From e2dcdfe95c0bd67e37db6057edd9c4ee1f1c7b17 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 28 Apr 2014 11:15:08 +0930 Subject: virtio: virtio_break_device() to mark all virtqueues broken. Good for post-apocalyptic scenarios, like S/390 hotplug. Signed-off-by: Rusty Russell --- drivers/virtio/virtio_ring.c | 15 +++++++++++++++ include/linux/virtio.h | 2 ++ 2 files changed, 17 insertions(+) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 1e443629f76d..4d08f45a9c29 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -865,4 +865,19 @@ bool virtqueue_is_broken(struct virtqueue *_vq) } EXPORT_SYMBOL_GPL(virtqueue_is_broken); +/* + * This should prevent the device from being used, allowing drivers to + * recover. You may need to grab appropriate locks to flush. + */ +void virtio_break_device(struct virtio_device *dev) +{ + struct virtqueue *_vq; + + list_for_each_entry(_vq, &dev->vqs, list) { + struct vring_virtqueue *vq = to_vvq(_vq); + vq->broken = true; + } +} +EXPORT_SYMBOL_GPL(virtio_break_device); + MODULE_LICENSE("GPL"); diff --git a/include/linux/virtio.h b/include/linux/virtio.h index e4abb84199be..b46671e28de2 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -106,6 +106,8 @@ static inline struct virtio_device *dev_to_virtio(struct device *_dev) int register_virtio_device(struct virtio_device *dev); void unregister_virtio_device(struct virtio_device *dev); +void virtio_break_device(struct virtio_device *dev); + /** * virtio_driver - operations for a virtio I/O driver * @driver: underlying device driver (populate name and owner). -- cgit v1.2.3 From e75279c4fb853f42004cbabb6dbf6b23188dc163 Mon Sep 17 00:00:00 2001 From: Heinz Graalfs Date: Mon, 28 Apr 2014 11:24:05 +0930 Subject: virtio_ccw: introduce device_lost in virtio_ccw_device When a device is lost, the common I/O layer calls the notification handler with CIO_GONE: In that event, flag device_lost as true. In case the device had been flagged as lost when the remove/offline callbacks are called, call the new virtio_break_device() function prior to invoking device_unregister(). This avoids hangs of I/O triggered via the device unregistration callbacks. Signed-off-by: Heinz Graalfs Reviewed-by: Cornelia Huck Signed-off-by: Rusty Russell --- drivers/s390/kvm/virtio_ccw.c | 49 ++++++++++++++++++++++++++++++++----------- 1 file changed, 37 insertions(+), 12 deletions(-) diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c index 1e1fc671f89a..d2c0b442bce5 100644 --- a/drivers/s390/kvm/virtio_ccw.c +++ b/drivers/s390/kvm/virtio_ccw.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -62,6 +63,7 @@ struct virtio_ccw_device { struct vq_config_block *config_block; bool is_thinint; bool going_away; + bool device_lost; void *airq_info; }; @@ -1010,11 +1012,14 @@ static void virtio_ccw_remove(struct ccw_device *cdev) unsigned long flags; struct virtio_ccw_device *vcdev = virtio_grab_drvdata(cdev); - if (vcdev && cdev->online) + if (vcdev && cdev->online) { + if (vcdev->device_lost) + virtio_break_device(&vcdev->vdev); unregister_virtio_device(&vcdev->vdev); - spin_lock_irqsave(get_ccwdev_lock(cdev), flags); - dev_set_drvdata(&cdev->dev, NULL); - spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags); + spin_lock_irqsave(get_ccwdev_lock(cdev), flags); + dev_set_drvdata(&cdev->dev, NULL); + spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags); + } cdev->handler = NULL; } @@ -1023,12 +1028,14 @@ static int virtio_ccw_offline(struct ccw_device *cdev) unsigned long flags; struct virtio_ccw_device *vcdev = virtio_grab_drvdata(cdev); - if (vcdev) { - unregister_virtio_device(&vcdev->vdev); - spin_lock_irqsave(get_ccwdev_lock(cdev), flags); - dev_set_drvdata(&cdev->dev, NULL); - spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags); - } + if (!vcdev) + return 0; + if (vcdev->device_lost) + virtio_break_device(&vcdev->vdev); + unregister_virtio_device(&vcdev->vdev); + spin_lock_irqsave(get_ccwdev_lock(cdev), flags); + dev_set_drvdata(&cdev->dev, NULL); + spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags); return 0; } @@ -1096,8 +1103,26 @@ out_free: static int virtio_ccw_cio_notify(struct ccw_device *cdev, int event) { - /* TODO: Check whether we need special handling here. */ - return 0; + int rc; + struct virtio_ccw_device *vcdev = dev_get_drvdata(&cdev->dev); + + /* + * Make sure vcdev is set + * i.e. set_offline/remove callback not already running + */ + if (!vcdev) + return NOTIFY_DONE; + + switch (event) { + case CIO_GONE: + vcdev->device_lost = true; + rc = NOTIFY_DONE; + break; + default: + rc = NOTIFY_DONE; + break; + } + return rc; } static struct ccw_device_id virtio_ids[] = { -- cgit v1.2.3 From 08e53fbdb85c0f6f45c0f7c1ea3defc1752a95ce Mon Sep 17 00:00:00 2001 From: Amos Kong Date: Wed, 14 May 2014 10:33:46 +0930 Subject: virtio-rng: support multiple virtio-rng devices Current hwrng core supports to register multiple hwrng devices, and there is only one device really works in the same time. QEMU alsu supports to have multiple virtio-rng backends. This patch changes virtio-rng driver to support multiple virtio-rng devices. ]# cat /sys/class/misc/hw_random/rng_available virtio_rng.0 virtio_rng.1 ]# cat /sys/class/misc/hw_random/rng_current virtio_rng.0 ]# echo -n virtio_rng.1 > /sys/class/misc/hw_random/rng_current ]# dd if=/dev/hwrng of=/dev/null Signed-off-by: Amos Kong Signed-off-by: Rusty Russell --- drivers/char/hw_random/virtio-rng.c | 102 ++++++++++++++++++++++-------------- include/linux/hw_random.h | 2 +- 2 files changed, 64 insertions(+), 40 deletions(-) diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c index 2ce0e225e58c..12e242bbb0f5 100644 --- a/drivers/char/hw_random/virtio-rng.c +++ b/drivers/char/hw_random/virtio-rng.c @@ -25,88 +25,108 @@ #include #include -static struct virtqueue *vq; -static unsigned int data_avail; -static DECLARE_COMPLETION(have_data); -static bool busy; + +struct virtrng_info { + struct virtio_device *vdev; + struct hwrng hwrng; + struct virtqueue *vq; + unsigned int data_avail; + struct completion have_data; + bool busy; +}; static void random_recv_done(struct virtqueue *vq) { + struct virtrng_info *vi = vq->vdev->priv; + /* We can get spurious callbacks, e.g. shared IRQs + virtio_pci. */ - if (!virtqueue_get_buf(vq, &data_avail)) + if (!virtqueue_get_buf(vi->vq, &vi->data_avail)) return; - complete(&have_data); + complete(&vi->have_data); } /* The host will fill any buffer we give it with sweet, sweet randomness. */ -static void register_buffer(u8 *buf, size_t size) +static void register_buffer(struct virtrng_info *vi, u8 *buf, size_t size) { struct scatterlist sg; sg_init_one(&sg, buf, size); /* There should always be room for one buffer. */ - virtqueue_add_inbuf(vq, &sg, 1, buf, GFP_KERNEL); + virtqueue_add_inbuf(vi->vq, &sg, 1, buf, GFP_KERNEL); - virtqueue_kick(vq); + virtqueue_kick(vi->vq); } static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait) { int ret; + struct virtrng_info *vi = (struct virtrng_info *)rng->priv; - if (!busy) { - busy = true; - init_completion(&have_data); - register_buffer(buf, size); + if (!vi->busy) { + vi->busy = true; + init_completion(&vi->have_data); + register_buffer(vi, buf, size); } if (!wait) return 0; - ret = wait_for_completion_killable(&have_data); + ret = wait_for_completion_killable(&vi->have_data); if (ret < 0) return ret; - busy = false; + vi->busy = false; - return data_avail; + return vi->data_avail; } static void virtio_cleanup(struct hwrng *rng) { - if (busy) - wait_for_completion(&have_data); -} - + struct virtrng_info *vi = (struct virtrng_info *)rng->priv; -static struct hwrng virtio_hwrng = { - .name = "virtio", - .cleanup = virtio_cleanup, - .read = virtio_read, -}; + if (vi->busy) + wait_for_completion(&vi->have_data); +} static int probe_common(struct virtio_device *vdev) { - int err; + int err, i; + struct virtrng_info *vi = NULL; + + vi = kmalloc(sizeof(struct virtrng_info), GFP_KERNEL); + vi->hwrng.name = kmalloc(40, GFP_KERNEL); + init_completion(&vi->have_data); + + vi->hwrng.read = virtio_read; + vi->hwrng.cleanup = virtio_cleanup; + vi->hwrng.priv = (unsigned long)vi; + vdev->priv = vi; - if (vq) { - /* We only support one device for now */ - return -EBUSY; - } /* We expect a single virtqueue. */ - vq = virtio_find_single_vq(vdev, random_recv_done, "input"); - if (IS_ERR(vq)) { - err = PTR_ERR(vq); - vq = NULL; + vi->vq = virtio_find_single_vq(vdev, random_recv_done, "input"); + if (IS_ERR(vi->vq)) { + err = PTR_ERR(vi->vq); + kfree(vi->hwrng.name); + vi->vq = NULL; + kfree(vi); + vi = NULL; return err; } - err = hwrng_register(&virtio_hwrng); + i = 0; + do { + sprintf(vi->hwrng.name, "virtio_rng.%d", i++); + err = hwrng_register(&vi->hwrng); + } while (err == -EEXIST); + if (err) { vdev->config->del_vqs(vdev); - vq = NULL; + kfree(vi->hwrng.name); + vi->vq = NULL; + kfree(vi); + vi = NULL; return err; } @@ -115,11 +135,15 @@ static int probe_common(struct virtio_device *vdev) static void remove_common(struct virtio_device *vdev) { + struct virtrng_info *vi = vdev->priv; vdev->config->reset(vdev); - busy = false; - hwrng_unregister(&virtio_hwrng); + vi->busy = false; + hwrng_unregister(&vi->hwrng); vdev->config->del_vqs(vdev); - vq = NULL; + kfree(vi->hwrng.name); + vi->vq = NULL; + kfree(vi); + vi = NULL; } static int virtrng_probe(struct virtio_device *vdev) diff --git a/include/linux/hw_random.h b/include/linux/hw_random.h index b4b0eef5fddf..02d9c87be54c 100644 --- a/include/linux/hw_random.h +++ b/include/linux/hw_random.h @@ -31,7 +31,7 @@ * @priv: Private data, for use by the RNG driver. */ struct hwrng { - const char *name; + char *name; int (*init)(struct hwrng *rng); void (*cleanup)(struct hwrng *rng); int (*data_present)(struct hwrng *rng, int wait); -- cgit v1.2.3 From e5d23a8cc38c555f9f3a40dcc5d14030105df9a8 Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Fri, 16 May 2014 11:41:57 +0930 Subject: virtio-rng: fix boot with virtio-rng device Commit "virtio-rng: support multiple virtio-rng devices" has broken boot with a virtio-rng device because the 'init' callback of the virtio-rng device was left unitialized to garbage, and got called by the hwrng infrastructure, killing the guest on boot. Signed-off-by: Sasha Levin Signed-off-by: Rusty Russell Fixes: 08e53fbdb85c0f6f45c0f7c1ea3defc1752a95ce --- drivers/char/hw_random/virtio-rng.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c index 12e242bbb0f5..5b25daa7f798 100644 --- a/drivers/char/hw_random/virtio-rng.c +++ b/drivers/char/hw_random/virtio-rng.c @@ -95,7 +95,7 @@ static int probe_common(struct virtio_device *vdev) int err, i; struct virtrng_info *vi = NULL; - vi = kmalloc(sizeof(struct virtrng_info), GFP_KERNEL); + vi = kzalloc(sizeof(struct virtrng_info), GFP_KERNEL); vi->hwrng.name = kmalloc(40, GFP_KERNEL); init_completion(&vi->have_data); -- cgit v1.2.3 From a17597d3b418ca5a394d14724ccfc295cb3186c8 Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Fri, 16 May 2014 11:42:43 +0930 Subject: virtio-rng: fixes for device registration/unregistration There are several fixes in this patch (mostly because it's hard splitting them up): - Revert the name field in struct hwrng back to 'const'. Also, don't do an extra kmalloc for the name - just wasteful. - Deal with allocation failures properly. - Use IDA to allocate device number instead of brute forcing one. Signed-off-by: Sasha Levin Signed-off-by: Rusty Russell --- drivers/char/hw_random/virtio-rng.c | 41 +++++++++++++++++++++---------------- include/linux/hw_random.h | 2 +- 2 files changed, 24 insertions(+), 19 deletions(-) diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c index 5b25daa7f798..f3e71501de54 100644 --- a/drivers/char/hw_random/virtio-rng.c +++ b/drivers/char/hw_random/virtio-rng.c @@ -25,6 +25,7 @@ #include #include +static DEFINE_IDA(rng_index_ida); struct virtrng_info { struct virtio_device *vdev; @@ -33,6 +34,8 @@ struct virtrng_info { unsigned int data_avail; struct completion have_data; bool busy; + char name[25]; + int index; }; static void random_recv_done(struct virtqueue *vq) @@ -92,41 +95,45 @@ static void virtio_cleanup(struct hwrng *rng) static int probe_common(struct virtio_device *vdev) { - int err, i; + int err, index; struct virtrng_info *vi = NULL; vi = kzalloc(sizeof(struct virtrng_info), GFP_KERNEL); - vi->hwrng.name = kmalloc(40, GFP_KERNEL); + if (!vi) + return -ENOMEM; + + vi->index = index = ida_simple_get(&rng_index_ida, 0, 0, GFP_KERNEL); + if (index < 0) { + kfree(vi); + return index; + } + sprintf(vi->name, "virtio_rng.%d", index); init_completion(&vi->have_data); - vi->hwrng.read = virtio_read; - vi->hwrng.cleanup = virtio_cleanup; - vi->hwrng.priv = (unsigned long)vi; + vi->hwrng = (struct hwrng) { + .read = virtio_read, + .cleanup = virtio_cleanup, + .priv = (unsigned long)vi, + .name = vi->name, + }; vdev->priv = vi; /* We expect a single virtqueue. */ vi->vq = virtio_find_single_vq(vdev, random_recv_done, "input"); if (IS_ERR(vi->vq)) { err = PTR_ERR(vi->vq); - kfree(vi->hwrng.name); vi->vq = NULL; kfree(vi); - vi = NULL; + ida_simple_remove(&rng_index_ida, index); return err; } - i = 0; - do { - sprintf(vi->hwrng.name, "virtio_rng.%d", i++); - err = hwrng_register(&vi->hwrng); - } while (err == -EEXIST); - + err = hwrng_register(&vi->hwrng); if (err) { vdev->config->del_vqs(vdev); - kfree(vi->hwrng.name); vi->vq = NULL; kfree(vi); - vi = NULL; + ida_simple_remove(&rng_index_ida, index); return err; } @@ -140,10 +147,8 @@ static void remove_common(struct virtio_device *vdev) vi->busy = false; hwrng_unregister(&vi->hwrng); vdev->config->del_vqs(vdev); - kfree(vi->hwrng.name); - vi->vq = NULL; + ida_simple_remove(&rng_index_ida, vi->index); kfree(vi); - vi = NULL; } static int virtrng_probe(struct virtio_device *vdev) diff --git a/include/linux/hw_random.h b/include/linux/hw_random.h index 02d9c87be54c..b4b0eef5fddf 100644 --- a/include/linux/hw_random.h +++ b/include/linux/hw_random.h @@ -31,7 +31,7 @@ * @priv: Private data, for use by the RNG driver. */ struct hwrng { - char *name; + const char *name; int (*init)(struct hwrng *rng); void (*cleanup)(struct hwrng *rng); int (*data_present)(struct hwrng *rng, int wait); -- cgit v1.2.3 From c77fba9ab058d1e96ed51d4215e56905c9ef8d2a Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Wed, 21 May 2014 11:25:04 +0930 Subject: virtio_scsi: don't call virtqueue_add_sgs(... GFP_NOIO) holding spinlock. This triggers every time we do a SCSI abort: virtscsi_tmf -> virtscsi_kick_cmd (grab lock and call) -> virtscsi_add_cmd -> virtqueue_add_sgs (GFP_NOIO) Logs look like this: sd 0:0:0:0: [sda] abort BUG: sleeping function called from invalid context at mm/slub.c:966 in_atomic(): 1, irqs_disabled(): 1, pid: 6, name: kworker/u2:0 3 locks held by kworker/u2:0/6: #0: ("scsi_tmf_%d"shost->host_no){......}, at: [] process_one_work+0xe0/0x3d0 #1: ((&(&cmd->abort_work)->work)){......}, at: [] process_one_work+0xe0/0x3d0 #2: (&(&virtscsi_vq->vq_lock)->rlock){......}, at: [] virtscsi_kick_cmd+0x18/0x1b0 CPU: 0 PID: 6 Comm: kworker/u2:0 Not tainted 3.15.0-rc5+ #110 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-rc1-0-gb1d4dc9-20140515_140003-nilsson.home.kraxel.org 04/01/2014 Workqueue: scsi_tmf_0 scmd_eh_abort_handler Signed-off-by: Rusty Russell Acked-by: Paolo Bonzini --- drivers/scsi/virtio_scsi.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c index 16bfd50cd3fe..e2a68aece3da 100644 --- a/drivers/scsi/virtio_scsi.c +++ b/drivers/scsi/virtio_scsi.c @@ -433,11 +433,10 @@ static void virtscsi_event_done(struct virtqueue *vq) * @cmd : command structure * @req_size : size of the request buffer * @resp_size : size of the response buffer - * @gfp : flags to use for memory allocations */ static int virtscsi_add_cmd(struct virtqueue *vq, struct virtio_scsi_cmd *cmd, - size_t req_size, size_t resp_size, gfp_t gfp) + size_t req_size, size_t resp_size) { struct scsi_cmnd *sc = cmd->sc; struct scatterlist *sgs[4], req, resp; @@ -469,19 +468,19 @@ static int virtscsi_add_cmd(struct virtqueue *vq, if (in) sgs[out_num + in_num++] = in->sgl; - return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, gfp); + return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC); } static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq, struct virtio_scsi_cmd *cmd, - size_t req_size, size_t resp_size, gfp_t gfp) + size_t req_size, size_t resp_size) { unsigned long flags; int err; bool needs_kick = false; spin_lock_irqsave(&vq->vq_lock, flags); - err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size, gfp); + err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size); if (!err) needs_kick = virtqueue_kick_prepare(vq->vq); @@ -530,8 +529,7 @@ static int virtscsi_queuecommand(struct virtio_scsi *vscsi, memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len); if (virtscsi_kick_cmd(req_vq, cmd, - sizeof cmd->req.cmd, sizeof cmd->resp.cmd, - GFP_ATOMIC) == 0) + sizeof cmd->req.cmd, sizeof cmd->resp.cmd) == 0) ret = 0; else mempool_free(cmd, virtscsi_cmd_pool); @@ -596,8 +594,7 @@ static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd) cmd->comp = ∁ if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd, - sizeof cmd->req.tmf, sizeof cmd->resp.tmf, - GFP_NOIO) < 0) + sizeof cmd->req.tmf, sizeof cmd->resp.tmf) < 0) goto out; wait_for_completion(&comp); -- cgit v1.2.3