Hello Michael, Thanks for the review! On 10/11/2012 08:41 PM, Michael S. Tsirkin wrote: > On Tue, Oct 09, 2012 at 04:05:18PM +0800, Asias He wrote: >> vhost-blk is an in-kernel virito-blk device accelerator. >> >> Due to lack of proper in-kernel AIO interface, this version converts >> guest's I/O request to bio and use submit_bio() to submit I/O directly. >> So this version any supports raw block device as guest's disk image, >> e.g. /dev/sda, /dev/ram0. We can add file based image support to >> vhost-blk once we have in-kernel AIO interface. There are some work in >> progress for in-kernel AIO interface from Dave Kleikamp and Zach Brown: >> >> http://marc.info/?l=linux-fsdevel&m=133312234313122 >> >> Performance evaluation: >> ----------------------------- >> 1) LKVM >> Fio with libaio ioengine on Fusion IO device using kvm tool >> IOPS Before After Improvement >> seq-read 107 121 +13.0% >> seq-write 130 179 +37.6% >> rnd-read 102 122 +19.6% >> rnd-write 125 159 +27.0% >> >> 2) QEMU >> Fio with libaio ioengine on Fusion IO device using QEMU >> IOPS Before After Improvement >> seq-read 76 123 +61.8% >> seq-write 139 173 +24.4% >> rnd-read 73 120 +64.3% >> rnd-write 75 156 +108.0% >> >> Userspace bits: >> ----------------------------- >> 1) LKVM >> The latest vhost-blk userspace bits for kvm tool can be found here: >> git@xxxxxxxxxx:asias/linux-kvm.git blk.vhost-blk >> >> 2) QEMU >> The latest vhost-blk userspace prototype for QEMU can be found here: >> git@xxxxxxxxxx:asias/qemu.git blk.vhost-blk >> >> Signed-off-by: Asias He <asias@xxxxxxxxxx> >> --- >> drivers/vhost/Kconfig | 1 + >> drivers/vhost/Kconfig.blk | 10 + >> drivers/vhost/Makefile | 2 + >> drivers/vhost/blk.c | 641 ++++++++++++++++++++++++++++++++++++++++++++++ >> drivers/vhost/blk.h | 8 + >> 5 files changed, 662 insertions(+) >> create mode 100644 drivers/vhost/Kconfig.blk >> create mode 100644 drivers/vhost/blk.c >> create mode 100644 drivers/vhost/blk.h >> >> diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig >> index 202bba6..acd8038 100644 >> --- a/drivers/vhost/Kconfig >> +++ b/drivers/vhost/Kconfig >> @@ -11,4 +11,5 @@ config VHOST_NET >> >> if STAGING >> source "drivers/vhost/Kconfig.tcm" >> +source "drivers/vhost/Kconfig.blk" >> endif >> diff --git a/drivers/vhost/Kconfig.blk b/drivers/vhost/Kconfig.blk >> new file mode 100644 >> index 0000000..ff8ab76 >> --- /dev/null >> +++ b/drivers/vhost/Kconfig.blk >> @@ -0,0 +1,10 @@ >> +config VHOST_BLK >> + tristate "Host kernel accelerator for virtio blk (EXPERIMENTAL)" >> + depends on BLOCK && EXPERIMENTAL && m >> + ---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 a27b053..1a8a4a5 100644 >> --- a/drivers/vhost/Makefile >> +++ b/drivers/vhost/Makefile >> @@ -2,3 +2,5 @@ obj-$(CONFIG_VHOST_NET) += vhost_net.o >> vhost_net-y := vhost.o net.o >> >> obj-$(CONFIG_TCM_VHOST) += tcm_vhost.o >> +obj-$(CONFIG_VHOST_BLK) += vhost_blk.o >> +vhost_blk-y := blk.o >> diff --git a/drivers/vhost/blk.c b/drivers/vhost/blk.c >> new file mode 100644 >> index 0000000..6b2445a >> --- /dev/null >> +++ b/drivers/vhost/blk.c >> @@ -0,0 +1,641 @@ >> +/* >> + * Copyright (C) 2011 Taobao, Inc. >> + * Author: Liu Yuan <tailai.ly@xxxxxxxxxx> >> + * >> + * Copyright (C) 2012 Red Hat, Inc. >> + * Author: Asias He <asias@xxxxxxxxxx> >> + * >> + * 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/mutex.h> >> +#include <linux/file.h> >> +#include <linux/kthread.h> >> +#include <linux/blkdev.h> >> + >> +#include "vhost.c" >> +#include "vhost.h" >> +#include "blk.h" >> + >> +#define BLK_HDR 0 > > What's this for, exactly? Please add a comment. The block headr is in the first and separate buffer. >> + >> +static DEFINE_IDA(vhost_blk_index_ida); >> + >> +enum { >> + VHOST_BLK_VQ_REQ = 0, >> + VHOST_BLK_VQ_MAX = 1, >> +}; >> + >> +struct req_page_list { >> + struct page **pages; >> + int pages_nr; >> +}; >> + >> +struct vhost_blk_req { >> + struct llist_node llnode; >> + struct req_page_list *pl; >> + struct vhost_blk *blk; >> + >> + struct iovec *iov; >> + int iov_nr; >> + >> + struct bio **bio; >> + atomic_t bio_nr; >> + >> + sector_t sector; >> + int write; >> + u16 head; >> + long len; >> + >> + u8 *status; > > Is this a userspace pointer? If yes it must be tagged as such. Will fix. > Please run code checker - it will catch other bugs for you too. Could you name one that you use? >> +}; >> + >> +struct vhost_blk { >> + struct task_struct *host_kick; >> + struct vhost_blk_req *reqs; >> + struct vhost_virtqueue vq; >> + struct llist_head llhead; >> + struct vhost_dev dev; >> + u16 reqs_nr; >> + int index; >> +}; >> + >> +static inline int iov_num_pages(struct iovec *iov) >> +{ >> + return (PAGE_ALIGN((unsigned long)iov->iov_base + iov->iov_len) - >> + ((unsigned long)iov->iov_base & PAGE_MASK)) >> PAGE_SHIFT; >> +} >> + >> +static int vhost_blk_setup(struct vhost_blk *blk) >> +{ >> + blk->reqs_nr = blk->vq.num; >> + >> + blk->reqs = kmalloc(sizeof(struct vhost_blk_req) * blk->reqs_nr, >> + GFP_KERNEL); >> + if (!blk->reqs) >> + return -ENOMEM; >> + >> + return 0; >> +} >> + >> +static inline int vhost_blk_set_status(struct vhost_blk_req *req, u8 status) >> +{ >> + struct vhost_blk *blk = req->blk; >> + >> + if (copy_to_user(req->status, &status, sizeof(status))) { > > Does this write into guest memory, right? This write needs to be tracked in > log in case it's enabled. Yes. Log is not enabled currently. I am wondering why is the log useful? > Also, __copy_to_user should be enough here, right? > Hmm, why? >> + 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->host_kick); >> +} >> + >> +static void vhost_blk_req_done(struct bio *bio, int err) >> +{ >> + struct vhost_blk_req *req = bio->bi_private; >> + struct vhost_blk *blk = req->blk; >> + >> + if (err) >> + req->len = err; >> + >> + if (atomic_dec_and_test(&req->bio_nr)) { >> + llist_add(&req->llnode, &blk->llhead); >> + wake_up_process(blk->host_kick); >> + } >> + >> + bio_put(bio); >> +} >> + >> +static void vhost_blk_req_umap(struct vhost_blk_req *req) >> +{ >> + struct req_page_list *pl; >> + int i, j; >> + >> + if (!req->pl) >> + return; >> + >> + for (i = 0; i < req->iov_nr; i++) { >> + pl = &req->pl[i]; >> + for (j = 0; j < pl->pages_nr; j++) { >> + if (!req->write) >> + set_page_dirty_lock(pl->pages[j]); >> + page_cache_release(pl->pages[j]); >> + } >> + } >> + >> + kfree(req->pl); >> +} >> + >> +static int vhost_blk_bio_make(struct vhost_blk_req *req, >> + struct block_device *bdev) >> +{ >> + int pages_nr_total, i, j, ret; >> + struct iovec *iov = req->iov; >> + int iov_nr = req->iov_nr; >> + struct page **pages, *page; >> + struct bio *bio = NULL; >> + int bio_nr = 0; >> + >> + req->len = 0; >> + pages_nr_total = 0; >> + for (i = 0; i < iov_nr; i++) { >> + req->len += iov[i].iov_len; >> + pages_nr_total += iov_num_pages(&iov[i]); >> + } >> + >> + req->pl = kmalloc((iov_nr * sizeof(struct req_page_list)) + >> + (pages_nr_total * sizeof(struct page *)) + >> + (pages_nr_total * sizeof(struct bio *)), >> + GFP_KERNEL); >> + if (!req->pl) >> + return -ENOMEM; >> + pages = (struct page **)&req->pl[iov_nr]; >> + req->bio = (struct bio **)&pages[pages_nr_total]; >> + >> + req->iov_nr = 0; >> + for (i = 0; i < iov_nr; i++) { >> + int pages_nr = iov_num_pages(&iov[i]); >> + unsigned long iov_base, iov_len; >> + struct req_page_list *pl; >> + >> + iov_base = (unsigned long)iov[i].iov_base; >> + iov_len = (unsigned long)iov[i].iov_len; >> + >> + ret = get_user_pages_fast(iov_base, pages_nr, >> + !req->write, pages); >> + if (ret != pages_nr) >> + goto fail; >> + >> + req->iov_nr++; >> + pl = &req->pl[i]; >> + pl->pages_nr = pages_nr; >> + pl->pages = pages; >> + >> + for (j = 0; j < pages_nr; j++) { >> + unsigned int off, len; >> + page = pages[j]; >> + off = iov_base & ~PAGE_MASK; >> + len = PAGE_SIZE - off; >> + if (len > iov_len) >> + len = iov_len; >> + >> + while (!bio || bio_add_page(bio, page, len, off) <= 0) { >> + bio = bio_alloc(GFP_KERNEL, pages_nr); >> + if (!bio) >> + goto fail; >> + bio->bi_sector = req->sector; >> + bio->bi_bdev = bdev; >> + bio->bi_private = req; >> + bio->bi_end_io = vhost_blk_req_done; >> + req->bio[bio_nr++] = bio; >> + } >> + req->sector += len >> 9; >> + iov_base += len; >> + iov_len -= len; >> + } >> + >> + pages += pages_nr; >> + } >> + atomic_set(&req->bio_nr, bio_nr); >> + >> + return 0; >> + >> +fail: >> + for (i = 0; i < bio_nr; i++) >> + bio_put(req->bio[i]); >> + vhost_blk_req_umap(req); >> + return -ENOMEM; >> +} >> + >> +static inline void vhost_blk_bio_send(struct vhost_blk_req *req) >> +{ >> + struct blk_plug plug; >> + int i, bio_nr; >> + >> + bio_nr = atomic_read(&req->bio_nr); >> + blk_start_plug(&plug); >> + for (i = 0; i < bio_nr; i++) >> + submit_bio(req->write, req->bio[i]); >> + blk_finish_plug(&plug); >> +} >> + >> +static int vhost_blk_req_submit(struct vhost_blk_req *req, struct file *file) >> +{ >> + >> + struct inode *inode = file->f_mapping->host; >> + struct block_device *bdev = inode->i_bdev; >> + int ret; >> + >> + ret = vhost_blk_bio_make(req, bdev); >> + if (ret < 0) >> + return ret; >> + >> + vhost_blk_bio_send(req); >> + >> + return ret; >> +} >> + >> +static int vhost_blk_req_done_thread(void *data) >> +{ >> + mm_segment_t oldfs = get_fs(); >> + struct vhost_blk *blk = data; >> + struct vhost_virtqueue *vq; >> + struct llist_node *llnode; >> + struct vhost_blk_req *req; >> + bool added; >> + u8 status; >> + int ret; >> + >> + vq = &blk->vq; >> + set_fs(USER_DS); >> + use_mm(blk->dev.mm); >> + for (;;) { >> + llnode = llist_del_all(&blk->llhead); > > > Interesting, I didn't consider llist - maybe vhost.c > could switch to that too? If we do how to handle flushing? > If we do we can move some common code out here. Will take a look. >> + if (!llnode) { >> + set_current_state(TASK_INTERRUPTIBLE); >> + schedule(); >> + if (unlikely(kthread_should_stop())) >> + break; >> + continue; >> + } > > I think you need to call something like > if (need_resched()) > schedule(); > once in a while even if the list is not empty. Yes. We need similar stuff as commit d550dda192c1bd039afb774b99485e88b70d7cb8 did. I had this in the some previous versions. Somehow it's not here. >> + added = false; >> + while (llnode) { >> + req = llist_entry(llnode, struct vhost_blk_req, llnode); >> + llnode = llist_next(llnode); >> + >> + vhost_blk_req_umap(req); >> + >> + status = req->len > 0 ? >> + VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR; >> + ret = copy_to_user(req->status, &status, >> + sizeof(status)); > > use vhost_blk_set_status? Why not? Okay. >> + if (unlikely(ret)) { >> + vq_err(&blk->vq, "Failed to write status\n"); >> + return -1; > > This will kill this thread. Likely not what was intended. Yes, it kill this thread. But I am wondering when and how this copy_to_user() of status would fail and what is the best thing to do in this case: ignore the status and call vhost_add_used() anyway or ... >> + } >> + vhost_add_used(&blk->vq, req->head, req->len); >> + added = true; >> + } >> + if (likely(added)) >> + vhost_signal(&blk->dev, &blk->vq); >> + > > Pls dont add empty line here. okay. >> + } >> + unuse_mm(blk->dev.mm); >> + set_fs(oldfs); >> + return 0; >> +} >> + >> +static void vhost_blk_flush(struct vhost_blk *blk) >> +{ >> + vhost_poll_flush(&blk->vq.poll); > > Hmm but blk kthread could still be processing requests, no? > Need to flush these too I think? The blk kthread does not access the *rcu* protected vq->private_data (file). Do we still need the flush for it? >> +} >> + >> +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); > > Is this wrapper worth it? Also maybe just return file? Hmm. Okay. I will kill vhost_blk_stop_vq() and move it to vhost_blk_stop(). I wanted it to be simialr with vhost_net_stop(). >> +} >> + >> +/* Handle guest request */ >> +static int vhost_blk_req_handle(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 vhost_blk_req *req; >> + int iov_nr, ret; >> + u8 status; >> + >> + if (hdr->type == VIRTIO_BLK_T_IN || hdr->type == VIRTIO_BLK_T_GET_ID) >> + iov_nr = in - 1; >> + else >> + iov_nr = out - 1; >> + >> + req = &blk->reqs[head]; >> + req->head = head; >> + req->status = blk->vq.iov[iov_nr + 1].iov_base; >> + req->blk = blk; >> + req->iov = &vq->iov[BLK_HDR + 1]; > > Lots of manual mangling of iovecs here and elsewhere is scary. > First, there should not be so many assumptions about how buffers > are laid out. virtio-blk.c do set the buffer layout this way, no? > Second, there seems to be no validation that iovec > is large enough. It is preferable to use memcpy_toiovecend and friends > which validate input. This applied to many places below, please > audit code for such uses. Where you find it necessary to > handle iovec directly, please add comments explaining where > it's validated and why it's safe. The vq->iov is defined as vq->iov[UIO_MAXIOV]. The iov_nr is based on the in and out buffer number. The largest queue size I see is 256 in kvm tool. qemu is 128. What do we need to validate here? btw, memcpy_toiovecend() is in net/core/iovec.c. > > >> + req->iov_nr = iov_nr; >> + req->sector = hdr->sector; >> + >> + switch (hdr->type) { >> + case VIRTIO_BLK_T_OUT: >> + req->write = WRITE; >> + ret = vhost_blk_req_submit(req, file); >> + break; >> + case VIRTIO_BLK_T_IN: >> + req->write = READ; >> + ret = vhost_blk_req_submit(req, file); >> + break; >> + case VIRTIO_BLK_T_FLUSH: >> + ret = vfs_fsync(file, 1); >> + status = ret < 0 ? VIRTIO_BLK_S_IOERR : VIRTIO_BLK_S_OK; >> + if (!vhost_blk_set_status(req, status)) >> + vhost_add_used_and_signal(&blk->dev, vq, head, ret); > > This should discard on error, no? Also return error to caller? > r = vhost_blk_set_status(req, status); > if (r) { > ret = r; > break; > } > vhost_add_used_and_signal(&blk->dev, vq, head, ret); > return 0; > > and move discard outside switch below. The flush code is changed in v3 already. >> + break; >> + case VIRTIO_BLK_T_GET_ID: >> + ret = snprintf(vq->iov[BLK_HDR + 1].iov_base, >> + VIRTIO_BLK_ID_BYTES, "vhost-blk%d", blk->index); > > snprintf into a userspace buffer? Uh oh. Ah, will fix this *crap*. > >> + status = ret < 0 ? VIRTIO_BLK_S_IOERR : VIRTIO_BLK_S_OK; >> + if (!vhost_blk_set_status(req, status)) >> + vhost_add_used_and_signal(&blk->dev, vq, head, ret); >> + break; >> + default: >> + pr_warn("Unsupported request type %d\n", hdr->type); > > This can be triggered by userspace so vq_err? Okay. > >> + vhost_discard_vq_desc(vq, 1); > > Note this does not skip this descriptor - it gives userspace > chance to correct it and retry. Is this the intended behaviour? > Should not we fail request instead? We should fail the request here. > >> + 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 blk_plug plug; >> + 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); >> + blk_start_plug(&plug); >> + 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(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 (vhost_blk_req_handle(vq, &hdr, head, out, in, f) < 0) >> + break; >> + } >> + blk_finish_plug(&plug); >> +} >> + >> +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; >> + } >> + >> + ret = ida_simple_get(&vhost_blk_index_ida, 0, 0, GFP_KERNEL); >> + if (ret < 0) >> + goto out_dev; >> + blk->index = ret; >> + >> + 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; >> + file->private_data = blk; >> + >> + blk->host_kick = kthread_create(vhost_blk_req_done_thread, >> + blk, "vhost-blk-%d", current->pid); >> + if (IS_ERR(blk->host_kick)) { >> + ret = PTR_ERR(blk->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; >> + >> + ida_simple_remove(&vhost_blk_index_ida, blk->index); >> + vhost_blk_stop(blk, &file); >> + vhost_blk_flush(blk); >> + vhost_dev_cleanup(&blk->dev, false); >> + if (file) >> + fput(file); >> + kthread_stop(blk->host_kick); >> + 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); > > We also need to flush outstanding requets normally. > If not needed here pls add a comment why. Will add a flush here. >> + >> + 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("0.0.3"); >> +MODULE_LICENSE("GPL v2"); >> +MODULE_AUTHOR("Asias He"); >> +MODULE_DESCRIPTION("Host kernel accelerator for virtio_blk"); >> diff --git a/drivers/vhost/blk.h b/drivers/vhost/blk.h >> new file mode 100644 >> index 0000000..2f674f0 >> --- /dev/null >> +++ b/drivers/vhost/blk.h >> @@ -0,0 +1,8 @@ >> +#include <linux/vhost.h> >> + >> +enum { >> + VHOST_BLK_FEATURES = (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | >> + (1ULL << VIRTIO_RING_F_EVENT_IDX), >> +}; >> +/* VHOST_BLK specific defines */ >> +#define VHOST_BLK_SET_BACKEND _IOW(VHOST_VIRTIO, 0x50, struct vhost_vring_file) >> -- >> 1.7.11.4 Thanks. -- Asias -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
