1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright(c) 2019 Intel Corporation. All rights rsvd. */ 3 #include <linux/init.h> 4 #include <linux/kernel.h> 5 #include <linux/module.h> 6 #include <linux/pci.h> 7 #include <uapi/linux/idxd.h> 8 #include "idxd.h" 9 #include "registers.h" 10 11 static struct idxd_desc *__get_desc(struct idxd_wq *wq, int idx, int cpu) 12 { 13 struct idxd_desc *desc; 14 struct idxd_device *idxd = wq->idxd; 15 16 desc = wq->descs[idx]; 17 memset(desc->hw, 0, sizeof(struct dsa_hw_desc)); 18 memset(desc->completion, 0, idxd->data->compl_size); 19 desc->cpu = cpu; 20 21 if (device_pasid_enabled(idxd)) 22 desc->hw->pasid = idxd->pasid; 23 24 /* 25 * On host, MSIX vecotr 0 is used for misc interrupt. Therefore when we match 26 * vector 1:1 to the WQ id, we need to add 1 27 */ 28 if (!idxd->int_handles) 29 desc->hw->int_handle = wq->id + 1; 30 else 31 desc->hw->int_handle = idxd->int_handles[wq->id]; 32 33 return desc; 34 } 35 36 struct idxd_desc *idxd_alloc_desc(struct idxd_wq *wq, enum idxd_op_type optype) 37 { 38 int cpu, idx; 39 struct idxd_device *idxd = wq->idxd; 40 DEFINE_SBQ_WAIT(wait); 41 struct sbq_wait_state *ws; 42 struct sbitmap_queue *sbq; 43 44 if (idxd->state != IDXD_DEV_ENABLED) 45 return ERR_PTR(-EIO); 46 47 sbq = &wq->sbq; 48 idx = sbitmap_queue_get(sbq, &cpu); 49 if (idx < 0) { 50 if (optype == IDXD_OP_NONBLOCK) 51 return ERR_PTR(-EAGAIN); 52 } else { 53 return __get_desc(wq, idx, cpu); 54 } 55 56 ws = &sbq->ws[0]; 57 for (;;) { 58 sbitmap_prepare_to_wait(sbq, ws, &wait, TASK_INTERRUPTIBLE); 59 if (signal_pending_state(TASK_INTERRUPTIBLE, current)) 60 break; 61 idx = sbitmap_queue_get(sbq, &cpu); 62 if (idx >= 0) 63 break; 64 schedule(); 65 } 66 67 sbitmap_finish_wait(sbq, ws, &wait); 68 if (idx < 0) 69 return ERR_PTR(-EAGAIN); 70 71 return __get_desc(wq, idx, cpu); 72 } 73 74 void idxd_free_desc(struct idxd_wq *wq, struct idxd_desc *desc) 75 { 76 int cpu = desc->cpu; 77 78 desc->cpu = -1; 79 sbitmap_queue_clear(&wq->sbq, desc->id, cpu); 80 } 81 82 static struct idxd_desc *list_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie, 83 struct idxd_desc *desc) 84 { 85 struct idxd_desc *d, *n; 86 87 lockdep_assert_held(&ie->list_lock); 88 list_for_each_entry_safe(d, n, &ie->work_list, list) { 89 if (d == desc) { 90 list_del(&d->list); 91 return d; 92 } 93 } 94 95 /* 96 * At this point, the desc needs to be aborted is held by the completion 97 * handler where it has taken it off the pending list but has not added to the 98 * work list. It will be cleaned up by the interrupt handler when it sees the 99 * IDXD_COMP_DESC_ABORT for completion status. 100 */ 101 return NULL; 102 } 103 104 static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie, 105 struct idxd_desc *desc) 106 { 107 struct idxd_desc *d, *t, *found = NULL; 108 struct llist_node *head; 109 110 desc->completion->status = IDXD_COMP_DESC_ABORT; 111 /* 112 * Grab the list lock so it will block the irq thread handler. This allows the 113 * abort code to locate the descriptor need to be aborted. 114 */ 115 spin_lock(&ie->list_lock); 116 head = llist_del_all(&ie->pending_llist); 117 if (head) { 118 llist_for_each_entry_safe(d, t, head, llnode) { 119 if (d == desc) { 120 found = desc; 121 continue; 122 } 123 list_add_tail(&desc->list, &ie->work_list); 124 } 125 } 126 127 if (!found) 128 found = list_abort_desc(wq, ie, desc); 129 spin_unlock(&ie->list_lock); 130 131 if (found) 132 complete_desc(found, IDXD_COMPLETE_ABORT); 133 } 134 135 int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc) 136 { 137 struct idxd_device *idxd = wq->idxd; 138 struct idxd_irq_entry *ie = NULL; 139 void __iomem *portal; 140 int rc; 141 142 if (idxd->state != IDXD_DEV_ENABLED) { 143 idxd_free_desc(wq, desc); 144 return -EIO; 145 } 146 147 if (!percpu_ref_tryget_live(&wq->wq_active)) { 148 idxd_free_desc(wq, desc); 149 return -ENXIO; 150 } 151 152 portal = idxd_wq_portal_addr(wq); 153 154 /* 155 * The wmb() flushes writes to coherent DMA data before 156 * possibly triggering a DMA read. The wmb() is necessary 157 * even on UP because the recipient is a device. 158 */ 159 wmb(); 160 161 /* 162 * Pending the descriptor to the lockless list for the irq_entry 163 * that we designated the descriptor to. 164 */ 165 if (desc->hw->flags & IDXD_OP_FLAG_RCI) { 166 ie = &idxd->irq_entries[wq->id + 1]; 167 llist_add(&desc->llnode, &ie->pending_llist); 168 } 169 170 if (wq_dedicated(wq)) { 171 iosubmit_cmds512(portal, desc->hw, 1); 172 } else { 173 /* 174 * It's not likely that we would receive queue full rejection 175 * since the descriptor allocation gates at wq size. If we 176 * receive a -EAGAIN, that means something went wrong such as the 177 * device is not accepting descriptor at all. 178 */ 179 rc = enqcmds(portal, desc->hw); 180 if (rc < 0) { 181 percpu_ref_put(&wq->wq_active); 182 /* abort operation frees the descriptor */ 183 if (ie) 184 llist_abort_desc(wq, ie, desc); 185 else 186 idxd_free_desc(wq, desc); 187 return rc; 188 } 189 } 190 191 percpu_ref_put(&wq->wq_active); 192 return 0; 193 } 194