From 28457ee69c473a903e51e26c7bcd6f1e9eceb93e Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 9 Mar 2010 19:24:45 +0100 Subject: vhost: add __rcu annotations Also add rcu_dereference_protected() for code paths where locks are held. Signed-off-by: Arnd Bergmann Signed-off-by: Paul E. McKenney Cc: "Michael S. Tsirkin" --- drivers/vhost/vhost.h | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'drivers/vhost/vhost.h') diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index afd77295971c..af3c11ded5fd 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -106,7 +106,7 @@ struct vhost_virtqueue { * vhost_work execution acts instead of rcu_read_lock() and the end of * vhost_work execution acts instead of rcu_read_lock(). * Writers use virtqueue mutex. */ - void *private_data; + void __rcu *private_data; /* Log write descriptors */ void __user *log_base; struct vhost_log log[VHOST_NET_MAX_SG]; @@ -116,7 +116,7 @@ struct vhost_dev { /* Readers use RCU to access memory table pointer * log base pointer and features. * Writers use mutex below.*/ - struct vhost_memory *memory; + struct vhost_memory __rcu *memory; struct mm_struct *mm; struct mutex mutex; unsigned acked_features; @@ -173,7 +173,11 @@ enum { static inline int vhost_has_feature(struct vhost_dev *dev, int bit) { - unsigned acked_features = rcu_dereference(dev->acked_features); + unsigned acked_features; + + acked_features = + rcu_dereference_index_check(dev->acked_features, + lockdep_is_held(&dev->mutex)); return acked_features & (1 << bit); } -- cgit v1.2.2 From e0e9b406470b8dd75a115cf82c4791f41615c4c3 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Tue, 14 Sep 2010 23:53:05 +0800 Subject: vhost: max s/g to match qemu Qemu supports up to UIO_MAXIOV s/g so we have to match that because guest drivers may rely on this. Allocate indirect and log arrays dynamically to avoid using too much contigious memory and make the length of hdr array to match the header length since each iovec entry has a least one byte. Test with copying large files w/ and w/o migration in both linux and windows guests. Signed-off-by: Jason Wang Signed-off-by: Michael S. Tsirkin --- drivers/vhost/vhost.h | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) (limited to 'drivers/vhost/vhost.h') diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index afd77295971c..edc892989992 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -15,11 +15,6 @@ struct vhost_device; -enum { - /* Enough place for all fragments, head, and virtio net header. */ - VHOST_NET_MAX_SG = MAX_SKB_FRAGS + 2, -}; - struct vhost_work; typedef void (*vhost_work_fn_t)(struct vhost_work *work); @@ -93,12 +88,15 @@ struct vhost_virtqueue { bool log_used; u64 log_addr; - struct iovec indirect[VHOST_NET_MAX_SG]; - struct iovec iov[VHOST_NET_MAX_SG]; - struct iovec hdr[VHOST_NET_MAX_SG]; + struct iovec iov[UIO_MAXIOV]; + /* hdr is used to store the virtio header. + * Since each iovec has >= 1 byte length, we never need more than + * header length entries to store the header. */ + struct iovec hdr[sizeof(struct virtio_net_hdr_mrg_rxbuf)]; + struct iovec *indirect; size_t vhost_hlen; size_t sock_hlen; - struct vring_used_elem heads[VHOST_NET_MAX_SG]; + struct vring_used_elem *heads; /* We use a kind of RCU to access private pointer. * All readers access it from worker, which makes it possible to * flush the vhost_work instead of synchronize_rcu. Therefore readers do @@ -109,7 +107,7 @@ struct vhost_virtqueue { void *private_data; /* Log write descriptors */ void __user *log_base; - struct vhost_log log[VHOST_NET_MAX_SG]; + struct vhost_log *log; }; struct vhost_dev { -- cgit v1.2.2 From a290aec88a9c4747353ea7aa9b2569bd61297c3c Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Mon, 29 Nov 2010 13:48:40 +0800 Subject: vhost: fix typos in comment Signed-off-by: Jason Wang Signed-off-by: Michael S. Tsirkin --- drivers/vhost/vhost.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/vhost/vhost.h') diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 073d06ae091f..2af44b7b1f3f 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -102,7 +102,7 @@ struct vhost_virtqueue { * flush the vhost_work instead of synchronize_rcu. Therefore readers do * not need to call rcu_read_lock/rcu_read_unlock: the beginning of * vhost_work execution acts instead of rcu_read_lock() and the end of - * vhost_work execution acts instead of rcu_read_lock(). + * vhost_work execution acts instead of rcu_read_unlock(). * Writers use virtqueue mutex. */ void __rcu *private_data; /* Log write descriptors */ -- cgit v1.2.2 From 5e18247b02d60a1ea4bf98c05e139461ca9aec64 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Tue, 18 Jan 2011 13:04:43 +0200 Subject: vhost: rcu annotation fixup When built with rcu checks enabled, vhost triggers bogus warnings as vhost features are read without dev->mutex sometimes, and private pointer is read with our kind of rcu where work serves as a read side critical section. Fixing it properly is not trivial. Disable the warnings by stubbing out the checks for now. Signed-off-by: Michael S. Tsirkin --- drivers/vhost/vhost.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/vhost/vhost.h') diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 2af44b7b1f3f..b3363ae38518 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -173,9 +173,9 @@ static inline int vhost_has_feature(struct vhost_dev *dev, int bit) { unsigned acked_features; - acked_features = - rcu_dereference_index_check(dev->acked_features, - lockdep_is_held(&dev->mutex)); + /* TODO: check that we are running from vhost_worker or dev mutex is + * held? */ + acked_features = rcu_dereference_index_check(dev->acked_features, 1); return acked_features & (1 << bit); } -- cgit v1.2.2 From 8ea8cf89e19aeb596b818ee5f2bec8a8b0586b60 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Fri, 20 May 2011 02:10:54 +0300 Subject: vhost: support event index Support the new event index feature. When acked, utilize it to reduce the # of interrupts sent to the guest. Signed-off-by: Michael S. Tsirkin Signed-off-by: Rusty Russell --- drivers/vhost/vhost.h | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) (limited to 'drivers/vhost/vhost.h') diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index b3363ae38518..8e03379dd30f 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -84,6 +84,12 @@ struct vhost_virtqueue { /* Used flags */ u16 used_flags; + /* Last used index value we have signalled on */ + u16 signalled_used; + + /* Last used index value we have signalled on */ + bool signalled_used_valid; + /* Log writes to used structure. */ bool log_used; u64 log_addr; @@ -149,8 +155,8 @@ void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *, void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *, struct vring_used_elem *heads, unsigned count); void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *); -void vhost_disable_notify(struct vhost_virtqueue *); -bool vhost_enable_notify(struct vhost_virtqueue *); +void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *); +bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *); int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, unsigned int log_num, u64 len); @@ -162,11 +168,12 @@ int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, } while (0) enum { - VHOST_FEATURES = (1 << VIRTIO_F_NOTIFY_ON_EMPTY) | - (1 << VIRTIO_RING_F_INDIRECT_DESC) | - (1 << VHOST_F_LOG_ALL) | - (1 << VHOST_NET_F_VIRTIO_NET_HDR) | - (1 << VIRTIO_NET_F_MRG_RXBUF), + VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | + (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | + (1ULL << VIRTIO_RING_F_EVENT_IDX) | + (1ULL << VHOST_F_LOG_ALL) | + (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) | + (1ULL << VIRTIO_NET_F_MRG_RXBUF), }; static inline int vhost_has_feature(struct vhost_dev *dev, int bit) -- cgit v1.2.2