/* * Virtio PCI driver * * This module allows virtio devices to be used over a virtual PCI device. * This can be used with QEMU based VMMs like KVM or Xen. * * Copyright IBM Corp. 2007 * * Authors: * Anthony Liguori <aliguori@us.ibm.com> * * This work is licensed under the terms of the GNU GPL, version 2 or later. * See the COPYING file in the top-level directory. * */ #include <linux/module.h> #include <linux/list.h> #include <linux/pci.h> #include <linux/slab.h> #include <linux/interrupt.h> #include <linux/virtio.h> #include <linux/virtio_config.h> #include <linux/virtio_ring.h> #include <linux/virtio_pci.h> #include <linux/highmem.h> #include <linux/spinlock.h> MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>"); MODULE_DESCRIPTION("virtio-pci"); MODULE_LICENSE("GPL"); MODULE_VERSION("1"); /* Our device structure */ struct virtio_pci_device { struct virtio_device vdev; struct pci_dev *pci_dev; /* the IO mapping for the PCI config space */ void __iomem *ioaddr; /* a list of queues so we can dispatch IRQs */ spinlock_t lock; struct list_head virtqueues; /* MSI-X support */ int msix_enabled; int intx_enabled; struct msix_entry *msix_entries; /* Name strings for interrupts. This size should be enough, * and I'm too lazy to allocate each name separately. */ char (*msix_names)[256]; /* Number of available vectors */ unsigned msix_vectors; /* Vectors allocated, excluding per-vq vectors if any */ unsigned msix_used_vectors; /* Whether we have vector per vq */ bool per_vq_vectors; }; /* Constants for MSI-X */ /* Use first vector for configuration changes, second and the rest for * virtqueues Thus, we need at least 2 vectors for MSI. */ enum { VP_MSIX_CONFIG_VECTOR = 0, VP_MSIX_VQ_VECTOR = 1, }; struct virtio_pci_vq_info { /* the actual virtqueue */ struct virtqueue *vq; /* the number of entries in the queue */ int num; /* the index of the queue */ int queue_index; /* the virtual address of the ring queue */ void *queue; /* the list node for the virtqueues list */ struct list_head node; /* MSI-X vector (or none) */ unsigned msix_vector; }; /* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */ static struct pci_device_id virtio_pci_id_table[] = { { 0x1af4, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 }, { 0 }, }; MODULE_DEVICE_TABLE(pci, virtio_pci_id_table); /* Convert a generic virtio device to our structure */ static struct virtio_pci_device *to_vp_device(struct virtio_device *vdev) { return container_of(vdev, struct virtio_pci_device, vdev); } /* virtio config->get_features() implementation */ static u32 vp_get_features(struct virtio_device *vdev) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); /* When someone needs more than 32 feature bits, we'll need to * steal a bit to indicate that the rest are somewhere else. */ return ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES); } /* virtio config->finalize_features() implementation */ static void vp_finalize_features(struct virtio_device *vdev) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); /* Give virtio_ring a chance to accept features. */ vring_transport_features(vdev); /* We only support 32 feature bits. */ BUILD_BUG_ON(ARRAY_SIZE(vdev->features) != 1); iowrite32(vdev->features[0], vp_dev->ioaddr+VIRTIO_PCI_GUEST_FEATURES); } /* virtio config->get() implementation */ static void vp_get(struct virtio_device *vdev, unsigned offset, void *buf, unsigned len) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); void __iomem *ioaddr = vp_dev->ioaddr + VIRTIO_PCI_CONFIG(vp_dev) + offset; u8 *ptr = buf; int i; for (i = 0; i < len; i++) ptr[i] = ioread8(ioaddr + i); } /* the config->set() implementation. it's symmetric to the config->get() * implementation */ static void vp_set(struct virtio_device *vdev, unsigned offset, const void *buf, unsigned len) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); void __iomem *ioaddr = vp_dev->ioaddr + VIRTIO_PCI_CONFIG(vp_dev) + offset; const u8 *ptr = buf; int i; for (i = 0; i < len; i++) iowrite8(ptr[i], ioaddr + i); } /* config->{get,set}_status() implementations */ static u8 vp_get_status(struct virtio_device *vdev) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); return ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS); } static void vp_set_status(struct virtio_device *vdev, u8 status) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); /* We should never be setting status to 0. */ BUG_ON(status == 0); iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_STATUS); } static void vp_reset(struct virtio_device *vdev) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); /* 0 status means a reset. */ iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS); } /* the notify function used when creating a virt queue */ static void vp_notify(struct virtqueue *vq) { struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev); struct virtio_pci_vq_info *info = vq->priv; /* we write the queue's selector into the notification register to * signal the other end */ iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY); } /* Handle a configuration change: Tell driver if it wants to know. */ static irqreturn_t vp_config_changed(int irq, void *opaque) { struct virtio_pci_device *vp_dev = opaque; struct virtio_driver *drv; drv = container_of(vp_dev->vdev.dev.driver, struct virtio_driver, driver); if (drv && drv->config_changed) drv->config_changed(&vp_dev->vdev); return IRQ_HANDLED; } /* Notify all virtqueues on an interrupt. */ static irqreturn_t vp_vring_interrupt(int irq, void *opaque) { struct virtio_pci_device *vp_dev = opaque; struct virtio_pci_vq_info *info; irqreturn_t ret = IRQ_NONE; unsigned long flags; spin_lock_irqsave(&vp_dev->lock, flags); list_for_each_entry(info, &vp_dev->virtqueues, node) { if (vring_interrupt(irq, info->vq) == IRQ_HANDLED) ret = IRQ_HANDLED; } spin_unlock_irqrestore(&vp_dev->lock, flags); return ret; } /* A small wrapper to also acknowledge the interrupt when it's handled. * I really need an EIO hook for the vring so I can ack the interrupt once we * know that we'll be handling the IRQ but before we invoke the callback since * the callback may notify the host which results in the host attempting to * raise an interrupt that we would then mask once we acknowledged the * interrupt. */ static irqreturn_t vp_interrupt(int irq, void *opaque) { struct virtio_pci_device *vp_dev = opaque; u8 isr; /* reading the ISR has the effect of also clearing it so it's very * important to save off the value. */ isr = ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR); /* It's definitely not us if the ISR was not high */ if (!isr) return IRQ_NONE; /* Configuration change? Tell driver if it wants to know. */ if (isr & VIRTIO_PCI_ISR_CONFIG) vp_config_changed(irq, opaque); return vp_vring_interrupt(irq, opaque); } static void vp_free_vectors(struct virtio_device *vdev) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); int i; if (vp_dev->intx_enabled) { free_irq(vp_dev->pci_dev->irq, vp_dev); vp_dev->intx_enabled = 0; } for (i = 0; i < vp_dev->msix_used_vectors; ++i) free_irq(vp_dev->msix_entries[i].vector, vp_dev); if (vp_dev->msix_enabled) { /* Disable the vector used for configuration */ iowrite16(VIRTIO_MSI_NO_VECTOR, vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR); /* Flush the write out to device */ ioread16(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR); pci_disable_msix(vp_dev->pci_dev); vp_dev->msix_enabled = 0; vp_dev->msix_vectors = 0; } vp_dev->msix_used_vectors = 0; kfree(vp_dev->msix_names); vp_dev->msix_names = NULL; kfree(vp_dev->msix_entries); vp_dev->msix_entries = NULL; } static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors, bool per_vq_vectors) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); const char *name = dev_name(&vp_dev->vdev.dev); unsigned i, v; int err = -ENOMEM; vp_dev->msix_entries = kmalloc(nvectors * sizeof *vp_dev->msix_entries, GFP_KERNEL); if (!vp_dev->msix_entries) goto error; vp_dev->msix_names = kmalloc(nvectors * sizeof *vp_dev->msix_names, GFP_KERNEL); if (!vp_dev->msix_names) goto error; for (i = 0; i < nvectors; ++i) vp_dev->msix_entries[i].entry = i; /* pci_enable_msix returns positive if we can't get this many. */ err = pci_enable_msix(vp_dev->pci_dev, vp_dev->msix_entries, nvectors); if (err > 0) err = -ENOSPC; if (err) goto error; vp_dev->msix_vectors = nvectors; vp_dev->msix_enabled = 1; /* Set the vector used for configuration */ v = vp_dev->msix_used_vectors; snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names, "%s-config", name); err = request_irq(vp_dev->msix_entries[v].vector, vp_config_changed, 0, vp_dev->msix_names[v], vp_dev); if (err) goto error; ++vp_dev->msix_used_vectors; iowrite16(v, vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR); /* Verify we had enough resources to assign the vector */ v = ioread16(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR); if (v == VIRTIO_MSI_NO_VECTOR) { err = -EBUSY; goto error; } if (!per_vq_vectors) { /* Shared vector for all VQs */ v = vp_dev->msix_used_vectors; snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names, "%s-virtqueues", name); err = request_irq(vp_dev->msix_entries[v].vector, vp_vring_interrupt, 0, vp_dev->msix_names[v], vp_dev); if (err) goto error; ++vp_dev->msix_used_vectors; } return 0; error: vp_free_vectors(vdev); return err; } static int vp_request_intx(struct virtio_device *vdev) { int err; struct virtio_pci_device *vp_dev = to_vp_device(vdev); err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED, dev_name(&vdev->dev), vp_dev); if (!err) vp_dev->intx_enabled = 1; return err; } static struct virtqueue *setup_vq(struct virtio_device *vdev, unsigned index, void (*callback)(struct virtqueue *vq), const char *name, u16 msix_vec) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); struct virtio_pci_vq_info *info; struct virtqueue *vq; unsigned long flags, size; u16 num; int err; /* Select the queue we're interested in */ iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); /* Check if queue is either not available or already active. */ num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM); if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN)) return ERR_PTR(-ENOENT); /* allocate and fill out our structure the represents an active * queue */ info = kmalloc(sizeof(struct virtio_pci_vq_info), GFP_KERNEL); if (!info) return ERR_PTR(-ENOMEM); info->queue_index = index; info->num = num; info->msix_vector = msix_vec; size = PAGE_ALIGN(vring_size(num, VIRTIO_PCI_VRING_ALIGN)); info->queue = alloc_pages_exact(size, GFP_KERNEL|__GFP_ZERO); if (info->queue == NULL) { err = -ENOMEM; goto out_info; } /* activate the queue */ iowrite32(virt_to_phys(info->queue) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); /* create the vring */ vq = vring_new_virtqueue(info->num, VIRTIO_PCI_VRING_ALIGN, vdev, info->queue, vp_notify, callback, name); if (!vq) { err = -ENOMEM; goto out_activate_queue; } vq->priv = info; info->vq = vq; if (msix_vec != VIRTIO_MSI_NO_VECTOR) { iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); if (msix_vec == VIRTIO_MSI_NO_VECTOR) { err = -EBUSY; goto out_assign; } } spin_lock_irqsave(&vp_dev->lock, flags); list_add(&info->node, &vp_dev->virtqueues); spin_unlock_irqrestore(&vp_dev->lock, flags); return vq; out_assign: vring_del_virtqueue(vq); out_activate_queue: iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); free_pages_exact(info->queue, size); out_info: kfree(info); return ERR_PTR(err); } static void vp_del_vq(struct virtqueue *vq) { struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev); struct virtio_pci_vq_info *info = vq->priv; unsigned long flags, size; spin_lock_irqsave(&vp_dev->lock, flags); list_del(&info->node); spin_unlock_irqrestore(&vp_dev->lock, flags); iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); if (vp_dev->msix_enabled) { iowrite16(VIRTIO_MSI_NO_VECTOR, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); /* Flush the write out to device */ ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR); } vring_del_virtqueue(vq); /* Select and deactivate the queue */ iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); size = PAGE_ALIGN(vring_size(info->num, VIRTIO_PCI_VRING_ALIGN)); free_pages_exact(info->queue, size); kfree(info); } /* the config->del_vqs() implementation */ static void vp_del_vqs(struct virtio_device *vdev) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); struct virtqueue *vq, *n; struct virtio_pci_vq_info *info; list_for_each_entry_safe(vq, n, &vdev->vqs, list) { info = vq->priv; if (vp_dev->per_vq_vectors && info->msix_vector != VIRTIO_MSI_NO_VECTOR) free_irq(vp_dev->msix_entries[info->msix_vector].vector, vq); vp_del_vq(vq); } vp_dev->per_vq_vectors = false; vp_free_vectors(vdev); } static int vp_try_to_find_vqs(struct virtio_device *vdev, unsigned nvqs, struct virtqueue *vqs[], vq_callback_t *callbacks[], const char *names[], bool use_msix, bool per_vq_vectors) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); u16 msix_vec; int i, err, nvectors, allocated_vectors; if (!use_msix) { /* Old style: one normal interrupt for change and all vqs. */ err = vp_request_intx(vdev); if (err) goto error_request; } else { if (per_vq_vectors) { /* Best option: one for change interrupt, one per vq. */ nvectors = 1; for (i = 0; i < nvqs; ++i) if (callbacks[i]) ++nvectors; } else { /* Second best: one for change, shared for all vqs. */ nvectors = 2; } err = vp_request_msix_vectors(vdev, nvectors, per_vq_vectors); if (err) goto error_request; } vp_dev->per_vq_vectors = per_vq_vectors; allocated_vectors = vp_dev->msix_used_vectors; for (i = 0; i < nvqs; ++i) { if (!callbacks[i] || !vp_dev->msix_enabled) msix_vec = VIRTIO_MSI_NO_VECTOR; else if (vp_dev->per_vq_vectors) msix_vec = allocated_vectors++; else msix_vec = VP_MSIX_VQ_VECTOR; vqs[i] = setup_vq(vdev, i, callbacks[i], names[i], msix_vec); if (IS_ERR(vqs[i])) { err = PTR_ERR(vqs[i]); goto error_find; } if (!vp_dev->per_vq_vectors || msix_vec == VIRTIO_MSI_NO_VECTOR) continue; /* allocate per-vq irq if available and necessary */ snprintf(vp_dev->msix_names[msix_vec], sizeof *vp_dev->msix_names, "%s-%s", dev_name(&vp_dev->vdev.dev), names[i]); err = request_irq(vp_dev->msix_entries[msix_vec].vector, vring_interrupt, 0, vp_dev->msix_names[msix_vec], vqs[i]); if (err) { vp_del_vq(vqs[i]); goto error_find; } } return 0; error_find: vp_del_vqs(vdev); error_request: return err; } /* the config->find_vqs() implementation */ static int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs, struct virtqueue *vqs[], vq_callback_t *callbacks[], const char *names[]) { int err; /* Try MSI-X with one vector per queue. */ err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, true, true); if (!err) return 0; /* Fallback: MSI-X with one vector for config, one shared for queues. */ err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, true, false); if (!err) return 0; /* Finally fall back to regular interrupts. */ return vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, false, false); } static struct virtio_config_ops virtio_pci_config_ops = { .get = vp_get, .set = vp_set, .get_status = vp_get_status, .set_status = vp_set_status, .reset = vp_reset, .find_vqs = vp_find_vqs, .del_vqs = vp_del_vqs, .get_features = vp_get_features, .finalize_features = vp_finalize_features, }; static void virtio_pci_release_dev(struct device *_d) { struct virtio_device *dev = container_of(_d, struct virtio_device, dev); struct virtio_pci_device *vp_dev = to_vp_device(dev); struct pci_dev *pci_dev = vp_dev->pci_dev; vp_del_vqs(dev); pci_set_drvdata(pci_dev, NULL); pci_iounmap(pci_dev, vp_dev->ioaddr); pci_release_regions(pci_dev); pci_disable_device(pci_dev); kfree(vp_dev); } /* the PCI probing function */ static int __devinit virtio_pci_probe(struct pci_dev *pci_dev, const struct pci_device_id *id) { struct virtio_pci_device *vp_dev; int err; /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */ if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f) return -ENODEV; if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) { printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n", VIRTIO_PCI_ABI_VERSION, pci_dev->revision); return -ENODEV; } /* allocate our structure and fill it out */ vp_dev = kzalloc(sizeof(struct virtio_pci_device), GFP_KERNEL); if (vp_dev == NULL) return -ENOMEM; vp_dev->vdev.dev.parent = &pci_dev->dev; vp_dev->vdev.dev.release = virtio_pci_release_dev; vp_dev->vdev.config = &virtio_pci_config_ops; vp_dev->pci_dev = pci_dev; INIT_LIST_HEAD(&vp_dev->virtqueues); spin_lock_init(&vp_dev->lock); /* Disable MSI/MSIX to bring device to a known good state. */ pci_msi_off(pci_dev); /* enable the device */ err = pci_enable_device(pci_dev); if (err) goto out; err = pci_request_regions(pci_dev, "virtio-pci"); if (err) goto out_enable_device; vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0); if (vp_dev->ioaddr == NULL) goto out_req_regions; pci_set_drvdata(pci_dev, vp_dev); pci_set_master(pci_dev); /* we use the subsystem vendor/device id as the virtio vendor/device * id. this allows us to use the same PCI vendor/device id for all * virtio devices and to identify the particular virtio driver by * the subsystem ids */ vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor; vp_dev->vdev.id.device = pci_dev->subsystem_device; /* finally register the virtio device */ err = register_virtio_device(&vp_dev->vdev); if (err) goto out_set_drvdata; return 0; out_set_drvdata: pci_set_drvdata(pci_dev, NULL); pci_iounmap(pci_dev, vp_dev->ioaddr); out_req_regions: pci_release_regions(pci_dev); out_enable_device: pci_disable_device(pci_dev); out: kfree(vp_dev); return err; } static void __devexit virtio_pci_remove(struct pci_dev *pci_dev) { struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); unregister_virtio_device(&vp_dev->vdev); } #ifdef CONFIG_PM static int virtio_pci_suspend(struct pci_dev *pci_dev, pm_message_t state) { pci_save_state(pci_dev); pci_set_power_state(pci_dev, PCI_D3hot); return 0; } static int virtio_pci_resume(struct pci_dev *pci_dev) { pci_restore_state(pci_dev); pci_set_power_state(pci_dev, PCI_D0); return 0; } #endif static struct pci_driver virtio_pci_driver = { .name = "virtio-pci", .id_table = virtio_pci_id_table, .probe = virtio_pci_probe, .remove = __devexit_p(virtio_pci_remove), #ifdef CONFIG_PM .suspend = virtio_pci_suspend, .resume = virtio_pci_resume, #endif }; static int __init virtio_pci_init(void) { return pci_register_driver(&virtio_pci_driver); } module_init(virtio_pci_init); static void __exit virtio_pci_exit(void) { pci_unregister_driver(&virtio_pci_driver); } module_exit(virtio_pci_exit);