1 /* 2 * PCI Backend Operations - respond to PCI requests from Frontend 3 * 4 * Author: Ryan Wilson <hap9@epoch.ncsc.mil> 5 */ 6 #include <linux/module.h> 7 #include <linux/wait.h> 8 #include <linux/bitops.h> 9 #include <xen/events.h> 10 #include <linux/sched.h> 11 #include "pciback.h" 12 13 int verbose_request; 14 module_param(verbose_request, int, 0644); 15 16 static irqreturn_t xen_pcibk_guest_interrupt(int irq, void *dev_id); 17 18 /* Ensure a device is has the fake IRQ handler "turned on/off" and is 19 * ready to be exported. This MUST be run after xen_pcibk_reset_device 20 * which does the actual PCI device enable/disable. 21 */ 22 static void xen_pcibk_control_isr(struct pci_dev *dev, int reset) 23 { 24 struct xen_pcibk_dev_data *dev_data; 25 int rc; 26 int enable = 0; 27 28 dev_data = pci_get_drvdata(dev); 29 if (!dev_data) 30 return; 31 32 /* We don't deal with bridges */ 33 if (dev->hdr_type != PCI_HEADER_TYPE_NORMAL) 34 return; 35 36 if (reset) { 37 dev_data->enable_intx = 0; 38 dev_data->ack_intr = 0; 39 } 40 enable = dev_data->enable_intx; 41 42 /* Asked to disable, but ISR isn't runnig */ 43 if (!enable && !dev_data->isr_on) 44 return; 45 46 /* Squirrel away the IRQs in the dev_data. We need this 47 * b/c when device transitions to MSI, the dev->irq is 48 * overwritten with the MSI vector. 49 */ 50 if (enable) 51 dev_data->irq = dev->irq; 52 53 /* 54 * SR-IOV devices in all use MSI-X and have no legacy 55 * interrupts, so inhibit creating a fake IRQ handler for them. 56 */ 57 if (dev_data->irq == 0) 58 goto out; 59 60 dev_dbg(&dev->dev, "%s: #%d %s %s%s %s-> %s\n", 61 dev_data->irq_name, 62 dev_data->irq, 63 pci_is_enabled(dev) ? "on" : "off", 64 dev->msi_enabled ? "MSI" : "", 65 dev->msix_enabled ? "MSI/X" : "", 66 dev_data->isr_on ? "enable" : "disable", 67 enable ? "enable" : "disable"); 68 69 if (enable) { 70 rc = request_irq(dev_data->irq, 71 xen_pcibk_guest_interrupt, IRQF_SHARED, 72 dev_data->irq_name, dev); 73 if (rc) { 74 dev_err(&dev->dev, "%s: failed to install fake IRQ " \ 75 "handler for IRQ %d! (rc:%d)\n", 76 dev_data->irq_name, dev_data->irq, rc); 77 goto out; 78 } 79 } else { 80 free_irq(dev_data->irq, dev); 81 dev_data->irq = 0; 82 } 83 dev_data->isr_on = enable; 84 dev_data->ack_intr = enable; 85 out: 86 dev_dbg(&dev->dev, "%s: #%d %s %s%s %s\n", 87 dev_data->irq_name, 88 dev_data->irq, 89 pci_is_enabled(dev) ? "on" : "off", 90 dev->msi_enabled ? "MSI" : "", 91 dev->msix_enabled ? "MSI/X" : "", 92 enable ? (dev_data->isr_on ? "enabled" : "failed to enable") : 93 (dev_data->isr_on ? "failed to disable" : "disabled")); 94 } 95 96 /* Ensure a device is "turned off" and ready to be exported. 97 * (Also see xen_pcibk_config_reset to ensure virtual configuration space is 98 * ready to be re-exported) 99 */ 100 void xen_pcibk_reset_device(struct pci_dev *dev) 101 { 102 u16 cmd; 103 104 xen_pcibk_control_isr(dev, 1 /* reset device */); 105 106 /* Disable devices (but not bridges) */ 107 if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL) { 108 #ifdef CONFIG_PCI_MSI 109 /* The guest could have been abruptly killed without 110 * disabling MSI/MSI-X interrupts.*/ 111 if (dev->msix_enabled) 112 pci_disable_msix(dev); 113 if (dev->msi_enabled) 114 pci_disable_msi(dev); 115 #endif 116 pci_disable_device(dev); 117 118 pci_write_config_word(dev, PCI_COMMAND, 0); 119 120 dev->is_busmaster = 0; 121 } else { 122 pci_read_config_word(dev, PCI_COMMAND, &cmd); 123 if (cmd & (PCI_COMMAND_INVALIDATE)) { 124 cmd &= ~(PCI_COMMAND_INVALIDATE); 125 pci_write_config_word(dev, PCI_COMMAND, cmd); 126 127 dev->is_busmaster = 0; 128 } 129 } 130 } 131 132 #ifdef CONFIG_PCI_MSI 133 static 134 int xen_pcibk_enable_msi(struct xen_pcibk_device *pdev, 135 struct pci_dev *dev, struct xen_pci_op *op) 136 { 137 struct xen_pcibk_dev_data *dev_data; 138 int otherend = pdev->xdev->otherend_id; 139 int status; 140 141 if (unlikely(verbose_request)) 142 printk(KERN_DEBUG DRV_NAME ": %s: enable MSI\n", pci_name(dev)); 143 144 status = pci_enable_msi(dev); 145 146 if (status) { 147 printk(KERN_ERR "error enable msi for guest %x status %x\n", 148 otherend, status); 149 op->value = 0; 150 return XEN_PCI_ERR_op_failed; 151 } 152 153 /* The value the guest needs is actually the IDT vector, not the 154 * the local domain's IRQ number. */ 155 156 op->value = dev->irq ? xen_pirq_from_irq(dev->irq) : 0; 157 if (unlikely(verbose_request)) 158 printk(KERN_DEBUG DRV_NAME ": %s: MSI: %d\n", pci_name(dev), 159 op->value); 160 161 dev_data = pci_get_drvdata(dev); 162 if (dev_data) 163 dev_data->ack_intr = 0; 164 165 return 0; 166 } 167 168 static 169 int xen_pcibk_disable_msi(struct xen_pcibk_device *pdev, 170 struct pci_dev *dev, struct xen_pci_op *op) 171 { 172 struct xen_pcibk_dev_data *dev_data; 173 174 if (unlikely(verbose_request)) 175 printk(KERN_DEBUG DRV_NAME ": %s: disable MSI\n", 176 pci_name(dev)); 177 pci_disable_msi(dev); 178 179 op->value = dev->irq ? xen_pirq_from_irq(dev->irq) : 0; 180 if (unlikely(verbose_request)) 181 printk(KERN_DEBUG DRV_NAME ": %s: MSI: %d\n", pci_name(dev), 182 op->value); 183 dev_data = pci_get_drvdata(dev); 184 if (dev_data) 185 dev_data->ack_intr = 1; 186 return 0; 187 } 188 189 static 190 int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev, 191 struct pci_dev *dev, struct xen_pci_op *op) 192 { 193 struct xen_pcibk_dev_data *dev_data; 194 int i, result; 195 struct msix_entry *entries; 196 197 if (unlikely(verbose_request)) 198 printk(KERN_DEBUG DRV_NAME ": %s: enable MSI-X\n", 199 pci_name(dev)); 200 if (op->value > SH_INFO_MAX_VEC) 201 return -EINVAL; 202 203 entries = kmalloc(op->value * sizeof(*entries), GFP_KERNEL); 204 if (entries == NULL) 205 return -ENOMEM; 206 207 for (i = 0; i < op->value; i++) { 208 entries[i].entry = op->msix_entries[i].entry; 209 entries[i].vector = op->msix_entries[i].vector; 210 } 211 212 result = pci_enable_msix(dev, entries, op->value); 213 214 if (result == 0) { 215 for (i = 0; i < op->value; i++) { 216 op->msix_entries[i].entry = entries[i].entry; 217 if (entries[i].vector) 218 op->msix_entries[i].vector = 219 xen_pirq_from_irq(entries[i].vector); 220 if (unlikely(verbose_request)) 221 printk(KERN_DEBUG DRV_NAME ": %s: " \ 222 "MSI-X[%d]: %d\n", 223 pci_name(dev), i, 224 op->msix_entries[i].vector); 225 } 226 } else { 227 printk(KERN_WARNING DRV_NAME ": %s: failed to enable MSI-X: err %d!\n", 228 pci_name(dev), result); 229 } 230 kfree(entries); 231 232 op->value = result; 233 dev_data = pci_get_drvdata(dev); 234 if (dev_data) 235 dev_data->ack_intr = 0; 236 237 return result > 0 ? 0 : result; 238 } 239 240 static 241 int xen_pcibk_disable_msix(struct xen_pcibk_device *pdev, 242 struct pci_dev *dev, struct xen_pci_op *op) 243 { 244 struct xen_pcibk_dev_data *dev_data; 245 if (unlikely(verbose_request)) 246 printk(KERN_DEBUG DRV_NAME ": %s: disable MSI-X\n", 247 pci_name(dev)); 248 pci_disable_msix(dev); 249 250 /* 251 * SR-IOV devices (which don't have any legacy IRQ) have 252 * an undefined IRQ value of zero. 253 */ 254 op->value = dev->irq ? xen_pirq_from_irq(dev->irq) : 0; 255 if (unlikely(verbose_request)) 256 printk(KERN_DEBUG DRV_NAME ": %s: MSI-X: %d\n", pci_name(dev), 257 op->value); 258 dev_data = pci_get_drvdata(dev); 259 if (dev_data) 260 dev_data->ack_intr = 1; 261 return 0; 262 } 263 #endif 264 /* 265 * Now the same evtchn is used for both pcifront conf_read_write request 266 * as well as pcie aer front end ack. We use a new work_queue to schedule 267 * xen_pcibk conf_read_write service for avoiding confict with aer_core 268 * do_recovery job which also use the system default work_queue 269 */ 270 void xen_pcibk_test_and_schedule_op(struct xen_pcibk_device *pdev) 271 { 272 /* Check that frontend is requesting an operation and that we are not 273 * already processing a request */ 274 if (test_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags) 275 && !test_and_set_bit(_PDEVF_op_active, &pdev->flags)) { 276 queue_work(xen_pcibk_wq, &pdev->op_work); 277 } 278 /*_XEN_PCIB_active should have been cleared by pcifront. And also make 279 sure xen_pcibk is waiting for ack by checking _PCIB_op_pending*/ 280 if (!test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags) 281 && test_bit(_PCIB_op_pending, &pdev->flags)) { 282 wake_up(&xen_pcibk_aer_wait_queue); 283 } 284 } 285 286 /* Performing the configuration space reads/writes must not be done in atomic 287 * context because some of the pci_* functions can sleep (mostly due to ACPI 288 * use of semaphores). This function is intended to be called from a work 289 * queue in process context taking a struct xen_pcibk_device as a parameter */ 290 291 void xen_pcibk_do_op(struct work_struct *data) 292 { 293 struct xen_pcibk_device *pdev = 294 container_of(data, struct xen_pcibk_device, op_work); 295 struct pci_dev *dev; 296 struct xen_pcibk_dev_data *dev_data = NULL; 297 struct xen_pci_op *op = &pdev->sh_info->op; 298 int test_intx = 0; 299 300 dev = xen_pcibk_get_pci_dev(pdev, op->domain, op->bus, op->devfn); 301 302 if (dev == NULL) 303 op->err = XEN_PCI_ERR_dev_not_found; 304 else { 305 dev_data = pci_get_drvdata(dev); 306 if (dev_data) 307 test_intx = dev_data->enable_intx; 308 switch (op->cmd) { 309 case XEN_PCI_OP_conf_read: 310 op->err = xen_pcibk_config_read(dev, 311 op->offset, op->size, &op->value); 312 break; 313 case XEN_PCI_OP_conf_write: 314 op->err = xen_pcibk_config_write(dev, 315 op->offset, op->size, op->value); 316 break; 317 #ifdef CONFIG_PCI_MSI 318 case XEN_PCI_OP_enable_msi: 319 op->err = xen_pcibk_enable_msi(pdev, dev, op); 320 break; 321 case XEN_PCI_OP_disable_msi: 322 op->err = xen_pcibk_disable_msi(pdev, dev, op); 323 break; 324 case XEN_PCI_OP_enable_msix: 325 op->err = xen_pcibk_enable_msix(pdev, dev, op); 326 break; 327 case XEN_PCI_OP_disable_msix: 328 op->err = xen_pcibk_disable_msix(pdev, dev, op); 329 break; 330 #endif 331 default: 332 op->err = XEN_PCI_ERR_not_implemented; 333 break; 334 } 335 } 336 if (!op->err && dev && dev_data) { 337 /* Transition detected */ 338 if ((dev_data->enable_intx != test_intx)) 339 xen_pcibk_control_isr(dev, 0 /* no reset */); 340 } 341 /* Tell the driver domain that we're done. */ 342 wmb(); 343 clear_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags); 344 notify_remote_via_irq(pdev->evtchn_irq); 345 346 /* Mark that we're done. */ 347 smp_mb__before_clear_bit(); /* /after/ clearing PCIF_active */ 348 clear_bit(_PDEVF_op_active, &pdev->flags); 349 smp_mb__after_clear_bit(); /* /before/ final check for work */ 350 351 /* Check to see if the driver domain tried to start another request in 352 * between clearing _XEN_PCIF_active and clearing _PDEVF_op_active. 353 */ 354 xen_pcibk_test_and_schedule_op(pdev); 355 } 356 357 irqreturn_t xen_pcibk_handle_event(int irq, void *dev_id) 358 { 359 struct xen_pcibk_device *pdev = dev_id; 360 361 xen_pcibk_test_and_schedule_op(pdev); 362 363 return IRQ_HANDLED; 364 } 365 static irqreturn_t xen_pcibk_guest_interrupt(int irq, void *dev_id) 366 { 367 struct pci_dev *dev = (struct pci_dev *)dev_id; 368 struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev); 369 370 if (dev_data->isr_on && dev_data->ack_intr) { 371 dev_data->handled++; 372 if ((dev_data->handled % 1000) == 0) { 373 if (xen_test_irq_shared(irq)) { 374 printk(KERN_INFO "%s IRQ line is not shared " 375 "with other domains. Turning ISR off\n", 376 dev_data->irq_name); 377 dev_data->ack_intr = 0; 378 } 379 } 380 return IRQ_HANDLED; 381 } 382 return IRQ_NONE; 383 } 384