Currently, vhost-net is the only consumer of vhost infrastructure. So
vhost infrastructure and vhost-net driver are in a single module.
Separating this as a vhost.ko module and a vhost-net.ko module makes it
is easier to share code with other vhost drivers, e.g. vhost-blk.ko,
tcm-vhost.ko.
Signed-off-by: Asias He <asias at redhat.com>
---
drivers/vhost/Kconfig | 10 +++++++++-
drivers/vhost/Makefile | 4 +++-
drivers/vhost/vhost.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
drivers/vhost/vhost.h | 1 +
4 files changed, 61 insertions(+), 2 deletions(-)
diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
index e4e2fd1..c387067 100644
--- a/drivers/vhost/Kconfig
+++ b/drivers/vhost/Kconfig
@@ -1,6 +1,14 @@
+config VHOST
+ tristate "Host kernel accelerator for virtio (EXPERIMENTAL)"
+ ---help---
+ This kernel module can be loaded in host kernel to accelerate
+ guest networking and block.
+
+ To compile this driver as a module, choose M here: the module will
+ be called vhost_net.
config VHOST_NET
tristate "Host kernel accelerator for virtio net (EXPERIMENTAL)"
- depends on NET && EVENTFD && (TUN || !TUN) && (MACVTAP
|| !MACVTAP) && EXPERIMENTAL
+ depends on VHOST && NET && EVENTFD && (TUN || !TUN)
&& (MACVTAP || !MACVTAP) && EXPERIMENTAL
---help---
This kernel module can be loaded in host kernel to accelerate
guest networking with virtio_net. Not to be confused with virtio_net
diff --git a/drivers/vhost/Makefile b/drivers/vhost/Makefile
index 72dd020..cd36885 100644
--- a/drivers/vhost/Makefile
+++ b/drivers/vhost/Makefile
@@ -1,2 +1,4 @@
+obj-$(CONFIG_VHOST) += vhost.o
obj-$(CONFIG_VHOST_NET) += vhost_net.o
-vhost_net-y := vhost.o net.o
+
+vhost_net-y := net.o
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 112156f..6e9f586 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -25,6 +25,7 @@
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/cgroup.h>
+#include <linux/module.h>
#include <linux/net.h>
#include <linux/if_packet.h>
@@ -84,6 +85,7 @@ void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t
fn,
vhost_work_init(&poll->work, fn);
}
+EXPORT_SYMBOL_GPL(vhost_poll_init);
/* Start polling a file. We add ourselves to file's wait queue. The caller
must
* keep a reference to a file until after vhost_poll_stop is called. */
@@ -95,6 +97,7 @@ void vhost_poll_start(struct vhost_poll *poll, struct file
*file)
if (mask)
vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask);
}
+EXPORT_SYMBOL_GPL(vhost_poll_start);
/* Stop polling a file. After this function returns, it becomes safe to drop
the
* file reference. You must also flush afterwards. */
@@ -102,6 +105,7 @@ void vhost_poll_stop(struct vhost_poll *poll)
{
remove_wait_queue(poll->wqh, &poll->wait);
}
+EXPORT_SYMBOL_GPL(vhost_poll_stop);
static bool vhost_work_seq_done(struct vhost_dev *dev, struct vhost_work *work,
unsigned seq)
@@ -136,6 +140,7 @@ void vhost_poll_flush(struct vhost_poll *poll)
{
vhost_work_flush(poll->dev, &poll->work);
}
+EXPORT_SYMBOL_GPL(vhost_poll_flush);
static inline void vhost_work_queue(struct vhost_dev *dev,
struct vhost_work *work)
@@ -155,6 +160,7 @@ void vhost_poll_queue(struct vhost_poll *poll)
{
vhost_work_queue(poll->dev, &poll->work);
}
+EXPORT_SYMBOL_GPL(vhost_poll_queue);
static void vhost_vq_reset(struct vhost_dev *dev,
struct vhost_virtqueue *vq)
@@ -251,6 +257,7 @@ void vhost_enable_zcopy(int vq)
{
vhost_zcopy_mask |= 0x1 << vq;
}
+EXPORT_SYMBOL_GPL(vhost_enable_zcopy);
/* Helper to allocate iovec buffers for all vqs. */
static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
@@ -322,6 +329,7 @@ long vhost_dev_init(struct vhost_dev *dev,
return 0;
}
+EXPORT_SYMBOL_GPL(vhost_dev_init);
/* Caller should have device mutex */
long vhost_dev_check_owner(struct vhost_dev *dev)
@@ -329,6 +337,7 @@ long vhost_dev_check_owner(struct vhost_dev *dev)
/* Are you the owner? If not, I don't think you mean to do that */
return dev->mm == current->mm ? 0 : -EPERM;
}
+EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
struct vhost_attach_cgroups_struct {
struct vhost_work work;
@@ -414,6 +423,7 @@ long vhost_dev_reset_owner(struct vhost_dev *dev)
RCU_INIT_POINTER(dev->memory, memory);
return 0;
}
+EXPORT_SYMBOL_GPL(vhost_dev_reset_owner);
/* In case of DMA done not in order in lower device driver for some reason.
* upend_idx is used to track end of used idx, done_idx is used to track head
@@ -438,6 +448,7 @@ int vhost_zerocopy_signal_used(struct vhost_virtqueue *vq)
vq->done_idx = i;
return j;
}
+EXPORT_SYMBOL_GPL(vhost_zerocopy_signal_used);
/* Caller should have device mutex if and only if locked is set */
void vhost_dev_cleanup(struct vhost_dev *dev, bool locked)
@@ -489,6 +500,7 @@ void vhost_dev_cleanup(struct vhost_dev *dev, bool locked)
mmput(dev->mm);
dev->mm = NULL;
}
+EXPORT_SYMBOL_GPL(vhost_dev_cleanup);
static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
{
@@ -574,6 +586,7 @@ int vhost_log_access_ok(struct vhost_dev *dev)
lockdep_is_held(&dev->mutex));
return memory_access_ok(dev, mp, 1);
}
+EXPORT_SYMBOL_GPL(vhost_log_access_ok);
/* Verify access for write logging. */
/* Caller should have vq mutex and device mutex */
@@ -599,6 +612,7 @@ int vhost_vq_access_ok(struct vhost_virtqueue *vq)
return vq_access_ok(vq->dev, vq->num, vq->desc, vq->avail,
vq->used) &&
vq_log_access_ok(vq->dev, vq, vq->log_base);
}
+EXPORT_SYMBOL_GPL(vhost_vq_access_ok);
static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user
*m)
{
@@ -909,6 +923,7 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int
ioctl, unsigned long arg)
done:
return r;
}
+EXPORT_SYMBOL_GPL(vhost_dev_ioctl);
static const struct vhost_memory_region *find_region(struct vhost_memory *mem,
__u64 addr, __u32 len)
@@ -1000,6 +1015,7 @@ int vhost_log_write(struct vhost_virtqueue *vq, struct
vhost_log *log,
BUG();
return 0;
}
+EXPORT_SYMBOL_GPL(vhost_log_write);
static int vhost_update_used_flags(struct vhost_virtqueue *vq)
{
@@ -1051,6 +1067,7 @@ int vhost_init_used(struct vhost_virtqueue *vq)
vq->signalled_used_valid = false;
return get_user(vq->last_used_idx, &vq->used->idx);
}
+EXPORT_SYMBOL_GPL(vhost_init_used);
static int translate_desc(struct vhost_dev *dev, u64 addr, u32 len,
struct iovec iov[], int iov_size)
@@ -1327,12 +1344,14 @@ int vhost_get_vq_desc(struct vhost_dev *dev, struct
vhost_virtqueue *vq,
BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
return head;
}
+EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
/* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
{
vq->last_avail_idx -= n;
}
+EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
/* After we've used one of their buffers, we tell them about it. We'll
then
* want to notify the guest, using eventfd. */
@@ -1381,6 +1400,7 @@ int vhost_add_used(struct vhost_virtqueue *vq, unsigned
int head, int len)
vq->signalled_used_valid = false;
return 0;
}
+EXPORT_SYMBOL_GPL(vhost_add_used);
static int __vhost_add_used_n(struct vhost_virtqueue *vq,
struct vring_used_elem *heads,
@@ -1450,6 +1470,7 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct
vring_used_elem *heads,
}
return r;
}
+EXPORT_SYMBOL_GPL(vhost_add_used_n);
static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
{
@@ -1494,6 +1515,7 @@ void vhost_signal(struct vhost_dev *dev, struct
vhost_virtqueue *vq)
if (vq->call_ctx && vhost_notify(dev, vq))
eventfd_signal(vq->call_ctx, 1);
}
+EXPORT_SYMBOL_GPL(vhost_signal);
/* And here's the combo meal deal. Supersize me! */
void vhost_add_used_and_signal(struct vhost_dev *dev,
@@ -1503,6 +1525,7 @@ void vhost_add_used_and_signal(struct vhost_dev *dev,
vhost_add_used(vq, head, len);
vhost_signal(dev, vq);
}
+EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
/* multi-buffer version of vhost_add_used_and_signal */
void vhost_add_used_and_signal_n(struct vhost_dev *dev,
@@ -1512,6 +1535,7 @@ void vhost_add_used_and_signal_n(struct vhost_dev *dev,
vhost_add_used_n(vq, heads, count);
vhost_signal(dev, vq);
}
+EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
/* OK, now we need to know about added descriptors. */
bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
@@ -1549,6 +1573,7 @@ bool vhost_enable_notify(struct vhost_dev *dev, struct
vhost_virtqueue *vq)
return avail_idx != vq->avail_idx;
}
+EXPORT_SYMBOL_GPL(vhost_enable_notify);
/* We don't need to be notified again. */
void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
@@ -1565,6 +1590,7 @@ void vhost_disable_notify(struct vhost_dev *dev, struct
vhost_virtqueue *vq)
&vq->used->flags, r);
}
}
+EXPORT_SYMBOL_GPL(vhost_disable_notify);
static void vhost_zerocopy_done_signal(struct kref *kref)
{
@@ -1588,11 +1614,13 @@ struct vhost_ubuf_ref *vhost_ubuf_alloc(struct
vhost_virtqueue *vq,
ubufs->vq = vq;
return ubufs;
}
+EXPORT_SYMBOL_GPL(vhost_ubuf_alloc);
void vhost_ubuf_put(struct vhost_ubuf_ref *ubufs)
{
kref_put(&ubufs->kref, vhost_zerocopy_done_signal);
}
+EXPORT_SYMBOL_GPL(vhost_ubuf_put);
void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *ubufs)
{
@@ -1600,6 +1628,7 @@ void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *ubufs)
wait_event(ubufs->wait, !atomic_read(&ubufs->kref.refcount));
kfree(ubufs);
}
+EXPORT_SYMBOL_GPL(vhost_ubuf_put_and_wait);
void vhost_zerocopy_callback(struct ubuf_info *ubuf)
{
@@ -1611,3 +1640,22 @@ void vhost_zerocopy_callback(struct ubuf_info *ubuf)
vq->heads[ubuf->desc].len = VHOST_DMA_DONE_LEN;
kref_put(&ubufs->kref, vhost_zerocopy_done_signal);
}
+EXPORT_SYMBOL_GPL(vhost_zerocopy_callback);
+
+static int __init vhost_init(void)
+{
+ return 0;
+}
+
+static void __exit vhost_exit(void)
+{
+ return;
+}
+
+module_init(vhost_init);
+module_exit(vhost_exit);
+
+MODULE_VERSION("0.0.1");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Michael S. Tsirkin");
+MODULE_DESCRIPTION("Host kernel accelerator for virtio");
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 8de1fd5..c5c7fb0 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -12,6 +12,7 @@
#include <linux/virtio_config.h>
#include <linux/virtio_ring.h>
#include <linux/atomic.h>
+#include <linux/virtio_net.h>
/* This is for zerocopy, used buffer len is set to 1 when lower device DMA
* done */
--
1.7.10.4
Asias He
2012-Jul-12 15:45 UTC
[PATCH 4/5] vhost-net: Use VHOST_NET_FEATURES for vhost-net
vhost-net's feature does not deseve the name VHOST_FEATURES. Use
VHOST_NET_FEATURES instead.
Signed-off-by: Asias He <asias at redhat.com>
---
drivers/vhost/net.c | 4 ++--
drivers/vhost/test.c | 4 ++--
drivers/vhost/vhost.h | 12 ++++++------
3 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index f82a739..072cbba 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -823,14 +823,14 @@ static long vhost_net_ioctl(struct file *f, unsigned int
ioctl,
return -EFAULT;
return vhost_net_set_backend(n, backend.index, backend.fd);
case VHOST_GET_FEATURES:
- features = VHOST_FEATURES;
+ features = VHOST_NET_FEATURES;
if (copy_to_user(featurep, &features, sizeof features))
return -EFAULT;
return 0;
case VHOST_SET_FEATURES:
if (copy_from_user(&features, featurep, sizeof features))
return -EFAULT;
- if (features & ~VHOST_FEATURES)
+ if (features & ~VHOST_NET_FEATURES)
return -EOPNOTSUPP;
return vhost_net_set_features(n, features);
case VHOST_RESET_OWNER:
diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c
index 3de00d9..91d6f06 100644
--- a/drivers/vhost/test.c
+++ b/drivers/vhost/test.c
@@ -261,14 +261,14 @@ static long vhost_test_ioctl(struct file *f, unsigned int
ioctl,
return -EFAULT;
return vhost_test_run(n, test);
case VHOST_GET_FEATURES:
- features = VHOST_FEATURES;
+ features = VHOST_NET_FEATURES;
if (copy_to_user(featurep, &features, sizeof features))
return -EFAULT;
return 0;
case VHOST_SET_FEATURES:
if (copy_from_user(&features, featurep, sizeof features))
return -EFAULT;
- if (features & ~VHOST_FEATURES)
+ if (features & ~VHOST_NET_FEATURES)
return -EOPNOTSUPP;
return vhost_test_set_features(n, features);
case VHOST_RESET_OWNER:
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index c5c7fb0..cc046a9 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -199,12 +199,12 @@ int vhost_zerocopy_signal_used(struct vhost_virtqueue
*vq);
} while (0)
enum {
- VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
- (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
- (1ULL << VIRTIO_RING_F_EVENT_IDX) |
- (1ULL << VHOST_F_LOG_ALL) |
- (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
- (1ULL << VIRTIO_NET_F_MRG_RXBUF),
+ VHOST_NET_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
+ (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
+ (1ULL << VIRTIO_RING_F_EVENT_IDX) |
+ (1ULL << VHOST_F_LOG_ALL) |
+ (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
+ (1ULL << VIRTIO_NET_F_MRG_RXBUF),
};
static inline int vhost_has_feature(struct vhost_dev *dev, int bit)
--
1.7.10.4
vhost-blk is a in kernel virito-blk device accelerator.
This patch is based on Liu Yuan's implementation with various
improvements and bug fixes. Notably, this patch makes guest notify and
host completion processing in parallel which gives about 60% performance
improvement compared to Liu Yuan's implementation.
Performance evaluation:
-----------------------------
The comparison is between kvm tool with usersapce implementation and kvm
tool with vhost-blk.
1) Fio with libaio ioengine on Fusion IO device
With bio-based IO path, sequential read/write, random read/write
IOPS boost : 8.4%, 15.3%, 10.4%, 14.6%
Latency improvement: 8.5%, 15.4%, 10.4%, 15.1%
2) Fio with vsync ioengine on Fusion IO device
With bio-based IO path, sequential read/write, random read/write
IOPS boost : 10.5%, 4.8%, 5.2%, 5.6%
Latency improvement: 11.4%, 5.0%, 5.2%, 5.8%
Signed-off-by: Asias He <asias at redhat.com>
---
drivers/vhost/Kconfig | 10 +
drivers/vhost/Makefile | 2 +
drivers/vhost/blk.c | 600 ++++++++++++++++++++++++++++++++++++++++++++++++
drivers/vhost/vhost.h | 5 +
include/linux/vhost.h | 1 +
5 files changed, 618 insertions(+)
create mode 100644 drivers/vhost/blk.c
diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
index c387067..fa071a8 100644
--- a/drivers/vhost/Kconfig
+++ b/drivers/vhost/Kconfig
@@ -16,4 +16,14 @@ config VHOST_NET
To compile this driver as a module, choose M here: the module will
be called vhost_net.
+config VHOST_BLK
+ tristate "Host kernel accelerator for virtio blk (EXPERIMENTAL)"
+ depends on VHOST && BLOCK && AIO && EVENTFD &&
EXPERIMENTAL
+ ---help---
+ This kernel module can be loaded in host kernel to accelerate
+ guest block with virtio_blk. Not to be confused with virtio_blk
+ module itself which needs to be loaded in guest kernel.
+
+ To compile this driver as a module, choose M here: the module will
+ be called vhost_blk.
diff --git a/drivers/vhost/Makefile b/drivers/vhost/Makefile
index cd36885..aa461d5 100644
--- a/drivers/vhost/Makefile
+++ b/drivers/vhost/Makefile
@@ -1,4 +1,6 @@
obj-$(CONFIG_VHOST) += vhost.o
obj-$(CONFIG_VHOST_NET) += vhost_net.o
+obj-$(CONFIG_VHOST_BLK) += vhost_blk.o
vhost_net-y := net.o
+vhost_blk-y := blk.o
diff --git a/drivers/vhost/blk.c b/drivers/vhost/blk.c
new file mode 100644
index 0000000..6a94894
--- /dev/null
+++ b/drivers/vhost/blk.c
@@ -0,0 +1,600 @@
+/*
+ * Copyright (C) 2011 Taobao, Inc.
+ * Author: Liu Yuan <tailai.ly at taobao.com>
+ *
+ * Copyright (C) 2012 Red Hat, Inc.
+ * Author: Asias He <asias at redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ *
+ * virtio-blk server in host kernel.
+ */
+
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/vhost.h>
+#include <linux/virtio_blk.h>
+#include <linux/eventfd.h>
+#include <linux/mutex.h>
+#include <linux/file.h>
+#include <linux/mmu_context.h>
+#include <linux/anon_inodes.h>
+#include <linux/kthread.h>
+#include <linux/blkdev.h>
+
+#include "vhost.h"
+
+#define BLK_HDR 0
+
+enum {
+ VHOST_BLK_VQ_REQ = 0,
+ VHOST_BLK_VQ_MAX = 1,
+};
+
+struct vhost_blk_req {
+ u16 head;
+ u8 *status;
+};
+
+struct vhost_blk {
+ struct task_struct *worker_host_kick;
+ struct task_struct *worker;
+ struct vhost_blk_req *reqs;
+ struct vhost_virtqueue vq;
+ struct eventfd_ctx *ectx;
+ struct io_event *ioevent;
+ struct kioctx *ioctx;
+ struct vhost_dev dev;
+ struct file *efile;
+ u64 ioevent_nr;
+ bool stop;
+};
+
+static inline int vhost_blk_read_events(struct vhost_blk *blk, long nr)
+{
+ mm_segment_t old_fs = get_fs();
+ int ret;
+
+ set_fs(KERNEL_DS);
+ ret = read_events(blk->ioctx, nr, nr, blk->ioevent, NULL);
+ set_fs(old_fs);
+
+ return ret;
+}
+
+static int vhost_blk_setup(struct vhost_blk *blk)
+{
+ struct kioctx *ctx;
+
+ if (blk->ioctx)
+ return 0;
+
+ blk->ioevent_nr = blk->vq.num;
+ ctx = ioctx_alloc(blk->ioevent_nr);
+ if (IS_ERR(ctx)) {
+ pr_err("Failed to ioctx_alloc");
+ return PTR_ERR(ctx);
+ }
+ put_ioctx(ctx);
+ blk->ioctx = ctx;
+
+ blk->ioevent = kmalloc(sizeof(struct io_event) * blk->ioevent_nr,
+ GFP_KERNEL);
+ if (!blk->ioevent) {
+ pr_err("Failed to allocate memory for io_events");
+ return -ENOMEM;
+ }
+
+ blk->reqs = kmalloc(sizeof(struct vhost_blk_req) * blk->ioevent_nr,
+ GFP_KERNEL);
+ if (!blk->reqs) {
+ pr_err("Failed to allocate memory for vhost_blk_req");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static inline int vhost_blk_set_status(struct vhost_blk *blk, u8 *statusp,
+ u8 status)
+{
+ if (copy_to_user(statusp, &status, sizeof(status))) {
+ vq_err(&blk->vq, "Failed to write status\n");
+ vhost_discard_vq_desc(&blk->vq, 1);
+ return -EFAULT;
+ }
+
+ return 0;
+}
+
+static void vhost_blk_enable_vq(struct vhost_blk *blk,
+ struct vhost_virtqueue *vq)
+{
+ wake_up_process(blk->worker_host_kick);
+}
+
+static int vhost_blk_io_submit(struct vhost_blk *blk, struct file *file,
+ struct vhost_blk_req *req,
+ struct iovec *iov, u64 nr_vecs, loff_t offset,
+ int opcode)
+{
+ struct kioctx *ioctx = blk->ioctx;
+ mm_segment_t oldfs = get_fs();
+ struct kiocb_batch batch;
+ struct blk_plug plug;
+ struct kiocb *iocb;
+ int ret;
+
+ if (!try_get_ioctx(ioctx)) {
+ pr_info("Failed to get ioctx");
+ return -EAGAIN;
+ }
+
+ atomic_long_inc_not_zero(&file->f_count);
+ eventfd_ctx_get(blk->ectx);
+
+ /* TODO: batch to 1 is not good! */
+ kiocb_batch_init(&batch, 1);
+ blk_start_plug(&plug);
+
+ iocb = aio_get_req(ioctx, &batch);
+ if (unlikely(!iocb)) {
+ ret = -EAGAIN;
+ goto out;
+ }
+
+ iocb->ki_filp = file;
+ iocb->ki_pos = offset;
+ iocb->ki_buf = (void *)iov;
+ iocb->ki_left = nr_vecs;
+ iocb->ki_nbytes = nr_vecs;
+ iocb->ki_opcode = opcode;
+ iocb->ki_obj.user = req;
+ iocb->ki_eventfd = blk->ectx;
+
+ set_fs(KERNEL_DS);
+ ret = aio_setup_iocb(iocb, false);
+ set_fs(oldfs);
+ if (unlikely(ret))
+ goto out_put_iocb;
+
+ spin_lock_irq(&ioctx->ctx_lock);
+ if (unlikely(ioctx->dead)) {
+ spin_unlock_irq(&ioctx->ctx_lock);
+ ret = -EINVAL;
+ goto out_put_iocb;
+ }
+ aio_run_iocb(iocb);
+ spin_unlock_irq(&ioctx->ctx_lock);
+
+ aio_put_req(iocb);
+
+ blk_finish_plug(&plug);
+ kiocb_batch_free(ioctx, &batch);
+ put_ioctx(ioctx);
+
+ return ret;
+out_put_iocb:
+ aio_put_req(iocb); /* Drop extra ref to req */
+ aio_put_req(iocb); /* Drop I/O ref to req */
+out:
+ put_ioctx(ioctx);
+ return ret;
+}
+
+static void vhost_blk_flush(struct vhost_blk *blk)
+{
+ vhost_poll_flush(&blk->vq.poll);
+}
+
+static struct file *vhost_blk_stop_vq(struct vhost_blk *blk,
+ struct vhost_virtqueue *vq)
+{
+ struct file *file;
+
+ mutex_lock(&vq->mutex);
+ file = rcu_dereference_protected(vq->private_data,
+ lockdep_is_held(&vq->mutex));
+ rcu_assign_pointer(vq->private_data, NULL);
+ mutex_unlock(&vq->mutex);
+
+ return file;
+
+}
+
+static inline void vhost_blk_stop(struct vhost_blk *blk, struct file **file)
+{
+
+ *file = vhost_blk_stop_vq(blk, &blk->vq);
+}
+
+/* Handle guest request */
+static int vhost_blk_do_req(struct vhost_virtqueue *vq,
+ struct virtio_blk_outhdr *hdr,
+ u16 head, u16 out, u16 in,
+ struct file *file)
+{
+ struct vhost_blk *blk = container_of(vq->dev, struct vhost_blk, dev);
+ struct iovec *iov = &vq->iov[BLK_HDR + 1];
+ loff_t offset = hdr->sector << 9;
+ struct vhost_blk_req *req;
+ u64 nr_vecs;
+ int ret = 0;
+ u8 status;
+
+ if (hdr->type == VIRTIO_BLK_T_IN || hdr->type == VIRTIO_BLK_T_GET_ID)
+ nr_vecs = in - 1;
+ else
+ nr_vecs = out - 1;
+
+ req = &blk->reqs[head];
+ req->head = head;
+ req->status = blk->vq.iov[nr_vecs + 1].iov_base;
+
+ switch (hdr->type) {
+ case VIRTIO_BLK_T_OUT:
+ ret = vhost_blk_io_submit(blk, file, req, iov, nr_vecs, offset,
+ IOCB_CMD_PWRITEV);
+ break;
+ case VIRTIO_BLK_T_IN:
+ ret = vhost_blk_io_submit(blk, file, req, iov, nr_vecs, offset,
+ IOCB_CMD_PREADV);
+ break;
+ case VIRTIO_BLK_T_FLUSH:
+ ret = vfs_fsync(file, 1);
+ status = ret < 0 ? VIRTIO_BLK_S_IOERR : VIRTIO_BLK_S_OK;
+ ret = vhost_blk_set_status(blk, req->status, status);
+ if (!ret)
+ vhost_add_used_and_signal(&blk->dev, vq, head, ret);
+ break;
+ case VIRTIO_BLK_T_GET_ID:
+ /* TODO: need a real ID string */
+ ret = snprintf(vq->iov[BLK_HDR + 1].iov_base,
+ VIRTIO_BLK_ID_BYTES, "VHOST-BLK-DISK");
+ status = ret < 0 ? VIRTIO_BLK_S_IOERR : VIRTIO_BLK_S_OK;
+ ret = vhost_blk_set_status(blk, req->status, status);
+ if (!ret)
+ vhost_add_used_and_signal(&blk->dev, vq, head,
+ VIRTIO_BLK_ID_BYTES);
+ break;
+ default:
+ pr_warn("Unsupported request type %d\n", hdr->type);
+ vhost_discard_vq_desc(vq, 1);
+ ret = -EFAULT;
+ break;
+ }
+
+ return ret;
+}
+
+/* Guest kick us for IO request */
+static void vhost_blk_handle_guest_kick(struct vhost_work *work)
+{
+ struct virtio_blk_outhdr hdr;
+ struct vhost_virtqueue *vq;
+ struct vhost_blk *blk;
+ struct file *f;
+ int in, out;
+ u16 head;
+
+ vq = container_of(work, struct vhost_virtqueue, poll.work);
+ blk = container_of(vq->dev, struct vhost_blk, dev);
+
+ /* TODO: check that we are running from vhost_worker? */
+ f = rcu_dereference_check(vq->private_data, 1);
+ if (!f)
+ return;
+
+ vhost_disable_notify(&blk->dev, vq);
+ for (;;) {
+ head = vhost_get_vq_desc(&blk->dev, vq, vq->iov,
+ ARRAY_SIZE(vq->iov),
+ &out, &in, NULL, NULL);
+ if (unlikely(head < 0))
+ break;
+
+ if (unlikely(head == vq->num)) {
+ if (unlikely(vhost_enable_notify(&blk->dev, vq))) {
+ vhost_disable_notify(&blk->dev, vq);
+ continue;
+ }
+ break;
+ }
+
+ if (unlikely(vq->iov[BLK_HDR].iov_len != sizeof(hdr))) {
+ vq_err(vq, "Bad block header lengh!\n");
+ vhost_discard_vq_desc(vq, 1);
+ break;
+ }
+
+ if (unlikely(copy_from_user(&hdr, vq->iov[BLK_HDR].iov_base,
+ sizeof(hdr)))) {
+ vq_err(vq, "Failed to get block header!\n");
+ vhost_discard_vq_desc(vq, 1);
+ break;
+ }
+
+
+ if (unlikely(vhost_blk_do_req(vq, &hdr, head, out, in, f) < 0))
+ break;
+ }
+}
+
+/* Complete the IO request */
+static int vhost_blk_host_kick_thread(void *data)
+{
+ mm_segment_t oldfs = get_fs();
+ struct vhost_blk *blk = data;
+ struct vhost_virtqueue *vq;
+ struct vhost_blk_req *req;
+ struct io_event *e;
+ int ret, i, len;
+ u64 count, nr;
+ u8 status;
+
+ vq = &blk->vq;
+ set_fs(USER_DS);
+ use_mm(blk->dev.mm);
+ for (;;) {
+ do {
+ ret = eventfd_ctx_read(blk->ectx, 0, &count);
+ if (unlikely(kthread_should_stop() || blk->stop))
+ goto out;
+ } while (ret != 0);
+
+ do {
+ nr = vhost_blk_read_events(blk,
+ min(count, blk->ioevent_nr));
+ if (unlikely(nr <= 0))
+ continue;
+ count -= nr;
+
+ for (i = 0; i < nr; i++) {
+ e = &blk->ioevent[i];
+ req = (void *)e->obj;
+ len = e->res;
+ status = len > 0 ? VIRTIO_BLK_S_OK :
+ VIRTIO_BLK_S_IOERR;
+ ret = copy_to_user(req->status, &status,
+ sizeof(status));
+ if (unlikely(ret)) {
+ vq_err(&blk->vq,
+ "Failed to write status\n");
+ continue;
+ }
+ vhost_add_used(&blk->vq, req->head, len);
+ }
+ vhost_signal(&blk->dev, &blk->vq);
+ } while (count > 0);
+ }
+
+out:
+ unuse_mm(blk->dev.mm);
+ set_fs(oldfs);
+ return 0;
+}
+
+static int vhost_blk_open(struct inode *inode, struct file *file)
+{
+ struct vhost_blk *blk;
+ int ret;
+
+ blk = kzalloc(sizeof(*blk), GFP_KERNEL);
+ if (!blk) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ blk->vq.handle_kick = vhost_blk_handle_guest_kick;
+
+ ret = vhost_dev_init(&blk->dev, &blk->vq, VHOST_BLK_VQ_MAX);
+ if (ret < 0)
+ goto out_dev;
+ /*
+ * Create an eventfd which is used by aio code to
+ * notify guest when request is completed.
+ */
+ blk->efile = eventfd_file_create(0, 0);
+ if (IS_ERR(blk->efile))
+ goto out_dev;
+ blk->ectx = eventfd_ctx_fileget(blk->efile);
+ if (IS_ERR(blk->ectx))
+ goto out_dev;
+
+ file->private_data = blk;
+
+ blk->worker_host_kick = kthread_create(vhost_blk_host_kick_thread,
+ blk, "vhost-blk-%d", current->pid);
+ if (IS_ERR(blk->worker_host_kick)) {
+ ret = PTR_ERR(blk->worker_host_kick);
+ goto out_dev;
+ }
+
+ return ret;
+out_dev:
+ kfree(blk);
+out:
+ return ret;
+}
+
+static int vhost_blk_release(struct inode *inode, struct file *f)
+{
+ struct vhost_blk *blk = f->private_data;
+ struct file *file;
+
+ vhost_blk_stop(blk, &file);
+ vhost_blk_flush(blk);
+ vhost_dev_cleanup(&blk->dev, false);
+ if (file)
+ fput(file);
+
+ blk->stop = true;
+ eventfd_signal(blk->ectx, 1);
+ kthread_stop(blk->worker_host_kick);
+
+ eventfd_ctx_put(blk->ectx);
+ if (blk->efile)
+ fput(blk->efile);
+
+ kfree(blk->ioevent);
+ kfree(blk->reqs);
+ kfree(blk);
+
+ return 0;
+}
+
+static int vhost_blk_set_features(struct vhost_blk *blk, u64 features)
+{
+ mutex_lock(&blk->dev.mutex);
+ blk->dev.acked_features = features;
+ mutex_unlock(&blk->dev.mutex);
+
+ return 0;
+}
+
+static long vhost_blk_set_backend(struct vhost_blk *blk, unsigned index, int
fd)
+{
+ struct vhost_virtqueue *vq = &blk->vq;
+ struct file *file, *oldfile;
+ int ret;
+
+ mutex_lock(&blk->dev.mutex);
+ ret = vhost_dev_check_owner(&blk->dev);
+ if (ret)
+ goto out_dev;
+
+ if (index >= VHOST_BLK_VQ_MAX) {
+ ret = -ENOBUFS;
+ goto out_dev;
+ }
+
+ mutex_lock(&vq->mutex);
+
+ if (!vhost_vq_access_ok(vq)) {
+ ret = -EFAULT;
+ goto out_vq;
+ }
+
+ file = fget(fd);
+ if (IS_ERR(file)) {
+ ret = PTR_ERR(file);
+ goto out_vq;
+ }
+
+ oldfile = rcu_dereference_protected(vq->private_data,
+ lockdep_is_held(&vq->mutex));
+ if (file != oldfile) {
+ rcu_assign_pointer(vq->private_data, file);
+ vhost_blk_enable_vq(blk, vq);
+
+ ret = vhost_init_used(vq);
+ if (ret)
+ goto out_vq;
+ }
+
+ mutex_unlock(&vq->mutex);
+
+ if (oldfile) {
+ vhost_blk_flush(blk);
+ fput(oldfile);
+ }
+
+ mutex_unlock(&blk->dev.mutex);
+ return 0;
+
+out_vq:
+ mutex_unlock(&vq->mutex);
+out_dev:
+ mutex_unlock(&blk->dev.mutex);
+ return ret;
+}
+
+static long vhost_blk_reset_owner(struct vhost_blk *blk)
+{
+ struct file *file = NULL;
+ int err;
+
+ mutex_lock(&blk->dev.mutex);
+ err = vhost_dev_check_owner(&blk->dev);
+ if (err)
+ goto done;
+ vhost_blk_stop(blk, &file);
+ vhost_blk_flush(blk);
+ err = vhost_dev_reset_owner(&blk->dev);
+done:
+ mutex_unlock(&blk->dev.mutex);
+ if (file)
+ fput(file);
+ return err;
+}
+
+static long vhost_blk_ioctl(struct file *f, unsigned int ioctl,
+ unsigned long arg)
+{
+ struct vhost_blk *blk = f->private_data;
+ void __user *argp = (void __user *)arg;
+ struct vhost_vring_file backend;
+ u64 __user *featurep = argp;
+ u64 features;
+ int ret;
+
+ switch (ioctl) {
+ case VHOST_BLK_SET_BACKEND:
+ if (copy_from_user(&backend, argp, sizeof backend))
+ return -EFAULT;
+ return vhost_blk_set_backend(blk, backend.index, backend.fd);
+ case VHOST_GET_FEATURES:
+ features = VHOST_BLK_FEATURES;
+ if (copy_to_user(featurep, &features, sizeof features))
+ return -EFAULT;
+ return 0;
+ case VHOST_SET_FEATURES:
+ if (copy_from_user(&features, featurep, sizeof features))
+ return -EFAULT;
+ if (features & ~VHOST_BLK_FEATURES)
+ return -EOPNOTSUPP;
+ return vhost_blk_set_features(blk, features);
+ case VHOST_RESET_OWNER:
+ return vhost_blk_reset_owner(blk);
+ default:
+ mutex_lock(&blk->dev.mutex);
+ ret = vhost_dev_ioctl(&blk->dev, ioctl, arg);
+ if (!ret && ioctl == VHOST_SET_VRING_NUM)
+ ret = vhost_blk_setup(blk);
+ vhost_blk_flush(blk);
+ mutex_unlock(&blk->dev.mutex);
+ return ret;
+ }
+}
+
+static const struct file_operations vhost_blk_fops = {
+ .owner = THIS_MODULE,
+ .open = vhost_blk_open,
+ .release = vhost_blk_release,
+ .llseek = noop_llseek,
+ .unlocked_ioctl = vhost_blk_ioctl,
+};
+
+static struct miscdevice vhost_blk_misc = {
+ MISC_DYNAMIC_MINOR,
+ "vhost-blk",
+ &vhost_blk_fops,
+};
+
+int vhost_blk_init(void)
+{
+ return misc_register(&vhost_blk_misc);
+}
+
+void vhost_blk_exit(void)
+{
+ misc_deregister(&vhost_blk_misc);
+}
+
+module_init(vhost_blk_init);
+module_exit(vhost_blk_exit);
+
+MODULE_VERSION("0.0.2");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Asias He");
+MODULE_DESCRIPTION("Host kernel accelerator for virtio_blk");
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index cc046a9..1d4db7b 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -205,6 +205,11 @@ enum {
(1ULL << VHOST_F_LOG_ALL) |
(1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
(1ULL << VIRTIO_NET_F_MRG_RXBUF),
+
+ VHOST_BLK_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
+ (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
+ (1ULL << VIRTIO_RING_F_EVENT_IDX) |
+ (1ULL << VHOST_F_LOG_ALL),
};
static inline int vhost_has_feature(struct vhost_dev *dev, int bit)
diff --git a/include/linux/vhost.h b/include/linux/vhost.h
index e847f1e..c7e764f 100644
--- a/include/linux/vhost.h
+++ b/include/linux/vhost.h
@@ -120,6 +120,7 @@ struct vhost_memory {
* used for transmit. Pass fd -1 to unbind from the socket and the transmit
* device. This can be used to stop the ring (e.g. for migration). */
#define VHOST_NET_SET_BACKEND _IOW(VHOST_VIRTIO, 0x30, struct vhost_vring_file)
+#define VHOST_BLK_SET_BACKEND _IOW(VHOST_VIRTIO, 0x31, struct vhost_vring_file)
/* Feature bits */
/* Log all write descriptors. Can be changed while device is active. */
--
1.7.10.4