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virtio/vhost: new features, performance improvements, cleanups 

This adds basic polling support for vhost.
 Reworks virtio to optionally use DMA API, fixing it on Xen.
 Balloon stats gained a new entry.
 Using the new napi_alloc_skb speeds up virtio net.
 virtio blk stats can now be read while another VCPU
 us busy inflating or deflating the balloon.
 Plus misc cleanups in various places.
 
 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio/vhost updates from Michael Tsirkin:
 "New features, performance improvements, cleanups:

   - basic polling support for vhost
   - rework virtio to optionally use DMA API, fixing it on Xen
   - balloon stats gained a new entry
   - using the new napi_alloc_skb speeds up virtio net
   - virtio blk stats can now be read while another VCPU is busy
     inflating or deflating the balloon

  plus misc cleanups in various places"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio_net: replace netdev_alloc_skb_ip_align() with napi_alloc_skb()
  vhost_net: basic polling support
  vhost: introduce vhost_vq_avail_empty()
  vhost: introduce vhost_has_work()
  virtio_balloon: Allow to resize and update the balloon stats in parallel
  virtio_balloon: Use a workqueue instead of "vballoon" kthread
  virtio/s390: size of SET_IND payload
  virtio/s390: use dev_to_virtio
  vhost: rename vhost_init_used()
  vhost: rename cross-endian helpers
  virtio_blk: VIRTIO_BLK_F_WCE->VIRTIO_BLK_F_FLUSH
  vring: Use the DMA API on Xen
  virtio_pci: Use the DMA API if enabled
  virtio_mmio: Use the DMA API if enabled
  virtio: Add improved queue allocation API
  virtio_ring: Support DMA APIs
  vring: Introduce vring_use_dma_api()
  s390/dma: Allow per device dma ops
  alpha/dma: use common noop dma ops
  dma: Provide simple noop dma ops
This commit is contained in:
Linus Torvalds 2016-03-20 13:28:18 -07:00
parent 2b2f72d8ce c67f5db820
commit f0691533b7
29 changed files with 821 additions and 333 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
arch/alpha/kernel/pci-noop.c
View File

@ -123,44 +123,6 @@ static void *alpha_noop_alloc_coherent(struct device *dev, size_t size,
return ret;
}
static void alpha_noop_free_coherent(struct device *dev, size_t size,
void *cpu_addr, dma_addr_t dma_addr,
struct dma_attrs *attrs)
{
free_pages((unsigned long)cpu_addr, get_order(size));
}
static dma_addr_t alpha_noop_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction dir,
struct dma_attrs *attrs)
{
return page_to_pa(page) + offset;
}
static int alpha_noop_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
enum dma_data_direction dir, struct dma_attrs *attrs)
{
int i;
struct scatterlist *sg;
for_each_sg(sgl, sg, nents, i) {
void *va;
BUG_ON(!sg_page(sg));
va = sg_virt(sg);
sg_dma_address(sg) = (dma_addr_t)virt_to_phys(va);
sg_dma_len(sg) = sg->length;
}
return nents;
}
static int alpha_noop_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
return 0;
}
static int alpha_noop_supported(struct device *dev, u64 mask)
{
return mask < 0x00ffffffUL ? 0 : 1;
@ -168,10 +130,10 @@ static int alpha_noop_supported(struct device *dev, u64 mask)
struct dma_map_ops alpha_noop_ops = {
.alloc = alpha_noop_alloc_coherent,
.free = alpha_noop_free_coherent,
.map_page = alpha_noop_map_page,
.map_sg = alpha_noop_map_sg,
.mapping_error = alpha_noop_mapping_error,
.free = dma_noop_free_coherent,
.map_page = dma_noop_map_page,
.map_sg = dma_noop_map_sg,
.mapping_error = dma_noop_mapping_error,
.dma_supported = alpha_noop_supported,
};

5
arch/s390/Kconfig
View File

@ -124,6 +124,7 @@ config S390
select HAVE_CMPXCHG_DOUBLE
select HAVE_CMPXCHG_LOCAL
select HAVE_DEBUG_KMEMLEAK
select HAVE_DMA_API_DEBUG
select HAVE_DYNAMIC_FTRACE
select HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_FTRACE_MCOUNT_RECORD
@ -617,10 +618,6 @@ config HAS_IOMEM
config IOMMU_HELPER
def_bool PCI
config HAS_DMA
def_bool PCI
select HAVE_DMA_API_DEBUG
config NEED_SG_DMA_LENGTH
def_bool PCI

6
arch/s390/include/asm/device.h
View File

@ -3,5 +3,9 @@
*
* This file is released under the GPLv2
*/
#include <asm-generic/device.h>
struct dev_archdata {
struct dma_map_ops *dma_ops;
};
struct pdev_archdata {
};

6
arch/s390/include/asm/dma-mapping.h
View File

@ -11,11 +11,13 @@
#define DMA_ERROR_CODE (~(dma_addr_t) 0x0)
extern struct dma_map_ops s390_dma_ops;
extern struct dma_map_ops s390_pci_dma_ops;
static inline struct dma_map_ops *get_dma_ops(struct device *dev)
{
return &s390_dma_ops;
if (dev && dev->archdata.dma_ops)
return dev->archdata.dma_ops;
return &dma_noop_ops;
}
static inline void dma_cache_sync(struct device *dev, void *vaddr, size_t size,

1
arch/s390/pci/pci.c
View File

@ -641,6 +641,7 @@ int pcibios_add_device(struct pci_dev *pdev)
int i;
pdev->dev.groups = zpci_attr_groups;
pdev->dev.archdata.dma_ops = &s390_pci_dma_ops;
zpci_map_resources(pdev);
for (i = 0; i < PCI_BAR_COUNT; i++) {

4
arch/s390/pci/pci_dma.c
View File

@ -547,7 +547,7 @@ static int __init dma_debug_do_init(void)
}
fs_initcall(dma_debug_do_init);
struct dma_map_ops s390_dma_ops = {
struct dma_map_ops s390_pci_dma_ops = {
.alloc = s390_dma_alloc,
.free = s390_dma_free,
.map_sg = s390_dma_map_sg,
@ -558,7 +558,7 @@ struct dma_map_ops s390_dma_ops = {
.is_phys = 0,
/* dma_supported is unconditionally true without a callback */
};
EXPORT_SYMBOL_GPL(s390_dma_ops);
EXPORT_SYMBOL_GPL(s390_pci_dma_ops);
static int __init s390_iommu_setup(char *str)
{

11
drivers/block/virtio_blk.c
View File

@ -477,8 +477,13 @@ static int virtblk_get_cache_mode(struct virtio_device *vdev)
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE,
struct virtio_blk_config, wce,
&writeback);
/*
* If WCE is not configurable and flush is not available,
* assume no writeback cache is in use.
*/
if (err)
writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE);
writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH);
return writeback;
}
@ -833,14 +838,14 @@ static const struct virtio_device_id id_table[] = {
static unsigned int features_legacy[] = {
VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI,
VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
VIRTIO_BLK_F_MQ,
}
;
static unsigned int features[] = {
VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
VIRTIO_BLK_F_MQ,
};

2
drivers/net/virtio_net.c
View File

@ -260,7 +260,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
p = page_address(page) + offset;
/* copy small packet so we can reuse these pages for small data */
skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
skb = napi_alloc_skb(&rq->napi, GOOD_COPY_LEN);
if (unlikely(!skb))
return NULL;

15
drivers/s390/virtio/virtio_ccw.c
View File

@ -342,13 +342,14 @@ static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
ccw->count = sizeof(*thinint_area);
ccw->cda = (__u32)(unsigned long) thinint_area;
} else {
/* payload is the address of the indicators */
indicatorp = kmalloc(sizeof(&vcdev->indicators),
GFP_DMA | GFP_KERNEL);
if (!indicatorp)
return;
*indicatorp = 0;
ccw->cmd_code = CCW_CMD_SET_IND;
ccw->count = sizeof(vcdev->indicators);
ccw->count = sizeof(&vcdev->indicators);
ccw->cda = (__u32)(unsigned long) indicatorp;
}
/* Deregister indicators from host. */
@ -656,7 +657,10 @@ static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
}
}
ret = -ENOMEM;
/* We need a data area under 2G to communicate. */
/*
* We need a data area under 2G to communicate. Our payload is
* the address of the indicators.
*/
indicatorp = kmalloc(sizeof(&vcdev->indicators), GFP_DMA | GFP_KERNEL);
if (!indicatorp)
goto out;
@ -672,7 +676,7 @@ static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
vcdev->indicators = 0;
ccw->cmd_code = CCW_CMD_SET_IND;
ccw->flags = 0;
ccw->count = sizeof(vcdev->indicators);
ccw->count = sizeof(&vcdev->indicators);
ccw->cda = (__u32)(unsigned long) indicatorp;
ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_SET_IND);
if (ret)
@ -683,7 +687,7 @@ static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
vcdev->indicators2 = 0;
ccw->cmd_code = CCW_CMD_SET_CONF_IND;
ccw->flags = 0;
ccw->count = sizeof(vcdev->indicators2);
ccw->count = sizeof(&vcdev->indicators2);
ccw->cda = (__u32)(unsigned long) indicatorp;
ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_SET_CONF_IND);
if (ret)
@ -945,8 +949,7 @@ static struct virtio_config_ops virtio_ccw_config_ops = {
static void virtio_ccw_release_dev(struct device *_d)
{
struct virtio_device *dev = container_of(_d, struct virtio_device,
dev);
struct virtio_device *dev = dev_to_virtio(_d);
struct virtio_ccw_device *vcdev = to_vc_device(dev);
kfree(vcdev->status);

80
drivers/vhost/net.c
View File

@ -287,6 +287,43 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success)
rcu_read_unlock_bh();
}
static inline unsigned long busy_clock(void)
{
return local_clock() >> 10;
}
static bool vhost_can_busy_poll(struct vhost_dev *dev,
unsigned long endtime)
{
return likely(!need_resched()) &&
likely(!time_after(busy_clock(), endtime)) &&
likely(!signal_pending(current)) &&
!vhost_has_work(dev);
}
static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
struct vhost_virtqueue *vq,
struct iovec iov[], unsigned int iov_size,
unsigned int *out_num, unsigned int *in_num)
{
unsigned long uninitialized_var(endtime);
int r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
out_num, in_num, NULL, NULL);
if (r == vq->num && vq->busyloop_timeout) {
preempt_disable();
endtime = busy_clock() + vq->busyloop_timeout;
while (vhost_can_busy_poll(vq->dev, endtime) &&
vhost_vq_avail_empty(vq->dev, vq))
cpu_relax_lowlatency();
preempt_enable();
r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
out_num, in_num, NULL, NULL);
}
return r;
}
/* Expects to be always run from workqueue - which acts as
* read-size critical section for our kind of RCU. */
static void handle_tx(struct vhost_net *net)
@ -331,10 +368,9 @@ static void handle_tx(struct vhost_net *net)
% UIO_MAXIOV == nvq->done_idx))
break;
head = vhost_get_vq_desc(vq, vq->iov,
ARRAY_SIZE(vq->iov),
&out, &in,
NULL, NULL);
head = vhost_net_tx_get_vq_desc(net, vq, vq->iov,
ARRAY_SIZE(vq->iov),
&out, &in);
/* On error, stop handling until the next kick. */
if (unlikely(head < 0))
break;
@ -435,6 +471,38 @@ static int peek_head_len(struct sock *sk)
return len;
}
static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk)
{
struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
struct vhost_virtqueue *vq = &nvq->vq;
unsigned long uninitialized_var(endtime);
int len = peek_head_len(sk);
if (!len && vq->busyloop_timeout) {
/* Both tx vq and rx socket were polled here */
mutex_lock(&vq->mutex);
vhost_disable_notify(&net->dev, vq);
preempt_disable();
endtime = busy_clock() + vq->busyloop_timeout;
while (vhost_can_busy_poll(&net->dev, endtime) &&
skb_queue_empty(&sk->sk_receive_queue) &&
vhost_vq_avail_empty(&net->dev, vq))
cpu_relax_lowlatency();
preempt_enable();
if (vhost_enable_notify(&net->dev, vq))
vhost_poll_queue(&vq->poll);
mutex_unlock(&vq->mutex);
len = peek_head_len(sk);
}
return len;
}
/* This is a multi-buffer version of vhost_get_desc, that works if
* vq has read descriptors only.
* @vq - the relevant virtqueue
@ -553,7 +621,7 @@ static void handle_rx(struct vhost_net *net)
vq->log : NULL;
mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF);
while ((sock_len = peek_head_len(sock->sk))) {
while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk))) {
sock_len += sock_hlen;
vhost_len = sock_len + vhost_hlen;
headcount = get_rx_bufs(vq, vq->heads, vhost_len,
@ -917,7 +985,7 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
vhost_net_disable_vq(n, vq);
vq->private_data = sock;
r = vhost_init_used(vq);
r = vhost_vq_init_access(vq);
if (r)
goto err_used;
r = vhost_net_enable_vq(n, vq);

2
drivers/vhost/scsi.c
View File

@ -1274,7 +1274,7 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
vq = &vs->vqs[i].vq;
mutex_lock(&vq->mutex);
vq->private_data = vs_tpg;
vhost_init_used(vq);
vhost_vq_init_access(vq);
mutex_unlock(&vq->mutex);
}
ret = 0;

2
drivers/vhost/test.c
View File

@ -196,7 +196,7 @@ static long vhost_test_run(struct vhost_test *n, int test)
oldpriv = vq->private_data;
vq->private_data = priv;
r = vhost_init_used(&n->vqs[index]);
r = vhost_vq_init_access(&n->vqs[index]);
mutex_unlock(&vq->mutex);

69
drivers/vhost/vhost.c
View File

@ -43,11 +43,21 @@ enum {
#define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num])
#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
static void vhost_vq_reset_user_be(struct vhost_virtqueue *vq)
static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
{
vq->user_be = !virtio_legacy_is_little_endian();
}
static void vhost_enable_cross_endian_big(struct vhost_virtqueue *vq)
{
vq->user_be = true;
}
static void vhost_enable_cross_endian_little(struct vhost_virtqueue *vq)
{
vq->user_be = false;
}
static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
{
struct vhost_vring_state s;
@ -62,7 +72,10 @@ static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
s.num != VHOST_VRING_BIG_ENDIAN)
return -EINVAL;
vq->user_be = s.num;
if (s.num == VHOST_VRING_BIG_ENDIAN)
vhost_enable_cross_endian_big(vq);
else
vhost_enable_cross_endian_little(vq);
return 0;
}
@ -91,7 +104,7 @@ static void vhost_init_is_le(struct vhost_virtqueue *vq)
vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) || !vq->user_be;
}
#else
static void vhost_vq_reset_user_be(struct vhost_virtqueue *vq)
static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
{
}
@ -113,6 +126,11 @@ static void vhost_init_is_le(struct vhost_virtqueue *vq)
}
#endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
static void vhost_reset_is_le(struct vhost_virtqueue *vq)
{
vq->is_le = virtio_legacy_is_little_endian();
}
static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
poll_table *pt)
{
@ -245,6 +263,13 @@ void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)
}
EXPORT_SYMBOL_GPL(vhost_work_queue);
/* A lockless hint for busy polling code to exit the loop */
bool vhost_has_work(struct vhost_dev *dev)
{
return !list_empty(&dev->work_list);
}
EXPORT_SYMBOL_GPL(vhost_has_work);
void vhost_poll_queue(struct vhost_poll *poll)
{
vhost_work_queue(poll->dev, &poll->work);
@ -276,8 +301,9 @@ static void vhost_vq_reset(struct vhost_dev *dev,
vq->call = NULL;
vq->log_ctx = NULL;
vq->memory = NULL;
vq->is_le = virtio_legacy_is_little_endian();
vhost_vq_reset_user_be(vq);
vhost_reset_is_le(vq);
vhost_disable_cross_endian(vq);
vq->busyloop_timeout = 0;
}
static int vhost_worker(void *data)
@ -912,6 +938,19 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
case VHOST_GET_VRING_ENDIAN:
r = vhost_get_vring_endian(vq, idx, argp);
break;
case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
if (copy_from_user(&s, argp, sizeof(s))) {
r = -EFAULT;
break;
}
vq->busyloop_timeout = s.num;
break;
case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
s.index = idx;
s.num = vq->busyloop_timeout;
if (copy_to_user(argp, &s, sizeof(s)))
r = -EFAULT;
break;
default:
r = -ENOIOCTLCMD;
}
@ -1152,14 +1191,14 @@ static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
return 0;
}
int vhost_init_used(struct vhost_virtqueue *vq)
int vhost_vq_init_access(struct vhost_virtqueue *vq)
{
__virtio16 last_used_idx;
int r;
bool is_le = vq->is_le;
if (!vq->private_data) {
vq->is_le = virtio_legacy_is_little_endian();
vhost_reset_is_le(vq);
return 0;
}
@ -1182,7 +1221,7 @@ err:
vq->is_le = is_le;
return r;
}
EXPORT_SYMBOL_GPL(vhost_init_used);
EXPORT_SYMBOL_GPL(vhost_vq_init_access);
static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
struct iovec iov[], int iov_size)
@ -1633,6 +1672,20 @@ void vhost_add_used_and_signal_n(struct vhost_dev *dev,
}
EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
/* return true if we're sure that avaiable ring is empty */
bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
{
__virtio16 avail_idx;
int r;
r = __get_user(avail_idx, &vq->avail->idx);
if (r)
return false;
return vhost16_to_cpu(vq, avail_idx) == vq->avail_idx;
}
EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
/* OK, now we need to know about added descriptors. */
bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
{

5
drivers/vhost/vhost.h
View File

@ -37,6 +37,7 @@ struct vhost_poll {
void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
bool vhost_has_work(struct vhost_dev *dev);
void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
unsigned long mask, struct vhost_dev *dev);
@ -114,6 +115,7 @@ struct vhost_virtqueue {
/* Ring endianness requested by userspace for cross-endian support. */
bool user_be;
#endif
u32 busyloop_timeout;
};
struct vhost_dev {
@ -148,7 +150,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *,
struct vhost_log *log, unsigned int *log_num);
void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
int vhost_init_used(struct vhost_virtqueue *);
int vhost_vq_init_access(struct vhost_virtqueue *);
int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
unsigned count);
@ -158,6 +160,7 @@ void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
struct vring_used_elem *heads, unsigned count);
void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,

2
drivers/virtio/Kconfig
View File

@ -60,7 +60,7 @@ config VIRTIO_INPUT
config VIRTIO_MMIO
tristate "Platform bus driver for memory mapped virtio devices"
depends on HAS_IOMEM
depends on HAS_IOMEM && HAS_DMA
select VIRTIO
---help---
This drivers provides support for memory mapped virtio

116
drivers/virtio/virtio_balloon.c
View File

@ -22,8 +22,7 @@
#include <linux/virtio.h>
#include <linux/virtio_balloon.h>
#include <linux/swap.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/workqueue.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/module.h>
@ -50,11 +49,13 @@ struct virtio_balloon {
struct virtio_device *vdev;
struct virtqueue *inflate_vq, *deflate_vq, *stats_vq;
/* Where the ballooning thread waits for config to change. */
wait_queue_head_t config_change;
/* The balloon servicing is delegated to a freezable workqueue. */
struct work_struct update_balloon_stats_work;
struct work_struct update_balloon_size_work;
/* The thread servicing the balloon. */
struct task_struct *thread;
/* Prevent updating balloon when it is being canceled. */
spinlock_t stop_update_lock;
bool stop_update;
/* Waiting for host to ack the pages we released. */
wait_queue_head_t acked;
@ -77,7 +78,6 @@ struct virtio_balloon {
u32 pfns[VIRTIO_BALLOON_ARRAY_PFNS_MAX];
/* Memory statistics */
int need_stats_update;
struct virtio_balloon_stat stats[VIRTIO_BALLOON_S_NR];
/* To register callback in oom notifier call chain */
@ -124,6 +124,7 @@ static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq)
/* When host has read buffer, this completes via balloon_ack */
wait_event(vb->acked, virtqueue_get_buf(vq, &len));
}
static void set_page_pfns(u32 pfns[], struct page *page)
@ -136,9 +137,10 @@ static void set_page_pfns(u32 pfns[], struct page *page)
pfns[i] = page_to_balloon_pfn(page) + i;
}
static void fill_balloon(struct virtio_balloon *vb, size_t num)
static unsigned fill_balloon(struct virtio_balloon *vb, size_t num)
{
struct balloon_dev_info *vb_dev_info = &vb->vb_dev_info;
unsigned num_allocated_pages;
/* We can only do one array worth at a time. */
num = min(num, ARRAY_SIZE(vb->pfns));
@ -163,10 +165,13 @@ static void fill_balloon(struct virtio_balloon *vb, size_t num)
adjust_managed_page_count(page, -1);
}
num_allocated_pages = vb->num_pfns;
/* Did we get any? */
if (vb->num_pfns != 0)
tell_host(vb, vb->inflate_vq);
mutex_unlock(&vb->balloon_lock);
return num_allocated_pages;
}
static void release_pages_balloon(struct virtio_balloon *vb)
@ -257,14 +262,17 @@ static void update_balloon_stats(struct virtio_balloon *vb)
* with a single buffer. From that point forward, all conversations consist of
* a hypervisor request (a call to this function) which directs us to refill
* the virtqueue with a fresh stats buffer. Since stats collection can sleep,
* we notify our kthread which does the actual work via stats_handle_request().
* we delegate the job to a freezable workqueue that will do the actual work via
* stats_handle_request().
*/
static void stats_request(struct virtqueue *vq)
{
struct virtio_balloon *vb = vq->vdev->priv;
vb->need_stats_update = 1;
wake_up(&vb->config_change);
spin_lock(&vb->stop_update_lock);
if (!vb->stop_update)
queue_work(system_freezable_wq, &vb->update_balloon_stats_work);
spin_unlock(&vb->stop_update_lock);
}
static void stats_handle_request(struct virtio_balloon *vb)
@ -273,7 +281,6 @@ static void stats_handle_request(struct virtio_balloon *vb)
struct scatterlist sg;
unsigned int len;
vb->need_stats_update = 0;
update_balloon_stats(vb);
vq = vb->stats_vq;
@ -287,8 +294,12 @@ static void stats_handle_request(struct virtio_balloon *vb)
static void virtballoon_changed(struct virtio_device *vdev)
{
struct virtio_balloon *vb = vdev->priv;
unsigned long flags;
wake_up(&vb->config_change);
spin_lock_irqsave(&vb->stop_update_lock, flags);
if (!vb->stop_update)
queue_work(system_freezable_wq, &vb->update_balloon_size_work);
spin_unlock_irqrestore(&vb->stop_update_lock, flags);
}
static inline s64 towards_target(struct virtio_balloon *vb)
@ -351,43 +362,32 @@ static int virtballoon_oom_notify(struct notifier_block *self,
return NOTIFY_OK;
}
static int balloon(void *_vballoon)
static void update_balloon_stats_func(struct work_struct *work)
{
struct virtio_balloon *vb = _vballoon;
DEFINE_WAIT_FUNC(wait, woken_wake_function);
struct virtio_balloon *vb;
set_freezable();
while (!kthread_should_stop()) {
s64 diff;
vb = container_of(work, struct virtio_balloon,
update_balloon_stats_work);
stats_handle_request(vb);
}
try_to_freeze();
static void update_balloon_size_func(struct work_struct *work)
{
struct virtio_balloon *vb;
s64 diff;
add_wait_queue(&vb->config_change, &wait);
for (;;) {
if ((diff = towards_target(vb)) != 0 ||
vb->need_stats_update ||
kthread_should_stop() ||
freezing(current))
break;
wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
}
remove_wait_queue(&vb->config_change, &wait);
vb = container_of(work, struct virtio_balloon,
update_balloon_size_work);
diff = towards_target(vb);
if (vb->need_stats_update)
stats_handle_request(vb);
if (diff > 0)
fill_balloon(vb, diff);
else if (diff < 0)
leak_balloon(vb, -diff);
update_balloon_size(vb);
if (diff > 0)
diff -= fill_balloon(vb, diff);
else if (diff < 0)
diff += leak_balloon(vb, -diff);
update_balloon_size(vb);
/*
* For large balloon changes, we could spend a lot of time
* and always have work to do. Be nice if preempt disabled.
*/
cond_resched();
}
return 0;
if (diff)
queue_work(system_freezable_wq, work);
}
static int init_vqs(struct virtio_balloon *vb)
@ -505,12 +505,14 @@ static int virtballoon_probe(struct virtio_device *vdev)
goto out;
}
INIT_WORK(&vb->update_balloon_stats_work, update_balloon_stats_func);
INIT_WORK(&vb->update_balloon_size_work, update_balloon_size_func);
spin_lock_init(&vb->stop_update_lock);
vb->stop_update = false;
vb->num_pages = 0;
mutex_init(&vb->balloon_lock);
init_waitqueue_head(&vb->config_change);
init_waitqueue_head(&vb->acked);
vb->vdev = vdev;
vb->need_stats_update = 0;
balloon_devinfo_init(&vb->vb_dev_info);
#ifdef CONFIG_BALLOON_COMPACTION
@ -529,16 +531,8 @@ static int virtballoon_probe(struct virtio_device *vdev)
virtio_device_ready(vdev);
vb->thread = kthread_run(balloon, vb, "vballoon");
if (IS_ERR(vb->thread)) {
err = PTR_ERR(vb->thread);
goto out_del_vqs;
}
return 0;
out_del_vqs:
unregister_oom_notifier(&vb->nb);
out_oom_notify:
vdev->config->del_vqs(vdev);
out_free_vb:
@ -565,7 +559,13 @@ static void virtballoon_remove(struct virtio_device *vdev)
struct virtio_balloon *vb = vdev->priv;
unregister_oom_notifier(&vb->nb);
kthread_stop(vb->thread);
spin_lock_irq(&vb->stop_update_lock);
vb->stop_update = true;
spin_unlock_irq(&vb->stop_update_lock);
cancel_work_sync(&vb->update_balloon_size_work);
cancel_work_sync(&vb->update_balloon_stats_work);
remove_common(vb);
kfree(vb);
}
@ -576,10 +576,9 @@ static int virtballoon_freeze(struct virtio_device *vdev)
struct virtio_balloon *vb = vdev->priv;
/*
* The kthread is already frozen by the PM core before this
* The workqueue is already frozen by the PM core before this
* function is called.
*/
remove_common(vb);
return 0;
}
@ -595,7 +594,8 @@ static int virtballoon_restore(struct virtio_device *vdev)
virtio_device_ready(vdev);
fill_balloon(vb, towards_target(vb));
if (towards_target(vb))
virtballoon_changed(vdev);
update_balloon_size(vb);
return 0;
}

67
drivers/virtio/virtio_mmio.c
View File

@ -99,12 +99,6 @@ 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;
};
@ -322,15 +316,13 @@ 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 long flags;
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);
if (vm_dev->version == 1) {
@ -340,8 +332,8 @@ static void vm_del_vq(struct virtqueue *vq)
WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
}
size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
free_pages_exact(info->queue, size);
vring_del_virtqueue(vq);
kfree(info);
}
@ -356,8 +348,6 @@ static void vm_del_vqs(struct virtio_device *vdev)
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)
@ -365,7 +355,8 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
struct virtio_mmio_vq_info *info;
struct virtqueue *vq;
unsigned long flags, size;
unsigned long flags;
unsigned int num;
int err;
if (!name)
@ -388,66 +379,40 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
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) {
num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
if (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;
goto error_new_virtqueue;
}
/* Create the vring */
vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
true, info->queue, vm_notify, callback, name);
vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev,
true, true, vm_notify, callback, name);
if (!vq) {
err = -ENOMEM;
goto error_new_virtqueue;
}
/* Activate the queue */
writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
writel(virtqueue_get_vring_size(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
if (vm_dev->version == 1) {
writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
writel(virtqueue_get_desc_addr(vq) >> PAGE_SHIFT,
vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
} else {
u64 addr;
addr = virt_to_phys(info->queue);
addr = virtqueue_get_desc_addr(vq);
writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_LOW);
writel((u32)(addr >> 32),
vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_HIGH);
addr = virt_to_phys(virtqueue_get_avail(vq));
addr = virtqueue_get_avail_addr(vq);
writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_LOW);
writel((u32)(addr >> 32),
vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_HIGH);
addr = virt_to_phys(virtqueue_get_used(vq));
addr = virtqueue_get_used_addr(vq);
writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_USED_LOW);
writel((u32)(addr >> 32),
vm_dev->base + VIRTIO_MMIO_QUEUE_USED_HIGH);
@ -471,8 +436,6 @@ error_new_virtqueue:
writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
}
free_pages_exact(info->queue, size);
error_alloc_pages:
kfree(info);
error_kmalloc:
error_available:

6
drivers/virtio/virtio_pci_common.h
View File

@ -35,12 +35,6 @@ struct virtio_pci_vq_info {
/* the actual virtqueue */
struct virtqueue *vq;
/* the number of entries in the queue */
int num;
/* the virtual address of the ring queue */
void *queue;
/* the list node for the virtqueues list */
struct list_head node;

42
drivers/virtio/virtio_pci_legacy.c
View File

@ -119,7 +119,6 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
u16 msix_vec)
{
struct virtqueue *vq;
unsigned long size;
u16 num;
int err;
@ -131,27 +130,19 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN))
return ERR_PTR(-ENOENT);
info->num = num;
info->msix_vector = msix_vec;
size = PAGE_ALIGN(vring_size(num, VIRTIO_PCI_VRING_ALIGN));
info->queue = alloc_pages_exact(size, GFP_KERNEL|__GFP_ZERO);
if (info->queue == NULL)
/* create the vring */
vq = vring_create_virtqueue(index, num,
VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,
true, false, vp_notify, callback, name);
if (!vq)
return ERR_PTR(-ENOMEM);
/* activate the queue */
iowrite32(virt_to_phys(info->queue) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT,
iowrite32(virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT,
vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
/* create the vring */
vq = vring_new_virtqueue(index, info->num,
VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,
true, info->queue, vp_notify, callback, name);
if (!vq) {
err = -ENOMEM;
goto out_activate_queue;
}
vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
@ -159,17 +150,15 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
err = -EBUSY;
goto out_assign;
goto out_deactivate;
}
}
return vq;
out_assign:
vring_del_virtqueue(vq);
out_activate_queue:
out_deactivate:
iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
free_pages_exact(info->queue, size);
vring_del_virtqueue(vq);
return ERR_PTR(err);
}
@ -177,7 +166,6 @@ 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);
unsigned long size;
iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
@ -188,13 +176,10 @@ static void del_vq(struct virtio_pci_vq_info *info)
ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR);
}
vring_del_virtqueue(vq);
/* Select and deactivate the queue */
iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
size = PAGE_ALIGN(vring_size(info->num, VIRTIO_PCI_VRING_ALIGN));
free_pages_exact(info->queue, size);
vring_del_virtqueue(vq);
}
static const struct virtio_config_ops virtio_pci_config_ops = {
@ -227,6 +212,13 @@ int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)
return -ENODEV;
}
rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(64));
if (rc)
rc = dma_set_mask_and_coherent(&pci_dev->dev,
DMA_BIT_MASK(32));
if (rc)
dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA. Trying to continue, but this might not work.\n");
rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy");
if (rc)
return rc;

61
drivers/virtio/virtio_pci_modern.c
View File

@ -287,31 +287,6 @@ static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
return vp_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,
@ -343,29 +318,22 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
/* get offset of notification word for this vq */
off = vp_ioread16(&cfg->queue_notify_off);
info->num = num;
info->msix_vector = msix_vec;
info->queue = alloc_virtqueue_pages(&info->num);
if (info->queue == NULL)
/* create the vring */
vq = vring_create_virtqueue(index, num,
SMP_CACHE_BYTES, &vp_dev->vdev,
true, true, vp_notify, callback, name);
if (!vq)
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 */
vp_iowrite16(num, &cfg->queue_size);
vp_iowrite64_twopart(virt_to_phys(info->queue),
vp_iowrite16(virtqueue_get_vring_size(vq), &cfg->queue_size);
vp_iowrite64_twopart(virtqueue_get_desc_addr(vq),
&cfg->queue_desc_lo, &cfg->queue_desc_hi);
vp_iowrite64_twopart(virt_to_phys(virtqueue_get_avail(vq)),
vp_iowrite64_twopart(virtqueue_get_avail_addr(vq),
&cfg->queue_avail_lo, &cfg->queue_avail_hi);
vp_iowrite64_twopart(virt_to_phys(virtqueue_get_used(vq)),
vp_iowrite64_twopart(virtqueue_get_used_addr(vq),
&cfg->queue_used_lo, &cfg->queue_used_hi);
if (vp_dev->notify_base) {
@ -410,8 +378,6 @@ 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);
}
@ -456,8 +422,6 @@ static void del_vq(struct virtio_pci_vq_info *info)
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_nodev_ops = {
@ -641,6 +605,13 @@ int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
return -EINVAL;
}
err = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(64));
if (err)
err = dma_set_mask_and_coherent(&pci_dev->dev,
DMA_BIT_MASK(32));
if (err)
dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA. Trying to continue, but this might not work.\n");
/* Device capability is only mandatory for devices that have
* device-specific configuration.
*/

441
drivers/virtio/virtio_ring.c
View File

@ -24,6 +24,8 @@
#include <linux/module.h>
#include <linux/hrtimer.h>
#include <linux/kmemleak.h>
#include <linux/dma-mapping.h>
#include <xen/xen.h>
#ifdef DEBUG
/* For development, we want to crash whenever the ring is screwed. */
@ -54,6 +56,11 @@
#define END_USE(vq)
#endif
struct vring_desc_state {
void *data; /* Data for callback. */
struct vring_desc *indir_desc; /* Indirect descriptor, if any. */
};
struct vring_virtqueue {
struct virtqueue vq;
@ -89,6 +96,11 @@ struct vring_virtqueue {
/* How to notify other side. FIXME: commonalize hcalls! */
bool (*notify)(struct virtqueue *vq);
/* DMA, allocation, and size information */
bool we_own_ring;
size_t queue_size_in_bytes;
dma_addr_t queue_dma_addr;
#ifdef DEBUG
/* They're supposed to lock for us. */
unsigned int in_use;
@ -98,12 +110,120 @@ struct vring_virtqueue {
ktime_t last_add_time;
#endif
/* Tokens for callbacks. */
void *data[];
/* Per-descriptor state. */
struct vring_desc_state desc_state[];
};
#define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq)
/*
* The interaction between virtio and a possible IOMMU is a mess.
*
* On most systems with virtio, physical addresses match bus addresses,
* and it doesn't particularly matter whether we use the DMA API.
*
* On some systems, including Xen and any system with a physical device
* that speaks virtio behind a physical IOMMU, we must use the DMA API
* for virtio DMA to work at all.
*
* On other systems, including SPARC and PPC64, virtio-pci devices are
* enumerated as though they are behind an IOMMU, but the virtio host
* ignores the IOMMU, so we must either pretend that the IOMMU isn't
* there or somehow map everything as the identity.
*
* For the time being, we preserve historic behavior and bypass the DMA
* API.
*/
static bool vring_use_dma_api(struct virtio_device *vdev)
{
/*
* In theory, it's possible to have a buggy QEMU-supposed
* emulated Q35 IOMMU and Xen enabled at the same time. On
* such a configuration, virtio has never worked and will
* not work without an even larger kludge. Instead, enable
* the DMA API if we're a Xen guest, which at least allows
* all of the sensible Xen configurations to work correctly.
*/
if (xen_domain())
return true;
return false;
}
/*
* The DMA ops on various arches are rather gnarly right now, and
* making all of the arch DMA ops work on the vring device itself
* is a mess. For now, we use the parent device for DMA ops.
*/
struct device *vring_dma_dev(const struct vring_virtqueue *vq)
{
return vq->vq.vdev->dev.parent;
}
/* Map one sg entry. */
static dma_addr_t vring_map_one_sg(const struct vring_virtqueue *vq,
struct scatterlist *sg,
enum dma_data_direction direction)
{
if (!vring_use_dma_api(vq->vq.vdev))
return (dma_addr_t)sg_phys(sg);
/*
* We can't use dma_map_sg, because we don't use scatterlists in
* the way it expects (we don't guarantee that the scatterlist
* will exist for the lifetime of the mapping).
*/
return dma_map_page(vring_dma_dev(vq),
sg_page(sg), sg->offset, sg->length,
direction);
}
static dma_addr_t vring_map_single(const struct vring_virtqueue *vq,
void *cpu_addr, size_t size,
enum dma_data_direction direction)
{
if (!vring_use_dma_api(vq->vq.vdev))
return (dma_addr_t)virt_to_phys(cpu_addr);
return dma_map_single(vring_dma_dev(vq),
cpu_addr, size, direction);
}
static void vring_unmap_one(const struct vring_virtqueue *vq,
struct vring_desc *desc)
{
u16 flags;
if (!vring_use_dma_api(vq->vq.vdev))
return;
flags = virtio16_to_cpu(vq->vq.vdev, desc->flags);
if (flags & VRING_DESC_F_INDIRECT) {
dma_unmap_single(vring_dma_dev(vq),
virtio64_to_cpu(vq->vq.vdev, desc->addr),
virtio32_to_cpu(vq->vq.vdev, desc->len),
(flags & VRING_DESC_F_WRITE) ?
DMA_FROM_DEVICE : DMA_TO_DEVICE);
} else {
dma_unmap_page(vring_dma_dev(vq),
virtio64_to_cpu(vq->vq.vdev, desc->addr),
virtio32_to_cpu(vq->vq.vdev, desc->len),
(flags & VRING_DESC_F_WRITE) ?
DMA_FROM_DEVICE : DMA_TO_DEVICE);
}
}
static int vring_mapping_error(const struct vring_virtqueue *vq,
dma_addr_t addr)
{
if (!vring_use_dma_api(vq->vq.vdev))
return 0;
return dma_mapping_error(vring_dma_dev(vq), addr);
}
static struct vring_desc *alloc_indirect(struct virtqueue *_vq,
unsigned int total_sg, gfp_t gfp)
{
@ -137,7 +257,7 @@ static inline int virtqueue_add(struct virtqueue *_vq,
struct vring_virtqueue *vq = to_vvq(_vq);
struct scatterlist *sg;
struct vring_desc *desc;
unsigned int i, n, avail, descs_used, uninitialized_var(prev);
unsigned int i, n, avail, descs_used, uninitialized_var(prev), err_idx;
int head;
bool indirect;
@ -177,21 +297,15 @@ static inline int virtqueue_add(struct virtqueue *_vq,
if (desc) {
/* Use a single buffer which doesn't continue */
vq->vring.desc[head].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_INDIRECT);
vq->vring.desc[head].addr = cpu_to_virtio64(_vq->vdev, virt_to_phys(desc));
/* avoid kmemleak false positive (hidden by virt_to_phys) */
kmemleak_ignore(desc);
vq->vring.desc[head].len = cpu_to_virtio32(_vq->vdev, total_sg * sizeof(struct vring_desc));
indirect = true;
/* Set up rest to use this indirect table. */
i = 0;
descs_used = 1;
indirect = true;
} else {
indirect = false;
desc = vq->vring.desc;
i = head;
descs_used = total_sg;
indirect = false;
}
if (vq->vq.num_free < descs_used) {
@ -206,13 +320,14 @@ static inline int virtqueue_add(struct virtqueue *_vq,
return -ENOSPC;
}
/* We're about to use some buffers from the free list. */
vq->vq.num_free -= descs_used;
for (n = 0; n < out_sgs; n++) {
for (sg = sgs[n]; sg; sg = sg_next(sg)) {
dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_TO_DEVICE);
if (vring_mapping_error(vq, addr))
goto unmap_release;
desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT);
desc[i].addr = cpu_to_virtio64(_vq->vdev, sg_phys(sg));
desc[i].addr = cpu_to_virtio64(_vq->vdev, addr);
desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length);
prev = i;
i = virtio16_to_cpu(_vq->vdev, desc[i].next);
@ -220,8 +335,12 @@ static inline int virtqueue_add(struct virtqueue *_vq,
}
for (; n < (out_sgs + in_sgs); n++) {
for (sg = sgs[n]; sg; sg = sg_next(sg)) {
dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_FROM_DEVICE);
if (vring_mapping_error(vq, addr))
goto unmap_release;
desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT | VRING_DESC_F_WRITE);
desc[i].addr = cpu_to_virtio64(_vq->vdev, sg_phys(sg));
desc[i].addr = cpu_to_virtio64(_vq->vdev, addr);
desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length);
prev = i;
i = virtio16_to_cpu(_vq->vdev, desc[i].next);
@ -230,14 +349,33 @@ static inline int virtqueue_add(struct virtqueue *_vq,
/* Last one doesn't continue. */
desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT);
if (indirect) {
/* Now that the indirect table is filled in, map it. */
dma_addr_t addr = vring_map_single(
vq, desc, total_sg * sizeof(struct vring_desc),
DMA_TO_DEVICE);
if (vring_mapping_error(vq, addr))
goto unmap_release;
vq->vring.desc[head].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_INDIRECT);
vq->vring.desc[head].addr = cpu_to_virtio64(_vq->vdev, addr);
vq->vring.desc[head].len = cpu_to_virtio32(_vq->vdev, total_sg * sizeof(struct vring_desc));
}
/* We're using some buffers from the free list. */
vq->vq.num_free -= descs_used;
/* Update free pointer */
if (indirect)
vq->free_head = virtio16_to_cpu(_vq->vdev, vq->vring.desc[head].next);
else
vq->free_head = i;
/* Set token. */
vq->data[head] = data;
/* Store token and indirect buffer state. */
vq->desc_state[head].data = data;
if (indirect)
vq->desc_state[head].indir_desc = desc;
/* Put entry in available array (but don't update avail->idx until they
* do sync). */
@ -260,6 +398,24 @@ static inline int virtqueue_add(struct virtqueue *_vq,
virtqueue_kick(_vq);
return 0;
unmap_release:
err_idx = i;
i = head;
for (n = 0; n < total_sg; n++) {
if (i == err_idx)
break;
vring_unmap_one(vq, &desc[i]);
i = vq->vring.desc[i].next;
}
vq->vq.num_free += total_sg;
if (indirect)
kfree(desc);
return -EIO;
}
/**
@ -430,27 +586,43 @@ EXPORT_SYMBOL_GPL(virtqueue_kick);
static void detach_buf(struct vring_virtqueue *vq, unsigned int head)
{
unsigned int i;
unsigned int i, j;
u16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT);
/* Clear data ptr. */
vq->data[head] = NULL;
vq->desc_state[head].data = NULL;
/* Put back on free list: find end */
/* Put back on free list: unmap first-level descriptors and find end */
i = head;
/* Free the indirect table */
if (vq->vring.desc[i].flags & cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT))
kfree(phys_to_virt(virtio64_to_cpu(vq->vq.vdev, vq->vring.desc[i].addr)));
while (vq->vring.desc[i].flags & cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT)) {
while (vq->vring.desc[i].flags & nextflag) {
vring_unmap_one(vq, &vq->vring.desc[i]);
i = virtio16_to_cpu(vq->vq.vdev, vq->vring.desc[i].next);
vq->vq.num_free++;
}
vring_unmap_one(vq, &vq->vring.desc[i]);
vq->vring.desc[i].next = cpu_to_virtio16(vq->vq.vdev, vq->free_head);
vq->free_head = head;
/* Plus final descriptor */
vq->vq.num_free++;
/* Free the indirect table, if any, now that it's unmapped. */
if (vq->desc_state[head].indir_desc) {
struct vring_desc *indir_desc = vq->desc_state[head].indir_desc;
u32 len = virtio32_to_cpu(vq->vq.vdev, vq->vring.desc[head].len);
BUG_ON(!(vq->vring.desc[head].flags &
cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT)));
BUG_ON(len == 0 || len % sizeof(struct vring_desc));
for (j = 0; j < len / sizeof(struct vring_desc); j++)
vring_unmap_one(vq, &indir_desc[j]);
kfree(vq->desc_state[head].indir_desc);
vq->desc_state[head].indir_desc = NULL;
}
}
static inline bool more_used(const struct vring_virtqueue *vq)
@ -505,13 +677,13 @@ void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
BAD_RING(vq, "id %u out of range\n", i);
return NULL;
}
if (unlikely(!vq->data[i])) {
if (unlikely(!vq->desc_state[i].data)) {
BAD_RING(vq, "id %u is not a head!\n", i);
return NULL;
}
/* detach_buf clears data, so grab it now. */
ret = vq->data[i];
ret = vq->desc_state[i].data;
detach_buf(vq, i);
vq->last_used_idx++;
/* If we expect an interrupt for the next entry, tell host
@ -685,10 +857,10 @@ void *virtqueue_detach_unused_buf(struct virtqueue *_vq)
START_USE(vq);
for (i = 0; i < vq->vring.num; i++) {
if (!vq->data[i])
if (!vq->desc_state[i].data)
continue;
/* detach_buf clears data, so grab it now. */
buf = vq->data[i];
buf = vq->desc_state[i].data;
detach_buf(vq, i);
vq->avail_idx_shadow--;
vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev, vq->avail_idx_shadow);
@ -723,35 +895,31 @@ irqreturn_t vring_interrupt(int irq, void *_vq)
}
EXPORT_SYMBOL_GPL(vring_interrupt);
struct virtqueue *vring_new_virtqueue(unsigned int index,
unsigned int num,
unsigned int vring_align,
struct virtio_device *vdev,
bool weak_barriers,
void *pages,
bool (*notify)(struct virtqueue *),
void (*callback)(struct virtqueue *),
const char *name)
struct virtqueue *__vring_new_virtqueue(unsigned int index,
struct vring vring,
struct virtio_device *vdev,
bool weak_barriers,
bool (*notify)(struct virtqueue *),
void (*callback)(struct virtqueue *),
const char *name)
{
struct vring_virtqueue *vq;
unsigned int i;
struct vring_virtqueue *vq;
/* We assume num is a power of 2. */
if (num & (num - 1)) {
dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num);
return NULL;
}
vq = kmalloc(sizeof(*vq) + sizeof(void *)*num, GFP_KERNEL);
vq = kmalloc(sizeof(*vq) + vring.num * sizeof(struct vring_desc_state),
GFP_KERNEL);
if (!vq)
return NULL;
vring_init(&vq->vring, num, pages, vring_align);
vq->vring = vring;
vq->vq.callback = callback;
vq->vq.vdev = vdev;
vq->vq.name = name;
vq->vq.num_free = num;
vq->vq.num_free = vring.num;
vq->vq.index = index;
vq->we_own_ring = false;
vq->queue_dma_addr = 0;
vq->queue_size_in_bytes = 0;
vq->notify = notify;
vq->weak_barriers = weak_barriers;
vq->broken = false;
@ -776,20 +944,145 @@ struct virtqueue *vring_new_virtqueue(unsigned int index,
/* Put everything in free lists. */
vq->free_head = 0;
for (i = 0; i < num-1; i++) {
for (i = 0; i < vring.num-1; i++)
vq->vring.desc[i].next = cpu_to_virtio16(vdev, i + 1);
vq->data[i] = NULL;
}
vq->data[i] = NULL;
memset(vq->desc_state, 0, vring.num * sizeof(struct vring_desc_state));
return &vq->vq;
}
EXPORT_SYMBOL_GPL(__vring_new_virtqueue);
static void *vring_alloc_queue(struct virtio_device *vdev, size_t size,
dma_addr_t *dma_handle, gfp_t flag)
{
if (vring_use_dma_api(vdev)) {
return dma_alloc_coherent(vdev->dev.parent, size,
dma_handle, flag);
} else {
void *queue = alloc_pages_exact(PAGE_ALIGN(size), flag);
if (queue) {
phys_addr_t phys_addr = virt_to_phys(queue);
*dma_handle = (dma_addr_t)phys_addr;
/*
* Sanity check: make sure we dind't truncate
* the address. The only arches I can find that
* have 64-bit phys_addr_t but 32-bit dma_addr_t
* are certain non-highmem MIPS and x86
* configurations, but these configurations
* should never allocate physical pages above 32
* bits, so this is fine. Just in case, throw a
* warning and abort if we end up with an
* unrepresentable address.
*/
if (WARN_ON_ONCE(*dma_handle != phys_addr)) {
free_pages_exact(queue, PAGE_ALIGN(size));
return NULL;
}
}
return queue;
}
}
static void vring_free_queue(struct virtio_device *vdev, size_t size,
void *queue, dma_addr_t dma_handle)
{
if (vring_use_dma_api(vdev)) {
dma_free_coherent(vdev->dev.parent, size, queue, dma_handle);
} else {
free_pages_exact(queue, PAGE_ALIGN(size));
}
}
struct virtqueue *vring_create_virtqueue(
unsigned int index,
unsigned int num,
unsigned int vring_align,
struct virtio_device *vdev,
bool weak_barriers,
bool may_reduce_num,
bool (*notify)(struct virtqueue *),
void (*callback)(struct virtqueue *),
const char *name)
{
struct virtqueue *vq;
void *queue;
dma_addr_t dma_addr;
size_t queue_size_in_bytes;
struct vring vring;
/* We assume num is a power of 2. */
if (num & (num - 1)) {
dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num);
return NULL;
}
/* TODO: allocate each queue chunk individually */
for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) {
queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
&dma_addr,
GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
if (queue)
break;
}
if (!num)
return NULL;
if (!queue) {
/* Try to get a single page. You are my only hope! */
queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
&dma_addr, GFP_KERNEL|__GFP_ZERO);
}
if (!queue)
return NULL;
queue_size_in_bytes = vring_size(num, vring_align);
vring_init(&vring, num, queue, vring_align);
vq = __vring_new_virtqueue(index, vring, vdev, weak_barriers,
notify, callback, name);
if (!vq) {
vring_free_queue(vdev, queue_size_in_bytes, queue,
dma_addr);
return NULL;
}
to_vvq(vq)->queue_dma_addr = dma_addr;
to_vvq(vq)->queue_size_in_bytes = queue_size_in_bytes;
to_vvq(vq)->we_own_ring = true;
return vq;
}
EXPORT_SYMBOL_GPL(vring_create_virtqueue);
struct virtqueue *vring_new_virtqueue(unsigned int index,
unsigned int num,
unsigned int vring_align,
struct virtio_device *vdev,
bool weak_barriers,
void *pages,
bool (*notify)(struct virtqueue *vq),
void (*callback)(struct virtqueue *vq),
const char *name)
{
struct vring vring;
vring_init(&vring, num, pages, vring_align);
return __vring_new_virtqueue(index, vring, vdev, weak_barriers,
notify, callback, name);
}
EXPORT_SYMBOL_GPL(vring_new_virtqueue);
void vring_del_virtqueue(struct virtqueue *vq)
void vring_del_virtqueue(struct virtqueue *_vq)
{
list_del(&vq->list);
kfree(to_vvq(vq));
struct vring_virtqueue *vq = to_vvq(_vq);
if (vq->we_own_ring) {
vring_free_queue(vq->vq.vdev, vq->queue_size_in_bytes,
vq->vring.desc, vq->queue_dma_addr);
}
list_del(&_vq->list);
kfree(vq);
}
EXPORT_SYMBOL_GPL(vring_del_virtqueue);
@ -853,20 +1146,42 @@ void virtio_break_device(struct virtio_device *dev)
}
EXPORT_SYMBOL_GPL(virtio_break_device);
void *virtqueue_get_avail(struct virtqueue *_vq)
dma_addr_t virtqueue_get_desc_addr(struct virtqueue *_vq)
{
struct vring_virtqueue *vq = to_vvq(_vq);
return vq->vring.avail;
}
EXPORT_SYMBOL_GPL(virtqueue_get_avail);
BUG_ON(!vq->we_own_ring);
void *virtqueue_get_used(struct virtqueue *_vq)
return vq->queue_dma_addr;
}
EXPORT_SYMBOL_GPL(virtqueue_get_desc_addr);
dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq)
{
struct vring_virtqueue *vq = to_vvq(_vq);
return vq->vring.used;
BUG_ON(!vq->we_own_ring);
return vq->queue_dma_addr +
((char *)vq->vring.avail - (char *)vq->vring.desc);
}
EXPORT_SYMBOL_GPL(virtqueue_get_used);
EXPORT_SYMBOL_GPL(virtqueue_get_avail_addr);
dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq)
{
struct vring_virtqueue *vq = to_vvq(_vq);
BUG_ON(!vq->we_own_ring);
return vq->queue_dma_addr +
((char *)vq->vring.used - (char *)vq->vring.desc);
}
EXPORT_SYMBOL_GPL(virtqueue_get_used_addr);
const struct vring *virtqueue_get_vring(struct virtqueue *vq)
{
return &to_vvq(vq)->vring;
}
EXPORT_SYMBOL_GPL(virtqueue_get_vring);
MODULE_LICENSE("GPL");

2
include/linux/dma-mapping.h
View File

@ -70,6 +70,8 @@ struct dma_map_ops {
int is_phys;
};
extern struct dma_map_ops dma_noop_ops;
#define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
#define DMA_MASK_NONE 0x0ULL

23
include/linux/virtio.h
View File

@ -75,8 +75,27 @@ unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
bool virtqueue_is_broken(struct virtqueue *vq);
void *virtqueue_get_avail(struct virtqueue *vq);
void *virtqueue_get_used(struct virtqueue *vq);
const struct vring *virtqueue_get_vring(struct virtqueue *vq);
dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq);
dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq);
dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq);
/*
* Legacy accessors -- in almost all cases, these are the wrong functions
* to use.
*/
static inline void *virtqueue_get_desc(struct virtqueue *vq)
{
return virtqueue_get_vring(vq)->desc;
}
static inline void *virtqueue_get_avail(struct virtqueue *vq)
{
return virtqueue_get_vring(vq)->avail;
}
static inline void *virtqueue_get_used(struct virtqueue *vq)
{
return virtqueue_get_vring(vq)->used;
}
/**
* virtio_device - representation of a device using virtio

35
include/linux/virtio_ring.h
View File

@ -59,6 +59,35 @@ static inline void virtio_store_mb(bool weak_barriers,
struct virtio_device;
struct virtqueue;
/*
* Creates a virtqueue and allocates the descriptor ring. If
* may_reduce_num is set, then this may allocate a smaller ring than
* expected. The caller should query virtqueue_get_ring_size to learn
* the actual size of the ring.
*/
struct virtqueue *vring_create_virtqueue(unsigned int index,
unsigned int num,
unsigned int vring_align,
struct virtio_device *vdev,
bool weak_barriers,
bool may_reduce_num,
bool (*notify)(struct virtqueue *vq),
void (*callback)(struct virtqueue *vq),
const char *name);
/* Creates a virtqueue with a custom layout. */
struct virtqueue *__vring_new_virtqueue(unsigned int index,
struct vring vring,
struct virtio_device *vdev,
bool weak_barriers,
bool (*notify)(struct virtqueue *),
void (*callback)(struct virtqueue *),
const char *name);
/*
* Creates a virtqueue with a standard layout but a caller-allocated
* ring.
*/
struct virtqueue *vring_new_virtqueue(unsigned int index,
unsigned int num,
unsigned int vring_align,
@ -68,7 +97,13 @@ struct virtqueue *vring_new_virtqueue(unsigned int index,
bool (*notify)(struct virtqueue *vq),
void (*callback)(struct virtqueue *vq),
const char *name);
/*
* Destroys a virtqueue. If created with vring_create_virtqueue, this
* also frees the ring.
*/
void vring_del_virtqueue(struct virtqueue *vq);
/* Filter out transport-specific feature bits. */
void vring_transport_features(struct virtio_device *vdev);

6
include/uapi/linux/vhost.h
View File

@ -126,6 +126,12 @@ struct vhost_memory {
#define VHOST_SET_VRING_CALL _IOW(VHOST_VIRTIO, 0x21, struct vhost_vring_file)
/* Set eventfd to signal an error */
#define VHOST_SET_VRING_ERR _IOW(VHOST_VIRTIO, 0x22, struct vhost_vring_file)
/* Set busy loop timeout (in us) */
#define VHOST_SET_VRING_BUSYLOOP_TIMEOUT _IOW(VHOST_VIRTIO, 0x23, \
struct vhost_vring_state)
/* Get busy loop timeout (in us) */
#define VHOST_GET_VRING_BUSYLOOP_TIMEOUT _IOW(VHOST_VIRTIO, 0x24, \
struct vhost_vring_state)
/* VHOST_NET specific defines */

6
include/uapi/linux/virtio_blk.h
View File

@ -43,11 +43,11 @@
#ifndef VIRTIO_BLK_NO_LEGACY
#define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */
#define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */
#define VIRTIO_BLK_F_WCE 9 /* Writeback mode enabled after reset */
#define VIRTIO_BLK_F_FLUSH 9 /* Flush command supported */
#define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */
#ifndef __KERNEL__
/* Old (deprecated) name for VIRTIO_BLK_F_WCE. */
#define VIRTIO_BLK_F_FLUSH VIRTIO_BLK_F_WCE
/* Old (deprecated) name for VIRTIO_BLK_F_FLUSH. */
#define VIRTIO_BLK_F_WCE VIRTIO_BLK_F_FLUSH
#endif
#endif /* !VIRTIO_BLK_NO_LEGACY */

1
lib/Makefile
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@ -18,6 +18,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
obj-$(CONFIG_ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS) += usercopy.o
lib-$(CONFIG_MMU) += ioremap.o
lib-$(CONFIG_SMP) += cpumask.o
lib-$(CONFIG_HAS_DMA) += dma-noop.o
lib-y += kobject.o klist.o
obj-y += lockref.o

75
lib/dma-noop.c Normal file
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@ -0,0 +1,75 @@
/*
* lib/dma-noop.c
*
* Simple DMA noop-ops that map 1:1 with memory
*/
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <linux/scatterlist.h>
static void *dma_noop_alloc(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp,
struct dma_attrs *attrs)
{
void *ret;
ret = (void *)__get_free_pages(gfp, get_order(size));
if (ret)
*dma_handle = virt_to_phys(ret);
return ret;
}
static void dma_noop_free(struct device *dev, size_t size,
void *cpu_addr, dma_addr_t dma_addr,
struct dma_attrs *attrs)
{
free_pages((unsigned long)cpu_addr, get_order(size));
}
static dma_addr_t dma_noop_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction dir,
struct dma_attrs *attrs)
{
return page_to_phys(page) + offset;
}
static int dma_noop_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
enum dma_data_direction dir, struct dma_attrs *attrs)
{
int i;
struct scatterlist *sg;
for_each_sg(sgl, sg, nents, i) {
void *va;
BUG_ON(!sg_page(sg));
va = sg_virt(sg);
sg_dma_address(sg) = (dma_addr_t)virt_to_phys(va);
sg_dma_len(sg) = sg->length;
}
return nents;
}
static int dma_noop_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
return 0;
}
static int dma_noop_supported(struct device *dev, u64 mask)
{
return 1;
}
struct dma_map_ops dma_noop_ops = {
.alloc = dma_noop_alloc,
.free = dma_noop_free,
.map_page = dma_noop_map_page,
.map_sg = dma_noop_map_sg,
.mapping_error = dma_noop_mapping_error,
.dma_supported = dma_noop_supported,
};
EXPORT_SYMBOL(dma_noop_ops);

17
tools/virtio/linux/dma-mapping.h Normal file
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@ -0,0 +1,17 @@
#ifndef _LINUX_DMA_MAPPING_H
#define _LINUX_DMA_MAPPING_H
#ifdef CONFIG_HAS_DMA
# error Virtio userspace code does not support CONFIG_HAS_DMA
#endif
#define PCI_DMA_BUS_IS_PHYS 1
enum dma_data_direction {
DMA_BIDIRECTIONAL = 0,
DMA_TO_DEVICE = 1,
DMA_FROM_DEVICE = 2,
DMA_NONE = 3,
};
#endif