diff options
Diffstat (limited to 'drivers/xen/xen-pciback/pciback_ops.c')
| -rw-r--r-- | drivers/xen/xen-pciback/pciback_ops.c | 443 |
1 files changed, 443 insertions, 0 deletions
diff --git a/drivers/xen/xen-pciback/pciback_ops.c b/drivers/xen/xen-pciback/pciback_ops.c new file mode 100644 index 000000000..84e014490 --- /dev/null +++ b/drivers/xen/xen-pciback/pciback_ops.c @@ -0,0 +1,443 @@ +// 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 +#define dev_fmt pr_fmt + +#include <linux/moduleparam.h> +#include <linux/wait.h> +#include <linux/bitops.h> +#include <xen/events.h> +#include <linux/sched.h> +#include "pciback.h" + +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 (dev->msi_enabled) + status = -EALREADY; + else if (dev->msix_enabled) + status = -ENXIO; + else + status = pci_enable_msi(dev); + + if (status) { + dev_warn_ratelimited(&dev->dev, "error enabling MSI for guest %u: err %d\n", + 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 local domain's IRQ number. */ + + op->value = dev->irq ? xen_pirq_from_irq(dev->irq) : 0; + + dev_dbg(&dev->dev, "MSI: %d\n", 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 (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; + + dev_dbg(&dev->dev, "MSI: %d\n", 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; + + dev_dbg(&dev->dev, "enable MSI-X\n"); + + 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); + dev_dbg(&dev->dev, "MSI-X[%d]: %d\n", i, + op->msix_entries[i].vector); + } + } + } else + dev_warn_ratelimited(&dev->dev, "error enabling MSI-X for guest %u: err %d!\n", + 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 (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; + + dev_dbg(&dev->dev, "MSI-X: %d\n", op->value); + + return 0; +} +#endif + +static inline bool xen_pcibk_test_op_pending(struct xen_pcibk_device *pdev) +{ + return test_bit(_XEN_PCIF_active, + (unsigned long *)&pdev->sh_info->flags) && + !test_and_set_bit(_PDEVF_op_active, &pdev->flags); +} + +/* +* 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 +*/ +static void xen_pcibk_test_and_schedule_op(struct xen_pcibk_device *pdev) +{ + bool eoi = true; + + /* Check that frontend is requesting an operation and that we are not + * already processing a request */ + if (xen_pcibk_test_op_pending(pdev)) { + schedule_work(&pdev->op_work); + eoi = false; + } + /*_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); + eoi = false; + } + + /* EOI if there was nothing to do. */ + if (eoi) + xen_pcibk_lateeoi(pdev, XEN_EOI_FLAG_SPURIOUS); +} + +/* 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 */ + +static void xen_pcibk_do_one_op(struct xen_pcibk_device *pdev) +{ + 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 */ +} + +void xen_pcibk_do_op(struct work_struct *data) +{ + struct xen_pcibk_device *pdev = + container_of(data, struct xen_pcibk_device, op_work); + + do { + xen_pcibk_do_one_op(pdev); + } while (xen_pcibk_test_op_pending(pdev)); + + xen_pcibk_lateeoi(pdev, 0); +} + +irqreturn_t xen_pcibk_handle_event(int irq, void *dev_id) +{ + struct xen_pcibk_device *pdev = dev_id; + bool eoi; + + /* IRQs might come in before pdev->evtchn_irq is written. */ + if (unlikely(pdev->evtchn_irq != irq)) + pdev->evtchn_irq = irq; + + eoi = test_and_set_bit(_EOI_pending, &pdev->flags); + WARN(eoi, "IRQ while EOI pending\n"); + + 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)) { + dev_info(&dev->dev, "%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; +} |