From 44653eae1407f79dff6f52fcf594ae84cb165ec4 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 25 Jul 2008 12:06:04 -0500 Subject: virtio: don't always force a notification when ring is full We force notification when the ring is full, even if the host has indicated it doesn't want to know. This seemed like a good idea at the time: if we fill the transmit ring, we should tell the host immediately. Unfortunately this logic also applies to the receiving ring, which is refilled constantly. We should introduce real notification thesholds to replace this logic. Meanwhile, removing the logic altogether breaks the heuristics which KVM uses, so we use a hack: only notify if there are outgoing parts of the new buffer. Here are the number of exits with lguest's crappy network implementation: Before: network xmit 7859051 recv 236420 After: network xmit 7858610 recv 118136 Signed-off-by: Rusty Russell --- drivers/virtio/virtio_ring.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'drivers/virtio') diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 72bf8bc09014..21d9a62767af 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -87,8 +87,11 @@ static int vring_add_buf(struct virtqueue *_vq, if (vq->num_free < out + in) { pr_debug("Can't add buf len %i - avail = %i\n", out + in, vq->num_free); - /* We notify *even if* VRING_USED_F_NO_NOTIFY is set here. */ - vq->notify(&vq->vq); + /* FIXME: for historical reasons, we force a notify here if + * there are outgoing parts to the buffer. Presumably the + * host should service the ring ASAP. */ + if (out) + vq->notify(&vq->vq); END_USE(vq); return -ENOSPC; } -- cgit v1.2.2 From e962fa660d391fc9b90988e6538c94c858c099f9 Mon Sep 17 00:00:00 2001 From: Mark McLoughlin Date: Fri, 13 Jun 2008 13:46:40 +0100 Subject: virtio: Use bus_type probe and remove methods Hook up to the probe() and remove() methods in bus_type rather than device_driver. The latter has been preferred since 2.6.16. Signed-off-by: Mark McLoughlin Signed-off-by: Rusty Russell --- drivers/virtio/virtio.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) (limited to 'drivers/virtio') diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index 7084e7e146c0..fc85cba64578 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -71,13 +71,6 @@ static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env) dev->id.device, dev->id.vendor); } -static struct bus_type virtio_bus = { - .name = "virtio", - .match = virtio_dev_match, - .dev_attrs = virtio_dev_attrs, - .uevent = virtio_uevent, -}; - static void add_status(struct virtio_device *dev, unsigned status) { dev->config->set_status(dev, dev->config->get_status(dev) | status); @@ -147,13 +140,20 @@ static int virtio_dev_remove(struct device *_d) return 0; } +static struct bus_type virtio_bus = { + .name = "virtio", + .match = virtio_dev_match, + .dev_attrs = virtio_dev_attrs, + .uevent = virtio_uevent, + .probe = virtio_dev_probe, + .remove = virtio_dev_remove, +}; + int register_virtio_driver(struct virtio_driver *driver) { /* Catch this early. */ BUG_ON(driver->feature_table_size && !driver->feature_table); driver->driver.bus = &virtio_bus; - driver->driver.probe = virtio_dev_probe; - driver->driver.remove = virtio_dev_remove; return driver_register(&driver->driver); } EXPORT_SYMBOL_GPL(register_virtio_driver); -- cgit v1.2.2 From dd7c7bc46211785a1aa7d70feb15830f62682b3c Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 25 Jul 2008 12:06:07 -0500 Subject: virtio: Formally reserve bits 28-31 to be 'transport' features. We assign feature bits as required, but it makes sense to reserve some for the particular transport, rather than the particular device. Signed-off-by: Rusty Russell --- drivers/virtio/virtio.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'drivers/virtio') diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index fc85cba64578..baf103361e3a 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -113,6 +113,11 @@ static int virtio_dev_probe(struct device *_d) set_bit(f, dev->features); } + /* Transport features are always preserved to pass to set_features. */ + for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) + if (device_features & (1 << i)) + set_bit(i, dev->features); + err = drv->probe(dev); if (err) add_status(dev, VIRTIO_CONFIG_S_FAILED); -- cgit v1.2.2 From c624896e488ba2bff5ae497782cfb265c8b00646 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 25 Jul 2008 12:06:07 -0500 Subject: virtio: Rename set_features to finalize_features Rather than explicitly handing the features to the lower-level, we just hand the virtio_device and have it set the features. This make it clear that it has the chance to manipulate the features of the device at this point (and that all feature negotiation is already done). Signed-off-by: Rusty Russell --- drivers/virtio/virtio.c | 5 ++--- drivers/virtio/virtio_pci.c | 10 ++++++---- 2 files changed, 8 insertions(+), 7 deletions(-) (limited to 'drivers/virtio') diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index baf103361e3a..5b78fd0aff0a 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -113,7 +113,7 @@ static int virtio_dev_probe(struct device *_d) set_bit(f, dev->features); } - /* Transport features are always preserved to pass to set_features. */ + /* Transport features always preserved to pass to finalize_features. */ for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) if (device_features & (1 << i)) set_bit(i, dev->features); @@ -122,8 +122,7 @@ static int virtio_dev_probe(struct device *_d) if (err) add_status(dev, VIRTIO_CONFIG_S_FAILED); else { - /* They should never have set feature bits beyond 32 */ - dev->config->set_features(dev, dev->features[0]); + dev->config->finalize_features(dev); add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); } return err; diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c index eae7236310e4..9855975a72a3 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -94,12 +94,14 @@ static u32 vp_get_features(struct virtio_device *vdev) return ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES); } -/* virtio config->set_features() implementation */ -static void vp_set_features(struct virtio_device *vdev, u32 features) +/* virtio config->finalize_features() implementation */ +static void vp_finalize_features(struct virtio_device *vdev) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); - iowrite32(features, vp_dev->ioaddr + VIRTIO_PCI_GUEST_FEATURES); + /* We only support 32 feature bits. */ + BUILD_BUG_ON(ARRAY_SIZE(vdev->features) != 1); + iowrite32(vdev->features[0], vp_dev->ioaddr+VIRTIO_PCI_GUEST_FEATURES); } /* virtio config->get() implementation */ @@ -297,7 +299,7 @@ static struct virtio_config_ops virtio_pci_config_ops = { .find_vq = vp_find_vq, .del_vq = vp_del_vq, .get_features = vp_get_features, - .set_features = vp_set_features, + .finalize_features = vp_finalize_features, }; /* the PCI probing function */ -- cgit v1.2.2 From e34f87256794b87e7f4a8f1812538be7b7b5214c Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 25 Jul 2008 12:06:13 -0500 Subject: virtio: Add transport feature handling stub for virtio_ring. To prepare for virtio_ring transport feature bits, hook in a call in all the users to manipulate them. This currently just clears all the bits, since it doesn't understand any features. Signed-off-by: Rusty Russell --- drivers/virtio/virtio_pci.c | 3 +++ drivers/virtio/virtio_ring.c | 16 ++++++++++++++++ 2 files changed, 19 insertions(+) (limited to 'drivers/virtio') diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c index 9855975a72a3..c7dc37c7cce9 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -99,6 +99,9 @@ static void vp_finalize_features(struct virtio_device *vdev) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); + /* Give virtio_ring a chance to accept features. */ + vring_transport_features(vdev); + /* We only support 32 feature bits. */ BUILD_BUG_ON(ARRAY_SIZE(vdev->features) != 1); iowrite32(vdev->features[0], vp_dev->ioaddr+VIRTIO_PCI_GUEST_FEATURES); diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 21d9a62767af..6eb5303fed11 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -18,6 +18,7 @@ */ #include #include +#include #include #ifdef DEBUG @@ -323,4 +324,19 @@ void vring_del_virtqueue(struct virtqueue *vq) } EXPORT_SYMBOL_GPL(vring_del_virtqueue); +/* Manipulates transport-specific feature bits. */ +void vring_transport_features(struct virtio_device *vdev) +{ + unsigned int i; + + for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) { + switch (i) { + default: + /* We don't understand this bit. */ + clear_bit(i, vdev->features); + } + } +} +EXPORT_SYMBOL_GPL(vring_transport_features); + MODULE_LICENSE("GPL"); -- cgit v1.2.2