swh:1:snp:c2847dfd741eae21606027cf29250d1ebcd63fb4
Tip revision: ba4f184e126b751d1bffad5897f263108befc780 authored by Linus Torvalds on 20 September 2020, 23:33:55 UTC
Linux 5.9-rc6
Linux 5.9-rc6
Tip revision: ba4f184
virtio_pci_common.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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>
*/
#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(pci_irq_vector(vp_dev->pci_dev, i));
}
/* 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 int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
bool per_vq_vectors, struct irq_affinity *desc)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
const char *name = dev_name(&vp_dev->vdev.dev);
unsigned flags = PCI_IRQ_MSIX;
unsigned i, v;
int err = -ENOMEM;
vp_dev->msix_vectors = nvectors;
vp_dev->msix_names = kmalloc_array(nvectors,
sizeof(*vp_dev->msix_names),
GFP_KERNEL);
if (!vp_dev->msix_names)
goto error;
vp_dev->msix_affinity_masks
= kcalloc(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;
if (desc) {
flags |= PCI_IRQ_AFFINITY;
desc->pre_vectors++; /* virtio config vector */
}
err = pci_alloc_irq_vectors_affinity(vp_dev->pci_dev, nvectors,
nvectors, flags, desc);
if (err < 0)
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(pci_irq_vector(vp_dev->pci_dev, v),
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(pci_irq_vector(vp_dev->pci_dev, v),
vp_vring_interrupt, 0, vp_dev->msix_names[v],
vp_dev);
if (err)
goto error;
++vp_dev->msix_used_vectors;
}
return 0;
error:
return err;
}
static struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned index,
void (*callback)(struct virtqueue *vq),
const char *name,
bool ctx,
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, ctx,
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;
int i;
list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
if (vp_dev->per_vq_vectors) {
int v = vp_dev->vqs[vq->index]->msix_vector;
if (v != VIRTIO_MSI_NO_VECTOR) {
int irq = pci_irq_vector(vp_dev->pci_dev, v);
irq_set_affinity_hint(irq, NULL);
free_irq(irq, vq);
}
}
vp_del_vq(vq);
}
vp_dev->per_vq_vectors = false;
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(pci_irq_vector(vp_dev->pci_dev, i), vp_dev);
if (vp_dev->msix_affinity_masks) {
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_free_irq_vectors(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_affinity_masks);
vp_dev->msix_affinity_masks = NULL;
kfree(vp_dev->vqs);
vp_dev->vqs = NULL;
}
static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
struct virtqueue *vqs[], vq_callback_t *callbacks[],
const char * const names[], bool per_vq_vectors,
const bool *ctx,
struct irq_affinity *desc)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
u16 msix_vec;
int i, err, nvectors, allocated_vectors, queue_idx = 0;
vp_dev->vqs = kcalloc(nvqs, sizeof(*vp_dev->vqs), GFP_KERNEL);
if (!vp_dev->vqs)
return -ENOMEM;
if (per_vq_vectors) {
/* Best option: one for change interrupt, one per vq. */
nvectors = 1;
for (i = 0; i < nvqs; ++i)
if (names[i] && 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,
per_vq_vectors ? desc : NULL);
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;
}
if (!callbacks[i])
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, queue_idx++, callbacks[i], names[i],
ctx ? ctx[i] : false,
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(pci_irq_vector(vp_dev->pci_dev, msix_vec),
vring_interrupt, 0,
vp_dev->msix_names[msix_vec],
vqs[i]);
if (err)
goto error_find;
}
return 0;
error_find:
vp_del_vqs(vdev);
return err;
}
static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned nvqs,
struct virtqueue *vqs[], vq_callback_t *callbacks[],
const char * const names[], const bool *ctx)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
int i, err, queue_idx = 0;
vp_dev->vqs = kcalloc(nvqs, sizeof(*vp_dev->vqs), GFP_KERNEL);
if (!vp_dev->vqs)
return -ENOMEM;
err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED,
dev_name(&vdev->dev), vp_dev);
if (err)
goto out_del_vqs;
vp_dev->intx_enabled = 1;
vp_dev->per_vq_vectors = false;
for (i = 0; i < nvqs; ++i) {
if (!names[i]) {
vqs[i] = NULL;
continue;
}
vqs[i] = vp_setup_vq(vdev, queue_idx++, callbacks[i], names[i],
ctx ? ctx[i] : false,
VIRTIO_MSI_NO_VECTOR);
if (IS_ERR(vqs[i])) {
err = PTR_ERR(vqs[i]);
goto out_del_vqs;
}
}
return 0;
out_del_vqs:
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 * const names[], const bool *ctx,
struct irq_affinity *desc)
{
int err;
/* Try MSI-X with one vector per queue. */
err = vp_find_vqs_msix(vdev, nvqs, vqs, callbacks, names, true, ctx, desc);
if (!err)
return 0;
/* Fallback: MSI-X with one vector for config, one shared for queues. */
err = vp_find_vqs_msix(vdev, nvqs, vqs, callbacks, names, false, ctx, desc);
if (!err)
return 0;
/* Finally fall back to regular interrupts. */
return vp_find_vqs_intx(vdev, nvqs, vqs, callbacks, names, ctx);
}
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, const struct cpumask *cpu_mask)
{
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 = pci_irq_vector(vp_dev->pci_dev, info->msix_vector);
if (!cpu_mask)
irq_set_affinity_hint(irq, NULL);
else {
cpumask_copy(mask, cpu_mask);
irq_set_affinity_hint(irq, mask);
}
}
return 0;
}
const struct cpumask *vp_get_vq_affinity(struct virtio_device *vdev, int index)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
if (!vp_dev->per_vq_vectors ||
vp_dev->vqs[index]->msix_vector == VIRTIO_MSI_NO_VECTOR)
return NULL;
return pci_irq_get_affinity(vp_dev->pci_dev,
vp_dev->vqs[index]->msix_vector);
}
#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(PCI_VENDOR_ID_REDHAT_QUMRANET, 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, *reg_dev = NULL;
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);
/* enable the device */
rc = pci_enable_device(pci_dev);
if (rc)
goto err_enable_device;
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);
reg_dev = vp_dev;
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_disable_device(pci_dev);
err_enable_device:
if (reg_dev)
put_device(&vp_dev->vdev.dev);
else
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);
struct device *dev = get_device(&vp_dev->vdev.dev);
pci_disable_sriov(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_disable_device(pci_dev);
put_device(dev);
}
static int virtio_pci_sriov_configure(struct pci_dev *pci_dev, int num_vfs)
{
struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
struct virtio_device *vdev = &vp_dev->vdev;
int ret;
if (!(vdev->config->get_status(vdev) & VIRTIO_CONFIG_S_DRIVER_OK))
return -EBUSY;
if (!__virtio_test_bit(vdev, VIRTIO_F_SR_IOV))
return -EINVAL;
if (pci_vfs_assigned(pci_dev))
return -EPERM;
if (num_vfs == 0) {
pci_disable_sriov(pci_dev);
return 0;
}
ret = pci_enable_sriov(pci_dev, num_vfs);
if (ret < 0)
return ret;
return num_vfs;
}
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
.sriov_configure = virtio_pci_sriov_configure,
};
module_pci_driver(virtio_pci_driver);
MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>");
MODULE_DESCRIPTION("virtio-pci");
MODULE_LICENSE("GPL");
MODULE_VERSION("1");