From f68d24082e22ccee3077d11aeb6dc5354f0ca7f1 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Wed, 23 Sep 2009 22:26:29 -0600 Subject: virtio_pci: minor MSI-X cleanups 1) Rename vp_request_vectors to vp_request_msix_vectors, and take non-MSI-X case out to caller. 2) Comment weird pci_enable_msix API 3) Rename vp_find_vq to setup_vq. 4) Fix spaces to tabs 5) Make nvectors calc internal to vp_try_to_find_vqs() 6) Rename vector to msix_vector for more clarity. Signed-off-by: Rusty Russell Cc: "Michael S. Tsirkin" --- drivers/virtio/virtio_pci.c | 125 +++++++++++++++++++++++++------------------- 1 file changed, 70 insertions(+), 55 deletions(-) diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c index 248e00ec4dc1..4a1f1ebff7bf 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -84,7 +84,7 @@ struct virtio_pci_vq_info struct list_head node; /* MSI-X vector (or none) */ - unsigned vector; + unsigned msix_vector; }; /* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */ @@ -280,25 +280,14 @@ static void vp_free_vectors(struct virtio_device *vdev) vp_dev->msix_entries = NULL; } -static int vp_request_vectors(struct virtio_device *vdev, int nvectors, - bool per_vq_vectors) +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; - if (!nvectors) { - /* Can't allocate 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) - return err; - vp_dev->intx_enabled = 1; - return 0; - } - vp_dev->msix_entries = kmalloc(nvectors * sizeof *vp_dev->msix_entries, GFP_KERNEL); if (!vp_dev->msix_entries) @@ -311,6 +300,7 @@ static int vp_request_vectors(struct virtio_device *vdev, int nvectors, 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; @@ -356,10 +346,22 @@ error: return err; } -static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index, - void (*callback)(struct virtqueue *vq), - const char *name, - u16 vector) +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; @@ -384,7 +386,7 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index, info->queue_index = index; info->num = num; - info->vector = vector; + 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); @@ -408,10 +410,10 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index, vq->priv = info; info->vq = vq; - if (vector != VIRTIO_MSI_NO_VECTOR) { - iowrite16(vector, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); - vector = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); - if (vector == VIRTIO_MSI_NO_VECTOR) { + 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; } @@ -472,7 +474,8 @@ static void vp_del_vqs(struct virtio_device *vdev) list_for_each_entry_safe(vq, n, &vdev->vqs, list) { info = vq->priv; if (vp_dev->per_vq_vectors) - free_irq(vp_dev->msix_entries[info->vector].vector, vq); + free_irq(vp_dev->msix_entries[info->msix_vector].vector, + vq); vp_del_vq(vq); } vp_dev->per_vq_vectors = false; @@ -484,38 +487,58 @@ static int vp_try_to_find_vqs(struct virtio_device *vdev, unsigned nvqs, struct virtqueue *vqs[], vq_callback_t *callbacks[], const char *names[], - int nvectors, + bool use_msix, bool per_vq_vectors) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); - u16 vector; - int i, err, allocated_vectors; + u16 msix_vec; + int i, err, nvectors, allocated_vectors; - err = vp_request_vectors(vdev, nvectors, per_vq_vectors); - if (err) - goto error_request; + 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) - vector = VIRTIO_MSI_NO_VECTOR; + msix_vec = VIRTIO_MSI_NO_VECTOR; else if (vp_dev->per_vq_vectors) - vector = allocated_vectors++; + msix_vec = allocated_vectors++; else - vector = VP_MSIX_VQ_VECTOR; - vqs[i] = vp_find_vq(vdev, i, callbacks[i], names[i], vector); + 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; } /* allocate per-vq irq if available and necessary */ - if (vp_dev->per_vq_vectors && vector != VIRTIO_MSI_NO_VECTOR) { - snprintf(vp_dev->msix_names[vector], sizeof *vp_dev->msix_names, - "%s-%s", dev_name(&vp_dev->vdev.dev), names[i]); - err = request_irq(vp_dev->msix_entries[vector].vector, - vring_interrupt, 0, - vp_dev->msix_names[vector], vqs[i]); + if (vp_dev->per_vq_vectors) { + 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(msix_vec, vring_interrupt, 0, + vp_dev->msix_names[msix_vec], + vqs[i]); if (err) { vp_del_vq(vqs[i]); goto error_find; @@ -537,28 +560,20 @@ static int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs, vq_callback_t *callbacks[], const char *names[]) { - int vectors = 0; - int i, uninitialized_var(err); - - /* How many vectors would we like? */ - for (i = 0; i < nvqs; ++i) - if (callbacks[i]) - ++vectors; + int err; - /* We want at most one vector per queue and one for config changes. */ - err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, - vectors + 1, true); + /* 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 to separate vectors for config and a shared for queues. */ + /* Fallback: MSI-X with one vector for config, one shared for queues. */ err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, - 2, false); + true, false); if (!err) return 0; /* Finally fall back to regular interrupts. */ - err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, - 0, false); - return err; + return vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, + false, false); } static struct virtio_config_ops virtio_pci_config_ops = { -- cgit v1.2.3-59-g8ed1b