg, sgl_count); - cmd->tvc_sgl_count = sgl_count; - - pr_debug("Mapping iovec %p for %u pages\n", &iov[0], sgl_count); - - for (i = 0; i < niov; i++) { - ret = vhost_scsi_map_to_sgl(cmd, iov[i].iov_base, iov[i].iov_len, - sg, write); - if (ret < 0) { - for (i = 0; i < cmd->tvc_sgl_count; i++) { - struct page *page = sg_page(&cmd->tvc_sgl[i]); - if (page) - put_page(page); - } - cmd->tvc_sgl_count = 0; - return ret; - } - sg += ret; - sgl_count -= ret; - } - return 0; -} - -static int -vhost_scsi_map_iov_to_prot(struct tcm_vhost_cmd *cmd, - struct iovec *iov, - int niov, - bool write) -{ - struct scatterlist *prot_sg = cmd->tvc_prot_sgl; - unsigned int prot_sgl_count = 0; - int ret, i; - - for (i = 0; i < niov; i++) - prot_sgl_count += iov_num_pages(iov[i].iov_base, iov[i].iov_len); - - if (prot_sgl_count > TCM_VHOST_PREALLOC_PROT_SGLS) { - pr_err("vhost_scsi_map_iov_to_prot() sgl_count: %u greater than" - " preallocated TCM_VHOST_PREALLOC_PROT_SGLS: %u\n", - prot_sgl_count, TCM_VHOST_PREALLOC_PROT_SGLS); - return -ENOBUFS; - } - - pr_debug("%s prot_sg %p prot_sgl_count %u\n", __func__, - prot_sg, prot_sgl_count); - sg_init_table(prot_sg, prot_sgl_count); - cmd->tvc_prot_sgl_count = prot_sgl_count; - - for (i = 0; i < niov; i++) { - ret = vhost_scsi_map_to_sgl(cmd, iov[i].iov_base, iov[i].iov_len, - prot_sg, write); - if (ret < 0) { - for (i = 0; i < cmd->tvc_prot_sgl_count; i++) { - struct page *page = sg_page(&cmd->tvc_prot_sgl[i]); - if (page) - put_page(page); - } - cmd->tvc_prot_sgl_count = 0; - return ret; - } - prot_sg += ret; - prot_sgl_count -= ret; - } - return 0; -} - static int vhost_scsi_calc_sgls(struct iov_iter *iter, size_t bytes, int max_sgls) { @@ -1064,19 +977,20 @@ vhost_scsi_send_bad_target(struct vhost_scsi *vs, static void vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) { - struct tcm_vhost_tpg **vs_tpg; + struct tcm_vhost_tpg **vs_tpg, *tpg; struct virtio_scsi_cmd_req v_req; struct virtio_scsi_cmd_req_pi v_req_pi; - struct tcm_vhost_tpg *tpg; struct tcm_vhost_cmd *cmd; + struct iov_iter out_iter, in_iter, prot_iter, data_iter; u64 tag; - u32 exp_data_len, data_first, data_num, data_direction, prot_first; - unsigned out, in, i; - int head, ret, data_niov, prot_niov, prot_bytes; - size_t req_size; + u32 exp_data_len, data_direction; + unsigned out, in; + int head, ret, prot_bytes; + size_t req_size, rsp_size = sizeof(struct virtio_scsi_cmd_resp); + size_t out_size, in_size; u16 lun; u8 *target, *lunp, task_attr; - bool hdr_pi; + bool t10_pi = vhost_has_feature(vq, VIRTIO_SCSI_F_T10_PI); void *req, *cdb; mutex_lock(&vq->mutex); @@ -1092,10 +1006,10 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) for (;;) { head = vhost_get_vq_desc(vq, vq->iov, - ARRAY_SIZE(vq->iov), &out, &in, - NULL, NULL); + ARRAY_SIZE(vq->iov), &out, &in, + NULL, NULL); pr_debug("vhost_get_vq_desc: head: %d, out: %u in: %u\n", - head, out, in); + head, out, in); /* On error, stop handling until the next kick. */ if (unlikely(head < 0)) break; @@ -1107,117 +1021,134 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) } break; } - - /* FIXME: BIDI operation */ - if (out == 1 && in == 1) { - data_direction = DMA_NONE; - data_first = 0; - data_num = 0; - } else if (out == 1 && in > 1) { - data_direction = DMA_FROM_DEVICE; - data_first = out + 1; - data_num = in - 1; - } else if (out > 1 && in == 1) { - data_direction = DMA_TO_DEVICE; - data_first = 1; - data_num = out - 1; - } else { - vq_err(vq, "Invalid buffer layout out: %u in: %u\n", - out, in); - break; - } - /* - * Check for a sane resp buffer so we can report errors to - * the guest. + * Check for a sane response buffer so we can report early + * errors back to the guest. */ - if (unlikely(vq->iov[out].iov_len != - sizeof(struct virtio_scsi_cmd_resp))) { - vq_err(vq, "Expecting virtio_scsi_cmd_resp, got %zu" - " bytes\n", vq->iov[out].iov_len); + if (unlikely(vq->iov[out].iov_len < rsp_size)) { + vq_err(vq, "Expecting at least virtio_scsi_cmd_resp" + " size, got %zu bytes\n", vq->iov[out].iov_len); break; } - - if (vhost_has_feature(vq, VIRTIO_SCSI_F_T10_PI)) { + /* + * Setup pointers and values based upon different virtio-scsi + * request header if T10_PI is enabled in KVM guest. + */ + if (t10_pi) { req = &v_req_pi; + req_size = sizeof(v_req_pi); lunp = &v_req_pi.lun[0]; target = &v_req_pi.lun[1]; - req_size = sizeof(v_req_pi); - hdr_pi = true; } else { req = &v_req; + req_size = sizeof(v_req); lunp = &v_req.lun[0]; target = &v_req.lun[1]; - req_size = sizeof(v_req); - hdr_pi = false; } + /* + * FIXME: Not correct for BIDI operation + */ + out_size = iov_length(vq->iov, out); + in_size = iov_length(&vq->iov[out], in); - if (unlikely(vq->iov[0].iov_len < req_size)) { - pr_err("Expecting virtio-scsi header: %zu, got %zu\n", - req_size, vq->iov[0].iov_len); - vhost_scsi_send_bad_target(vs, vq, head, out); - continue; - } - ret = memcpy_fromiovecend(req, &vq->iov[0], 0, req_size); - if (unlikely(ret)) { - vq_err(vq, "Faulted on virtio_scsi_cmd_req\n"); + /* + * Copy over the virtio-scsi request header, which for a + * ANY_LAYOUT enabled guest may span multiple iovecs, or a + * single iovec may contain both the header + outgoing + * WRITE payloads. + * + * copy_from_iter() will advance out_iter, so that it will + * point at the start of the outgoing WRITE payload, if + * DMA_TO_DEVICE is set. + */ + iov_iter_init(&out_iter, WRITE, vq->iov, out, out_size); + + ret = copy_from_iter(req, req_size, &out_iter); + if (unlikely(ret != req_size)) { + vq_err(vq, "Faulted on copy_from_iter\n"); vhost_scsi_send_bad_target(vs, vq, head, out); continue; } - /* virtio-scsi spec requires byte 0 of the lun to be 1 */ if (unlikely(*lunp != 1)) { + vq_err(vq, "Illegal virtio-scsi lun: %u\n", *lunp); vhost_scsi_send_bad_target(vs, vq, head, out); continue; } tpg = ACCESS_ONCE(vs_tpg[*target]); - - /* Target does not exist, fail the request */ if (unlikely(!tpg)) { + /* Target does not exist, fail the request */ vhost_scsi_send_bad_target(vs, vq, head, out); continue; } - - data_niov = data_num; - prot_niov = prot_first = prot_bytes = 0; /* - * Determine if any protection information iovecs are preceeding - * the actual data payload, and adjust data_first + data_niov - * values accordingly for vhost_scsi_map_iov_to_sgl() below. + * Determine data_direction by calculating the total outgoing + * iovec sizes + incoming iovec sizes vs. virtio-scsi request + + * response headers respectively. * - * Also extract virtio_scsi header bits for vhost_scsi_get_tag() + * For DMA_TO_DEVICE this is out_iter, which is already pointing + * to the right place. + * + * For DMA_FROM_DEVICE, the iovec will be just past the end + * of the virtio-scsi response header in either the same + * or immediately following iovec. + * + * Any associated T10_PI bytes for the outgoing / incoming + * payloads are included in calculation of exp_data_len here. + */ + prot_bytes = 0; + + if (out_size > req_size) { + data_direction = DMA_TO_DEVICE; + exp_data_len = out_size - req_size; + data_iter = out_iter; + } else if (in_size > rsp_size) { + data_direction = DMA_FROM_DEVICE; + exp_data_len = in_size - rsp_size; + + iov_iter_init(&in_iter, READ, &vq->iov[out], in, + rsp_size + exp_data_len); + iov_iter_advance(&in_iter, rsp_size); + data_iter = in_iter; + } else { + data_direction = DMA_NONE; + exp_data_len = 0; + } + /* + * If T10_PI header + payload is present, setup prot_iter values + * and recalculate data_iter for vhost_scsi_mapal() mapping to + * host scatterlists via get_user_pages_fast(). */ - if (hdr_pi) { + if (t10_pi) { if (v_req_pi.pi_bytesout) { if (data_direction != DMA_TO_DEVICE) { - vq_err(vq, "Received non zero do_pi_niov" - ", but wrong data_direction\n"); + vq_err(vq, "Received non zero pi_bytesout," + " but wrong data_direction\n"); vhost_scsi_send_bad_target(vs, vq, head, out); continue; } prot_bytes = vhost32_to_cpu(vq, v_req_pi.pi_bytesout); } else if (v_req_pi.pi_bytesin) { if (data_direction != DMA_FROM_DEVICE) { - vq_err(vq, "Received non zero di_pi_niov" - ", but wrong data_direction\n"); + vq_err(vq, "Received non zero pi_bytesin," + " but wrong data_direction\n"); vhost_scsi_send_bad_target(vs, vq, head, out); continue; } prot_bytes = vhost32_to_cpu(vq, v_req_pi.pi_bytesin); } + /* + * Set prot_iter to data_iter, and advance past any + * preceeding prot_bytes that may be present. + * + * Also fix up the exp_data_len to reflect only the + * actual data payload length. + */ if (prot_bytes) { - int tmp = 0; - - for (i = 0; i < data_num; i++) { - tmp += vq->iov[data_first + i].iov_len; - prot_niov++; - if (tmp >= prot_bytes) - break; - } - prot_first = data_first; - data_first += prot_niov; - data_niov = data_num - prot_niov; + exp_data_len -= prot_bytes; + prot_iter = data_iter; + iov_iter_advance(&data_iter, prot_bytes); } tag = vhost64_to_cpu(vq, v_req_pi.tag); task_attr = v_req_pi.task_attr; @@ -1229,12 +1160,10 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) cdb = &v_req.cdb[0]; lun = ((v_req.lun[2] << 8) | v_req.lun[3]) & 0x3FFF; } - exp_data_len = 0; - for (i = 0; i < data_niov; i++) - exp_data_len += vq->iov[data_first + i].iov_len; /* - * Check that the recieved CDB size does not exceeded our - * hardcoded max for vhost-scsi + * Check that the received CDB size does not exceeded our + * hardcoded max for vhost-scsi, then get a pre-allocated + * cmd descriptor for the new virtio-scsi tag. * * TODO what if cdb was too small for varlen cdb header? */ @@ -1245,44 +1174,29 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) vhost_scsi_send_bad_target(vs, vq, head, out); continue; } - cmd = vhost_scsi_get_tag(vq, tpg, cdb, tag, lun, task_attr, exp_data_len + prot_bytes, data_direction); if (IS_ERR(cmd)) { vq_err(vq, "vhost_scsi_get_tag failed %ld\n", - PTR_ERR(cmd)); + PTR_ERR(cmd)); vhost_scsi_send_bad_target(vs, vq, head, out); continue; } - - pr_debug("Allocated tv_cmd: %p exp_data_len: %d, data_direction" - ": %d\n", cmd, exp_data_len, data_direction); - cmd->tvc_vhost = vs; cmd->tvc_vq = vq; cmd->tvc_resp_iov = &vq->iov[out]; cmd->tvc_in_iovs = in; pr_debug("vhost_scsi got command opcode: %#02x, lun: %d\n", - cmd->tvc_cdb[0], cmd->tvc_lun); + cmd->tvc_cdb[0], cmd->tvc_lun); + pr_debug("cmd: %p exp_data_len: %d, prot_bytes: %d data_direction:" + " %d\n", cmd, exp_data_len, prot_bytes, data_direction); - if (prot_niov) { - ret = vhost_scsi_map_iov_to_prot(cmd, - &vq->iov[prot_first], prot_niov, - data_direction == DMA_FROM_DEVICE); - if (unlikely(ret)) { - vq_err(vq, "Failed to map iov to" - " prot_sgl\n"); - tcm_vhost_release_cmd(&cmd->tvc_se_cmd); - vhost_scsi_send_bad_target(vs, vq, head, out); - continue; - } - } if (data_direction != DMA_NONE) { - ret = vhost_scsi_map_iov_to_sgl(cmd, - &vq->iov[data_first], data_niov, - data_direction == DMA_FROM_DEVICE); + ret = vhost_scsi_mapal(cmd, + prot_bytes, &prot_iter, + exp_data_len, &data_iter); if (unlikely(ret)) { vq_err(vq, "Failed to map iov to sgl\n"); tcm_vhost_release_cmd(&cmd->tvc_se_cmd); @@ -1293,14 +1207,14 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) /* * Save the descriptor from vhost_get_vq_desc() to be used to * complete the virtio-scsi request in TCM callback context via - * tcm_vhost_queue_data_in() and tcm_vhost_queue_status() + * vhost_scsi_queue_data_in() and vhost_scsi_queue_status() */ cmd->tvc_vq_desc = head; /* - * Dispatch tv_cmd descriptor for cmwq execution in process - * context provided by tcm_vhost_workqueue. This also ensures - * tv_cmd is executed on the same kworker CPU as this vhost - * thread to gain positive L2 cache locality effects.. + * Dispatch cmd descriptor for cmwq execution in process + * context provided by vhost_scsi_workqueue. This also ensures + * cmd is executed on the same kworker CPU as this vhost + * thread to gain positive L2 cache locality effects. */ INIT_WORK(&cmd->work, tcm_vhost_submission_work); queue_work(tcm_vhost_workqueue, &cmd->work); -- 2.34.1