linux/drivers/virtio/virtio_mmio.c
Heinz Graalfs 46f9c2b925 virtio_ring: change host notification API
Currently a host kick error is silently ignored and not reflected in
the virtqueue of a particular virtio device.

Changing the notify API for guest->host notification seems to be one
prerequisite in order to be able to handle such errors in the context
where the kick is triggered.

This patch changes the notify API. The notify function must return a
bool return value. It returns false if the host notification failed.

Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-10-29 11:28:11 +10:30

667 lines
17 KiB
C

/*
* Virtio memory mapped device driver
*
* Copyright 2011, ARM Ltd.
*
* This module allows virtio devices to be used over a virtual, memory mapped
* platform device.
*
* The guest device(s) may be instantiated in one of three equivalent ways:
*
* 1. Static platform device in board's code, eg.:
*
* static struct platform_device v2m_virtio_device = {
* .name = "virtio-mmio",
* .id = -1,
* .num_resources = 2,
* .resource = (struct resource []) {
* {
* .start = 0x1001e000,
* .end = 0x1001e0ff,
* .flags = IORESOURCE_MEM,
* }, {
* .start = 42 + 32,
* .end = 42 + 32,
* .flags = IORESOURCE_IRQ,
* },
* }
* };
*
* 2. Device Tree node, eg.:
*
* virtio_block@1e000 {
* compatible = "virtio,mmio";
* reg = <0x1e000 0x100>;
* interrupts = <42>;
* }
*
* 3. Kernel module (or command line) parameter. Can be used more than once -
* one device will be created for each one. Syntax:
*
* [virtio_mmio.]device=<size>@<baseaddr>:<irq>[:<id>]
* where:
* <size> := size (can use standard suffixes like K, M or G)
* <baseaddr> := physical base address
* <irq> := interrupt number (as passed to request_irq())
* <id> := (optional) platform device id
* eg.:
* virtio_mmio.device=0x100@0x100b0000:48 \
* virtio_mmio.device=1K@0x1001e000:74
*
*
*
* Registers layout (all 32-bit wide):
*
* offset d. name description
* ------ -- ---------------- -----------------
*
* 0x000 R MagicValue Magic value "virt"
* 0x004 R Version Device version (current max. 1)
* 0x008 R DeviceID Virtio device ID
* 0x00c R VendorID Virtio vendor ID
*
* 0x010 R HostFeatures Features supported by the host
* 0x014 W HostFeaturesSel Set of host features to access via HostFeatures
*
* 0x020 W GuestFeatures Features activated by the guest
* 0x024 W GuestFeaturesSel Set of activated features to set via GuestFeatures
* 0x028 W GuestPageSize Size of guest's memory page in bytes
*
* 0x030 W QueueSel Queue selector
* 0x034 R QueueNumMax Maximum size of the currently selected queue
* 0x038 W QueueNum Queue size for the currently selected queue
* 0x03c W QueueAlign Used Ring alignment for the current queue
* 0x040 RW QueuePFN PFN for the currently selected queue
*
* 0x050 W QueueNotify Queue notifier
* 0x060 R InterruptStatus Interrupt status register
* 0x064 W InterruptACK Interrupt acknowledge register
* 0x070 RW Status Device status register
*
* 0x100+ RW Device-specific configuration space
*
* Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007
*
* 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 pr_fmt(fmt) "virtio-mmio: " fmt
#include <linux/highmem.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/virtio.h>
#include <linux/virtio_config.h>
#include <linux/virtio_mmio.h>
#include <linux/virtio_ring.h>
/* The alignment to use between consumer and producer parts of vring.
* Currently hardcoded to the page size. */
#define VIRTIO_MMIO_VRING_ALIGN PAGE_SIZE
#define to_virtio_mmio_device(_plat_dev) \
container_of(_plat_dev, struct virtio_mmio_device, vdev)
struct virtio_mmio_device {
struct virtio_device vdev;
struct platform_device *pdev;
void __iomem *base;
unsigned long version;
/* a list of queues so we can dispatch IRQs */
spinlock_t lock;
struct list_head virtqueues;
};
struct virtio_mmio_vq_info {
/* the actual virtqueue */
struct virtqueue *vq;
/* the number of entries in the queue */
unsigned int num;
/* the virtual address of the ring queue */
void *queue;
/* the list node for the virtqueues list */
struct list_head node;
};
/* Configuration interface */
static u32 vm_get_features(struct virtio_device *vdev)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
/* TODO: Features > 32 bits */
writel(0, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL);
return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES);
}
static void vm_finalize_features(struct virtio_device *vdev)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
int i;
/* Give virtio_ring a chance to accept features. */
vring_transport_features(vdev);
for (i = 0; i < ARRAY_SIZE(vdev->features); i++) {
writel(i, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
writel(vdev->features[i],
vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
}
}
static void vm_get(struct virtio_device *vdev, unsigned offset,
void *buf, unsigned len)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
u8 *ptr = buf;
int i;
for (i = 0; i < len; i++)
ptr[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
}
static void vm_set(struct virtio_device *vdev, unsigned offset,
const void *buf, unsigned len)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
const u8 *ptr = buf;
int i;
for (i = 0; i < len; i++)
writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
}
static u8 vm_get_status(struct virtio_device *vdev)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
}
static void vm_set_status(struct virtio_device *vdev, u8 status)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
/* We should never be setting status to 0. */
BUG_ON(status == 0);
writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
}
static void vm_reset(struct virtio_device *vdev)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
/* 0 status means a reset. */
writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
}
/* Transport interface */
/* the notify function used when creating a virt queue */
static bool vm_notify(struct virtqueue *vq)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
/* We write the queue's selector into the notification register to
* signal the other end */
writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
return true;
}
/* Notify all virtqueues on an interrupt. */
static irqreturn_t vm_interrupt(int irq, void *opaque)
{
struct virtio_mmio_device *vm_dev = opaque;
struct virtio_mmio_vq_info *info;
struct virtio_driver *vdrv = container_of(vm_dev->vdev.dev.driver,
struct virtio_driver, driver);
unsigned long status;
unsigned long flags;
irqreturn_t ret = IRQ_NONE;
/* Read and acknowledge interrupts */
status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)
&& vdrv && vdrv->config_changed) {
vdrv->config_changed(&vm_dev->vdev);
ret = IRQ_HANDLED;
}
if (likely(status & VIRTIO_MMIO_INT_VRING)) {
spin_lock_irqsave(&vm_dev->lock, flags);
list_for_each_entry(info, &vm_dev->virtqueues, node)
ret |= vring_interrupt(irq, info->vq);
spin_unlock_irqrestore(&vm_dev->lock, flags);
}
return ret;
}
static void vm_del_vq(struct virtqueue *vq)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
struct virtio_mmio_vq_info *info = vq->priv;
unsigned long flags, size;
unsigned int index = vq->index;
spin_lock_irqsave(&vm_dev->lock, flags);
list_del(&info->node);
spin_unlock_irqrestore(&vm_dev->lock, flags);
vring_del_virtqueue(vq);
/* Select and deactivate the queue */
writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
free_pages_exact(info->queue, size);
kfree(info);
}
static void vm_del_vqs(struct virtio_device *vdev)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
struct virtqueue *vq, *n;
list_for_each_entry_safe(vq, n, &vdev->vqs, list)
vm_del_vq(vq);
free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
}
static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
void (*callback)(struct virtqueue *vq),
const char *name)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
struct virtio_mmio_vq_info *info;
struct virtqueue *vq;
unsigned long flags, size;
int err;
if (!name)
return NULL;
/* Select the queue we're interested in */
writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
/* Queue shouldn't already be set up. */
if (readl(vm_dev->base + VIRTIO_MMIO_QUEUE_PFN)) {
err = -ENOENT;
goto error_available;
}
/* Allocate and fill out our active queue description */
info = kmalloc(sizeof(*info), GFP_KERNEL);
if (!info) {
err = -ENOMEM;
goto error_kmalloc;
}
/* Allocate pages for the queue - start with a queue as big as
* possible (limited by maximum size allowed by device), drop down
* to a minimal size, just big enough to fit descriptor table
* and two rings (which makes it "alignment_size * 2")
*/
info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
/* If the device reports a 0 entry queue, we won't be able to
* use it to perform I/O, and vring_new_virtqueue() can't create
* empty queues anyway, so don't bother to set up the device.
*/
if (info->num == 0) {
err = -ENOENT;
goto error_alloc_pages;
}
while (1) {
size = PAGE_ALIGN(vring_size(info->num,
VIRTIO_MMIO_VRING_ALIGN));
/* Did the last iter shrink the queue below minimum size? */
if (size < VIRTIO_MMIO_VRING_ALIGN * 2) {
err = -ENOMEM;
goto error_alloc_pages;
}
info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
if (info->queue)
break;
info->num /= 2;
}
/* Activate the queue */
writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
writel(VIRTIO_MMIO_VRING_ALIGN,
vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
/* Create the vring */
vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
true, info->queue, vm_notify, callback, name);
if (!vq) {
err = -ENOMEM;
goto error_new_virtqueue;
}
vq->priv = info;
info->vq = vq;
spin_lock_irqsave(&vm_dev->lock, flags);
list_add(&info->node, &vm_dev->virtqueues);
spin_unlock_irqrestore(&vm_dev->lock, flags);
return vq;
error_new_virtqueue:
writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
free_pages_exact(info->queue, size);
error_alloc_pages:
kfree(info);
error_kmalloc:
error_available:
return ERR_PTR(err);
}
static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
struct virtqueue *vqs[],
vq_callback_t *callbacks[],
const char *names[])
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
int i, err;
err = request_irq(irq, vm_interrupt, IRQF_SHARED,
dev_name(&vdev->dev), vm_dev);
if (err)
return err;
for (i = 0; i < nvqs; ++i) {
vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]);
if (IS_ERR(vqs[i])) {
vm_del_vqs(vdev);
return PTR_ERR(vqs[i]);
}
}
return 0;
}
static const char *vm_bus_name(struct virtio_device *vdev)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
return vm_dev->pdev->name;
}
static const struct virtio_config_ops virtio_mmio_config_ops = {
.get = vm_get,
.set = vm_set,
.get_status = vm_get_status,
.set_status = vm_set_status,
.reset = vm_reset,
.find_vqs = vm_find_vqs,
.del_vqs = vm_del_vqs,
.get_features = vm_get_features,
.finalize_features = vm_finalize_features,
.bus_name = vm_bus_name,
};
/* Platform device */
static int virtio_mmio_probe(struct platform_device *pdev)
{
struct virtio_mmio_device *vm_dev;
struct resource *mem;
unsigned long magic;
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mem)
return -EINVAL;
if (!devm_request_mem_region(&pdev->dev, mem->start,
resource_size(mem), pdev->name))
return -EBUSY;
vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
if (!vm_dev)
return -ENOMEM;
vm_dev->vdev.dev.parent = &pdev->dev;
vm_dev->vdev.config = &virtio_mmio_config_ops;
vm_dev->pdev = pdev;
INIT_LIST_HEAD(&vm_dev->virtqueues);
spin_lock_init(&vm_dev->lock);
vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
if (vm_dev->base == NULL)
return -EFAULT;
/* Check magic value */
magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
if (memcmp(&magic, "virt", 4) != 0) {
dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
return -ENODEV;
}
/* Check device version */
vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
if (vm_dev->version != 1) {
dev_err(&pdev->dev, "Version %ld not supported!\n",
vm_dev->version);
return -ENXIO;
}
vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
platform_set_drvdata(pdev, vm_dev);
return register_virtio_device(&vm_dev->vdev);
}
static int virtio_mmio_remove(struct platform_device *pdev)
{
struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
unregister_virtio_device(&vm_dev->vdev);
return 0;
}
/* Devices list parameter */
#if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
static struct device vm_cmdline_parent = {
.init_name = "virtio-mmio-cmdline",
};
static int vm_cmdline_parent_registered;
static int vm_cmdline_id;
static int vm_cmdline_set(const char *device,
const struct kernel_param *kp)
{
int err;
struct resource resources[2] = {};
char *str;
long long int base, size;
unsigned int irq;
int processed, consumed = 0;
struct platform_device *pdev;
/* Consume "size" part of the command line parameter */
size = memparse(device, &str);
/* Get "@<base>:<irq>[:<id>]" chunks */
processed = sscanf(str, "@%lli:%u%n:%d%n",
&base, &irq, &consumed,
&vm_cmdline_id, &consumed);
/*
* sscanf() must processes at least 2 chunks; also there
* must be no extra characters after the last chunk, so
* str[consumed] must be '\0'
*/
if (processed < 2 || str[consumed])
return -EINVAL;
resources[0].flags = IORESOURCE_MEM;
resources[0].start = base;
resources[0].end = base + size - 1;
resources[1].flags = IORESOURCE_IRQ;
resources[1].start = resources[1].end = irq;
if (!vm_cmdline_parent_registered) {
err = device_register(&vm_cmdline_parent);
if (err) {
pr_err("Failed to register parent device!\n");
return err;
}
vm_cmdline_parent_registered = 1;
}
pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
vm_cmdline_id,
(unsigned long long)resources[0].start,
(unsigned long long)resources[0].end,
(int)resources[1].start);
pdev = platform_device_register_resndata(&vm_cmdline_parent,
"virtio-mmio", vm_cmdline_id++,
resources, ARRAY_SIZE(resources), NULL, 0);
if (IS_ERR(pdev))
return PTR_ERR(pdev);
return 0;
}
static int vm_cmdline_get_device(struct device *dev, void *data)
{
char *buffer = data;
unsigned int len = strlen(buffer);
struct platform_device *pdev = to_platform_device(dev);
snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
pdev->resource[0].end - pdev->resource[0].start + 1ULL,
(unsigned long long)pdev->resource[0].start,
(unsigned long long)pdev->resource[1].start,
pdev->id);
return 0;
}
static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
{
buffer[0] = '\0';
device_for_each_child(&vm_cmdline_parent, buffer,
vm_cmdline_get_device);
return strlen(buffer) + 1;
}
static struct kernel_param_ops vm_cmdline_param_ops = {
.set = vm_cmdline_set,
.get = vm_cmdline_get,
};
device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
static int vm_unregister_cmdline_device(struct device *dev,
void *data)
{
platform_device_unregister(to_platform_device(dev));
return 0;
}
static void vm_unregister_cmdline_devices(void)
{
if (vm_cmdline_parent_registered) {
device_for_each_child(&vm_cmdline_parent, NULL,
vm_unregister_cmdline_device);
device_unregister(&vm_cmdline_parent);
vm_cmdline_parent_registered = 0;
}
}
#else
static void vm_unregister_cmdline_devices(void)
{
}
#endif
/* Platform driver */
static struct of_device_id virtio_mmio_match[] = {
{ .compatible = "virtio,mmio", },
{},
};
MODULE_DEVICE_TABLE(of, virtio_mmio_match);
static struct platform_driver virtio_mmio_driver = {
.probe = virtio_mmio_probe,
.remove = virtio_mmio_remove,
.driver = {
.name = "virtio-mmio",
.owner = THIS_MODULE,
.of_match_table = virtio_mmio_match,
},
};
static int __init virtio_mmio_init(void)
{
return platform_driver_register(&virtio_mmio_driver);
}
static void __exit virtio_mmio_exit(void)
{
platform_driver_unregister(&virtio_mmio_driver);
vm_unregister_cmdline_devices();
}
module_init(virtio_mmio_init);
module_exit(virtio_mmio_exit);
MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
MODULE_LICENSE("GPL");