| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * PCI Backend Operations - respond to PCI requests from Frontend |
| * |
| * Author: Ryan Wilson <hap9@epoch.ncsc.mil> |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/moduleparam.h> |
| #include <linux/wait.h> |
| #include <linux/bitops.h> |
| #include <xen/events.h> |
| #include <linux/sched.h> |
| #include "pciback.h" |
| |
| int verbose_request; |
| module_param(verbose_request, int, 0644); |
| |
| static irqreturn_t xen_pcibk_guest_interrupt(int irq, void *dev_id); |
| |
| /* Ensure a device is has the fake IRQ handler "turned on/off" and is |
| * ready to be exported. This MUST be run after xen_pcibk_reset_device |
| * which does the actual PCI device enable/disable. |
| */ |
| static void xen_pcibk_control_isr(struct pci_dev *dev, int reset) |
| { |
| struct xen_pcibk_dev_data *dev_data; |
| int rc; |
| int enable = 0; |
| |
| dev_data = pci_get_drvdata(dev); |
| if (!dev_data) |
| return; |
| |
| /* We don't deal with bridges */ |
| if (dev->hdr_type != PCI_HEADER_TYPE_NORMAL) |
| return; |
| |
| if (reset) { |
| dev_data->enable_intx = 0; |
| dev_data->ack_intr = 0; |
| } |
| enable = dev_data->enable_intx; |
| |
| /* Asked to disable, but ISR isn't runnig */ |
| if (!enable && !dev_data->isr_on) |
| return; |
| |
| /* Squirrel away the IRQs in the dev_data. We need this |
| * b/c when device transitions to MSI, the dev->irq is |
| * overwritten with the MSI vector. |
| */ |
| if (enable) |
| dev_data->irq = dev->irq; |
| |
| /* |
| * SR-IOV devices in all use MSI-X and have no legacy |
| * interrupts, so inhibit creating a fake IRQ handler for them. |
| */ |
| if (dev_data->irq == 0) |
| goto out; |
| |
| dev_dbg(&dev->dev, "%s: #%d %s %s%s %s-> %s\n", |
| dev_data->irq_name, |
| dev_data->irq, |
| pci_is_enabled(dev) ? "on" : "off", |
| dev->msi_enabled ? "MSI" : "", |
| dev->msix_enabled ? "MSI/X" : "", |
| dev_data->isr_on ? "enable" : "disable", |
| enable ? "enable" : "disable"); |
| |
| if (enable) { |
| /* |
| * The MSI or MSI-X should not have an IRQ handler. Otherwise |
| * if the guest terminates we BUG_ON in free_msi_irqs. |
| */ |
| if (dev->msi_enabled || dev->msix_enabled) |
| goto out; |
| |
| rc = request_irq(dev_data->irq, |
| xen_pcibk_guest_interrupt, IRQF_SHARED, |
| dev_data->irq_name, dev); |
| if (rc) { |
| dev_err(&dev->dev, "%s: failed to install fake IRQ " \ |
| "handler for IRQ %d! (rc:%d)\n", |
| dev_data->irq_name, dev_data->irq, rc); |
| goto out; |
| } |
| } else { |
| free_irq(dev_data->irq, dev); |
| dev_data->irq = 0; |
| } |
| dev_data->isr_on = enable; |
| dev_data->ack_intr = enable; |
| out: |
| dev_dbg(&dev->dev, "%s: #%d %s %s%s %s\n", |
| dev_data->irq_name, |
| dev_data->irq, |
| pci_is_enabled(dev) ? "on" : "off", |
| dev->msi_enabled ? "MSI" : "", |
| dev->msix_enabled ? "MSI/X" : "", |
| enable ? (dev_data->isr_on ? "enabled" : "failed to enable") : |
| (dev_data->isr_on ? "failed to disable" : "disabled")); |
| } |
| |
| /* Ensure a device is "turned off" and ready to be exported. |
| * (Also see xen_pcibk_config_reset to ensure virtual configuration space is |
| * ready to be re-exported) |
| */ |
| void xen_pcibk_reset_device(struct pci_dev *dev) |
| { |
| u16 cmd; |
| |
| xen_pcibk_control_isr(dev, 1 /* reset device */); |
| |
| /* Disable devices (but not bridges) */ |
| if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL) { |
| #ifdef CONFIG_PCI_MSI |
| /* The guest could have been abruptly killed without |
| * disabling MSI/MSI-X interrupts.*/ |
| if (dev->msix_enabled) |
| pci_disable_msix(dev); |
| if (dev->msi_enabled) |
| pci_disable_msi(dev); |
| #endif |
| if (pci_is_enabled(dev)) |
| pci_disable_device(dev); |
| |
| dev->is_busmaster = 0; |
| } else { |
| pci_read_config_word(dev, PCI_COMMAND, &cmd); |
| if (cmd & (PCI_COMMAND_INVALIDATE)) { |
| cmd &= ~(PCI_COMMAND_INVALIDATE); |
| pci_write_config_word(dev, PCI_COMMAND, cmd); |
| |
| dev->is_busmaster = 0; |
| } |
| } |
| } |
| |
| #ifdef CONFIG_PCI_MSI |
| static |
| int xen_pcibk_enable_msi(struct xen_pcibk_device *pdev, |
| struct pci_dev *dev, struct xen_pci_op *op) |
| { |
| struct xen_pcibk_dev_data *dev_data; |
| int status; |
| |
| if (unlikely(verbose_request)) |
| printk(KERN_DEBUG DRV_NAME ": %s: enable MSI\n", pci_name(dev)); |
| |
| if (dev->msi_enabled) |
| status = -EALREADY; |
| else if (dev->msix_enabled) |
| status = -ENXIO; |
| else |
| status = pci_enable_msi(dev); |
| |
| if (status) { |
| pr_warn_ratelimited("%s: error enabling MSI for guest %u: err %d\n", |
| pci_name(dev), pdev->xdev->otherend_id, |
| status); |
| op->value = 0; |
| return XEN_PCI_ERR_op_failed; |
| } |
| |
| /* The value the guest needs is actually the IDT vector, not the |
| * the local domain's IRQ number. */ |
| |
| op->value = dev->irq ? xen_pirq_from_irq(dev->irq) : 0; |
| if (unlikely(verbose_request)) |
| printk(KERN_DEBUG DRV_NAME ": %s: MSI: %d\n", pci_name(dev), |
| op->value); |
| |
| dev_data = pci_get_drvdata(dev); |
| if (dev_data) |
| dev_data->ack_intr = 0; |
| |
| return 0; |
| } |
| |
| static |
| int xen_pcibk_disable_msi(struct xen_pcibk_device *pdev, |
| struct pci_dev *dev, struct xen_pci_op *op) |
| { |
| if (unlikely(verbose_request)) |
| printk(KERN_DEBUG DRV_NAME ": %s: disable MSI\n", |
| pci_name(dev)); |
| |
| if (dev->msi_enabled) { |
| struct xen_pcibk_dev_data *dev_data; |
| |
| pci_disable_msi(dev); |
| |
| dev_data = pci_get_drvdata(dev); |
| if (dev_data) |
| dev_data->ack_intr = 1; |
| } |
| op->value = dev->irq ? xen_pirq_from_irq(dev->irq) : 0; |
| if (unlikely(verbose_request)) |
| printk(KERN_DEBUG DRV_NAME ": %s: MSI: %d\n", pci_name(dev), |
| op->value); |
| return 0; |
| } |
| |
| static |
| int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev, |
| struct pci_dev *dev, struct xen_pci_op *op) |
| { |
| struct xen_pcibk_dev_data *dev_data; |
| int i, result; |
| struct msix_entry *entries; |
| u16 cmd; |
| |
| if (unlikely(verbose_request)) |
| printk(KERN_DEBUG DRV_NAME ": %s: enable MSI-X\n", |
| pci_name(dev)); |
| |
| if (op->value > SH_INFO_MAX_VEC) |
| return -EINVAL; |
| |
| if (dev->msix_enabled) |
| return -EALREADY; |
| |
| /* |
| * PCI_COMMAND_MEMORY must be enabled, otherwise we may not be able |
| * to access the BARs where the MSI-X entries reside. |
| * But VF devices are unique in which the PF needs to be checked. |
| */ |
| pci_read_config_word(pci_physfn(dev), PCI_COMMAND, &cmd); |
| if (dev->msi_enabled || !(cmd & PCI_COMMAND_MEMORY)) |
| return -ENXIO; |
| |
| entries = kmalloc_array(op->value, sizeof(*entries), GFP_KERNEL); |
| if (entries == NULL) |
| return -ENOMEM; |
| |
| for (i = 0; i < op->value; i++) { |
| entries[i].entry = op->msix_entries[i].entry; |
| entries[i].vector = op->msix_entries[i].vector; |
| } |
| |
| result = pci_enable_msix_exact(dev, entries, op->value); |
| if (result == 0) { |
| for (i = 0; i < op->value; i++) { |
| op->msix_entries[i].entry = entries[i].entry; |
| if (entries[i].vector) { |
| op->msix_entries[i].vector = |
| xen_pirq_from_irq(entries[i].vector); |
| if (unlikely(verbose_request)) |
| printk(KERN_DEBUG DRV_NAME ": %s: " \ |
| "MSI-X[%d]: %d\n", |
| pci_name(dev), i, |
| op->msix_entries[i].vector); |
| } |
| } |
| } else |
| pr_warn_ratelimited("%s: error enabling MSI-X for guest %u: err %d!\n", |
| pci_name(dev), pdev->xdev->otherend_id, |
| result); |
| kfree(entries); |
| |
| op->value = result; |
| dev_data = pci_get_drvdata(dev); |
| if (dev_data) |
| dev_data->ack_intr = 0; |
| |
| return result > 0 ? 0 : result; |
| } |
| |
| static |
| int xen_pcibk_disable_msix(struct xen_pcibk_device *pdev, |
| struct pci_dev *dev, struct xen_pci_op *op) |
| { |
| if (unlikely(verbose_request)) |
| printk(KERN_DEBUG DRV_NAME ": %s: disable MSI-X\n", |
| pci_name(dev)); |
| |
| if (dev->msix_enabled) { |
| struct xen_pcibk_dev_data *dev_data; |
| |
| pci_disable_msix(dev); |
| |
| dev_data = pci_get_drvdata(dev); |
| if (dev_data) |
| dev_data->ack_intr = 1; |
| } |
| /* |
| * SR-IOV devices (which don't have any legacy IRQ) have |
| * an undefined IRQ value of zero. |
| */ |
| op->value = dev->irq ? xen_pirq_from_irq(dev->irq) : 0; |
| if (unlikely(verbose_request)) |
| printk(KERN_DEBUG DRV_NAME ": %s: MSI-X: %d\n", |
| pci_name(dev), op->value); |
| return 0; |
| } |
| #endif |
| /* |
| * Now the same evtchn is used for both pcifront conf_read_write request |
| * as well as pcie aer front end ack. We use a new work_queue to schedule |
| * xen_pcibk conf_read_write service for avoiding confict with aer_core |
| * do_recovery job which also use the system default work_queue |
| */ |
| void xen_pcibk_test_and_schedule_op(struct xen_pcibk_device *pdev) |
| { |
| /* Check that frontend is requesting an operation and that we are not |
| * already processing a request */ |
| if (test_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags) |
| && !test_and_set_bit(_PDEVF_op_active, &pdev->flags)) { |
| schedule_work(&pdev->op_work); |
| } |
| /*_XEN_PCIB_active should have been cleared by pcifront. And also make |
| sure xen_pcibk is waiting for ack by checking _PCIB_op_pending*/ |
| if (!test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags) |
| && test_bit(_PCIB_op_pending, &pdev->flags)) { |
| wake_up(&xen_pcibk_aer_wait_queue); |
| } |
| } |
| |
| /* Performing the configuration space reads/writes must not be done in atomic |
| * context because some of the pci_* functions can sleep (mostly due to ACPI |
| * use of semaphores). This function is intended to be called from a work |
| * queue in process context taking a struct xen_pcibk_device as a parameter */ |
| |
| void xen_pcibk_do_op(struct work_struct *data) |
| { |
| struct xen_pcibk_device *pdev = |
| container_of(data, struct xen_pcibk_device, op_work); |
| struct pci_dev *dev; |
| struct xen_pcibk_dev_data *dev_data = NULL; |
| struct xen_pci_op *op = &pdev->op; |
| int test_intx = 0; |
| #ifdef CONFIG_PCI_MSI |
| unsigned int nr = 0; |
| #endif |
| |
| *op = pdev->sh_info->op; |
| barrier(); |
| dev = xen_pcibk_get_pci_dev(pdev, op->domain, op->bus, op->devfn); |
| |
| if (dev == NULL) |
| op->err = XEN_PCI_ERR_dev_not_found; |
| else { |
| dev_data = pci_get_drvdata(dev); |
| if (dev_data) |
| test_intx = dev_data->enable_intx; |
| switch (op->cmd) { |
| case XEN_PCI_OP_conf_read: |
| op->err = xen_pcibk_config_read(dev, |
| op->offset, op->size, &op->value); |
| break; |
| case XEN_PCI_OP_conf_write: |
| op->err = xen_pcibk_config_write(dev, |
| op->offset, op->size, op->value); |
| break; |
| #ifdef CONFIG_PCI_MSI |
| case XEN_PCI_OP_enable_msi: |
| op->err = xen_pcibk_enable_msi(pdev, dev, op); |
| break; |
| case XEN_PCI_OP_disable_msi: |
| op->err = xen_pcibk_disable_msi(pdev, dev, op); |
| break; |
| case XEN_PCI_OP_enable_msix: |
| nr = op->value; |
| op->err = xen_pcibk_enable_msix(pdev, dev, op); |
| break; |
| case XEN_PCI_OP_disable_msix: |
| op->err = xen_pcibk_disable_msix(pdev, dev, op); |
| break; |
| #endif |
| default: |
| op->err = XEN_PCI_ERR_not_implemented; |
| break; |
| } |
| } |
| if (!op->err && dev && dev_data) { |
| /* Transition detected */ |
| if ((dev_data->enable_intx != test_intx)) |
| xen_pcibk_control_isr(dev, 0 /* no reset */); |
| } |
| pdev->sh_info->op.err = op->err; |
| pdev->sh_info->op.value = op->value; |
| #ifdef CONFIG_PCI_MSI |
| if (op->cmd == XEN_PCI_OP_enable_msix && op->err == 0) { |
| unsigned int i; |
| |
| for (i = 0; i < nr; i++) |
| pdev->sh_info->op.msix_entries[i].vector = |
| op->msix_entries[i].vector; |
| } |
| #endif |
| /* Tell the driver domain that we're done. */ |
| wmb(); |
| clear_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags); |
| notify_remote_via_irq(pdev->evtchn_irq); |
| |
| /* Mark that we're done. */ |
| smp_mb__before_atomic(); /* /after/ clearing PCIF_active */ |
| clear_bit(_PDEVF_op_active, &pdev->flags); |
| smp_mb__after_atomic(); /* /before/ final check for work */ |
| |
| /* Check to see if the driver domain tried to start another request in |
| * between clearing _XEN_PCIF_active and clearing _PDEVF_op_active. |
| */ |
| xen_pcibk_test_and_schedule_op(pdev); |
| } |
| |
| irqreturn_t xen_pcibk_handle_event(int irq, void *dev_id) |
| { |
| struct xen_pcibk_device *pdev = dev_id; |
| |
| xen_pcibk_test_and_schedule_op(pdev); |
| |
| return IRQ_HANDLED; |
| } |
| static irqreturn_t xen_pcibk_guest_interrupt(int irq, void *dev_id) |
| { |
| struct pci_dev *dev = (struct pci_dev *)dev_id; |
| struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev); |
| |
| if (dev_data->isr_on && dev_data->ack_intr) { |
| dev_data->handled++; |
| if ((dev_data->handled % 1000) == 0) { |
| if (xen_test_irq_shared(irq)) { |
| pr_info("%s IRQ line is not shared " |
| "with other domains. Turning ISR off\n", |
| dev_data->irq_name); |
| dev_data->ack_intr = 0; |
| } |
| } |
| return IRQ_HANDLED; |
| } |
| return IRQ_NONE; |
| } |