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
   7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   8
   9 #include <linux/module.h>
  10 #include <linux/wait.h>
  11 #include <linux/bitops.h>
  12 #include <xen/events.h>
  13 #include <linux/sched.h>
  14 #include "pciback.h"
  15
  16 int verbose_request;
  17 module_param(verbose_request, int, 0644);
  18
  19 static irqreturn_t xen_pcibk_guest_interrupt(int irq, void *dev_id);
  20
  21 /* Ensure a device is has the fake IRQ handler "turned on/off" and is
  22  * ready to be exported. This MUST be run after xen_pcibk_reset_device
  23  * which does the actual PCI device enable/disable.
  24  */
  25 static void xen_pcibk_control_isr(struct pci_dev *dev, int reset)
  26 {
  27         struct xen_pcibk_dev_data *dev_data;
  28         int rc;
  29         int enable = 0;
  30
  31         dev_data = pci_get_drvdata(dev);
  32         if (!dev_data)
  33                 return;
  34
  35         /* We don't deal with bridges */
  36         if (dev->hdr_type != PCI_HEADER_TYPE_NORMAL)
  37                 return;
  38
  39         if (reset) {
  40                 dev_data->enable_intx = 0;
  41                 dev_data->ack_intr = 0;
  42         }
  43         enable =  dev_data->enable_intx;
  44
  45         /* Asked to disable, but ISR isn't runnig */
  46         if (!enable && !dev_data->isr_on)
  47                 return;
  48
  49         /* Squirrel away the IRQs in the dev_data. We need this
  50          * b/c when device transitions to MSI, the dev->irq is
  51          * overwritten with the MSI vector.
  52          */
  53         if (enable)
  54                 dev_data->irq = dev->irq;
  55
  56         /*
  57          * SR-IOV devices in all use MSI-X and have no legacy
  58          * interrupts, so inhibit creating a fake IRQ handler for them.
  59          */
  60         if (dev_data->irq == 0)
  61                 goto out;
  62
  63         dev_dbg(&dev->dev, "%s: #%d %s %s%s %s-> %s\n",
  64                 dev_data->irq_name,
  65                 dev_data->irq,
  66                 pci_is_enabled(dev) ? "on" : "off",
  67                 dev->msi_enabled ? "MSI" : "",
  68                 dev->msix_enabled ? "MSI/X" : "",
  69                 dev_data->isr_on ? "enable" : "disable",
  70                 enable ? "enable" : "disable");
  71
  72         if (enable) {
  73                 rc = request_irq(dev_data->irq,
  74                                 xen_pcibk_guest_interrupt, IRQF_SHARED,
  75                                 dev_data->irq_name, dev);
  76                 if (rc) {
  77                         dev_err(&dev->dev, "%s: failed to install fake IRQ " \
  78                                 "handler for IRQ %d! (rc:%d)\n",
  79                                 dev_data->irq_name, dev_data->irq, rc);
  80                         goto out;
  81                 }
  82         } else {
  83                 free_irq(dev_data->irq, dev);
  84                 dev_data->irq = 0;
  85         }
  86         dev_data->isr_on = enable;
  87         dev_data->ack_intr = enable;
  88 out:
  89         dev_dbg(&dev->dev, "%s: #%d %s %s%s %s\n",
  90                 dev_data->irq_name,
  91                 dev_data->irq,
  92                 pci_is_enabled(dev) ? "on" : "off",
  93                 dev->msi_enabled ? "MSI" : "",
  94                 dev->msix_enabled ? "MSI/X" : "",
  95                 enable ? (dev_data->isr_on ? "enabled" : "failed to enable") :
  96                         (dev_data->isr_on ? "failed to disable" : "disabled"));
  97 }
  98
  99 /* Ensure a device is "turned off" and ready to be exported.
 100  * (Also see xen_pcibk_config_reset to ensure virtual configuration space is
 101  * ready to be re-exported)
 102  */
 103 void xen_pcibk_reset_device(struct pci_dev *dev)
 104 {
 105         u16 cmd;
 106
 107         xen_pcibk_control_isr(dev, 1 /* reset device */);
 108
 109         /* Disable devices (but not bridges) */
 110         if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL) {
 111 #ifdef CONFIG_PCI_MSI
 112                 /* The guest could have been abruptly killed without
 113                  * disabling MSI/MSI-X interrupts.*/
 114                 if (dev->msix_enabled)
 115                         pci_disable_msix(dev);
 116                 if (dev->msi_enabled)
 117                         pci_disable_msi(dev);
 118 #endif
 119                 if (pci_is_enabled(dev))
 120                         pci_disable_device(dev);
 121
 122                 pci_write_config_word(dev, PCI_COMMAND, 0);
 123
 124                 dev->is_busmaster = 0;
 125         } else {
 126                 pci_read_config_word(dev, PCI_COMMAND, &cmd);
 127                 if (cmd & (PCI_COMMAND_INVALIDATE)) {
 128                         cmd &= ~(PCI_COMMAND_INVALIDATE);
 129                         pci_write_config_word(dev, PCI_COMMAND, cmd);
 130
 131                         dev->is_busmaster = 0;
 132                 }
 133         }
 134 }
 135
 136 #ifdef CONFIG_PCI_MSI
 137 static
 138 int xen_pcibk_enable_msi(struct xen_pcibk_device *pdev,
 139                          struct pci_dev *dev, struct xen_pci_op *op)
 140 {
 141         struct xen_pcibk_dev_data *dev_data;
 142         int status;
 143
 144         if (unlikely(verbose_request))
 145                 printk(KERN_DEBUG DRV_NAME ": %s: enable MSI\n", pci_name(dev));
 146
 147         status = pci_enable_msi(dev);
 148
 149         if (status) {
 150                 pr_warn_ratelimited("%s: error enabling MSI for guest %u: err %d\n",
 151                                     pci_name(dev), pdev->xdev->otherend_id,
 152                                     status);
 153                 op->value = 0;
 154                 return XEN_PCI_ERR_op_failed;
 155         }
 156
 157         /* The value the guest needs is actually the IDT vector, not the
 158          * the local domain's IRQ number. */
 159
 160         op->value = dev->irq ? xen_pirq_from_irq(dev->irq) : 0;
 161         if (unlikely(verbose_request))
 162                 printk(KERN_DEBUG DRV_NAME ": %s: MSI: %d\n", pci_name(dev),
 163                         op->value);
 164
 165         dev_data = pci_get_drvdata(dev);
 166         if (dev_data)
 167                 dev_data->ack_intr = 0;
 168
 169         return 0;
 170 }
 171
 172 static
 173 int xen_pcibk_disable_msi(struct xen_pcibk_device *pdev,
 174                           struct pci_dev *dev, struct xen_pci_op *op)
 175 {
 176         struct xen_pcibk_dev_data *dev_data;
 177
 178         if (unlikely(verbose_request))
 179                 printk(KERN_DEBUG DRV_NAME ": %s: disable MSI\n",
 180                        pci_name(dev));
 181         pci_disable_msi(dev);
 182
 183         op->value = dev->irq ? xen_pirq_from_irq(dev->irq) : 0;
 184         if (unlikely(verbose_request))
 185                 printk(KERN_DEBUG DRV_NAME ": %s: MSI: %d\n", pci_name(dev),
 186                         op->value);
 187         dev_data = pci_get_drvdata(dev);
 188         if (dev_data)
 189                 dev_data->ack_intr = 1;
 190         return 0;
 191 }
 192
 193 static
 194 int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev,
 195                           struct pci_dev *dev, struct xen_pci_op *op)
 196 {
 197         struct xen_pcibk_dev_data *dev_data;
 198         int i, result;
 199         struct msix_entry *entries;
 200
 201         if (unlikely(verbose_request))
 202                 printk(KERN_DEBUG DRV_NAME ": %s: enable MSI-X\n",
 203                        pci_name(dev));
 204         if (op->value > SH_INFO_MAX_VEC)
 205                 return -EINVAL;
 206
 207         entries = kmalloc(op->value * sizeof(*entries), GFP_KERNEL);
 208         if (entries == NULL)
 209                 return -ENOMEM;
 210
 211         for (i = 0; i < op->value; i++) {
 212                 entries[i].entry = op->msix_entries[i].entry;
 213                 entries[i].vector = op->msix_entries[i].vector;
 214         }
 215
 216         result = pci_enable_msix(dev, entries, op->value);
 217
 218         if (result == 0) {
 219                 for (i = 0; i < op->value; i++) {
 220                         op->msix_entries[i].entry = entries[i].entry;
 221                         if (entries[i].vector)
 222                                 op->msix_entries[i].vector =
 223                                         xen_pirq_from_irq(entries[i].vector);
 224                                 if (unlikely(verbose_request))
 225                                         printk(KERN_DEBUG DRV_NAME ": %s: " \
 226                                                 "MSI-X[%d]: %d\n",
 227                                                 pci_name(dev), i,
 228                                                 op->msix_entries[i].vector);
 229                 }
 230         } else
 231                 pr_warn_ratelimited("%s: error enabling MSI-X for guest %u: err %d!\n",
 232                                     pci_name(dev), pdev->xdev->otherend_id,
 233                                     result);
 234         kfree(entries);
 235
 236         op->value = result;
 237         dev_data = pci_get_drvdata(dev);
 238         if (dev_data)
 239                 dev_data->ack_intr = 0;
 240
 241         return result > 0 ? 0 : result;
 242 }
 243
 244 static
 245 int xen_pcibk_disable_msix(struct xen_pcibk_device *pdev,
 246                            struct pci_dev *dev, struct xen_pci_op *op)
 247 {
 248         struct xen_pcibk_dev_data *dev_data;
 249         if (unlikely(verbose_request))
 250                 printk(KERN_DEBUG DRV_NAME ": %s: disable MSI-X\n",
 251                         pci_name(dev));
 252         pci_disable_msix(dev);
 253
 254         /*
 255          * SR-IOV devices (which don't have any legacy IRQ) have
 256          * an undefined IRQ value of zero.
 257          */
 258         op->value = dev->irq ? xen_pirq_from_irq(dev->irq) : 0;
 259         if (unlikely(verbose_request))
 260                 printk(KERN_DEBUG DRV_NAME ": %s: MSI-X: %d\n", pci_name(dev),
 261                         op->value);
 262         dev_data = pci_get_drvdata(dev);
 263         if (dev_data)
 264                 dev_data->ack_intr = 1;
 265         return 0;
 266 }
 267 #endif
 268 /*
 269 * Now the same evtchn is used for both pcifront conf_read_write request
 270 * as well as pcie aer front end ack. We use a new work_queue to schedule
 271 * xen_pcibk conf_read_write service for avoiding confict with aer_core
 272 * do_recovery job which also use the system default work_queue
 273 */
 274 void xen_pcibk_test_and_schedule_op(struct xen_pcibk_device *pdev)
 275 {
 276         /* Check that frontend is requesting an operation and that we are not
 277          * already processing a request */
 278         if (test_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags)
 279             && !test_and_set_bit(_PDEVF_op_active, &pdev->flags)) {
 280                 queue_work(xen_pcibk_wq, &pdev->op_work);
 281         }
 282         /*_XEN_PCIB_active should have been cleared by pcifront. And also make
 283         sure xen_pcibk is waiting for ack by checking _PCIB_op_pending*/
 284         if (!test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
 285             && test_bit(_PCIB_op_pending, &pdev->flags)) {
 286                 wake_up(&xen_pcibk_aer_wait_queue);
 287         }
 288 }
 289
 290 /* Performing the configuration space reads/writes must not be done in atomic
 291  * context because some of the pci_* functions can sleep (mostly due to ACPI
 292  * use of semaphores). This function is intended to be called from a work
 293  * queue in process context taking a struct xen_pcibk_device as a parameter */
 294
 295 void xen_pcibk_do_op(struct work_struct *data)
 296 {
 297         struct xen_pcibk_device *pdev =
 298                 container_of(data, struct xen_pcibk_device, op_work);
 299         struct pci_dev *dev;
 300         struct xen_pcibk_dev_data *dev_data = NULL;
 301         struct xen_pci_op *op = &pdev->sh_info->op;
 302         int test_intx = 0;
 303
 304         dev = xen_pcibk_get_pci_dev(pdev, op->domain, op->bus, op->devfn);
 305
 306         if (dev == NULL)
 307                 op->err = XEN_PCI_ERR_dev_not_found;
 308         else {
 309                 dev_data = pci_get_drvdata(dev);
 310                 if (dev_data)
 311                         test_intx = dev_data->enable_intx;
 312                 switch (op->cmd) {
 313                 case XEN_PCI_OP_conf_read:
 314                         op->err = xen_pcibk_config_read(dev,
 315                                   op->offset, op->size, &op->value);
 316                         break;
 317                 case XEN_PCI_OP_conf_write:
 318                         op->err = xen_pcibk_config_write(dev,
 319                                   op->offset, op->size, op->value);
 320                         break;
 321 #ifdef CONFIG_PCI_MSI
 322                 case XEN_PCI_OP_enable_msi:
 323                         op->err = xen_pcibk_enable_msi(pdev, dev, op);
 324                         break;
 325                 case XEN_PCI_OP_disable_msi:
 326                         op->err = xen_pcibk_disable_msi(pdev, dev, op);
 327                         break;
 328                 case XEN_PCI_OP_enable_msix:
 329                         op->err = xen_pcibk_enable_msix(pdev, dev, op);
 330                         break;
 331                 case XEN_PCI_OP_disable_msix:
 332                         op->err = xen_pcibk_disable_msix(pdev, dev, op);
 333                         break;
 334 #endif
 335                 default:
 336                         op->err = XEN_PCI_ERR_not_implemented;
 337                         break;
 338                 }
 339         }
 340         if (!op->err && dev && dev_data) {
 341                 /* Transition detected */
 342                 if ((dev_data->enable_intx != test_intx))
 343                         xen_pcibk_control_isr(dev, 0 /* no reset */);
 344         }
 345         /* Tell the driver domain that we're done. */
 346         wmb();
 347         clear_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
 348         notify_remote_via_irq(pdev->evtchn_irq);
 349
 350         /* Mark that we're done. */
 351         smp_mb__before_clear_bit(); /* /after/ clearing PCIF_active */
 352         clear_bit(_PDEVF_op_active, &pdev->flags);
 353         smp_mb__after_clear_bit(); /* /before/ final check for work */
 354
 355         /* Check to see if the driver domain tried to start another request in
 356          * between clearing _XEN_PCIF_active and clearing _PDEVF_op_active.
 357         */
 358         xen_pcibk_test_and_schedule_op(pdev);
 359 }
 360
 361 irqreturn_t xen_pcibk_handle_event(int irq, void *dev_id)
 362 {
 363         struct xen_pcibk_device *pdev = dev_id;
 364
 365         xen_pcibk_test_and_schedule_op(pdev);
 366
 367         return IRQ_HANDLED;
 368 }
 369 static irqreturn_t xen_pcibk_guest_interrupt(int irq, void *dev_id)
 370 {
 371         struct pci_dev *dev = (struct pci_dev *)dev_id;
 372         struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
 373
 374         if (dev_data->isr_on && dev_data->ack_intr) {
 375                 dev_data->handled++;
 376                 if ((dev_data->handled % 1000) == 0) {
 377                         if (xen_test_irq_shared(irq)) {
 378                                 pr_info("%s IRQ line is not shared "
 379                                         "with other domains. Turning ISR off\n",
 380                                          dev_data->irq_name);
 381                                 dev_data->ack_intr = 0;
 382                         }
 383                 }
 384                 return IRQ_HANDLED;
 385         }
 386         return IRQ_NONE;
 387 }