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path: root/drivers/virtio/virtio_pci_common.c
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Diffstat (limited to 'drivers/virtio/virtio_pci_common.c')
-rw-r--r--drivers/virtio/virtio_pci_common.c584
1 files changed, 584 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
new file mode 100644
index 000000000..eba1b7ac7
--- /dev/null
+++ b/drivers/virtio/virtio_pci_common.c
@@ -0,0 +1,584 @@
+/*
+ * Virtio PCI driver - common functionality for all device versions
+ *
+ * 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
+ * Copyright Red Hat, Inc. 2014
+ *
+ * Authors:
+ * Anthony Liguori <aliguori@us.ibm.com>
+ * Rusty Russell <rusty@rustcorp.com.au>
+ * Michael S. Tsirkin <mst@redhat.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 "virtio_pci_common.h"
+
+static bool force_legacy = false;
+
+#if IS_ENABLED(CONFIG_VIRTIO_PCI_LEGACY)
+module_param(force_legacy, bool, 0444);
+MODULE_PARM_DESC(force_legacy,
+ "Force legacy mode for transitional virtio 1 devices");
+#endif
+
+/* wait for pending irq handlers */
+void vp_synchronize_vectors(struct virtio_device *vdev)
+{
+ struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+ int i;
+
+ if (vp_dev->intx_enabled)
+ synchronize_irq(vp_dev->pci_dev->irq);
+
+ for (i = 0; i < vp_dev->msix_vectors; ++i)
+ synchronize_irq(vp_dev->msix_entries[i].vector);
+}
+
+/* the notify function used when creating a virt queue */
+bool vp_notify(struct virtqueue *vq)
+{
+ /* we write the queue's selector into the notification register to
+ * signal the other end */
+ iowrite16(vq->index, (void __iomem *)vq->priv);
+ return true;
+}
+
+/* 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;
+
+ virtio_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->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);
+
+ for (i = 0; i < vp_dev->msix_vectors; i++)
+ if (vp_dev->msix_affinity_masks[i])
+ free_cpumask_var(vp_dev->msix_affinity_masks[i]);
+
+ if (vp_dev->msix_enabled) {
+ /* Disable the vector used for configuration */
+ vp_dev->config_vector(vp_dev, VIRTIO_MSI_NO_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;
+ kfree(vp_dev->msix_affinity_masks);
+ vp_dev->msix_affinity_masks = 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_vectors = nvectors;
+
+ 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;
+ vp_dev->msix_affinity_masks
+ = kzalloc(nvectors * sizeof *vp_dev->msix_affinity_masks,
+ GFP_KERNEL);
+ if (!vp_dev->msix_affinity_masks)
+ goto error;
+ for (i = 0; i < nvectors; ++i)
+ if (!alloc_cpumask_var(&vp_dev->msix_affinity_masks[i],
+ GFP_KERNEL))
+ goto error;
+
+ for (i = 0; i < nvectors; ++i)
+ vp_dev->msix_entries[i].entry = i;
+
+ err = pci_enable_msix_exact(vp_dev->pci_dev,
+ vp_dev->msix_entries, nvectors);
+ if (err)
+ goto error;
+ 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;
+
+ v = vp_dev->config_vector(vp_dev, v);
+ /* Verify we had enough resources to assign the 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 *vp_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 = kmalloc(sizeof *info, GFP_KERNEL);
+ struct virtqueue *vq;
+ unsigned long flags;
+
+ /* fill out our structure that represents an active queue */
+ if (!info)
+ return ERR_PTR(-ENOMEM);
+
+ vq = vp_dev->setup_vq(vp_dev, info, index, callback, name, msix_vec);
+ if (IS_ERR(vq))
+ goto out_info;
+
+ info->vq = vq;
+ if (callback) {
+ spin_lock_irqsave(&vp_dev->lock, flags);
+ list_add(&info->node, &vp_dev->virtqueues);
+ spin_unlock_irqrestore(&vp_dev->lock, flags);
+ } else {
+ INIT_LIST_HEAD(&info->node);
+ }
+
+ vp_dev->vqs[index] = info;
+ return vq;
+
+out_info:
+ kfree(info);
+ return vq;
+}
+
+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 = vp_dev->vqs[vq->index];
+ unsigned long flags;
+
+ spin_lock_irqsave(&vp_dev->lock, flags);
+ list_del(&info->node);
+ spin_unlock_irqrestore(&vp_dev->lock, flags);
+
+ vp_dev->del_vq(info);
+ kfree(info);
+}
+
+/* the config->del_vqs() implementation */
+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 = vp_dev->vqs[vq->index];
+ 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);
+ kfree(vp_dev->vqs);
+ vp_dev->vqs = NULL;
+}
+
+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;
+
+ vp_dev->vqs = kmalloc(nvqs * sizeof *vp_dev->vqs, GFP_KERNEL);
+ if (!vp_dev->vqs)
+ return -ENOMEM;
+
+ if (!use_msix) {
+ /* Old style: one normal interrupt for change and all vqs. */
+ err = vp_request_intx(vdev);
+ if (err)
+ goto error_find;
+ } 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_find;
+ }
+
+ vp_dev->per_vq_vectors = per_vq_vectors;
+ allocated_vectors = vp_dev->msix_used_vectors;
+ for (i = 0; i < nvqs; ++i) {
+ if (!names[i]) {
+ vqs[i] = NULL;
+ continue;
+ } else 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] = vp_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);
+ return err;
+}
+
+/* the config->find_vqs() implementation */
+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);
+}
+
+const char *vp_bus_name(struct virtio_device *vdev)
+{
+ struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+
+ return pci_name(vp_dev->pci_dev);
+}
+
+/* Setup the affinity for a virtqueue:
+ * - force the affinity for per vq vector
+ * - OR over all affinities for shared MSI
+ * - ignore the affinity request if we're using INTX
+ */
+int vp_set_vq_affinity(struct virtqueue *vq, int cpu)
+{
+ struct virtio_device *vdev = vq->vdev;
+ struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+ struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index];
+ struct cpumask *mask;
+ unsigned int irq;
+
+ if (!vq->callback)
+ return -EINVAL;
+
+ if (vp_dev->msix_enabled) {
+ mask = vp_dev->msix_affinity_masks[info->msix_vector];
+ irq = vp_dev->msix_entries[info->msix_vector].vector;
+ if (cpu == -1)
+ irq_set_affinity_hint(irq, NULL);
+ else {
+ cpumask_clear(mask);
+ cpumask_set_cpu(cpu, mask);
+ irq_set_affinity_hint(irq, mask);
+ }
+ }
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int virtio_pci_freeze(struct device *dev)
+{
+ struct pci_dev *pci_dev = to_pci_dev(dev);
+ struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
+ int ret;
+
+ ret = virtio_device_freeze(&vp_dev->vdev);
+
+ if (!ret)
+ pci_disable_device(pci_dev);
+ return ret;
+}
+
+static int virtio_pci_restore(struct device *dev)
+{
+ struct pci_dev *pci_dev = to_pci_dev(dev);
+ struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
+ int ret;
+
+ ret = pci_enable_device(pci_dev);
+ if (ret)
+ return ret;
+
+ pci_set_master(pci_dev);
+ return virtio_device_restore(&vp_dev->vdev);
+}
+
+static const struct dev_pm_ops virtio_pci_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(virtio_pci_freeze, virtio_pci_restore)
+};
+#endif
+
+
+/* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */
+static const struct pci_device_id virtio_pci_id_table[] = {
+ { PCI_DEVICE(0x1af4, PCI_ANY_ID) },
+ { 0 }
+};
+
+MODULE_DEVICE_TABLE(pci, virtio_pci_id_table);
+
+static void virtio_pci_release_dev(struct device *_d)
+{
+ struct virtio_device *vdev = dev_to_virtio(_d);
+ struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+
+ /* As struct device is a kobject, it's not safe to
+ * free the memory (including the reference counter itself)
+ * until it's release callback. */
+ kfree(vp_dev);
+}
+
+static int virtio_pci_probe(struct pci_dev *pci_dev,
+ const struct pci_device_id *id)
+{
+ struct virtio_pci_device *vp_dev;
+ int rc;
+
+ /* allocate our structure and fill it out */
+ vp_dev = kzalloc(sizeof(struct virtio_pci_device), GFP_KERNEL);
+ if (!vp_dev)
+ return -ENOMEM;
+
+ pci_set_drvdata(pci_dev, vp_dev);
+ vp_dev->vdev.dev.parent = &pci_dev->dev;
+ vp_dev->vdev.dev.release = virtio_pci_release_dev;
+ 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 */
+ rc = pci_enable_device(pci_dev);
+ if (rc)
+ goto err_enable_device;
+
+ rc = pci_request_regions(pci_dev, "virtio-pci");
+ if (rc)
+ goto err_request_regions;
+
+ if (force_legacy) {
+ rc = virtio_pci_legacy_probe(vp_dev);
+ /* Also try modern mode if we can't map BAR0 (no IO space). */
+ if (rc == -ENODEV || rc == -ENOMEM)
+ rc = virtio_pci_modern_probe(vp_dev);
+ if (rc)
+ goto err_probe;
+ } else {
+ rc = virtio_pci_modern_probe(vp_dev);
+ if (rc == -ENODEV)
+ rc = virtio_pci_legacy_probe(vp_dev);
+ if (rc)
+ goto err_probe;
+ }
+
+ pci_set_master(pci_dev);
+
+ rc = register_virtio_device(&vp_dev->vdev);
+ if (rc)
+ goto err_register;
+
+ return 0;
+
+err_register:
+ if (vp_dev->ioaddr)
+ virtio_pci_legacy_remove(vp_dev);
+ else
+ virtio_pci_modern_remove(vp_dev);
+err_probe:
+ pci_release_regions(pci_dev);
+err_request_regions:
+ pci_disable_device(pci_dev);
+err_enable_device:
+ kfree(vp_dev);
+ return rc;
+}
+
+static void 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);
+
+ if (vp_dev->ioaddr)
+ virtio_pci_legacy_remove(vp_dev);
+ else
+ virtio_pci_modern_remove(vp_dev);
+
+ pci_release_regions(pci_dev);
+ pci_disable_device(pci_dev);
+}
+
+static struct pci_driver virtio_pci_driver = {
+ .name = "virtio-pci",
+ .id_table = virtio_pci_id_table,
+ .probe = virtio_pci_probe,
+ .remove = virtio_pci_remove,
+#ifdef CONFIG_PM_SLEEP
+ .driver.pm = &virtio_pci_pm_ops,
+#endif
+};
+
+module_pci_driver(virtio_pci_driver);
+
+MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>");
+MODULE_DESCRIPTION("virtio-pci");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1");
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-16 09:25:58 +0000