0513fe9e5b
If the device that is to be shared with a guest is a level device and the IRQ is shared with the initial domain we need to take actions. Mainly we install a dummy IRQ handler that will ACK on the interrupt line so as to not have the initial domain disable the interrupt line. This dummy IRQ handler is not enabled when the device MSI/MSI-X lines are set, nor for edge interrupts. And also not for level interrupts that are not shared amongst devices. Lastly, if the user passes to the guest all of the PCI devices on the shared line the we won't install the dummy handler either. There is also SysFS instrumentation to check its state and turn IRQ ACKing on/off if necessary. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
242 lines
6.8 KiB
C
242 lines
6.8 KiB
C
/*
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* PCI Backend Operations - respond to PCI requests from Frontend
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*
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* Author: Ryan Wilson <hap9@epoch.ncsc.mil>
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*/
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#include <linux/module.h>
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#include <linux/wait.h>
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#include <linux/bitops.h>
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#include <xen/events.h>
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#include <linux/sched.h>
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#include "pciback.h"
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int verbose_request;
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module_param(verbose_request, int, 0644);
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/* Ensure a device is has the fake IRQ handler "turned on/off" and is
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* ready to be exported. This MUST be run after pciback_reset_device
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* which does the actual PCI device enable/disable.
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*/
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void pciback_control_isr(struct pci_dev *dev, int reset)
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{
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struct pciback_dev_data *dev_data;
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int rc;
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int enable = 0;
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dev_data = pci_get_drvdata(dev);
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if (!dev_data)
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return;
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/* We don't deal with bridges */
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if (dev->hdr_type != PCI_HEADER_TYPE_NORMAL)
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return;
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if (reset) {
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dev_data->enable_intx = 0;
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dev_data->ack_intr = 0;
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}
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enable = dev_data->enable_intx;
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/* Asked to disable, but ISR isn't runnig */
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if (!enable && !dev_data->isr_on)
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return;
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/* Squirrel away the IRQs in the dev_data. We need this
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* b/c when device transitions to MSI, the dev->irq is
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* overwritten with the MSI vector.
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*/
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if (enable)
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dev_data->irq = dev->irq;
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dev_dbg(&dev->dev, "%s: #%d %s %s%s %s-> %s\n",
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dev_data->irq_name,
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dev_data->irq,
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pci_is_enabled(dev) ? "on" : "off",
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dev->msi_enabled ? "MSI" : "",
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dev->msix_enabled ? "MSI/X" : "",
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dev_data->isr_on ? "enable" : "disable",
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enable ? "enable" : "disable");
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if (enable) {
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rc = request_irq(dev_data->irq,
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pciback_guest_interrupt, IRQF_SHARED,
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dev_data->irq_name, dev);
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if (rc) {
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dev_err(&dev->dev, "%s: failed to install fake IRQ " \
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"handler for IRQ %d! (rc:%d)\n",
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dev_data->irq_name, dev_data->irq, rc);
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goto out;
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}
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} else {
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free_irq(dev_data->irq, dev);
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dev_data->irq = 0;
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}
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dev_data->isr_on = enable;
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dev_data->ack_intr = enable;
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out:
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dev_dbg(&dev->dev, "%s: #%d %s %s%s %s\n",
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dev_data->irq_name,
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dev_data->irq,
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pci_is_enabled(dev) ? "on" : "off",
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dev->msi_enabled ? "MSI" : "",
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dev->msix_enabled ? "MSI/X" : "",
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enable ? (dev_data->isr_on ? "enabled" : "failed to enable") :
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(dev_data->isr_on ? "failed to disable" : "disabled"));
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}
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/* Ensure a device is "turned off" and ready to be exported.
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* (Also see pciback_config_reset to ensure virtual configuration space is
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* ready to be re-exported)
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*/
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void pciback_reset_device(struct pci_dev *dev)
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{
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u16 cmd;
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pciback_control_isr(dev, 1 /* reset device */);
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/* Disable devices (but not bridges) */
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if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL) {
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#ifdef CONFIG_PCI_MSI
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/* The guest could have been abruptly killed without
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* disabling MSI/MSI-X interrupts.*/
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if (dev->msix_enabled)
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pci_disable_msix(dev);
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if (dev->msi_enabled)
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pci_disable_msi(dev);
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#endif
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pci_disable_device(dev);
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pci_write_config_word(dev, PCI_COMMAND, 0);
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dev->is_busmaster = 0;
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} else {
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pci_read_config_word(dev, PCI_COMMAND, &cmd);
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if (cmd & (PCI_COMMAND_INVALIDATE)) {
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cmd &= ~(PCI_COMMAND_INVALIDATE);
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pci_write_config_word(dev, PCI_COMMAND, cmd);
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dev->is_busmaster = 0;
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}
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}
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}
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/*
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* Now the same evtchn is used for both pcifront conf_read_write request
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* as well as pcie aer front end ack. We use a new work_queue to schedule
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* pciback conf_read_write service for avoiding confict with aer_core
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* do_recovery job which also use the system default work_queue
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*/
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void test_and_schedule_op(struct pciback_device *pdev)
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{
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/* Check that frontend is requesting an operation and that we are not
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* already processing a request */
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if (test_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags)
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&& !test_and_set_bit(_PDEVF_op_active, &pdev->flags)) {
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queue_work(pciback_wq, &pdev->op_work);
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}
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/*_XEN_PCIB_active should have been cleared by pcifront. And also make
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sure pciback is waiting for ack by checking _PCIB_op_pending*/
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if (!test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
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&& test_bit(_PCIB_op_pending, &pdev->flags)) {
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wake_up(&aer_wait_queue);
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}
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}
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/* Performing the configuration space reads/writes must not be done in atomic
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* context because some of the pci_* functions can sleep (mostly due to ACPI
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* use of semaphores). This function is intended to be called from a work
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* queue in process context taking a struct pciback_device as a parameter */
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void pciback_do_op(struct work_struct *data)
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{
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struct pciback_device *pdev =
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container_of(data, struct pciback_device, op_work);
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struct pci_dev *dev;
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struct pciback_dev_data *dev_data = NULL;
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struct xen_pci_op *op = &pdev->sh_info->op;
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int test_intx = 0;
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dev = pciback_get_pci_dev(pdev, op->domain, op->bus, op->devfn);
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if (dev == NULL)
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op->err = XEN_PCI_ERR_dev_not_found;
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else {
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dev_data = pci_get_drvdata(dev);
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if (dev_data)
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test_intx = dev_data->enable_intx;
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switch (op->cmd) {
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case XEN_PCI_OP_conf_read:
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op->err = pciback_config_read(dev,
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op->offset, op->size, &op->value);
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break;
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case XEN_PCI_OP_conf_write:
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op->err = pciback_config_write(dev,
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op->offset, op->size, op->value);
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break;
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#ifdef CONFIG_PCI_MSI
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case XEN_PCI_OP_enable_msi:
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op->err = pciback_enable_msi(pdev, dev, op);
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break;
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case XEN_PCI_OP_disable_msi:
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op->err = pciback_disable_msi(pdev, dev, op);
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break;
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case XEN_PCI_OP_enable_msix:
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op->err = pciback_enable_msix(pdev, dev, op);
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break;
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case XEN_PCI_OP_disable_msix:
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op->err = pciback_disable_msix(pdev, dev, op);
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break;
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#endif
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default:
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op->err = XEN_PCI_ERR_not_implemented;
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break;
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}
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}
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if (!op->err && dev && dev_data) {
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/* Transition detected */
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if ((dev_data->enable_intx != test_intx))
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pciback_control_isr(dev, 0 /* no reset */);
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}
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/* Tell the driver domain that we're done. */
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wmb();
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clear_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
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notify_remote_via_irq(pdev->evtchn_irq);
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/* Mark that we're done. */
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smp_mb__before_clear_bit(); /* /after/ clearing PCIF_active */
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clear_bit(_PDEVF_op_active, &pdev->flags);
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smp_mb__after_clear_bit(); /* /before/ final check for work */
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/* Check to see if the driver domain tried to start another request in
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* between clearing _XEN_PCIF_active and clearing _PDEVF_op_active.
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*/
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test_and_schedule_op(pdev);
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}
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irqreturn_t pciback_handle_event(int irq, void *dev_id)
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{
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struct pciback_device *pdev = dev_id;
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test_and_schedule_op(pdev);
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return IRQ_HANDLED;
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}
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irqreturn_t pciback_guest_interrupt(int irq, void *dev_id)
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{
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struct pci_dev *dev = (struct pci_dev *)dev_id;
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struct pciback_dev_data *dev_data = pci_get_drvdata(dev);
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if (dev_data->isr_on && dev_data->ack_intr) {
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dev_data->handled++;
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if ((dev_data->handled % 1000) == 0) {
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if (xen_test_irq_shared(irq)) {
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printk(KERN_INFO "%s IRQ line is not shared "
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"with other domains. Turning ISR off\n",
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dev_data->irq_name);
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dev_data->ack_intr = 0;
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}
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}
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return IRQ_HANDLED;
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}
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return IRQ_NONE;
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}
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