diff options
| -rw-r--r-- | drivers/virtio/virtio_pci.c | 228 | ||||
| -rw-r--r-- | include/linux/virtio_pci.h | 10 |
2 files changed, 218 insertions, 20 deletions
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c index 951e673..193c8f0 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -42,6 +42,26 @@ struct virtio_pci_device /* 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 */ + unsigned msix_used_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 @@ -60,6 +80,9 @@ struct virtio_pci_vq_info /* the list node for the virtqueues list */ struct list_head node; + + /* MSI-X vector (or none) */ + unsigned vector; }; /* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */ @@ -109,7 +132,8 @@ 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 + offset; + void __iomem *ioaddr = vp_dev->ioaddr + + VIRTIO_PCI_CONFIG(vp_dev) + offset; u8 *ptr = buf; int i; @@ -123,7 +147,8 @@ 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 + offset; + void __iomem *ioaddr = vp_dev->ioaddr + + VIRTIO_PCI_CONFIG(vp_dev) + offset; const u8 *ptr = buf; int i; @@ -221,7 +246,122 @@ static irqreturn_t vp_interrupt(int irq, void *opaque) return vp_vring_interrupt(irq, opaque); } -/* the config->find_vq() implementation */ +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); + vp_dev->msix_used_vectors = 0; + + 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); + + vp_dev->msix_enabled = 0; + pci_disable_msix(vp_dev->pci_dev); + } +} + +static int vp_enable_msix(struct pci_dev *dev, struct msix_entry *entries, + int *options, int noptions) +{ + int i; + for (i = 0; i < noptions; ++i) + if (!pci_enable_msix(dev, entries, options[i])) + return options[i]; + return -EBUSY; +} + +static int vp_request_vectors(struct virtio_device *vdev, unsigned max_vqs) +{ + 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; + /* We want at most one vector per queue and one for config changes. + * Fallback to separate vectors for config and a shared for queues. + * Finally fall back to regular interrupts. */ + int options[] = { max_vqs + 1, 2 }; + int nvectors = max(options[0], options[1]); + + vp_dev->msix_entries = kmalloc(nvectors * sizeof *vp_dev->msix_entries, + GFP_KERNEL); + if (!vp_dev->msix_entries) + goto error_entries; + vp_dev->msix_names = kmalloc(nvectors * sizeof *vp_dev->msix_names, + GFP_KERNEL); + if (!vp_dev->msix_names) + goto error_names; + + for (i = 0; i < nvectors; ++i) + vp_dev->msix_entries[i].entry = i; + + err = vp_enable_msix(vp_dev->pci_dev, vp_dev->msix_entries, + options, ARRAY_SIZE(options)); + if (err < 0) { + /* Can't allocate enough MSI-X vectors, use regular interrupt */ + vp_dev->msix_vectors = 0; + err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, + IRQF_SHARED, name, vp_dev); + if (err) + goto error_irq; + vp_dev->intx_enabled = 1; + } else { + vp_dev->msix_vectors = err; + 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_irq; + ++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_irq; + } + } + + if (vp_dev->msix_vectors && vp_dev->msix_vectors != max_vqs + 1) { + /* 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_irq; + ++vp_dev->msix_used_vectors; + } + return 0; +error_irq: + vp_free_vectors(vdev); + kfree(vp_dev->msix_names); +error_names: + kfree(vp_dev->msix_entries); +error_entries: + return err; +} + static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index, void (*callback)(struct virtqueue *vq), const char *name) @@ -230,7 +370,7 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index, struct virtio_pci_vq_info *info; struct virtqueue *vq; unsigned long flags, size; - u16 num; + u16 num, vector; int err; /* Select the queue we're interested in */ @@ -249,6 +389,7 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index, info->queue_index = index; info->num = num; + info->vector = VIRTIO_MSI_NO_VECTOR; size = PAGE_ALIGN(vring_size(num, VIRTIO_PCI_VRING_ALIGN)); info->queue = alloc_pages_exact(size, GFP_KERNEL|__GFP_ZERO); @@ -272,12 +413,43 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index, vq->priv = info; info->vq = vq; + /* allocate per-vq vector if available and necessary */ + if (callback && vp_dev->msix_used_vectors < vp_dev->msix_vectors) { + vector = vp_dev->msix_used_vectors; + snprintf(vp_dev->msix_names[vector], sizeof *vp_dev->msix_names, + "%s-%s", dev_name(&vp_dev->vdev.dev), name); + err = request_irq(vp_dev->msix_entries[vector].vector, + vring_interrupt, 0, + vp_dev->msix_names[vector], vq); + if (err) + goto out_request_irq; + info->vector = vector; + ++vp_dev->msix_used_vectors; + } else + vector = VP_MSIX_VQ_VECTOR; + + if (callback && vp_dev->msix_enabled) { + iowrite16(vector, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); + vector = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); + if (vector == 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: + if (info->vector != VIRTIO_MSI_NO_VECTOR) { + free_irq(vp_dev->msix_entries[info->vector].vector, vq); + --vp_dev->msix_used_vectors; + } +out_request_irq: + vring_del_virtqueue(vq); out_activate_queue: iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); free_pages_exact(info->queue, size); @@ -286,17 +458,27 @@ out_info: return ERR_PTR(err); } -/* the config->del_vq() implementation */ 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 size; + iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); + + if (info->vector != VIRTIO_MSI_NO_VECTOR) + free_irq(vp_dev->msix_entries[info->vector].vector, vq); + + 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 */ - iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL); iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); size = PAGE_ALIGN(vring_size(info->num, VIRTIO_PCI_VRING_ALIGN)); @@ -304,30 +486,46 @@ static void vp_del_vq(struct virtqueue *vq) kfree(info); } +/* the config->del_vqs() implementation */ static void vp_del_vqs(struct virtio_device *vdev) { struct virtqueue *vq, *n; list_for_each_entry_safe(vq, n, &vdev->vqs, list) vp_del_vq(vq); + + vp_free_vectors(vdev); } +/* 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 i; + int vectors = 0; + int i, err; + + /* How many vectors would we like? */ + for (i = 0; i < nvqs; ++i) + if (callbacks[i]) + ++vectors; + + err = vp_request_vectors(vdev, vectors); + if (err) + goto error_request; for (i = 0; i < nvqs; ++i) { vqs[i] = vp_find_vq(vdev, i, callbacks[i], names[i]); if (IS_ERR(vqs[i])) - goto error; + goto error_find; } return 0; -error: +error_find: vp_del_vqs(vdev); + +error_request: return PTR_ERR(vqs[i]); } @@ -349,7 +547,7 @@ static void virtio_pci_release_dev(struct device *_d) struct virtio_pci_device *vp_dev = to_vp_device(dev); struct pci_dev *pci_dev = vp_dev->pci_dev; - free_irq(pci_dev->irq, vp_dev); + vp_del_vqs(dev); pci_set_drvdata(pci_dev, NULL); pci_iounmap(pci_dev, vp_dev->ioaddr); pci_release_regions(pci_dev); @@ -408,21 +606,13 @@ static int __devinit virtio_pci_probe(struct pci_dev *pci_dev, vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor; vp_dev->vdev.id.device = pci_dev->subsystem_device; - /* register a handler for the queue with the PCI device's interrupt */ - err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED, - dev_name(&vp_dev->vdev.dev), vp_dev); - if (err) - goto out_set_drvdata; - /* finally register the virtio device */ err = register_virtio_device(&vp_dev->vdev); if (err) - goto out_req_irq; + goto out_set_drvdata; return 0; -out_req_irq: - free_irq(pci_dev->irq, vp_dev); out_set_drvdata: pci_set_drvdata(pci_dev, NULL); pci_iounmap(pci_dev, vp_dev->ioaddr); diff --git a/include/linux/virtio_pci.h b/include/linux/virtio_pci.h index cd0fd5d..9a3d7c4 100644 --- a/include/linux/virtio_pci.h +++ b/include/linux/virtio_pci.h @@ -47,9 +47,17 @@ /* The bit of the ISR which indicates a device configuration change. */ #define VIRTIO_PCI_ISR_CONFIG 0x2 +/* MSI-X registers: only enabled if MSI-X is enabled. */ +/* A 16-bit vector for configuration changes. */ +#define VIRTIO_MSI_CONFIG_VECTOR 20 +/* A 16-bit vector for selected queue notifications. */ +#define VIRTIO_MSI_QUEUE_VECTOR 22 +/* Vector value used to disable MSI for queue */ +#define VIRTIO_MSI_NO_VECTOR 0xffff + /* The remaining space is defined by each driver as the per-driver * configuration space */ -#define VIRTIO_PCI_CONFIG 20 +#define VIRTIO_PCI_CONFIG(dev) ((dev)->msix_enabled ? 24 : 20) /* Virtio ABI version, this must match exactly */ #define VIRTIO_PCI_ABI_VERSION 0 |
