drivers/xen/xen-pciback/pciback_ops.c

   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;
 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 }