/* * VFIO PCI interrupt handling * * Copyright (C) 2012 Red Hat, Inc. All rights reserved. * Author: Alex Williamson <alex.williamson@redhat.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * Derived from original vfio: * Copyright 2010 Cisco Systems, Inc. All rights reserved. * Author: Tom Lyon, pugs@cisco.com */ #include <linux/device.h> #include <linux/interrupt.h> #include <linux/eventfd.h> #include <linux/msi.h> #include <linux/pci.h> #include <linux/file.h> #include <linux/vfio.h> #include <linux/wait.h> #include <linux/slab.h> #include "vfio_pci_private.h" /* * INTx */ static void vfio_send_intx_eventfd(void *opaque, void *unused) { struct vfio_pci_device *vdev = opaque; if (likely(is_intx(vdev) && !vdev->virq_disabled)) eventfd_signal(vdev->ctx[0].trigger, 1); } void vfio_pci_intx_mask(struct vfio_pci_device *vdev) { struct pci_dev *pdev = vdev->pdev; unsigned long flags; spin_lock_irqsave(&vdev->irqlock, flags); /* * Masking can come from interrupt, ioctl, or config space * via INTx disable. The latter means this can get called * even when not using intx delivery. In this case, just * try to have the physical bit follow the virtual bit. */ if (unlikely(!is_intx(vdev))) { if (vdev->pci_2_3) pci_intx(pdev, 0); } else if (!vdev->ctx[0].masked) { /* * Can't use check_and_mask here because we always want to * mask, not just when something is pending. */ if (vdev->pci_2_3) pci_intx(pdev, 0); else disable_irq_nosync(pdev->irq); vdev->ctx[0].masked = true; } spin_unlock_irqrestore(&vdev->irqlock, flags); } /* * If this is triggered by an eventfd, we can't call eventfd_signal * or else we'll deadlock on the eventfd wait queue. Return >0 when * a signal is necessary, which can then be handled via a work queue * or directly depending on the caller. */ static int vfio_pci_intx_unmask_handler(void *opaque, void *unused) { struct vfio_pci_device *vdev = opaque; struct pci_dev *pdev = vdev->pdev; unsigned long flags; int ret = 0; spin_lock_irqsave(&vdev->irqlock, flags); /* * Unmasking comes from ioctl or config, so again, have the * physical bit follow the virtual even when not using INTx. */ if (unlikely(!is_intx(vdev))) { if (vdev->pci_2_3) pci_intx(pdev, 1); } else if (vdev->ctx[0].masked && !vdev->virq_disabled) { /* * A pending interrupt here would immediately trigger, * but we can avoid that overhead by just re-sending * the interrupt to the user. */ if (vdev->pci_2_3) { if (!pci_check_and_unmask_intx(pdev)) ret = 1; } else enable_irq(pdev->irq); vdev->ctx[0].masked = (ret > 0); } spin_unlock_irqrestore(&vdev->irqlock, flags); return ret; } void vfio_pci_intx_unmask(struct vfio_pci_device *vdev) { if (vfio_pci_intx_unmask_handler(vdev, NULL) > 0) vfio_send_intx_eventfd(vdev, NULL); } static irqreturn_t vfio_intx_handler(int irq, void *dev_id) { struct vfio_pci_device *vdev = dev_id; unsigned long flags; int ret = IRQ_NONE; spin_lock_irqsave(&vdev->irqlock, flags); if (!vdev->pci_2_3) { disable_irq_nosync(vdev->pdev->irq); vdev->ctx[0].masked = true; ret = IRQ_HANDLED; } else if (!vdev->ctx[0].masked && /* may be shared */ pci_check_and_mask_intx(vdev->pdev)) { vdev->ctx[0].masked = true; ret = IRQ_HANDLED; } spin_unlock_irqrestore(&vdev->irqlock, flags); if (ret == IRQ_HANDLED) vfio_send_intx_eventfd(vdev, NULL); return ret; } static int vfio_intx_enable(struct vfio_pci_device *vdev) { if (!is_irq_none(vdev)) return -EINVAL; if (!vdev->pdev->irq) return -ENODEV; vdev->ctx = kzalloc(sizeof(struct vfio_pci_irq_ctx), GFP_KERNEL); if (!vdev->ctx) return -ENOMEM; vdev->num_ctx = 1; /* * If the virtual interrupt is masked, restore it. Devices * supporting DisINTx can be masked at the hardware level * here, non-PCI-2.3 devices will have to wait until the * interrupt is enabled. */ vdev->ctx[0].masked = vdev->virq_disabled; if (vdev->pci_2_3) pci_intx(vdev->pdev, !vdev->ctx[0].masked); vdev->irq_type = VFIO_PCI_INTX_IRQ_INDEX; return 0; } static int vfio_intx_set_signal(struct vfio_pci_device *vdev, int fd) { struct pci_dev *pdev = vdev->pdev; unsigned long irqflags = IRQF_SHARED; struct eventfd_ctx *trigger; unsigned long flags; int ret; if (vdev->ctx[0].trigger) { free_irq(pdev->irq, vdev); kfree(vdev->ctx[0].name); eventfd_ctx_put(vdev->ctx[0].trigger); vdev->ctx[0].trigger = NULL; } if (fd < 0) /* Disable only */ return 0; vdev->ctx[0].name = kasprintf(GFP_KERNEL, "vfio-intx(%s)", pci_name(pdev)); if (!vdev->ctx[0].name) return -ENOMEM; trigger = eventfd_ctx_fdget(fd); if (IS_ERR(trigger)) { kfree(vdev->ctx[0].name); return PTR_ERR(trigger); } vdev->ctx[0].trigger = trigger; if (!vdev->pci_2_3) irqflags = 0; ret = request_irq(pdev->irq, vfio_intx_handler, irqflags, vdev->ctx[0].name, vdev); if (ret) { vdev->ctx[0].trigger = NULL; kfree(vdev->ctx[0].name); eventfd_ctx_put(trigger); return ret; } /* * INTx disable will stick across the new irq setup, * disable_irq won't. */ spin_lock_irqsave(&vdev->irqlock, flags); if (!vdev->pci_2_3 && vdev->ctx[0].masked) disable_irq_nosync(pdev->irq); spin_unlock_irqrestore(&vdev->irqlock, flags); return 0; } static void vfio_intx_disable(struct vfio_pci_device *vdev) { vfio_virqfd_disable(&vdev->ctx[0].unmask); vfio_virqfd_disable(&vdev->ctx[0].mask); vfio_intx_set_signal(vdev, -1); vdev->irq_type = VFIO_PCI_NUM_IRQS; vdev->num_ctx = 0; kfree(vdev->ctx); } /* * MSI/MSI-X */ static irqreturn_t vfio_msihandler(int irq, void *arg) { struct eventfd_ctx *trigger = arg; eventfd_signal(trigger, 1); return IRQ_HANDLED; } static int vfio_msi_enable(struct vfio_pci_device *vdev, int nvec, bool msix) { struct pci_dev *pdev = vdev->pdev; unsigned int flag = msix ? PCI_IRQ_MSIX : PCI_IRQ_MSI; int ret; if (!is_irq_none(vdev)) return -EINVAL; vdev->ctx = kcalloc(nvec, sizeof(struct vfio_pci_irq_ctx), GFP_KERNEL); if (!vdev->ctx) return -ENOMEM; /* return the number of supported vectors if we can't get all: */ ret = pci_alloc_irq_vectors(pdev, 1, nvec, flag); if (ret < nvec) { if (ret > 0) pci_free_irq_vectors(pdev); kfree(vdev->ctx); return ret; } vdev->num_ctx = nvec; vdev->irq_type = msix ? VFIO_PCI_MSIX_IRQ_INDEX : VFIO_PCI_MSI_IRQ_INDEX; if (!msix) { /* * Compute the virtual hardware field for max msi vectors - * it is the log base 2 of the number of vectors. */ vdev->msi_qmax = fls(nvec * 2 - 1) - 1; } return 0; } static int vfio_msi_set_vector_signal(struct vfio_pci_device *vdev, int vector, int fd, bool msix) { struct pci_dev *pdev = vdev->pdev; struct eventfd_ctx *trigger; int irq, ret; if (vector < 0 || vector >= vdev->num_ctx) return -EINVAL; irq = pci_irq_vector(pdev, vector); if (vdev->ctx[vector].trigger) { free_irq(irq, vdev->ctx[vector].trigger); irq_bypass_unregister_producer(&vdev->ctx[vector].producer); kfree(vdev->ctx[vector].name); eventfd_ctx_put(vdev->ctx[vector].trigger); vdev->ctx[vector].trigger = NULL; } if (fd < 0) return 0; vdev->ctx[vector].name = kasprintf(GFP_KERNEL, "vfio-msi%s[%d](%s)", msix ? "x" : "", vector, pci_name(pdev)); if (!vdev->ctx[vector].name) return -ENOMEM; trigger = eventfd_ctx_fdget(fd); if (IS_ERR(trigger)) { kfree(vdev->ctx[vector].name); return PTR_ERR(trigger); } /* * The MSIx vector table resides in device memory which may be cleared * via backdoor resets. We don't allow direct access to the vector * table so even if a userspace driver attempts to save/restore around * such a reset it would be unsuccessful. To avoid this, restore the * cached value of the message prior to enabling. */ if (msix) { struct msi_msg msg; get_cached_msi_msg(irq, &msg); pci_write_msi_msg(irq, &msg); } ret = request_irq(irq, vfio_msihandler, 0, vdev->ctx[vector].name, trigger); if (ret) { kfree(vdev->ctx[vector].name); eventfd_ctx_put(trigger); return ret; } vdev->ctx[vector].producer.token = trigger; vdev->ctx[vector].producer.irq = irq; ret = irq_bypass_register_producer(&vdev->ctx[vector].producer); if (unlikely(ret)) dev_info(&pdev->dev, "irq bypass producer (token %p) registration fails: %d\n", vdev->ctx[vector].producer.token, ret); vdev->ctx[vector].trigger = trigger; return 0; } static int vfio_msi_set_block(struct vfio_pci_device *vdev, unsigned start, unsigned count, int32_t *fds, bool msix) { int i, j, ret = 0; if (start >= vdev->num_ctx || start + count > vdev->num_ctx) return -EINVAL; for (i = 0, j = start; i < count && !ret; i++, j++) { int fd = fds ? fds[i] : -1; ret = vfio_msi_set_vector_signal(vdev, j, fd, msix); } if (ret) { for (--j; j >= (int)start; j--) vfio_msi_set_vector_signal(vdev, j, -1, msix); } return ret; } static void vfio_msi_disable(struct vfio_pci_device *vdev, bool msix) { struct pci_dev *pdev = vdev->pdev; int i; for (i = 0; i < vdev->num_ctx; i++) { vfio_virqfd_disable(&vdev->ctx[i].unmask); vfio_virqfd_disable(&vdev->ctx[i].mask); } vfio_msi_set_block(vdev, 0, vdev->num_ctx, NULL, msix); pci_free_irq_vectors(pdev); /* * Both disable paths above use pci_intx_for_msi() to clear DisINTx * via their shutdown paths. Restore for NoINTx devices. */ if (vdev->nointx) pci_intx(pdev, 0); vdev->irq_type = VFIO_PCI_NUM_IRQS; vdev->num_ctx = 0; kfree(vdev->ctx); } /* * IOCTL support */ static int vfio_pci_set_intx_unmask(struct vfio_pci_device *vdev, unsigned index, unsigned start, unsigned count, uint32_t flags, void *data) { if (!is_intx(vdev) || start != 0 || count != 1) return -EINVAL; if (flags & VFIO_IRQ_SET_DATA_NONE) { vfio_pci_intx_unmask(vdev); } else if (flags & VFIO_IRQ_SET_DATA_BOOL) { uint8_t unmask = *(uint8_t *)data; if (unmask) vfio_pci_intx_unmask(vdev); } else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) { int32_t fd = *(int32_t *)data; if (fd >= 0) return vfio_virqfd_enable((void *) vdev, vfio_pci_intx_unmask_handler, vfio_send_intx_eventfd, NULL, &vdev->ctx[0].unmask, fd); vfio_virqfd_disable(&vdev->ctx[0].unmask); } return 0; } static int vfio_pci_set_intx_mask(struct vfio_pci_device *vdev, unsigned index, unsigned start, unsigned count, uint32_t flags, void *data) { if (!is_intx(vdev) || start != 0 || count != 1) return -EINVAL; if (flags & VFIO_IRQ_SET_DATA_NONE) { vfio_pci_intx_mask(vdev); } else if (flags & VFIO_IRQ_SET_DATA_BOOL) { uint8_t mask = *(uint8_t *)data; if (mask) vfio_pci_intx_mask(vdev); } else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) { return -ENOTTY; /* XXX implement me */ } return 0; } static int vfio_pci_set_intx_trigger(struct vfio_pci_device *vdev, unsigned index, unsigned start, unsigned count, uint32_t flags, void *data) { if (is_intx(vdev) && !count && (flags & VFIO_IRQ_SET_DATA_NONE)) { vfio_intx_disable(vdev); return 0; } if (!(is_intx(vdev) || is_irq_none(vdev)) || start != 0 || count != 1) return -EINVAL; if (flags & VFIO_IRQ_SET_DATA_EVENTFD) { int32_t fd = *(int32_t *)data; int ret; if (is_intx(vdev)) return vfio_intx_set_signal(vdev, fd); ret = vfio_intx_enable(vdev); if (ret) return ret; ret = vfio_intx_set_signal(vdev, fd); if (ret) vfio_intx_disable(vdev); return ret; } if (!is_intx(vdev)) return -EINVAL; if (flags & VFIO_IRQ_SET_DATA_NONE) { vfio_send_intx_eventfd(vdev, NULL); } else if (flags & VFIO_IRQ_SET_DATA_BOOL) { uint8_t trigger = *(uint8_t *)data; if (trigger) vfio_send_intx_eventfd(vdev, NULL); } return 0; } static int vfio_pci_set_msi_trigger(struct vfio_pci_device *vdev, unsigned index, unsigned start, unsigned count, uint32_t flags, void *data) { int i; bool msix = (index == VFIO_PCI_MSIX_IRQ_INDEX) ? true : false; if (irq_is(vdev, index) && !count && (flags & VFIO_IRQ_SET_DATA_NONE)) { vfio_msi_disable(vdev, msix); return 0; } if (!(irq_is(vdev, index) || is_irq_none(vdev))) return -EINVAL; if (flags & VFIO_IRQ_SET_DATA_EVENTFD) { int32_t *fds = data; int ret; if (vdev->irq_type == index) return vfio_msi_set_block(vdev, start, count, fds, msix); ret = vfio_msi_enable(vdev, start + count, msix); if (ret) return ret; ret = vfio_msi_set_block(vdev, start, count, fds, msix); if (ret) vfio_msi_disable(vdev, msix); return ret; } if (!irq_is(vdev, index) || start + count > vdev->num_ctx) return -EINVAL; for (i = start; i < start + count; i++) { if (!vdev->ctx[i].trigger) continue; if (flags & VFIO_IRQ_SET_DATA_NONE) { eventfd_signal(vdev->ctx[i].trigger, 1); } else if (flags & VFIO_IRQ_SET_DATA_BOOL) { uint8_t *bools = data; if (bools[i - start]) eventfd_signal(vdev->ctx[i].trigger, 1); } } return 0; } static int vfio_pci_set_ctx_trigger_single(struct eventfd_ctx **ctx, unsigned int count, uint32_t flags, void *data) { /* DATA_NONE/DATA_BOOL enables loopback testing */ if (flags & VFIO_IRQ_SET_DATA_NONE) { if (*ctx) { if (count) { eventfd_signal(*ctx, 1); } else { eventfd_ctx_put(*ctx); *ctx = NULL; } return 0; } } else if (flags & VFIO_IRQ_SET_DATA_BOOL) { uint8_t trigger; if (!count) return -EINVAL; trigger = *(uint8_t *)data; if (trigger && *ctx) eventfd_signal(*ctx, 1); return 0; } else if (flags & VFIO_IRQ_SET_DATA_EVENTFD) { int32_t fd; if (!count) return -EINVAL; fd = *(int32_t *)data; if (fd == -1) { if (*ctx) eventfd_ctx_put(*ctx); *ctx = NULL; } else if (fd >= 0) { struct eventfd_ctx *efdctx; efdctx = eventfd_ctx_fdget(fd); if (IS_ERR(efdctx)) return PTR_ERR(efdctx); if (*ctx) eventfd_ctx_put(*ctx); *ctx = efdctx; } return 0; } return -EINVAL; } static int vfio_pci_set_err_trigger(struct vfio_pci_device *vdev, unsigned index, unsigned start, unsigned count, uint32_t flags, void *data) { if (index != VFIO_PCI_ERR_IRQ_INDEX || start != 0 || count > 1) return -EINVAL; return vfio_pci_set_ctx_trigger_single(&vdev->err_trigger, count, flags, data); } static int vfio_pci_set_req_trigger(struct vfio_pci_device *vdev, unsigned index, unsigned start, unsigned count, uint32_t flags, void *data) { if (index != VFIO_PCI_REQ_IRQ_INDEX || start != 0 || count > 1) return -EINVAL; return vfio_pci_set_ctx_trigger_single(&vdev->req_trigger, count, flags, data); } int vfio_pci_set_irqs_ioctl(struct vfio_pci_device *vdev, uint32_t flags, unsigned index, unsigned start, unsigned count, void *data) { int (*func)(struct vfio_pci_device *vdev, unsigned index, unsigned start, unsigned count, uint32_t flags, void *data) = NULL; switch (index) { case VFIO_PCI_INTX_IRQ_INDEX: switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) { case VFIO_IRQ_SET_ACTION_MASK: func = vfio_pci_set_intx_mask; break; case VFIO_IRQ_SET_ACTION_UNMASK: func = vfio_pci_set_intx_unmask; break; case VFIO_IRQ_SET_ACTION_TRIGGER: func = vfio_pci_set_intx_trigger; break; } break; case VFIO_PCI_MSI_IRQ_INDEX: case VFIO_PCI_MSIX_IRQ_INDEX: switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) { case VFIO_IRQ_SET_ACTION_MASK: case VFIO_IRQ_SET_ACTION_UNMASK: /* XXX Need masking support exported */ break; case VFIO_IRQ_SET_ACTION_TRIGGER: func = vfio_pci_set_msi_trigger; break; } break; case VFIO_PCI_ERR_IRQ_INDEX: switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) { case VFIO_IRQ_SET_ACTION_TRIGGER: if (pci_is_pcie(vdev->pdev)) func = vfio_pci_set_err_trigger; break; } break; case VFIO_PCI_REQ_IRQ_INDEX: switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) { case VFIO_IRQ_SET_ACTION_TRIGGER: func = vfio_pci_set_req_trigger; break; } break; } if (!func) return -ENOTTY; return func(vdev, index, start, count, flags, data); }