diff options
Diffstat (limited to 'drivers/vfio/pci/vfio_pci_intrs.c')
-rw-r--r-- | drivers/vfio/pci/vfio_pci_intrs.c | 723 |
1 files changed, 723 insertions, 0 deletions
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c new file mode 100644 index 000000000..40c3d7cf1 --- /dev/null +++ b/drivers/vfio/pci/vfio_pci_intrs.c @@ -0,0 +1,723 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * VFIO PCI interrupt handling + * + * Copyright (C) 2012 Red Hat, Inc. All rights reserved. + * Author: Alex Williamson <alex.williamson@redhat.com> + * + * 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_priv.h" + +struct vfio_pci_irq_ctx { + struct eventfd_ctx *trigger; + struct virqfd *unmask; + struct virqfd *mask; + char *name; + bool masked; + struct irq_bypass_producer producer; +}; + +static bool irq_is(struct vfio_pci_core_device *vdev, int type) +{ + return vdev->irq_type == type; +} + +static bool is_intx(struct vfio_pci_core_device *vdev) +{ + return vdev->irq_type == VFIO_PCI_INTX_IRQ_INDEX; +} + +static bool is_irq_none(struct vfio_pci_core_device *vdev) +{ + return !(vdev->irq_type == VFIO_PCI_INTX_IRQ_INDEX || + vdev->irq_type == VFIO_PCI_MSI_IRQ_INDEX || + vdev->irq_type == VFIO_PCI_MSIX_IRQ_INDEX); +} + +/* + * INTx + */ +static void vfio_send_intx_eventfd(void *opaque, void *unused) +{ + struct vfio_pci_core_device *vdev = opaque; + + if (likely(is_intx(vdev) && !vdev->virq_disabled)) + eventfd_signal(vdev->ctx[0].trigger, 1); +} + +/* Returns true if the INTx vfio_pci_irq_ctx.masked value is changed. */ +bool vfio_pci_intx_mask(struct vfio_pci_core_device *vdev) +{ + struct pci_dev *pdev = vdev->pdev; + unsigned long flags; + bool masked_changed = false; + + 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; + masked_changed = true; + } + + spin_unlock_irqrestore(&vdev->irqlock, flags); + return masked_changed; +} + +/* + * 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_core_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_core_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_core_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_core_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_core_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_core_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_core_device *vdev, int nvec, bool msix) +{ + struct pci_dev *pdev = vdev->pdev; + unsigned int flag = msix ? PCI_IRQ_MSIX : PCI_IRQ_MSI; + int ret; + u16 cmd; + + 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: */ + cmd = vfio_pci_memory_lock_and_enable(vdev); + ret = pci_alloc_irq_vectors(pdev, 1, nvec, flag); + if (ret < nvec) { + if (ret > 0) + pci_free_irq_vectors(pdev); + vfio_pci_memory_unlock_and_restore(vdev, cmd); + kfree(vdev->ctx); + return ret; + } + vfio_pci_memory_unlock_and_restore(vdev, cmd); + + 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_core_device *vdev, + int vector, int fd, bool msix) +{ + struct pci_dev *pdev = vdev->pdev; + struct eventfd_ctx *trigger; + int irq, ret; + u16 cmd; + + if (vector < 0 || vector >= vdev->num_ctx) + return -EINVAL; + + irq = pci_irq_vector(pdev, vector); + + if (vdev->ctx[vector].trigger) { + irq_bypass_unregister_producer(&vdev->ctx[vector].producer); + + cmd = vfio_pci_memory_lock_and_enable(vdev); + free_irq(irq, vdev->ctx[vector].trigger); + vfio_pci_memory_unlock_and_restore(vdev, cmd); + + 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. + */ + cmd = vfio_pci_memory_lock_and_enable(vdev); + 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); + vfio_pci_memory_unlock_and_restore(vdev, cmd); + 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].producer.token = NULL; + } + vdev->ctx[vector].trigger = trigger; + + return 0; +} + +static int vfio_msi_set_block(struct vfio_pci_core_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_core_device *vdev, bool msix) +{ + struct pci_dev *pdev = vdev->pdev; + int i; + u16 cmd; + + 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); + + cmd = vfio_pci_memory_lock_and_enable(vdev); + pci_free_irq_vectors(pdev); + vfio_pci_memory_unlock_and_restore(vdev, cmd); + + /* + * 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_core_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_core_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_core_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_core_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_core_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_core_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_core_device *vdev, uint32_t flags, + unsigned index, unsigned start, unsigned count, + void *data) +{ + int (*func)(struct vfio_pci_core_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); +} |