1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * VFIO based Physical Subchannel device driver 4 * 5 * Copyright IBM Corp. 2017 6 * 7 * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> 8 * Xiao Feng Ren <renxiaof@linux.vnet.ibm.com> 9 */ 10 11 #include <linux/module.h> 12 #include <linux/init.h> 13 #include <linux/device.h> 14 #include <linux/slab.h> 15 #include <linux/uuid.h> 16 #include <linux/mdev.h> 17 18 #include <asm/isc.h> 19 20 #include "ioasm.h" 21 #include "css.h" 22 #include "vfio_ccw_private.h" 23 24 struct workqueue_struct *vfio_ccw_work_q; 25 static struct kmem_cache *vfio_ccw_io_region; 26 27 /* 28 * Helpers 29 */ 30 int vfio_ccw_sch_quiesce(struct subchannel *sch) 31 { 32 struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev); 33 DECLARE_COMPLETION_ONSTACK(completion); 34 int iretry, ret = 0; 35 36 spin_lock_irq(sch->lock); 37 if (!sch->schib.pmcw.ena) 38 goto out_unlock; 39 ret = cio_disable_subchannel(sch); 40 if (ret != -EBUSY) 41 goto out_unlock; 42 43 do { 44 iretry = 255; 45 46 ret = cio_cancel_halt_clear(sch, &iretry); 47 while (ret == -EBUSY) { 48 /* 49 * Flush all I/O and wait for 50 * cancel/halt/clear completion. 51 */ 52 private->completion = &completion; 53 spin_unlock_irq(sch->lock); 54 55 wait_for_completion_timeout(&completion, 3*HZ); 56 57 spin_lock_irq(sch->lock); 58 private->completion = NULL; 59 flush_workqueue(vfio_ccw_work_q); 60 ret = cio_cancel_halt_clear(sch, &iretry); 61 }; 62 63 ret = cio_disable_subchannel(sch); 64 } while (ret == -EBUSY); 65 out_unlock: 66 private->state = VFIO_CCW_STATE_NOT_OPER; 67 spin_unlock_irq(sch->lock); 68 return ret; 69 } 70 71 static void vfio_ccw_sch_io_todo(struct work_struct *work) 72 { 73 struct vfio_ccw_private *private; 74 struct irb *irb; 75 76 private = container_of(work, struct vfio_ccw_private, io_work); 77 irb = &private->irb; 78 79 if (scsw_is_solicited(&irb->scsw)) { 80 cp_update_scsw(&private->cp, &irb->scsw); 81 cp_free(&private->cp); 82 } 83 memcpy(private->io_region->irb_area, irb, sizeof(*irb)); 84 85 if (private->io_trigger) 86 eventfd_signal(private->io_trigger, 1); 87 88 if (private->mdev) 89 private->state = VFIO_CCW_STATE_IDLE; 90 } 91 92 /* 93 * Css driver callbacks 94 */ 95 static void vfio_ccw_sch_irq(struct subchannel *sch) 96 { 97 struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev); 98 99 inc_irq_stat(IRQIO_CIO); 100 vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT); 101 } 102 103 static int vfio_ccw_sch_probe(struct subchannel *sch) 104 { 105 struct pmcw *pmcw = &sch->schib.pmcw; 106 struct vfio_ccw_private *private; 107 int ret; 108 109 if (pmcw->qf) { 110 dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n", 111 dev_name(&sch->dev)); 112 return -ENODEV; 113 } 114 115 private = kzalloc(sizeof(*private), GFP_KERNEL | GFP_DMA); 116 if (!private) 117 return -ENOMEM; 118 119 private->io_region = kmem_cache_zalloc(vfio_ccw_io_region, 120 GFP_KERNEL | GFP_DMA); 121 if (!private->io_region) { 122 kfree(private); 123 return -ENOMEM; 124 } 125 126 private->sch = sch; 127 dev_set_drvdata(&sch->dev, private); 128 129 spin_lock_irq(sch->lock); 130 private->state = VFIO_CCW_STATE_NOT_OPER; 131 sch->isc = VFIO_CCW_ISC; 132 ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch); 133 spin_unlock_irq(sch->lock); 134 if (ret) 135 goto out_free; 136 137 INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo); 138 atomic_set(&private->avail, 1); 139 private->state = VFIO_CCW_STATE_STANDBY; 140 141 ret = vfio_ccw_mdev_reg(sch); 142 if (ret) 143 goto out_disable; 144 145 return 0; 146 147 out_disable: 148 cio_disable_subchannel(sch); 149 out_free: 150 dev_set_drvdata(&sch->dev, NULL); 151 kmem_cache_free(vfio_ccw_io_region, private->io_region); 152 kfree(private); 153 return ret; 154 } 155 156 static int vfio_ccw_sch_remove(struct subchannel *sch) 157 { 158 struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev); 159 160 vfio_ccw_sch_quiesce(sch); 161 162 vfio_ccw_mdev_unreg(sch); 163 164 dev_set_drvdata(&sch->dev, NULL); 165 166 kmem_cache_free(vfio_ccw_io_region, private->io_region); 167 kfree(private); 168 169 return 0; 170 } 171 172 static void vfio_ccw_sch_shutdown(struct subchannel *sch) 173 { 174 vfio_ccw_sch_quiesce(sch); 175 } 176 177 /** 178 * vfio_ccw_sch_event - process subchannel event 179 * @sch: subchannel 180 * @process: non-zero if function is called in process context 181 * 182 * An unspecified event occurred for this subchannel. Adjust data according 183 * to the current operational state of the subchannel. Return zero when the 184 * event has been handled sufficiently or -EAGAIN when this function should 185 * be called again in process context. 186 */ 187 static int vfio_ccw_sch_event(struct subchannel *sch, int process) 188 { 189 struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev); 190 unsigned long flags; 191 int rc = -EAGAIN; 192 193 spin_lock_irqsave(sch->lock, flags); 194 if (!device_is_registered(&sch->dev)) 195 goto out_unlock; 196 197 if (work_pending(&sch->todo_work)) 198 goto out_unlock; 199 200 if (cio_update_schib(sch)) { 201 vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER); 202 rc = 0; 203 goto out_unlock; 204 } 205 206 private = dev_get_drvdata(&sch->dev); 207 if (private->state == VFIO_CCW_STATE_NOT_OPER) { 208 private->state = private->mdev ? VFIO_CCW_STATE_IDLE : 209 VFIO_CCW_STATE_STANDBY; 210 } 211 rc = 0; 212 213 out_unlock: 214 spin_unlock_irqrestore(sch->lock, flags); 215 216 return rc; 217 } 218 219 static struct css_device_id vfio_ccw_sch_ids[] = { 220 { .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, }, 221 { /* end of list */ }, 222 }; 223 MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids); 224 225 static struct css_driver vfio_ccw_sch_driver = { 226 .drv = { 227 .name = "vfio_ccw", 228 .owner = THIS_MODULE, 229 }, 230 .subchannel_type = vfio_ccw_sch_ids, 231 .irq = vfio_ccw_sch_irq, 232 .probe = vfio_ccw_sch_probe, 233 .remove = vfio_ccw_sch_remove, 234 .shutdown = vfio_ccw_sch_shutdown, 235 .sch_event = vfio_ccw_sch_event, 236 }; 237 238 static int __init vfio_ccw_sch_init(void) 239 { 240 int ret; 241 242 vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw"); 243 if (!vfio_ccw_work_q) 244 return -ENOMEM; 245 246 vfio_ccw_io_region = kmem_cache_create_usercopy("vfio_ccw_io_region", 247 sizeof(struct ccw_io_region), 0, 248 SLAB_ACCOUNT, 0, 249 sizeof(struct ccw_io_region), NULL); 250 if (!vfio_ccw_io_region) { 251 destroy_workqueue(vfio_ccw_work_q); 252 return -ENOMEM; 253 } 254 255 isc_register(VFIO_CCW_ISC); 256 ret = css_driver_register(&vfio_ccw_sch_driver); 257 if (ret) { 258 isc_unregister(VFIO_CCW_ISC); 259 kmem_cache_destroy(vfio_ccw_io_region); 260 destroy_workqueue(vfio_ccw_work_q); 261 } 262 263 return ret; 264 } 265 266 static void __exit vfio_ccw_sch_exit(void) 267 { 268 css_driver_unregister(&vfio_ccw_sch_driver); 269 isc_unregister(VFIO_CCW_ISC); 270 kmem_cache_destroy(vfio_ccw_io_region); 271 destroy_workqueue(vfio_ccw_work_q); 272 } 273 module_init(vfio_ccw_sch_init); 274 module_exit(vfio_ccw_sch_exit); 275 276 MODULE_LICENSE("GPL v2"); 277