virtio_pci: modern driver

Lightly tested against qemu.

One thing *not* implemented here is separate mappings
for descriptor/avail/used rings. That's nice to have,
will be done later after we have core support.

This also exposes the PCI layout to userspace, and
adds macros for PCI layout offsets:

QEMU wants it, so why not?  Trust, but verify.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Michael S. Tsirkin 2014-12-11 13:59:51 +02:00 committed by Rusty Russell
parent 71d70c266c
commit 1fcf0512c9
5 changed files with 625 additions and 10 deletions

View File

@ -1,5 +1,5 @@
obj-$(CONFIG_VIRTIO) += virtio.o virtio_ring.o
obj-$(CONFIG_VIRTIO_MMIO) += virtio_mmio.o
obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o
virtio_pci-y := virtio_pci_legacy.o virtio_pci_common.o
virtio_pci-y := virtio_pci_modern.o virtio_pci_legacy.o virtio_pci_common.o
obj-$(CONFIG_VIRTIO_BALLOON) += virtio_balloon.o

View File

@ -505,7 +505,9 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
if (rc)
goto err_request_regions;
rc = virtio_pci_legacy_probe(vp_dev);
rc = virtio_pci_modern_probe(vp_dev);
if (rc == -ENODEV)
rc = virtio_pci_legacy_probe(vp_dev);
if (rc)
goto err_probe;
@ -518,7 +520,10 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
return 0;
err_register:
virtio_pci_legacy_remove(vp_dev);
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:
@ -534,7 +539,10 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
unregister_virtio_device(&vp_dev->vdev);
virtio_pci_legacy_remove(pci_dev);
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);

View File

@ -53,12 +53,29 @@ struct virtio_pci_device {
struct virtio_device vdev;
struct pci_dev *pci_dev;
/* In legacy mode, these two point to within ->legacy. */
/* Where to read and clear interrupt */
u8 __iomem *isr;
/* Modern only fields */
/* The IO mapping for the PCI config space (non-legacy mode) */
struct virtio_pci_common_cfg __iomem *common;
/* Device-specific data (non-legacy mode) */
void __iomem *device;
/* So we can sanity-check accesses. */
size_t device_len;
/* Capability for when we need to map notifications per-vq. */
int notify_map_cap;
/* Multiply queue_notify_off by this value. (non-legacy mode). */
u32 notify_offset_multiplier;
/* Legacy only field */
/* the IO mapping for the PCI config space */
void __iomem *ioaddr;
/* the IO mapping for ISR operation */
void __iomem *isr;
/* a list of queues so we can dispatch IRQs */
spinlock_t lock;
struct list_head virtqueues;
@ -129,5 +146,7 @@ int vp_set_vq_affinity(struct virtqueue *vq, int cpu);
int virtio_pci_legacy_probe(struct virtio_pci_device *);
void virtio_pci_legacy_remove(struct virtio_pci_device *);
int virtio_pci_modern_probe(struct virtio_pci_device *);
void virtio_pci_modern_remove(struct virtio_pci_device *);
#endif

View File

@ -0,0 +1,587 @@
/*
* Virtio PCI driver - modern (virtio 1.0) device support
*
* 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.
*
*/
#define VIRTIO_PCI_NO_LEGACY
#include "virtio_pci_common.h"
static void __iomem *map_capability(struct pci_dev *dev, int off,
size_t minlen,
u32 align,
u32 start, u32 size,
size_t *len)
{
u8 bar;
u32 offset, length;
void __iomem *p;
pci_read_config_byte(dev, off + offsetof(struct virtio_pci_cap,
bar),
&bar);
pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, offset),
&offset);
pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length),
&length);
if (length <= start) {
dev_err(&dev->dev,
"virtio_pci: bad capability len %u (>%u expected)\n",
length, start);
return NULL;
}
if (length - start < minlen) {
dev_err(&dev->dev,
"virtio_pci: bad capability len %u (>=%zu expected)\n",
length, minlen);
return NULL;
}
length -= start;
if (start + offset < offset) {
dev_err(&dev->dev,
"virtio_pci: map wrap-around %u+%u\n",
start, offset);
return NULL;
}
offset += start;
if (offset & (align - 1)) {
dev_err(&dev->dev,
"virtio_pci: offset %u not aligned to %u\n",
offset, align);
return NULL;
}
if (length > size)
length = size;
if (len)
*len = length;
if (minlen + offset < minlen ||
minlen + offset > pci_resource_len(dev, bar)) {
dev_err(&dev->dev,
"virtio_pci: map virtio %zu@%u "
"out of range on bar %i length %lu\n",
minlen, offset,
bar, (unsigned long)pci_resource_len(dev, bar));
return NULL;
}
p = pci_iomap_range(dev, bar, offset, length);
if (!p)
dev_err(&dev->dev,
"virtio_pci: unable to map virtio %u@%u on bar %i\n",
length, offset, bar);
return p;
}
static void iowrite64_twopart(u64 val, __le32 __iomem *lo, __le32 __iomem *hi)
{
iowrite32((u32)val, lo);
iowrite32(val >> 32, hi);
}
/* virtio config->get_features() implementation */
static u64 vp_get_features(struct virtio_device *vdev)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
u64 features;
iowrite32(0, &vp_dev->common->device_feature_select);
features = ioread32(&vp_dev->common->device_feature);
iowrite32(1, &vp_dev->common->device_feature_select);
features |= ((u64)ioread32(&vp_dev->common->device_feature) << 32);
return features;
}
/* virtio config->finalize_features() implementation */
static int vp_finalize_features(struct virtio_device *vdev)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
/* Give virtio_ring a chance to accept features. */
vring_transport_features(vdev);
if (!__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
dev_err(&vdev->dev, "virtio: device uses modern interface "
"but does not have VIRTIO_F_VERSION_1\n");
return -EINVAL;
}
iowrite32(0, &vp_dev->common->guest_feature_select);
iowrite32((u32)vdev->features, &vp_dev->common->guest_feature);
iowrite32(1, &vp_dev->common->guest_feature_select);
iowrite32(vdev->features >> 32, &vp_dev->common->guest_feature);
return 0;
}
/* virtio config->get() implementation */
static void vp_get(struct virtio_device *vdev, unsigned offset,
void *buf, unsigned len)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
u8 b;
__le16 w;
__le32 l;
BUG_ON(offset + len > vp_dev->device_len);
switch (len) {
case 1:
b = ioread8(vp_dev->device + offset);
memcpy(buf, &b, sizeof b);
break;
case 2:
w = cpu_to_le16(ioread16(vp_dev->device + offset));
memcpy(buf, &w, sizeof w);
break;
case 4:
l = cpu_to_le32(ioread32(vp_dev->device + offset));
memcpy(buf, &l, sizeof l);
break;
case 8:
l = cpu_to_le32(ioread32(vp_dev->device + offset));
memcpy(buf, &l, sizeof l);
l = cpu_to_le32(ioread32(vp_dev->device + offset + sizeof l));
memcpy(buf + sizeof l, &l, sizeof l);
break;
default:
BUG();
}
}
/* the config->set() implementation. it's symmetric to the config->get()
* implementation */
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);
u8 b;
__le16 w;
__le32 l;
BUG_ON(offset + len > vp_dev->device_len);
switch (len) {
case 1:
memcpy(&b, buf, sizeof b);
iowrite8(b, vp_dev->device + offset);
break;
case 2:
memcpy(&w, buf, sizeof w);
iowrite16(le16_to_cpu(w), vp_dev->device + offset);
break;
case 4:
memcpy(&l, buf, sizeof l);
iowrite32(le32_to_cpu(l), vp_dev->device + offset);
break;
case 8:
memcpy(&l, buf, sizeof l);
iowrite32(le32_to_cpu(l), vp_dev->device + offset);
memcpy(&l, buf + sizeof l, sizeof l);
iowrite32(le32_to_cpu(l), vp_dev->device + offset + sizeof l);
break;
default:
BUG();
}
}
static u32 vp_generation(struct virtio_device *vdev)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
return ioread8(&vp_dev->common->config_generation);
}
/* config->{get,set}_status() implementations */
static u8 vp_get_status(struct virtio_device *vdev)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
return ioread8(&vp_dev->common->device_status);
}
static void vp_set_status(struct virtio_device *vdev, u8 status)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
/* We should never be setting status to 0. */
BUG_ON(status == 0);
iowrite8(status, &vp_dev->common->device_status);
}
static void vp_reset(struct virtio_device *vdev)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
/* 0 status means a reset. */
iowrite8(0, &vp_dev->common->device_status);
/* Flush out the status write, and flush in device writes,
* including MSI-X interrupts, if any. */
ioread8(&vp_dev->common->device_status);
/* Flush pending VQ/configuration callbacks. */
vp_synchronize_vectors(vdev);
}
static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
{
/* Setup the vector used for configuration events */
iowrite16(vector, &vp_dev->common->msix_config);
/* Verify we had enough resources to assign the vector */
/* Will also flush the write out to device */
return ioread16(&vp_dev->common->msix_config);
}
static size_t vring_pci_size(u16 num)
{
/* We only need a cacheline separation. */
return PAGE_ALIGN(vring_size(num, SMP_CACHE_BYTES));
}
static void *alloc_virtqueue_pages(int *num)
{
void *pages;
/* TODO: allocate each queue chunk individually */
for (; *num && vring_pci_size(*num) > PAGE_SIZE; *num /= 2) {
pages = alloc_pages_exact(vring_pci_size(*num),
GFP_KERNEL|__GFP_ZERO|__GFP_NOWARN);
if (pages)
return pages;
}
if (!*num)
return NULL;
/* Try to get a single page. You are my only hope! */
return alloc_pages_exact(vring_pci_size(*num), GFP_KERNEL|__GFP_ZERO);
}
static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
struct virtio_pci_vq_info *info,
unsigned index,
void (*callback)(struct virtqueue *vq),
const char *name,
u16 msix_vec)
{
struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
struct virtqueue *vq;
u16 num, off;
int err;
if (index >= ioread16(&cfg->num_queues))
return ERR_PTR(-ENOENT);
/* Select the queue we're interested in */
iowrite16(index, &cfg->queue_select);
/* Check if queue is either not available or already active. */
num = ioread16(&cfg->queue_size);
if (!num || ioread8(&cfg->queue_enable))
return ERR_PTR(-ENOENT);
if (num & (num - 1)) {
dev_warn(&vp_dev->pci_dev->dev, "bad queue size %u", num);
return ERR_PTR(-EINVAL);
}
/* get offset of notification word for this vq */
off = ioread16(&cfg->queue_notify_off);
info->num = num;
info->msix_vector = msix_vec;
info->queue = alloc_virtqueue_pages(&info->num);
if (info->queue == NULL)
return ERR_PTR(-ENOMEM);
/* create the vring */
vq = vring_new_virtqueue(index, info->num,
SMP_CACHE_BYTES, &vp_dev->vdev,
true, info->queue, vp_notify, callback, name);
if (!vq) {
err = -ENOMEM;
goto err_new_queue;
}
/* activate the queue */
iowrite16(num, &cfg->queue_size);
iowrite64_twopart(virt_to_phys(info->queue),
&cfg->queue_desc_lo, &cfg->queue_desc_hi);
iowrite64_twopart(virt_to_phys(virtqueue_get_avail(vq)),
&cfg->queue_avail_lo, &cfg->queue_avail_hi);
iowrite64_twopart(virt_to_phys(virtqueue_get_used(vq)),
&cfg->queue_used_lo, &cfg->queue_used_hi);
vq->priv = (void __force *)map_capability(vp_dev->pci_dev,
vp_dev->notify_map_cap, 2, 2,
off * vp_dev->notify_offset_multiplier, 2,
NULL);
if (!vq->priv) {
err = -ENOMEM;
goto err_map_notify;
}
if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
iowrite16(msix_vec, &cfg->queue_msix_vector);
msix_vec = ioread16(&cfg->queue_msix_vector);
if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
err = -EBUSY;
goto err_assign_vector;
}
}
return vq;
err_assign_vector:
pci_iounmap(vp_dev->pci_dev, (void __iomem __force *)vq->priv);
err_map_notify:
vring_del_virtqueue(vq);
err_new_queue:
free_pages_exact(info->queue, vring_pci_size(info->num));
return ERR_PTR(err);
}
static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
struct virtqueue *vqs[],
vq_callback_t *callbacks[],
const char *names[])
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
struct virtqueue *vq;
int rc = vp_find_vqs(vdev, nvqs, vqs, callbacks, names);
if (rc)
return rc;
/* Select and activate all queues. Has to be done last: once we do
* this, there's no way to go back except reset.
*/
list_for_each_entry(vq, &vdev->vqs, list) {
iowrite16(vq->index, &vp_dev->common->queue_select);
iowrite8(1, &vp_dev->common->queue_enable);
}
return 0;
}
static void del_vq(struct virtio_pci_vq_info *info)
{
struct virtqueue *vq = info->vq;
struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
iowrite16(vq->index, &vp_dev->common->queue_select);
if (vp_dev->msix_enabled) {
iowrite16(VIRTIO_MSI_NO_VECTOR,
&vp_dev->common->queue_msix_vector);
/* Flush the write out to device */
ioread16(&vp_dev->common->queue_msix_vector);
}
pci_iounmap(vp_dev->pci_dev, (void __force __iomem *)vq->priv);
vring_del_virtqueue(vq);
free_pages_exact(info->queue, vring_pci_size(info->num));
}
static const struct virtio_config_ops virtio_pci_config_ops = {
.get = vp_get,
.set = vp_set,
.generation = vp_generation,
.get_status = vp_get_status,
.set_status = vp_set_status,
.reset = vp_reset,
.find_vqs = vp_modern_find_vqs,
.del_vqs = vp_del_vqs,
.get_features = vp_get_features,
.finalize_features = vp_finalize_features,
.bus_name = vp_bus_name,
.set_vq_affinity = vp_set_vq_affinity,
};
/**
* virtio_pci_find_capability - walk capabilities to find device info.
* @dev: the pci device
* @cfg_type: the VIRTIO_PCI_CAP_* value we seek
* @ioresource_types: IORESOURCE_MEM and/or IORESOURCE_IO.
*
* Returns offset of the capability, or 0.
*/
static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type,
u32 ioresource_types)
{
int pos;
for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
pos > 0;
pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
u8 type, bar;
pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
cfg_type),
&type);
pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
bar),
&bar);
/* Ignore structures with reserved BAR values */
if (bar > 0x5)
continue;
if (type == cfg_type) {
if (pci_resource_len(dev, bar) &&
pci_resource_flags(dev, bar) & ioresource_types)
return pos;
}
}
return 0;
}
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);
kfree(vp_dev);
}
/* TODO: validate the ABI statically. */
static inline void check_offsets(void)
{
}
/* the PCI probing function */
int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
{
struct pci_dev *pci_dev = vp_dev->pci_dev;
int err, common, isr, notify, device;
u32 notify_length;
check_offsets();
/* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */
if (pci_dev->device < 0x1000 || pci_dev->device > 0x107f)
return -ENODEV;
if (pci_dev->device < 0x1040) {
/* Transitional devices: use the PCI subsystem device id as
* virtio device id, same as legacy driver always did.
*/
vp_dev->vdev.id.device = pci_dev->subsystem_device;
} else {
/* Modern devices: simply use PCI device id, but start from 0x1040. */
vp_dev->vdev.id.device = pci_dev->device - 0x1040;
}
vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
if (virtio_device_is_legacy_only(vp_dev->vdev.id))
return -ENODEV;
/* check for a common config: if not, use legacy mode (bar 0). */
common = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG,
IORESOURCE_IO | IORESOURCE_MEM);
if (!common) {
dev_info(&pci_dev->dev,
"virtio_pci: leaving for legacy driver\n");
return -ENODEV;
}
/* If common is there, these should be too... */
isr = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_ISR_CFG,
IORESOURCE_IO | IORESOURCE_MEM);
notify = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_NOTIFY_CFG,
IORESOURCE_IO | IORESOURCE_MEM);
if (!isr || !notify) {
dev_err(&pci_dev->dev,
"virtio_pci: missing capabilities %i/%i/%i\n",
common, isr, notify);
return -EINVAL;
}
/* Device capability is only mandatory for devices that have
* device-specific configuration.
*/
device = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_DEVICE_CFG,
IORESOURCE_IO | IORESOURCE_MEM);
err = -EINVAL;
vp_dev->common = map_capability(pci_dev, common,
sizeof(struct virtio_pci_common_cfg), 4,
0, sizeof(struct virtio_pci_common_cfg),
NULL);
if (!vp_dev->common)
goto err_map_common;
vp_dev->isr = map_capability(pci_dev, isr, sizeof(u8), 1,
0, 1,
NULL);
if (!vp_dev->isr)
goto err_map_isr;
/* Read notify_off_multiplier from config space. */
pci_read_config_dword(pci_dev,
notify + offsetof(struct virtio_pci_notify_cap,
notify_off_multiplier),
&vp_dev->notify_offset_multiplier);
/* Read notify length from config space. */
pci_read_config_dword(pci_dev,
notify + offsetof(struct virtio_pci_notify_cap,
cap.length),
&notify_length);
vp_dev->notify_map_cap = notify;
/* Again, we don't know how much we should map, but PAGE_SIZE
* is more than enough for all existing devices.
*/
if (device) {
vp_dev->device = map_capability(pci_dev, device, 0, 4,
0, PAGE_SIZE,
&vp_dev->device_len);
if (!vp_dev->device)
goto err_map_device;
}
vp_dev->vdev.config = &virtio_pci_config_ops;
vp_dev->config_vector = vp_config_vector;
vp_dev->setup_vq = setup_vq;
vp_dev->del_vq = del_vq;
return 0;
err_map_device:
pci_iounmap(pci_dev, vp_dev->isr);
err_map_isr:
pci_iounmap(pci_dev, vp_dev->common);
err_map_common:
return err;
}
void virtio_pci_modern_remove(struct virtio_pci_device *vp_dev)
{
struct pci_dev *pci_dev = vp_dev->pci_dev;
if (vp_dev->device)
pci_iounmap(pci_dev, vp_dev->device);
pci_iounmap(pci_dev, vp_dev->isr);
pci_iounmap(pci_dev, vp_dev->common);
}

View File

@ -117,10 +117,11 @@ struct virtio_pci_cap {
__u8 cap_vndr; /* Generic PCI field: PCI_CAP_ID_VNDR */
__u8 cap_next; /* Generic PCI field: next ptr. */
__u8 cap_len; /* Generic PCI field: capability length */
__u8 type_and_bar; /* Upper 3 bits: bar.
* Lower 3 is VIRTIO_PCI_CAP_*_CFG. */
__u8 cfg_type; /* Identifies the structure. */
__u8 bar; /* Where to find it. */
__u8 padding[3]; /* Pad to full dword. */
__le32 offset; /* Offset within bar. */
__le32 length; /* Length. */
__le32 length; /* Length of the structure, in bytes. */
};
#define VIRTIO_PCI_CAP_BAR_SHIFT 5