virtio_pci: optional MSI-X support
This implements optional MSI-X support in virtio_pci. MSI-X is used whenever the host supports at least 2 MSI-X vectors: 1 for configuration changes and 1 for virtqueues. Per-virtqueue vectors are allocated if enough vectors available. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (+ whitespace, style)
This commit is contained in:
Michael S. Tsirkin
Rusty Russell
parent
77cf524654
commit
82af8ce84e
|
|
@ -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);
|
||||
|
|
|
|||
|
|
@ -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
|
||||
|
|
|
|||
Loading…
Reference in New Issue