From patchwork Tue Feb 3 06:29:59 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Nicholas A. 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[67.23.28.174]) by mx.google.com with ESMTPSA id t8sm10657870obv.22.2015.02.02.23.03.08 (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 02 Feb 2015 23:03:08 -0800 (PST) From: "Nicholas A. Bellinger" To: target-devel Cc: linux-scsi , kvm-devel , Paolo Bonzini , "Michael S. Tsirkin" , Al Viro , Christoph Hellwig , Nicholas Bellinger Subject: [PATCH-v3 5/9] vhost/scsi: Add ANY_LAYOUT vhost_virtqueue callback Date: Tue, 3 Feb 2015 06:29:59 +0000 Message-Id: <1422945003-24538-6-git-send-email-nab@daterainc.com> X-Mailer: git-send-email 1.7.2.5 In-Reply-To: <1422945003-24538-1-git-send-email-nab@daterainc.com> References: <1422945003-24538-1-git-send-email-nab@daterainc.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Nicholas Bellinger This patch adds ANY_LAYOUT support with a new vqs[].vq.handle_kick() callback in vhost_scsi_handle_vqal(). 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. v2 changes: - Fix up vhost_scsi_handle_vqal comments - Minor vhost_scsi_handle_vqal simplifications - Add missing minimum virtio-scsi response buffer size check - Fix pi_bytes* error message typo - Convert to use vhost_skip_iovec_bytes() common code - Add max_niov sanity checks vs. out + in offset into vq v3 changes: - Convert to copy_from_iter usage - Update vhost_scsi_handle_vqal comments for iov_iter usage - Convert prot_bytes offset to use iov_iter_advance - Drop max_niov usage in vhost_scsi_handle_vqal - Drop vhost_skip_iovec_bytes in favour of iov_iter Cc: Michael S. Tsirkin Cc: Paolo Bonzini Signed-off-by: Nicholas Bellinger --- drivers/vhost/scsi.c | 260 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 260 insertions(+) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 7dfff15..e1fe003 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -1062,6 +1062,266 @@ vhost_scsi_send_bad_target(struct vhost_scsi *vs, } static void +vhost_scsi_handle_vqal(struct vhost_scsi *vs, struct vhost_virtqueue *vq) +{ + 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_cmd *cmd; + struct iov_iter out_iter, in_iter, prot_iter, data_iter; + u64 tag; + u32 exp_data_len, data_direction; + unsigned out, in, i; + 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 t10_pi = vhost_has_feature(vq, VIRTIO_SCSI_F_T10_PI); + void *req, *cdb; + + mutex_lock(&vq->mutex); + /* + * We can handle the vq only after the endpoint is setup by calling the + * VHOST_SCSI_SET_ENDPOINT ioctl. + */ + vs_tpg = vq->private_data; + if (!vs_tpg) + goto out; + + vhost_disable_notify(&vs->dev, vq); + + for (;;) { + head = vhost_get_vq_desc(vq, vq->iov, + ARRAY_SIZE(vq->iov), &out, &in, + NULL, NULL); + pr_debug("vhost_get_vq_desc: head: %d, out: %u in: %u\n", + head, out, in); + /* On error, stop handling until the next kick. */ + if (unlikely(head < 0)) + break; + /* Nothing new? Wait for eventfd to tell us they refilled. */ + if (head == vq->num) { + if (unlikely(vhost_enable_notify(&vs->dev, vq))) { + vhost_disable_notify(&vs->dev, vq); + continue; + } + break; + } + /* + * Check for a sane response buffer so we can report early + * errors back to the guest. + */ + 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; + } + /* + * 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]; + } else { + req = &v_req; + req_size = sizeof(v_req); + lunp = &v_req.lun[0]; + target = &v_req.lun[1]; + } + /* + * Determine data_direction for ANY_LAYOUT by calculating the + * total outgoing iovec sizes / incoming iovec sizes vs. + * virtio-scsi request / response headers respectively. + * + * FIXME: Not correct for BIDI operation + */ + out_size = in_size = 0; + for (i = 0; i < out; i++) + out_size += vq->iov[i].iov_len; + for (i = out; i < out + in; i++) + in_size += vq->iov[i].iov_len; + /* + * Any associated T10_PI bytes for the outgoing / incoming + * payloads are included in calculation of exp_data_len here. + */ + if (out_size > req_size) { + data_direction = DMA_TO_DEVICE; + exp_data_len = out_size - req_size; + } else if (in_size > rsp_size) { + data_direction = DMA_FROM_DEVICE; + exp_data_len = in_size - rsp_size; + } else { + data_direction = DMA_NONE; + exp_data_len = 0; + } + /* + * Copy over the virtio-scsi request header, which when + * ANY_LAYOUT is enabled may span multiple iovecs, or a + * single iovec may contain both the header + outgoing + * WRITE payloads. + * + * copy_from_iter() is modifying the iovecs as copies over + * req_size bytes into req, so the returned out_iter.iov[0] + * will contain the correct start + offset of the outgoing + * WRITE payload, if DMA_TO_DEVICE is set. + */ + iov_iter_init(&out_iter, READ, &vq->iov[0], out, + (data_direction == DMA_TO_DEVICE) ? + req_size + exp_data_len : req_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]); + if (unlikely(!tpg)) { + /* Target does not exist, fail the request */ + vhost_scsi_send_bad_target(vs, vq, head, out); + continue; + } + /* + * Determine start of T10_PI or data payload iovec in ANY_LAYOUT + * mode based upon data_direction. + * + * For DMA_TO_DEVICE, this is iov_out from copy_from_iter() + * with the already recalculated iov_base + iov_len. + * + * 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. + */ + prot_bytes = 0; + + if (data_direction == DMA_TO_DEVICE) { + data_iter = out_iter; + } else if (data_direction == DMA_FROM_DEVICE) { + iov_iter_init(&in_iter, WRITE, &vq->iov[out], in, + rsp_size + exp_data_len); + iov_iter_advance(&in_iter, rsp_size); + data_iter = in_iter; + } + /* + * 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 (t10_pi) { + if (v_req_pi.pi_bytesout) { + if (data_direction != DMA_TO_DEVICE) { + 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 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) { + 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; + cdb = &v_req_pi.cdb[0]; + lun = ((v_req_pi.lun[2] << 8) | v_req_pi.lun[3]) & 0x3FFF; + } else { + tag = vhost64_to_cpu(vq, v_req.tag); + task_attr = v_req.task_attr; + cdb = &v_req.cdb[0]; + lun = ((v_req.lun[2] << 8) | v_req.lun[3]) & 0x3FFF; + } + /* + * Check that the recieved 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? + */ + if (unlikely(scsi_command_size(cdb) > TCM_VHOST_MAX_CDB_SIZE)) { + vq_err(vq, "Received SCSI CDB with command_size: %d that" + " exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n", + scsi_command_size(cdb), TCM_VHOST_MAX_CDB_SIZE); + 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)); + vhost_scsi_send_bad_target(vs, vq, head, out); + continue; + } + 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); + pr_debug("cmd: %p exp_data_len: %d, prot_bytes: %d data_direction:" + " %d\n", cmd, exp_data_len, prot_bytes, data_direction); + + if (data_direction != DMA_NONE) { + 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); + vhost_scsi_send_bad_target(vs, vq, head, out); + continue; + } + } + /* + * Save the descriptor from vhost_get_vq_desc() to be used to + * complete the virtio-scsi request in TCM callback context via + * vhost_scsi_queue_data_in() and vhost_scsi_queue_status() + */ + cmd->tvc_vq_desc = head; + /* + * 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); + } +out: + mutex_unlock(&vq->mutex); +} + +static void vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) { struct tcm_vhost_tpg **vs_tpg;