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