Michael S. Tsirkin
2014-Oct-13 07:48 UTC
[PATCH v4 00/25] virtio: fix spec compliance issues
Changes from v4: rename virtio_enable_vqs_early() to virtio_device_ready() Note: Rusty requested we add a BUG_ON in the virtio_ring code. This can be done by a separate patch on top. Good for bisectability in case BUG_ON starts triggering :) Rusty, please review this, and consider for this merge window. This fixes the following virtio spec compliance issues: 1. on restore, drivers use device before setting ACKNOWLEDGE and DRIVER bits 2. on probe, drivers aren't prepared to handle config interrupts arriving before probe returns 3. on probe, drivers use device before DRIVER_OK it set Note that 1 is a clear violation of virtio spec 0.9 and 1.0, so I am proposing the fix for stable. OTOH 2 is against 1.0 rules but is a known documented bug in many drivers, so let's fix it going forward, but it does not seem to be worth it to backport the changes. An error handling bugfix for virtio-net and a fix for a theoretical race condition in virtio scsi is also included. 2 is merely a theoretical race condition, but it seems important to address to make sure that changes to address 3 do not introduce instability. I also included patch to drop scan callback use from virtio scsi: using this callback creates asymmetry between probe and resume, and we actually had to add code comments so people can figure out the flow. Code flow becomes clearer with the new API. After this change, the only user of the scan callback is virtio rng. It's possible to modify it trivially and then drop scan callback from core, but I'm rather inclined to look at ways to make some rng core changes so that we don't need to have so many variables tracking device state. So this is deferred for now. Michael S. Tsirkin (24): virtio_pci: fix virtio spec compliance on restore virtio: unify config_changed handling virtio-pci: move freeze/restore to virtio core virtio: defer config changed notifications virtio_blk: drop config_enable virtio-blk: drop config_mutex virtio_net: drop config_enable virtio-net: drop config_mutex virtio_net: minor cleanup virtio: add API to enable VQs early virtio_net: enable VQs early virtio_blk: enable VQs early virtio_console: enable VQs early 9p/trans_virtio: enable VQs early virtio_net: fix use after free on allocation failure virtio_scsi: move kick event out from virtscsi_init virtio_blk: enable VQs early on restore virtio_scsi: enable VQs early on restore virtio_console: enable VQs early on restore virtio_net: enable VQs early on restore virtio_scsi: fix race on device removal virtio_balloon: enable VQs early on restore virtio_scsi: drop scan callback virtio-rng: refactor probe error handling Paolo Bonzini (1): virito_scsi: use freezable WQ for events include/linux/virtio.h | 14 +++++ include/linux/virtio_config.h | 17 ++++++ drivers/block/virtio_blk.c | 40 ++++---------- drivers/char/hw_random/virtio-rng.c | 15 +++--- drivers/char/virtio_console.c | 4 ++ drivers/misc/mic/card/mic_virtio.c | 6 +-- drivers/net/virtio_net.c | 44 +++++----------- drivers/s390/kvm/kvm_virtio.c | 9 +--- drivers/s390/kvm/virtio_ccw.c | 6 +-- drivers/scsi/virtio_scsi.c | 42 +++++++++------ drivers/virtio/virtio.c | 102 ++++++++++++++++++++++++++++++++++++ drivers/virtio/virtio_balloon.c | 2 + drivers/virtio/virtio_mmio.c | 7 +-- drivers/virtio/virtio_pci.c | 33 ++---------- net/9p/trans_virtio.c | 2 + 15 files changed, 206 insertions(+), 137 deletions(-) -- MST
Michael S. Tsirkin
2014-Oct-13 07:48 UTC
[PATCH v4 01/25] virtio_pci: fix virtio spec compliance on restore
On restore, virtio pci does the following: + set features + init vqs etc - device can be used at this point! + set ACKNOWLEDGE,DRIVER and DRIVER_OK status bits This is in violation of the virtio spec, which requires the following order: - ACKNOWLEDGE - DRIVER - init vqs - DRIVER_OK This behaviour will break with hypervisors that assume spec compliant behaviour. It seems like a good idea to have this patch applied to stable branches to reduce the support butden for the hypervisors. Cc: stable at vger.kernel.org Cc: Amit Shah <amit.shah at redhat.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/virtio/virtio_pci.c | 33 ++++++++++++++++++++++++++++++--- 1 file changed, 30 insertions(+), 3 deletions(-) diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c index 3d1463c..add40d0 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -789,6 +789,7 @@ static int virtio_pci_restore(struct device *dev) struct pci_dev *pci_dev = to_pci_dev(dev); struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); struct virtio_driver *drv; + unsigned status = 0; int ret; drv = container_of(vp_dev->vdev.dev.driver, @@ -799,14 +800,40 @@ static int virtio_pci_restore(struct device *dev) return ret; pci_set_master(pci_dev); + /* We always start by resetting the device, in case a previous + * driver messed it up. */ + vp_reset(&vp_dev->vdev); + + /* Acknowledge that we've seen the device. */ + status |= VIRTIO_CONFIG_S_ACKNOWLEDGE; + vp_set_status(&vp_dev->vdev, status); + + /* Maybe driver failed before freeze. + * Restore the failed status, for debugging. */ + status |= vp_dev->saved_status & VIRTIO_CONFIG_S_FAILED; + vp_set_status(&vp_dev->vdev, status); + + if (!drv) + return 0; + + /* We have a driver! */ + status |= VIRTIO_CONFIG_S_DRIVER; + vp_set_status(&vp_dev->vdev, status); + vp_finalize_features(&vp_dev->vdev); - if (drv && drv->restore) + if (drv->restore) { ret = drv->restore(&vp_dev->vdev); + if (ret) { + status |= VIRTIO_CONFIG_S_FAILED; + vp_set_status(&vp_dev->vdev, status); + return ret; + } + } /* Finally, tell the device we're all set */ - if (!ret) - vp_set_status(&vp_dev->vdev, vp_dev->saved_status); + status |= VIRTIO_CONFIG_S_DRIVER_OK; + vp_set_status(&vp_dev->vdev, status); return ret; } -- MST
Michael S. Tsirkin
2014-Oct-13 07:48 UTC
[PATCH v4 02/25] virtio: unify config_changed handling
Replace duplicated code in all transports with a single wrapper in virtio.c. The only functional change is in virtio_mmio.c: if a buggy device sends us an interrupt before driver is set, we previously returned IRQ_NONE, now we return IRQ_HANDLED. As this must not happen in practice, this does not look like a big deal. See also commit 3fff0179e33cd7d0a688dab65700c46ad089e934 virtio-pci: do not oops on config change if driver not loaded. for the original motivation behind the driver check. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck at de.ibm.com> --- include/linux/virtio.h | 2 ++ drivers/misc/mic/card/mic_virtio.c | 6 +----- drivers/s390/kvm/kvm_virtio.c | 9 +-------- drivers/s390/kvm/virtio_ccw.c | 6 +----- drivers/virtio/virtio.c | 9 +++++++++ drivers/virtio/virtio_mmio.c | 7 ++----- drivers/virtio/virtio_pci.c | 6 +----- 7 files changed, 17 insertions(+), 28 deletions(-) diff --git a/include/linux/virtio.h b/include/linux/virtio.h index b46671e..3c19bd3 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -108,6 +108,8 @@ void unregister_virtio_device(struct virtio_device *dev); void virtio_break_device(struct virtio_device *dev); +void virtio_config_changed(struct virtio_device *dev); + /** * virtio_driver - operations for a virtio I/O driver * @driver: underlying device driver (populate name and owner). diff --git a/drivers/misc/mic/card/mic_virtio.c b/drivers/misc/mic/card/mic_virtio.c index f14b600..e647947 100644 --- a/drivers/misc/mic/card/mic_virtio.c +++ b/drivers/misc/mic/card/mic_virtio.c @@ -462,16 +462,12 @@ static void mic_handle_config_change(struct mic_device_desc __iomem *d, struct mic_device_ctrl __iomem *dc = (void __iomem *)d + mic_aligned_desc_size(d); struct mic_vdev *mvdev = (struct mic_vdev *)ioread64(&dc->vdev); - struct virtio_driver *drv; if (ioread8(&dc->config_change) != MIC_VIRTIO_PARAM_CONFIG_CHANGED) return; dev_dbg(mdrv->dev, "%s %d\n", __func__, __LINE__); - drv = container_of(mvdev->vdev.dev.driver, - struct virtio_driver, driver); - if (drv->config_changed) - drv->config_changed(&mvdev->vdev); + virtio_config_changed(&mvdev->vdev); iowrite8(1, &dc->guest_ack); } diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c index a134965..6431290 100644 --- a/drivers/s390/kvm/kvm_virtio.c +++ b/drivers/s390/kvm/kvm_virtio.c @@ -406,15 +406,8 @@ static void kvm_extint_handler(struct ext_code ext_code, switch (param) { case VIRTIO_PARAM_CONFIG_CHANGED: - { - struct virtio_driver *drv; - drv = container_of(vq->vdev->dev.driver, - struct virtio_driver, driver); - if (drv->config_changed) - drv->config_changed(vq->vdev); - + virtio_config_changed(vq->vdev); break; - } case VIRTIO_PARAM_DEV_ADD: schedule_work(&hotplug_work); break; diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c index d2c0b44..6cbe6ef 100644 --- a/drivers/s390/kvm/virtio_ccw.c +++ b/drivers/s390/kvm/virtio_ccw.c @@ -940,11 +940,7 @@ static void virtio_ccw_int_handler(struct ccw_device *cdev, vring_interrupt(0, vq); } if (test_bit(0, &vcdev->indicators2)) { - drv = container_of(vcdev->vdev.dev.driver, - struct virtio_driver, driver); - - if (drv && drv->config_changed) - drv->config_changed(&vcdev->vdev); + virtio_config_changed(&vcdev->vdev); clear_bit(0, &vcdev->indicators2); } } diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index fed0ce1..3980687 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -239,6 +239,15 @@ void unregister_virtio_device(struct virtio_device *dev) } EXPORT_SYMBOL_GPL(unregister_virtio_device); +void virtio_config_changed(struct virtio_device *dev) +{ + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); + + if (drv && drv->config_changed) + drv->config_changed(dev); +} +EXPORT_SYMBOL_GPL(virtio_config_changed); + static int virtio_init(void) { if (bus_register(&virtio_bus) != 0) diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c index c600ccf..ef9a165 100644 --- a/drivers/virtio/virtio_mmio.c +++ b/drivers/virtio/virtio_mmio.c @@ -234,8 +234,6 @@ static irqreturn_t vm_interrupt(int irq, void *opaque) { struct virtio_mmio_device *vm_dev = opaque; struct virtio_mmio_vq_info *info; - struct virtio_driver *vdrv = container_of(vm_dev->vdev.dev.driver, - struct virtio_driver, driver); unsigned long status; unsigned long flags; irqreturn_t ret = IRQ_NONE; @@ -244,9 +242,8 @@ static irqreturn_t vm_interrupt(int irq, void *opaque) status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS); writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK); - if (unlikely(status & VIRTIO_MMIO_INT_CONFIG) - && vdrv && vdrv->config_changed) { - vdrv->config_changed(&vm_dev->vdev); + if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)) { + virtio_config_changed(&vm_dev->vdev); ret = IRQ_HANDLED; } diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c index add40d0..f39f4e7 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -211,12 +211,8 @@ static bool vp_notify(struct virtqueue *vq) static irqreturn_t vp_config_changed(int irq, void *opaque) { struct virtio_pci_device *vp_dev = opaque; - struct virtio_driver *drv; - drv = container_of(vp_dev->vdev.dev.driver, - struct virtio_driver, driver); - if (drv && drv->config_changed) - drv->config_changed(&vp_dev->vdev); + virtio_config_changed(&vp_dev->vdev); return IRQ_HANDLED; } -- MST
Michael S. Tsirkin
2014-Oct-13 07:48 UTC
[PATCH v4 03/25] virtio-pci: move freeze/restore to virtio core
This is in preparation to extending config changed event handling in core. Wrapping these in an API also seems to make for a cleaner code. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck at de.ibm.com> --- include/linux/virtio.h | 6 +++++ drivers/virtio/virtio.c | 54 +++++++++++++++++++++++++++++++++++++++++++++ drivers/virtio/virtio_pci.c | 54 ++------------------------------------------- 3 files changed, 62 insertions(+), 52 deletions(-) diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 3c19bd3..8df7ba8 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -78,6 +78,7 @@ bool virtqueue_is_broken(struct virtqueue *vq); /** * virtio_device - representation of a device using virtio * @index: unique position on the virtio bus + * @failed: saved value for CONFIG_S_FAILED bit (for restore) * @dev: underlying device. * @id: the device type identification (used to match it with a driver). * @config: the configuration ops for this device. @@ -88,6 +89,7 @@ bool virtqueue_is_broken(struct virtqueue *vq); */ struct virtio_device { int index; + bool failed; struct device dev; struct virtio_device_id id; const struct virtio_config_ops *config; @@ -109,6 +111,10 @@ void unregister_virtio_device(struct virtio_device *dev); void virtio_break_device(struct virtio_device *dev); void virtio_config_changed(struct virtio_device *dev); +#ifdef CONFIG_PM_SLEEP +int virtio_device_freeze(struct virtio_device *dev); +int virtio_device_restore(struct virtio_device *dev); +#endif /** * virtio_driver - operations for a virtio I/O driver diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index 3980687..8216b73 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -248,6 +248,60 @@ void virtio_config_changed(struct virtio_device *dev) } EXPORT_SYMBOL_GPL(virtio_config_changed); +#ifdef CONFIG_PM_SLEEP +int virtio_device_freeze(struct virtio_device *dev) +{ + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); + + dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED; + + if (drv && drv->freeze) + return drv->freeze(dev); + + return 0; +} +EXPORT_SYMBOL_GPL(virtio_device_freeze); + +int virtio_device_restore(struct virtio_device *dev) +{ + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); + + /* We always start by resetting the device, in case a previous + * driver messed it up. */ + dev->config->reset(dev); + + /* Acknowledge that we've seen the device. */ + add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); + + /* Maybe driver failed before freeze. + * Restore the failed status, for debugging. */ + if (dev->failed) + add_status(dev, VIRTIO_CONFIG_S_FAILED); + + if (!drv) + return 0; + + /* We have a driver! */ + add_status(dev, VIRTIO_CONFIG_S_DRIVER); + + dev->config->finalize_features(dev); + + if (drv->restore) { + int ret = drv->restore(dev); + if (ret) { + add_status(dev, VIRTIO_CONFIG_S_FAILED); + return ret; + } + } + + /* Finally, tell the device we're all set */ + add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); + + return 0; +} +EXPORT_SYMBOL_GPL(virtio_device_restore); +#endif + static int virtio_init(void) { if (bus_register(&virtio_bus) != 0) diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c index f39f4e7..d34ebfa 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -57,9 +57,6 @@ struct virtio_pci_device /* Vectors allocated, excluding per-vq vectors if any */ unsigned msix_used_vectors; - /* Status saved during hibernate/restore */ - u8 saved_status; - /* Whether we have vector per vq */ bool per_vq_vectors; }; @@ -764,16 +761,9 @@ static int virtio_pci_freeze(struct device *dev) { struct pci_dev *pci_dev = to_pci_dev(dev); struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); - struct virtio_driver *drv; int ret; - drv = container_of(vp_dev->vdev.dev.driver, - struct virtio_driver, driver); - - ret = 0; - vp_dev->saved_status = vp_get_status(&vp_dev->vdev); - if (drv && drv->freeze) - ret = drv->freeze(&vp_dev->vdev); + ret = virtio_device_freeze(&vp_dev->vdev); if (!ret) pci_disable_device(pci_dev); @@ -784,54 +774,14 @@ static int virtio_pci_restore(struct device *dev) { struct pci_dev *pci_dev = to_pci_dev(dev); struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev); - struct virtio_driver *drv; - unsigned status = 0; int ret; - drv = container_of(vp_dev->vdev.dev.driver, - struct virtio_driver, driver); - ret = pci_enable_device(pci_dev); if (ret) return ret; pci_set_master(pci_dev); - /* We always start by resetting the device, in case a previous - * driver messed it up. */ - vp_reset(&vp_dev->vdev); - - /* Acknowledge that we've seen the device. */ - status |= VIRTIO_CONFIG_S_ACKNOWLEDGE; - vp_set_status(&vp_dev->vdev, status); - - /* Maybe driver failed before freeze. - * Restore the failed status, for debugging. */ - status |= vp_dev->saved_status & VIRTIO_CONFIG_S_FAILED; - vp_set_status(&vp_dev->vdev, status); - - if (!drv) - return 0; - - /* We have a driver! */ - status |= VIRTIO_CONFIG_S_DRIVER; - vp_set_status(&vp_dev->vdev, status); - - vp_finalize_features(&vp_dev->vdev); - - if (drv->restore) { - ret = drv->restore(&vp_dev->vdev); - if (ret) { - status |= VIRTIO_CONFIG_S_FAILED; - vp_set_status(&vp_dev->vdev, status); - return ret; - } - } - - /* Finally, tell the device we're all set */ - status |= VIRTIO_CONFIG_S_DRIVER_OK; - vp_set_status(&vp_dev->vdev, status); - - return ret; + return virtio_device_restore(&vp_dev->vdev); } static const struct dev_pm_ops virtio_pci_pm_ops = { -- MST
Michael S. Tsirkin
2014-Oct-13 07:50 UTC
[PATCH v4 04/25] virtio: defer config changed notifications
Defer config changed notifications that arrive during probe/scan/freeze/restore. This will allow drivers to set DRIVER_OK earlier, without worrying about racing with config change interrupts. This change will also benefit old hypervisors (before 2009) that send interrupts without checking DRIVER_OK: previously, the callback could race with driver-specific initialization. This will also help simplify drivers. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck at de.ibm.com> --- include/linux/virtio.h | 6 ++++++ drivers/virtio/virtio.c | 57 +++++++++++++++++++++++++++++++++++++++++-------- 2 files changed, 54 insertions(+), 9 deletions(-) diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 8df7ba8..5636b11 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -79,6 +79,9 @@ bool virtqueue_is_broken(struct virtqueue *vq); * virtio_device - representation of a device using virtio * @index: unique position on the virtio bus * @failed: saved value for CONFIG_S_FAILED bit (for restore) + * @config_enabled: configuration change reporting enabled + * @config_changed: configuration change reported while disabled + * @config_lock: protects configuration change reporting * @dev: underlying device. * @id: the device type identification (used to match it with a driver). * @config: the configuration ops for this device. @@ -90,6 +93,9 @@ bool virtqueue_is_broken(struct virtqueue *vq); struct virtio_device { int index; bool failed; + bool config_enabled; + bool config_changed; + spinlock_t config_lock; struct device dev; struct virtio_device_id id; const struct virtio_config_ops *config; diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index 8216b73..2536701 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -117,6 +117,42 @@ void virtio_check_driver_offered_feature(const struct virtio_device *vdev, } EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature); +static void __virtio_config_changed(struct virtio_device *dev) +{ + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); + + if (!dev->config_enabled) + dev->config_changed = true; + else if (drv && drv->config_changed) + drv->config_changed(dev); +} + +void virtio_config_changed(struct virtio_device *dev) +{ + unsigned long flags; + + spin_lock_irqsave(&dev->config_lock, flags); + __virtio_config_changed(dev); + spin_unlock_irqrestore(&dev->config_lock, flags); +} +EXPORT_SYMBOL_GPL(virtio_config_changed); + +static void virtio_config_disable(struct virtio_device *dev) +{ + spin_lock_irq(&dev->config_lock); + dev->config_enabled = false; + spin_unlock_irq(&dev->config_lock); +} + +static void virtio_config_enable(struct virtio_device *dev) +{ + spin_lock_irq(&dev->config_lock); + dev->config_enabled = true; + __virtio_config_changed(dev); + dev->config_changed = false; + spin_unlock_irq(&dev->config_lock); +} + static int virtio_dev_probe(struct device *_d) { int err, i; @@ -153,6 +189,8 @@ static int virtio_dev_probe(struct device *_d) add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); if (drv->scan) drv->scan(dev); + + virtio_config_enable(dev); } return err; @@ -163,6 +201,8 @@ static int virtio_dev_remove(struct device *_d) struct virtio_device *dev = dev_to_virtio(_d); struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); + virtio_config_disable(dev); + drv->remove(dev); /* Driver should have reset device. */ @@ -211,6 +251,10 @@ int register_virtio_device(struct virtio_device *dev) dev->index = err; dev_set_name(&dev->dev, "virtio%u", dev->index); + spin_lock_init(&dev->config_lock); + dev->config_enabled = false; + dev->config_changed = false; + /* We always start by resetting the device, in case a previous * driver messed it up. This also tests that code path a little. */ dev->config->reset(dev); @@ -239,20 +283,13 @@ void unregister_virtio_device(struct virtio_device *dev) } EXPORT_SYMBOL_GPL(unregister_virtio_device); -void virtio_config_changed(struct virtio_device *dev) -{ - struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); - - if (drv && drv->config_changed) - drv->config_changed(dev); -} -EXPORT_SYMBOL_GPL(virtio_config_changed); - #ifdef CONFIG_PM_SLEEP int virtio_device_freeze(struct virtio_device *dev) { struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); + virtio_config_disable(dev); + dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED; if (drv && drv->freeze) @@ -297,6 +334,8 @@ int virtio_device_restore(struct virtio_device *dev) /* Finally, tell the device we're all set */ add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); + virtio_config_enable(dev); + return 0; } EXPORT_SYMBOL_GPL(virtio_device_restore); -- MST
Now that virtio core ensures config changes don't arrive during probing, drop config_enable flag in virtio blk. On removal, flush is now sufficient to guarantee that no change work is queued. This help simplify the driver, and will allow setting DRIVER_OK earlier without losing config change notifications. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck at de.ibm.com> --- drivers/block/virtio_blk.c | 23 ++++------------------- 1 file changed, 4 insertions(+), 19 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 0a58140..91272f1a 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -44,9 +44,6 @@ struct virtio_blk /* Lock for config space updates */ struct mutex config_lock; - /* enable config space updates */ - bool config_enable; - /* What host tells us, plus 2 for header & tailer. */ unsigned int sg_elems; @@ -348,8 +345,6 @@ static void virtblk_config_changed_work(struct work_struct *work) u64 capacity, size; mutex_lock(&vblk->config_lock); - if (!vblk->config_enable) - goto done; /* Host must always specify the capacity. */ virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity); @@ -374,7 +369,7 @@ static void virtblk_config_changed_work(struct work_struct *work) set_capacity(vblk->disk, capacity); revalidate_disk(vblk->disk); kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp); -done: + mutex_unlock(&vblk->config_lock); } @@ -609,7 +604,6 @@ static int virtblk_probe(struct virtio_device *vdev) mutex_init(&vblk->config_lock); INIT_WORK(&vblk->config_work, virtblk_config_changed_work); - vblk->config_enable = true; err = init_vq(vblk); if (err) @@ -771,10 +765,8 @@ static void virtblk_remove(struct virtio_device *vdev) int index = vblk->index; int refc; - /* Prevent config work handler from accessing the device. */ - mutex_lock(&vblk->config_lock); - vblk->config_enable = false; - mutex_unlock(&vblk->config_lock); + /* Make sure no work handler is accessing the device. */ + flush_work(&vblk->config_work); del_gendisk(vblk->disk); blk_cleanup_queue(vblk->disk->queue); @@ -784,8 +776,6 @@ static void virtblk_remove(struct virtio_device *vdev) /* Stop all the virtqueues. */ vdev->config->reset(vdev); - flush_work(&vblk->config_work); - refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount); put_disk(vblk->disk); vdev->config->del_vqs(vdev); @@ -805,11 +795,7 @@ static int virtblk_freeze(struct virtio_device *vdev) /* Ensure we don't receive any more interrupts */ vdev->config->reset(vdev); - /* Prevent config work handler from accessing the device. */ - mutex_lock(&vblk->config_lock); - vblk->config_enable = false; - mutex_unlock(&vblk->config_lock); - + /* Make sure no work handler is accessing the device. */ flush_work(&vblk->config_work); blk_mq_stop_hw_queues(vblk->disk->queue); @@ -823,7 +809,6 @@ static int virtblk_restore(struct virtio_device *vdev) struct virtio_blk *vblk = vdev->priv; int ret; - vblk->config_enable = true; ret = init_vq(vdev->priv); if (!ret) blk_mq_start_stopped_hw_queues(vblk->disk->queue, true); -- MST
config_mutex served two purposes: prevent multiple concurrent config change handlers, and synchronize access to config_enable flag. Since commit dbf2576e37da0fcc7aacbfbb9fd5d3de7888a3c1 workqueue: make all workqueues non-reentrant all workqueues are non-reentrant, and config_enable is now gone. Get rid of the unnecessary lock. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck at de.ibm.com> --- drivers/block/virtio_blk.c | 8 -------- 1 file changed, 8 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 91272f1a..89ba8d6 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -41,9 +41,6 @@ struct virtio_blk /* Process context for config space updates */ struct work_struct config_work; - /* Lock for config space updates */ - struct mutex config_lock; - /* What host tells us, plus 2 for header & tailer. */ unsigned int sg_elems; @@ -344,8 +341,6 @@ static void virtblk_config_changed_work(struct work_struct *work) char *envp[] = { "RESIZE=1", NULL }; u64 capacity, size; - mutex_lock(&vblk->config_lock); - /* Host must always specify the capacity. */ virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity); @@ -369,8 +364,6 @@ static void virtblk_config_changed_work(struct work_struct *work) set_capacity(vblk->disk, capacity); revalidate_disk(vblk->disk); kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp); - - mutex_unlock(&vblk->config_lock); } static void virtblk_config_changed(struct virtio_device *vdev) @@ -601,7 +594,6 @@ static int virtblk_probe(struct virtio_device *vdev) vblk->vdev = vdev; vblk->sg_elems = sg_elems; - mutex_init(&vblk->config_lock); INIT_WORK(&vblk->config_work, virtblk_config_changed_work); -- MST
Now that virtio core ensures config changes don't arrive during probing, drop config_enable flag in virtio net. On removal, flush is now sufficient to guarantee that no change work is queued. This help simplify the driver, and will allow setting DRIVER_OK earlier without losing config change notifications. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck at de.ibm.com> --- drivers/net/virtio_net.c | 27 ++++----------------------- 1 file changed, 4 insertions(+), 23 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 59caa06..743fb04 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -123,9 +123,6 @@ struct virtnet_info { /* Host can handle any s/g split between our header and packet data */ bool any_header_sg; - /* enable config space updates */ - bool config_enable; - /* Active statistics */ struct virtnet_stats __percpu *stats; @@ -1408,9 +1405,6 @@ static void virtnet_config_changed_work(struct work_struct *work) u16 v; mutex_lock(&vi->config_lock); - if (!vi->config_enable) - goto done; - if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS, struct virtio_net_config, status, &v) < 0) goto done; @@ -1758,7 +1752,6 @@ static int virtnet_probe(struct virtio_device *vdev) } mutex_init(&vi->config_lock); - vi->config_enable = true; INIT_WORK(&vi->config_work, virtnet_config_changed_work); /* If we can receive ANY GSO packets, we must allocate large ones. */ @@ -1875,17 +1868,13 @@ static void virtnet_remove(struct virtio_device *vdev) unregister_hotcpu_notifier(&vi->nb); - /* Prevent config work handler from accessing the device. */ - mutex_lock(&vi->config_lock); - vi->config_enable = false; - mutex_unlock(&vi->config_lock); + /* Make sure no work handler is accessing the device. */ + flush_work(&vi->config_work); unregister_netdev(vi->dev); remove_vq_common(vi); - flush_work(&vi->config_work); - free_percpu(vi->stats); free_netdev(vi->dev); } @@ -1898,10 +1887,8 @@ static int virtnet_freeze(struct virtio_device *vdev) unregister_hotcpu_notifier(&vi->nb); - /* Prevent config work handler from accessing the device */ - mutex_lock(&vi->config_lock); - vi->config_enable = false; - mutex_unlock(&vi->config_lock); + /* Make sure no work handler is accessing the device */ + flush_work(&vi->config_work); netif_device_detach(vi->dev); cancel_delayed_work_sync(&vi->refill); @@ -1916,8 +1903,6 @@ static int virtnet_freeze(struct virtio_device *vdev) remove_vq_common(vi); - flush_work(&vi->config_work); - return 0; } @@ -1941,10 +1926,6 @@ static int virtnet_restore(struct virtio_device *vdev) netif_device_attach(vi->dev); - mutex_lock(&vi->config_lock); - vi->config_enable = true; - mutex_unlock(&vi->config_lock); - rtnl_lock(); virtnet_set_queues(vi, vi->curr_queue_pairs); rtnl_unlock(); -- MST
config_mutex served two purposes: prevent multiple concurrent config change handlers, and synchronize access to config_enable flag. Since commit dbf2576e37da0fcc7aacbfbb9fd5d3de7888a3c1 workqueue: make all workqueues non-reentrant all workqueues are non-reentrant, and config_enable is now gone. Get rid of the unnecessary lock. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck at de.ibm.com> --- drivers/net/virtio_net.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 743fb04..23e4a69 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -132,9 +132,6 @@ struct virtnet_info { /* Work struct for config space updates */ struct work_struct config_work; - /* Lock for config space updates */ - struct mutex config_lock; - /* Does the affinity hint is set for virtqueues? */ bool affinity_hint_set; @@ -1404,7 +1401,6 @@ static void virtnet_config_changed_work(struct work_struct *work) container_of(work, struct virtnet_info, config_work); u16 v; - mutex_lock(&vi->config_lock); if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS, struct virtio_net_config, status, &v) < 0) goto done; @@ -1430,7 +1426,7 @@ static void virtnet_config_changed_work(struct work_struct *work) netif_tx_stop_all_queues(vi->dev); } done: - mutex_unlock(&vi->config_lock); + return; } static void virtnet_config_changed(struct virtio_device *vdev) @@ -1751,7 +1747,6 @@ static int virtnet_probe(struct virtio_device *vdev) u64_stats_init(&virtnet_stats->rx_syncp); } - mutex_init(&vi->config_lock); INIT_WORK(&vi->config_work, virtnet_config_changed_work); /* If we can receive ANY GSO packets, we must allocate large ones. */ -- MST
goto done; done: return; is ugly, it was put there to make diff review easier. replace by open-coded return. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Acked-by: Cornelia Huck <cornelia.huck at de.ibm.com> --- drivers/net/virtio_net.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 23e4a69..ef04d23 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1403,7 +1403,7 @@ static void virtnet_config_changed_work(struct work_struct *work) if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS, struct virtio_net_config, status, &v) < 0) - goto done; + return; if (v & VIRTIO_NET_S_ANNOUNCE) { netdev_notify_peers(vi->dev); @@ -1414,7 +1414,7 @@ static void virtnet_config_changed_work(struct work_struct *work) v &= VIRTIO_NET_S_LINK_UP; if (vi->status == v) - goto done; + return; vi->status = v; @@ -1425,8 +1425,6 @@ static void virtnet_config_changed_work(struct work_struct *work) netif_carrier_off(vi->dev); netif_tx_stop_all_queues(vi->dev); } -done: - return; } static void virtnet_config_changed(struct virtio_device *vdev) -- MST
Michael S. Tsirkin
2014-Oct-13 07:50 UTC
[PATCH v4 10/25] virtio: add API to enable VQs early
virtio spec 0.9.X requires DRIVER_OK to be set before VQs are used, but some drivers use VQs before probe function returns. Since DRIVER_OK is set after probe, this violates the spec. Even though under virtio 1.0 transitional devices support this behaviour, we want to make it possible for those early callers to become spec compliant and eventually support non-transitional devices. Add API for drivers to call before using VQs. Sets DRIVER_OK internally. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck at de.ibm.com> --- include/linux/virtio_config.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index e8f8f71..e36403b 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -109,6 +109,23 @@ struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, return vq; } +/** + * virtio_device_ready - enable vq use in probe function + * @vdev: the device + * + * Driver must call this to use vqs in the probe function. + * + * Note: vqs are enabled automatically after probe returns. + */ +static inline +void virtio_device_ready(struct virtio_device *dev) +{ + unsigned status = dev->config->get_status(dev); + + BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK); + dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK); +} + static inline const char *virtio_bus_name(struct virtio_device *vdev) { -- MST
virtio spec requires drivers to set DRIVER_OK before using VQs. This is set automatically after probe returns, virtio net violated this rule by using receive VQs within probe. To fix, call virtio_device_ready before using VQs. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck at de.ibm.com> --- drivers/net/virtio_net.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index ef04d23..430f3ae 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1792,6 +1792,8 @@ static int virtnet_probe(struct virtio_device *vdev) goto free_vqs; } + virtio_device_ready(vdev); + /* Last of all, set up some receive buffers. */ for (i = 0; i < vi->curr_queue_pairs; i++) { try_fill_recv(&vi->rq[i], GFP_KERNEL); -- MST
virtio spec requires drivers to set DRIVER_OK before using VQs. This is set automatically after probe returns, virtio block violated this rule by calling add_disk, which causes the VQ to be used directly within probe. To fix, call virtio_device_ready before using VQs. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck at de.ibm.com> --- drivers/block/virtio_blk.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 89ba8d6..46b04bf 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -719,6 +719,8 @@ static int virtblk_probe(struct virtio_device *vdev) if (!err && opt_io_size) blk_queue_io_opt(q, blk_size * opt_io_size); + virtio_device_ready(vdev); + add_disk(vblk->disk); err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial); if (err) -- MST
Michael S. Tsirkin
2014-Oct-13 07:50 UTC
[PATCH v4 13/25] virtio_console: enable VQs early
virtio spec requires drivers to set DRIVER_OK before using VQs. This is set automatically after probe returns, virtio console violated this rule by adding inbufs, which causes the VQ to be used directly within probe. To fix, call virtio_device_ready before using VQs. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/char/virtio_console.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index b585b47..6ebe8f6 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -1449,6 +1449,8 @@ static int add_port(struct ports_device *portdev, u32 id) spin_lock_init(&port->outvq_lock); init_waitqueue_head(&port->waitqueue); + virtio_device_ready(portdev->vdev); + /* Fill the in_vq with buffers so the host can send us data. */ nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock); if (!nr_added_bufs) { -- MST
Michael S. Tsirkin
2014-Oct-13 07:50 UTC
[PATCH v4 14/25] 9p/trans_virtio: enable VQs early
virtio spec requires drivers to set DRIVER_OK before using VQs. This is set automatically after probe returns, but virtio 9p device adds self to channel list within probe, at which point VQ can be used in violation of the spec. To fix, call virtio_device_ready before using VQs. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- net/9p/trans_virtio.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index 6940d8f..766ba48 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -575,6 +575,8 @@ static int p9_virtio_probe(struct virtio_device *vdev) /* Ceiling limit to avoid denial of service attacks */ chan->p9_max_pages = nr_free_buffer_pages()/4; + virtio_device_ready(vdev); + mutex_lock(&virtio_9p_lock); list_add_tail(&chan->chan_list, &virtio_chan_list); mutex_unlock(&virtio_9p_lock); -- MST
Michael S. Tsirkin
2014-Oct-13 07:50 UTC
[PATCH v4 15/25] virtio_net: fix use after free on allocation failure
In the extremely unlikely event that driver initialization fails after RX buffers are added, virtio net frees RX buffers while VQs are still active, potentially causing device to use a freed buffer. To fix, reset device first - same as we do on device removal. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck at de.ibm.com> --- drivers/net/virtio_net.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 430f3ae..3551417 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1830,6 +1830,8 @@ static int virtnet_probe(struct virtio_device *vdev) return 0; free_recv_bufs: + vi->vdev->config->reset(vdev); + free_receive_bufs(vi); unregister_netdev(dev); free_vqs: -- MST
Michael S. Tsirkin
2014-Oct-13 07:51 UTC
[PATCH v4 16/25] virtio_scsi: move kick event out from virtscsi_init
We currently kick event within virtscsi_init, before host is fully initialized. This can in theory confuse guest if device consumes the buffers immediately. To fix, move virtscsi_kick_event_all out to scan/restore. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/scsi/virtio_scsi.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c index eee1bc0..0642ce3 100644 --- a/drivers/scsi/virtio_scsi.c +++ b/drivers/scsi/virtio_scsi.c @@ -853,7 +853,11 @@ static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq, static void virtscsi_scan(struct virtio_device *vdev) { - struct Scsi_Host *shost = (struct Scsi_Host *)vdev->priv; + struct Scsi_Host *shost = virtio_scsi_host(vdev); + struct virtio_scsi *vscsi = shost_priv(shost); + + if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) + virtscsi_kick_event_all(vscsi); scsi_scan_host(shost); } @@ -916,9 +920,6 @@ static int virtscsi_init(struct virtio_device *vdev, virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE); virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE); - if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) - virtscsi_kick_event_all(vscsi); - err = 0; out: @@ -1048,8 +1049,13 @@ static int virtscsi_restore(struct virtio_device *vdev) return err; err = register_hotcpu_notifier(&vscsi->nb); - if (err) + if (err) { vdev->config->del_vqs(vdev); + return err; + } + + if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) + virtscsi_kick_event_all(vscsi); return err; } -- MST
Michael S. Tsirkin
2014-Oct-13 07:51 UTC
[PATCH v4 17/25] virtio_blk: enable VQs early on restore
virtio spec requires drivers to set DRIVER_OK before using VQs. This is set automatically after restore returns, virtio block violated this rule on restore by restarting queues, which might in theory cause the VQ to be used directly within restore. To fix, call virtio_device_ready before using starting queues. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/block/virtio_blk.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 46b04bf..1c95af5 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -804,10 +804,13 @@ static int virtblk_restore(struct virtio_device *vdev) int ret; ret = init_vq(vdev->priv); - if (!ret) - blk_mq_start_stopped_hw_queues(vblk->disk->queue, true); + if (ret) + return ret; + + virtio_device_ready(vdev); - return ret; + blk_mq_start_stopped_hw_queues(vblk->disk->queue, true); + return 0; } #endif -- MST
Michael S. Tsirkin
2014-Oct-13 07:51 UTC
[PATCH v4 18/25] virtio_scsi: enable VQs early on restore
virtio spec requires drivers to set DRIVER_OK before using VQs. This is set automatically after restore returns, virtio scsi violated this rule on restore by kicking event vq within restore. To fix, call virtio_device_ready before using event queue. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/scsi/virtio_scsi.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c index 0642ce3..2b565b3 100644 --- a/drivers/scsi/virtio_scsi.c +++ b/drivers/scsi/virtio_scsi.c @@ -1054,6 +1054,8 @@ static int virtscsi_restore(struct virtio_device *vdev) return err; } + virtio_device_ready(vdev); + if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) virtscsi_kick_event_all(vscsi); -- MST
Michael S. Tsirkin
2014-Oct-13 07:51 UTC
[PATCH v4 19/25] virtio_console: enable VQs early on restore
virtio spec requires drivers to set DRIVER_OK before using VQs. This is set automatically after resume returns, virtio console violated this rule by adding inbufs, which causes the VQ to be used directly within restore. To fix, call virtio_device_ready before using VQs. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/char/virtio_console.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 6ebe8f6..2ae843f 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -2184,6 +2184,8 @@ static int virtcons_restore(struct virtio_device *vdev) if (ret) return ret; + virtio_device_ready(portdev->vdev); + if (use_multiport(portdev)) fill_queue(portdev->c_ivq, &portdev->c_ivq_lock); -- MST
Michael S. Tsirkin
2014-Oct-13 07:51 UTC
[PATCH v4 20/25] virtio_net: enable VQs early on restore
virtio spec requires drivers to set DRIVER_OK before using VQs. This is set automatically after restore returns, virtio net violated this rule by using receive VQs within restore. To fix, call virtio_device_ready before using VQs. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck at de.ibm.com> --- drivers/net/virtio_net.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 3551417..6b6e136 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1912,6 +1912,8 @@ static int virtnet_restore(struct virtio_device *vdev) if (err) return err; + virtio_device_ready(vdev); + if (netif_running(vi->dev)) { for (i = 0; i < vi->curr_queue_pairs; i++) if (!try_fill_recv(&vi->rq[i], GFP_KERNEL)) -- MST
Michael S. Tsirkin
2014-Oct-13 07:51 UTC
[PATCH v4 21/25] virito_scsi: use freezable WQ for events
From: Paolo Bonzini <pbonzini at redhat.com> Michael S. Tsirkin noticed a race condition: we reset device on freeze, but system WQ is still running so it might try adding bufs to a VQ meanwhile. To fix, switch to handling events from the freezable WQ. Reported-by: Michael S. Tsirkin <mst at redhat.com> Signed-off-by: Paolo Bonzini <pbonzini at redhat.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/scsi/virtio_scsi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c index 2b565b3..501838d 100644 --- a/drivers/scsi/virtio_scsi.c +++ b/drivers/scsi/virtio_scsi.c @@ -390,7 +390,7 @@ static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf) { struct virtio_scsi_event_node *event_node = buf; - schedule_work(&event_node->work); + queue_work(system_freezable_wq, &event_node->work); } static void virtscsi_event_done(struct virtqueue *vq) -- MST
Michael S. Tsirkin
2014-Oct-13 07:51 UTC
[PATCH v4 22/25] virtio_scsi: fix race on device removal
We cancel event work on device removal, but an interrupt could trigger immediately after this, and queue it again. To fix, set a flag. Loosely based on patch by Paolo Bonzini Signed-off-by: Paolo Bonzini <pbonzini at redhat.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/scsi/virtio_scsi.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c index 501838d..327eba0 100644 --- a/drivers/scsi/virtio_scsi.c +++ b/drivers/scsi/virtio_scsi.c @@ -110,6 +110,9 @@ struct virtio_scsi { /* CPU hotplug notifier */ struct notifier_block nb; + /* Protected by event_vq lock */ + bool stop_events; + struct virtio_scsi_vq ctrl_vq; struct virtio_scsi_vq event_vq; struct virtio_scsi_vq req_vqs[]; @@ -303,6 +306,11 @@ static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi) { int i; + /* Stop scheduling work before calling cancel_work_sync. */ + spin_lock_irq(&vscsi->event_vq.vq_lock); + vscsi->stop_events = true; + spin_unlock_irq(&vscsi->event_vq.vq_lock); + for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) cancel_work_sync(&vscsi->event_list[i].work); } @@ -390,7 +398,8 @@ static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf) { struct virtio_scsi_event_node *event_node = buf; - queue_work(system_freezable_wq, &event_node->work); + if (!vscsi->stop_events) + queue_work(system_freezable_wq, &event_node->work); } static void virtscsi_event_done(struct virtqueue *vq) -- MST
Michael S. Tsirkin
2014-Oct-13 07:51 UTC
[PATCH v4 23/25] virtio_balloon: enable VQs early on restore
virtio spec requires drivers to set DRIVER_OK before using VQs. This is set automatically after resume returns, virtio balloon violated this rule by adding bufs, which causes the VQ to be used directly within restore. To fix, call virtio_device_ready before using VQ. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/virtio/virtio_balloon.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 25ebe8e..9629fad 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -538,6 +538,8 @@ static int virtballoon_restore(struct virtio_device *vdev) if (ret) return ret; + virtio_device_ready(vdev); + fill_balloon(vb, towards_target(vb)); update_balloon_size(vb); return 0; -- MST
Enable VQs early like we do for restore. This makes it possible to drop the scan callback, moving scanning into the probe function, and making code simpler. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/scsi/virtio_scsi.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-) diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c index 327eba0..5f022ff 100644 --- a/drivers/scsi/virtio_scsi.c +++ b/drivers/scsi/virtio_scsi.c @@ -860,17 +860,6 @@ static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq, virtscsi_vq->vq = vq; } -static void virtscsi_scan(struct virtio_device *vdev) -{ - struct Scsi_Host *shost = virtio_scsi_host(vdev); - struct virtio_scsi *vscsi = shost_priv(shost); - - if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) - virtscsi_kick_event_all(vscsi); - - scsi_scan_host(shost); -} - static void virtscsi_remove_vqs(struct virtio_device *vdev) { struct Scsi_Host *sh = virtio_scsi_host(vdev); @@ -1007,10 +996,13 @@ static int virtscsi_probe(struct virtio_device *vdev) err = scsi_add_host(shost, &vdev->dev); if (err) goto scsi_add_host_failed; - /* - * scsi_scan_host() happens in virtscsi_scan() via virtio_driver->scan() - * after VIRTIO_CONFIG_S_DRIVER_OK has been set.. - */ + + virtio_device_ready(vdev); + + if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) + virtscsi_kick_event_all(vscsi); + + scsi_scan_host(shost); return 0; scsi_add_host_failed: @@ -1090,7 +1082,6 @@ static struct virtio_driver virtio_scsi_driver = { .driver.owner = THIS_MODULE, .id_table = id_table, .probe = virtscsi_probe, - .scan = virtscsi_scan, #ifdef CONFIG_PM_SLEEP .freeze = virtscsi_freeze, .restore = virtscsi_restore, -- MST
Michael S. Tsirkin
2014-Oct-13 07:51 UTC
[PATCH v4 25/25] virtio-rng: refactor probe error handling
Code like vi->vq = NULL; kfree(vi) does not make sense. Clean it up, use goto error labels for cleanup. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/char/hw_random/virtio-rng.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c index 132c9cc..72295ea 100644 --- a/drivers/char/hw_random/virtio-rng.c +++ b/drivers/char/hw_random/virtio-rng.c @@ -109,8 +109,8 @@ static int probe_common(struct virtio_device *vdev) vi->index = index = ida_simple_get(&rng_index_ida, 0, 0, GFP_KERNEL); if (index < 0) { - kfree(vi); - return index; + err = index; + goto err_ida; } sprintf(vi->name, "virtio_rng.%d", index); init_completion(&vi->have_data); @@ -128,13 +128,16 @@ static int probe_common(struct virtio_device *vdev) vi->vq = virtio_find_single_vq(vdev, random_recv_done, "input"); if (IS_ERR(vi->vq)) { err = PTR_ERR(vi->vq); - vi->vq = NULL; - kfree(vi); - ida_simple_remove(&rng_index_ida, index); - return err; + goto err_find; } return 0; + +err_find: + ida_simple_remove(&rng_index_ida, index); +err_ida: + kfree(vi); + return err; } static void remove_common(struct virtio_device *vdev) -- MST
Rusty Russell
2014-Oct-14 00:31 UTC
[PATCH v4 04/25] virtio: defer config changed notifications
"Michael S. Tsirkin" <mst at redhat.com> writes:> Defer config changed notifications that arrive during > probe/scan/freeze/restore. > > This will allow drivers to set DRIVER_OK earlier, without worrying about > racing with config change interrupts. > > This change will also benefit old hypervisors (before 2009) > that send interrupts without checking DRIVER_OK: previously, > the callback could race with driver-specific initialization. > > This will also help simplify drivers.But AFAICT you never *read* dev->config_changed. You unconditionally trigger a config_changed event in virtio_config_enable(). That's a bit weird, but probably OK. How about the following change (on top of your patch). I think the renaming is clearer, and note the added if() test in virtio_config_enable(). If you approve, I'll fold it in. Cheers, Rusty. diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index 2536701b098b..df598dd8c5c8 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -122,7 +122,7 @@ static void __virtio_config_changed(struct virtio_device *dev) struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); if (!dev->config_enabled) - dev->config_changed = true; + dev->config_change_pending = true; else if (drv && drv->config_changed) drv->config_changed(dev); } @@ -148,8 +148,9 @@ static void virtio_config_enable(struct virtio_device *dev) { spin_lock_irq(&dev->config_lock); dev->config_enabled = true; - __virtio_config_changed(dev); - dev->config_changed = false; + if (dev->config_change_pending) + __virtio_config_changed(dev); + dev->config_change_pending = false; spin_unlock_irq(&dev->config_lock); } @@ -253,7 +254,7 @@ int register_virtio_device(struct virtio_device *dev) spin_lock_init(&dev->config_lock); dev->config_enabled = false; - dev->config_changed = false; + dev->config_change_pending = false; /* We always start by resetting the device, in case a previous * driver messed it up. This also tests that code path a little. */ diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 5636b119dc25..65261a7244fc 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -80,7 +80,7 @@ bool virtqueue_is_broken(struct virtqueue *vq); * @index: unique position on the virtio bus * @failed: saved value for CONFIG_S_FAILED bit (for restore) * @config_enabled: configuration change reporting enabled - * @config_changed: configuration change reported while disabled + * @config_change_pending: configuration change reported while disabled * @config_lock: protects configuration change reporting * @dev: underlying device. * @id: the device type identification (used to match it with a driver). @@ -94,7 +94,7 @@ struct virtio_device { int index; bool failed; bool config_enabled; - bool config_changed; + bool config_change_pending; spinlock_t config_lock; struct device dev; struct virtio_device_id id;
Paul Bolle
2014-Oct-15 07:05 UTC
[PATCH v4 03/25] virtio-pci: move freeze/restore to virtio core
On Mon, 2014-10-13 at 10:48 +0300, Michael S. Tsirkin wrote:> This is in preparation to extending config changed event handling > in core. > Wrapping these in an API also seems to make for a cleaner code. > > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > Reviewed-by: Cornelia Huck <cornelia.huck at de.ibm.com>This patch landed in today's linux-next (next-20141015).> include/linux/virtio.h | 6 +++++ > drivers/virtio/virtio.c | 54 +++++++++++++++++++++++++++++++++++++++++++++ > drivers/virtio/virtio_pci.c | 54 ++------------------------------------------- > 3 files changed, 62 insertions(+), 52 deletions(-) > > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > index 3c19bd3..8df7ba8 100644 > --- a/include/linux/virtio.h > +++ b/include/linux/virtio.h > @@ -78,6 +78,7 @@ bool virtqueue_is_broken(struct virtqueue *vq); > /** > * virtio_device - representation of a device using virtio > * @index: unique position on the virtio bus > + * @failed: saved value for CONFIG_S_FAILED bit (for restore)s/CONFIG_S_FAILED/VIRTIO_CONFIG_S_FAILED/?> * @dev: underlying device. > * @id: the device type identification (used to match it with a driver). > * @config: the configuration ops for this device.Paul Bolle
On 10/13/14 at 10:50am, Michael S. Tsirkin wrote:> virtio spec requires drivers to set DRIVER_OK before using VQs. > This is set automatically after probe returns, virtio console violated this > rule by adding inbufs, which causes the VQ to be used directly within > probe. > > To fix, call virtio_device_ready before using VQs. > > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > --- > drivers/char/virtio_console.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c > index b585b47..6ebe8f6 100644 > --- a/drivers/char/virtio_console.c > +++ b/drivers/char/virtio_console.c > @@ -1449,6 +1449,8 @@ static int add_port(struct ports_device *portdev, u32 id) > spin_lock_init(&port->outvq_lock); > init_waitqueue_head(&port->waitqueue); > > + virtio_device_ready(portdev->vdev); > + > /* Fill the in_vq with buffers so the host can send us data. */ > nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock); > if (!nr_added_bufs) {Seems like probe and add_port() now both set VIRTIO_CONFIG_S_DRIVER_OK 1.839658] kernel BUG at include/linux/virtio_config.h:125! [ 1.839995] invalid opcode: 0000 [#1] SMP [ 1.840169] Modules linked in: serio_raw virtio_balloon pcspkr virtio_net virtio_console soundcore parport_pc floppy pvpanic parport i2c_piix4 nfsd auth_rpcgss nfs_acl lockd grace sunrpc qxl drm_kms_helper ttm drm virtio_blk i2c_core virtio_pci ata_generic virtio_ring virtio pata_acpi [ 1.840169] CPU: 2 PID: 266 Comm: kworker/2:2 Not tainted 3.17.0+ #1 [ 1.840169] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 1.840169] Workqueue: events control_work_handler [virtio_console] [ 1.840169] task: ffff8800364bc840 ti: ffff880078490000 task.ti: ffff880078490000 [ 1.840169] RIP: 0010:[<ffffffffa01d92c6>] [<ffffffffa01d92c6>] virtio_device_ready.part.12+0x4/0x6 [virtio_console] [ 1.840169] RSP: 0018:ffff880078493c78 EFLAGS: 00010202 [ 1.840169] RAX: 0000000000000007 RBX: ffff880036406200 RCX: 0000000000006e39 [ 1.840169] RDX: 000000000000c0b2 RSI: 0000000000000000 RDI: 000000000001c0b2 [ 1.840169] RBP: ffff880078493c78 R08: ffffffff81d2c6f8 R09: 0000000000000000 [ 1.840169] R10: 0000000000000001 R11: ffff8800364bd000 R12: ffff880036618400 [ 1.840169] R13: 0000000000000001 R14: ffff8800368c6800 R15: ffff880036406220 [ 1.840169] FS: 0000000000000000(0000) GS:ffff88007fd00000(0000) knlGS:0000000000000000 [ 1.840169] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 1.840169] CR2: 00007f1c31c90000 CR3: 0000000001c14000 CR4: 00000000000006e0 [ 1.840169] Stack: [ 1.840169] ffff880078493ce8 ffffffffa01d886a ffff880000000001 ffffffff810e20cd [ 1.840169] ffff880078493cb8 0000000000000282 0000000000000000 0000000087f90194 [ 1.840169] ffff880078493ce8 ffff88007ab1d4e0 ffff880036618498 ffff880036618410 [ 1.840169] Call Trace: [ 1.840169] [<ffffffffa01d886a>] add_port+0x40a/0x440 [virtio_console] [ 1.840169] [<ffffffff810e20cd>] ? trace_hardirqs_on+0xd/0x10 [ 1.840169] [<ffffffffa01d8c6a>] control_work_handler+0x3ca/0x420 [virtio_console] [ 1.840169] [<ffffffff810b0e7b>] ? process_one_work+0x15b/0x530 [ 1.840169] [<ffffffff810b0ef4>] process_one_work+0x1d4/0x530 [ 1.840169] [<ffffffff810b0e7b>] ? process_one_work+0x15b/0x530 [ 1.840169] [<ffffffff810b136b>] worker_thread+0x11b/0x490 [ 1.840169] [<ffffffff810b1250>] ? process_one_work+0x530/0x530 [ 1.840169] [<ffffffff810b67c3>] kthread+0xf3/0x110 [ 1.840169] [<ffffffff81788f00>] ? _raw_spin_unlock_irq+0x30/0x50 [ 1.840169] [<ffffffff810b66d0>] ? kthread_create_on_node+0x240/0x240 [ 1.840169] [<ffffffff81789a7c>] ret_from_fork+0x7c/0xb0 [ 1.840169] [<ffffffff810b66d0>] ? kthread_create_on_node+0x240/0x240 [ 1.840169] Code: ff 49 89 c4 4d 85 e4 0f 8f 25 ff ff ff eb ad 48 c7 c0 f4 ff ff ff e9 17 ff ff ff e8 f5 cd eb e0 90 55 48 89 e5 0f 0b 55 48 89 e5 <0f> 0b 55 48 89 e5 0f 0b 55 48 89 e5 e8 99 e2 ff ff 48 c7 c7 c0 [ 1.840169] RIP [<ffffffffa01d92c6>] virtio_device_ready.part.12+0x4/0x6 [virtio_console] [ 1.840169] RSP <ffff880078493c78>
On 10/13/2014 12:50 AM, Michael S. Tsirkin wrote:> virtio spec 0.9.X requires DRIVER_OK to be set before > VQs are used, but some drivers use VQs before probe > function returns. > Since DRIVER_OK is set after probe, this violates the spec. > > Even though under virtio 1.0 transitional devices support this > behaviour, we want to make it possible for those early callers to become > spec compliant and eventually support non-transitional devices. > > Add API for drivers to call before using VQs. > > Sets DRIVER_OK internally. > > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > Reviewed-by: Cornelia Huck <cornelia.huck at de.ibm.com> > --- > include/linux/virtio_config.h | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h > index e8f8f71..e36403b 100644 > --- a/include/linux/virtio_config.h > +++ b/include/linux/virtio_config.h > @@ -109,6 +109,23 @@ struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, > return vq; > } > > +/** > + * virtio_device_ready - enable vq use in probe function > + * @vdev: the device > + * > + * Driver must call this to use vqs in the probe function. > + * > + * Note: vqs are enabled automatically after probe returns. > + */ > +static inline > +void virtio_device_ready(struct virtio_device *dev) > +{ > + unsigned status = dev->config->get_status(dev); > + > + BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK); > + dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK); > +}Getting a BUG when booting via KVM, host Fedora 20, guest Fedora 20. my config is at: https://fedorapeople.org/~grover/config-20141110 [ 0.828494] ------------[ cut here ]------------ [ 0.829039] kernel BUG at /home/agrover/git/kernel/include/linux/virtio_config.h:125! [ 0.831266] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC [ 0.831266] Modules linked in: [ 0.831266] CPU: 1 PID: 30 Comm: kworker/1:1 Not tainted 3.18.0-rc4 #120 [ 0.831266] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 0.831266] Workqueue: events control_work_handler [ 0.831266] task: ffff88003cd98000 ti: ffff88003cd94000 task.ti: ffff88003cd94000 [ 0.831266] RIP: 0010:[<ffffffff81445004>] [<ffffffff81445004>] add_port+0x264/0x410 [ 0.831266] RSP: 0000:ffff88003cd97c78 EFLAGS: 00010202 [ 0.831266] RAX: 0000000000000007 RBX: ffff88003c58c400 RCX: 0000000000000001 [ 0.831266] RDX: 000000000000c132 RSI: ffffffff81a955e9 RDI: 000000000001c132 [ 0.831266] RBP: ffff88003cd97cc8 R08: 0000000000000000 R09: 0000000000000000 [ 0.831266] R10: 0000000000000001 R11: 0000000000000000 R12: ffff88003c58be00 [ 0.831266] R13: 0000000000000001 R14: ffff8800395ca800 R15: ffff88003c58c420 [ 0.831266] FS: 0000000000000000(0000) GS:ffff88003fa00000(0000) knlGS:0000000000000000 [ 0.831266] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 0.831266] CR2: 0000000000000000 CR3: 0000000001c11000 CR4: 00000000000006e0 [ 0.831266] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 0.831266] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 0.831266] Stack: [ 0.831266] ffff880000000001 0000000000000292 0000000000000000 0000000000000001 [ 0.831266] ffff88003cd97cc8 ffff88003dfa8a20 ffff88003c58beb8 ffff88003c58be10 [ 0.831266] ffff8800395a2000 0000000000000000 ffff88003cd97d38 ffffffff8144531a [ 0.831266] Call Trace: [ 0.831266] [<ffffffff8144531a>] control_work_handler+0x16a/0x3c0 [ 0.831266] [<ffffffff8108b0c8>] ? process_one_work+0x208/0x500 [ 0.831266] [<ffffffff8108b16c>] process_one_work+0x2ac/0x500 [ 0.831266] [<ffffffff8108b0c8>] ? process_one_work+0x208/0x500 [ 0.831266] [<ffffffff8108b68e>] worker_thread+0x2ce/0x4e0 [ 0.831266] [<ffffffff8108b3c0>] ? process_one_work+0x500/0x500 [ 0.831266] [<ffffffff81090b28>] kthread+0xf8/0x100 [ 0.831266] [<ffffffff810bad7d>] ? trace_hardirqs_on+0xd/0x10 [ 0.831266] [<ffffffff81090a30>] ? kthread_stop+0x140/0x140 [ 0.831266] [<ffffffff816ea92c>] ret_from_fork+0x7c/0xb0 [ 0.831266] [<ffffffff81090a30>] ? kthread_stop+0x140/0x140 [ 0.831266] Code: c7 c2 48 31 01 83 48 c7 c6 e9 55 a9 81 e8 55 b4 c6 ff 4d 8b b4 24 58 01 00 00 49 8b 86 e8 04 00 00 4c 89 f7 ff 50 10 a8 04 74 0c <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 49 8b 96 e8 04 00 00 83 c8 [ 0.831266] RIP [<ffffffff81445004>] add_port+0x264/0x410 [ 0.831266] RSP <ffff88003cd97c78> [ 0.878202] ---[ end trace f98fbb172cc7bbf4 ]--- Thanks -- Andy
Possibly Parallel Threads
- [PATCH v4 04/25] virtio: defer config changed notifications
- [PATCH v4 04/25] virtio: defer config changed notifications
- [PATCH 05/16] virtio: defer config changed notifications
- [PATCH v2 04/15] virtio: defer config changed notifications
- [PATCH 05/16] virtio: defer config changed notifications