search for: vhost_vq_sync_access

...???????????????????????????????????????????????????????????????????????????????????????????????????????????????????? ??????? /* Ensure map was read after incresing the counter. Paired?????????????????????????????????????????????????????????????????????????????????????? ???????? * with smp_mb() in vhost_vq_sync_access().????????????????????????????????????????????????????????????????????????????????????????????????????? ???????? */????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? ??????? smp_mb();???????????????????????...

...ONCE(vq->ref); If the write to vq->ref is not locked this algorithm won't work, if it is locked the READ_ONCE is not needed. > + /* Make sure vq access is done before increasing ref counter */ > + smp_store_release(&vq->ref, ref + 1); > +} > + > +static void inline vhost_vq_sync_access(struct vhost_virtqueue *vq) > +{ > + int ref; > + > + /* Make sure map change was done before checking ref counter */ > + smp_mb(); This is probably smp_rmb after reading ref, and if you are setting ref with smp_store_release then this should be smp_load_acquire() without an explici...

...ONCE(vq->ref); If the write to vq->ref is not locked this algorithm won't work, if it is locked the READ_ONCE is not needed. > + /* Make sure vq access is done before increasing ref counter */ > + smp_store_release(&vq->ref, ref + 1); > +} > + > +static void inline vhost_vq_sync_access(struct vhost_virtqueue *vq) > +{ > + int ref; > + > + /* Make sure map change was done before checking ref counter */ > + smp_mb(); This is probably smp_rmb after reading ref, and if you are setting ref with smp_store_release then this should be smp_load_acquire() without an explici...

...>ref is not locked this algorithm won't work, if it > is locked the READ_ONCE is not needed. Yes. > >> + /* Make sure vq access is done before increasing ref counter */ >> + smp_store_release(&vq->ref, ref + 1); >> +} >> + >> +static void inline vhost_vq_sync_access(struct vhost_virtqueue *vq) >> +{ >> + int ref; >> + >> + /* Make sure map change was done before checking ref counter */ >> + smp_mb(); > This is probably smp_rmb after reading ref, and if you are setting ref > with smp_store_release then this should be smp_load...

Hi all: This series try to fix several issues introduced by meta data accelreation series. Please review. Changes from V1: - Try not use RCU to syncrhonize MMU notifier with vhost worker - set dirty pages after no readers - return -EAGAIN only when we find the range is overlapped with metadata Jason Wang (9): vhost: don't set uaddr for invalid address vhost: validate MMU notifier

...+++------------- > 1 file changed, 19 insertions(+), 13 deletions(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index fc2da8a0c671..96c6aeb1871f 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -399,16 +399,19 @@ static void inline vhost_vq_sync_access(struct vhost_virtqueue *vq) > smp_mb(); > } > > -static void vhost_invalidate_vq_start(struct vhost_virtqueue *vq, > - int index, > - unsigned long start, > - unsigned long end) > +static int vhost_invalidate_vq_start(struct vhost_virtqueue *v...

On Wed, Aug 07, 2019 at 03:06:15AM -0400, Jason Wang wrote: > We used to use RCU to synchronize MMU notifier with worker. This leads > calling synchronize_rcu() in invalidate_range_start(). But on a busy > system, there would be many factors that may slow down the > synchronize_rcu() which makes it unsuitable to be called in MMU > notifier. > > So this patch switches use

On Wed, Aug 07, 2019 at 03:06:15AM -0400, Jason Wang wrote: > We used to use RCU to synchronize MMU notifier with worker. This leads > calling synchronize_rcu() in invalidate_range_start(). But on a busy > system, there would be many factors that may slow down the > synchronize_rcu() which makes it unsuitable to be called in MMU > notifier. > > So this patch switches use

...t; + > +static void inline vhost_vq_access_map_end(struct vhost_virtqueue *vq) > +{ > + int ref = READ_ONCE(vq->ref); > + > + /* Make sure vq access is done before increasing ref counter */ > + smp_store_release(&vq->ref, ref + 1); > +} > + > +static void inline vhost_vq_sync_access(struct vhost_virtqueue *vq) > +{ > + int ref; > + > + /* Make sure map change was done before checking ref counter */ > + smp_mb(); > + > + ref = READ_ONCE(vq->ref); > + if (ref & 0x1) { Please document the even/odd trick here too, not just in the commit log. > +...

...t; + > +static void inline vhost_vq_access_map_end(struct vhost_virtqueue *vq) > +{ > + int ref = READ_ONCE(vq->ref); > + > + /* Make sure vq access is done before increasing ref counter */ > + smp_store_release(&vq->ref, ref + 1); > +} > + > +static void inline vhost_vq_sync_access(struct vhost_virtqueue *vq) > +{ > + int ref; > + > + /* Make sure map change was done before checking ref counter */ > + smp_mb(); > + > + ref = READ_ONCE(vq->ref); > + if (ref & 0x1) { Please document the even/odd trick here too, not just in the commit log. > +...

...s_map_end(struct vhost_virtqueue *vq) > { > - int ref = READ_ONCE(vq->ref); > - > - /* Make sure vq access is done before increasing ref counter */ > - smp_store_release(&vq->ref, ref + 1); > + write_seqcount_end(&vq->seq); > } > > static void inline vhost_vq_sync_access(struct vhost_virtqueue *vq) > { > - int ref; > + unsigned int ret; > > /* Make sure map change was done before checking ref counter */ > smp_mb(); > - > - ref = READ_ONCE(vq->ref); > - if (ref & 0x1) { > - /* When ref change, we are sure no reader can se...

Hi all: This series try to fix several issues introduced by meta data accelreation series. Please review. Changes from V2: - use seqlck helper to synchronize MMU notifier with vhost worker Changes from V1: - try not use RCU to syncrhonize MMU notifier with vhost worker - set dirty pages after no readers - return -EAGAIN only when we find the range is overlapped with metadata Jason Wang (9):

...seq); } static void inline vhost_vq_access_map_end(struct vhost_virtqueue *vq) { - int ref = READ_ONCE(vq->ref); - - /* Make sure vq access is done before increasing ref counter */ - smp_store_release(&vq->ref, ref + 1); + write_seqcount_end(&vq->seq); } static void inline vhost_vq_sync_access(struct vhost_virtqueue *vq) { - int ref; + unsigned int ret; /* Make sure map change was done before checking ref counter */ smp_mb(); - - ref = READ_ONCE(vq->ref); - if (ref & 0x1) { - /* When ref change, we are sure no reader can see + ret = raw_read_seqcount(&vq->seq); + if...

Hi all: This series try to fix several issues introduced by meta data accelreation series. Please review. Changes from V3: - remove the unnecessary patch Changes from V2: - use seqlck helper to synchronize MMU notifier with vhost worker Changes from V1: - try not use RCU to syncrhonize MMU notifier with vhost worker - set dirty pages after no readers - return -EAGAIN only when we find the

Hi all: This series try to fix several issues introduced by meta data accelreation series. Please review. Changes from V3: - remove the unnecessary patch Changes from V2: - use seqlck helper to synchronize MMU notifier with vhost worker Changes from V1: - try not use RCU to syncrhonize MMU notifier with vhost worker - set dirty pages after no readers - return -EAGAIN only when we find the

...>uaddr - 1 + uaddr->size); } +static void inline vhost_vq_access_map_begin(struct vhost_virtqueue *vq) +{ + write_seqcount_begin(&vq->seq); +} + +static void inline vhost_vq_access_map_end(struct vhost_virtqueue *vq) +{ + write_seqcount_end(&vq->seq); +} + +static void inline vhost_vq_sync_access(struct vhost_virtqueue *vq) +{ + unsigned int seq; + + /* Make sure any changes to map was done before checking seq + * counter. Paired with smp_wmb() in write_seqcount_begin(). + */ + smp_mb(); + seq = raw_read_seqcount(&vq->seq); + /* Odd means the map was currently accessed by vhost wor...

...map */ + smp_load_acquire(&vq->ref); +} + +static void inline vhost_vq_access_map_end(struct vhost_virtqueue *vq) +{ + int ref = READ_ONCE(vq->ref); + + /* Make sure vq access is done before increasing ref counter */ + smp_store_release(&vq->ref, ref + 1); +} + +static void inline vhost_vq_sync_access(struct vhost_virtqueue *vq) +{ + int ref; + + /* Make sure map change was done before checking ref counter */ + smp_mb(); + + ref = READ_ONCE(vq->ref); + if (ref & 0x1) { + /* When ref change, we are sure no reader can see + * previous map */ + while (READ_ONCE(vq->ref) == ref) { +...

...vhost/vhost.c | 32 +++++++++++++++++++------------- 1 file changed, 19 insertions(+), 13 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index fc2da8a0c671..96c6aeb1871f 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -399,16 +399,19 @@ static void inline vhost_vq_sync_access(struct vhost_virtqueue *vq) smp_mb(); } -static void vhost_invalidate_vq_start(struct vhost_virtqueue *vq, - int index, - unsigned long start, - unsigned long end) +static int vhost_invalidate_vq_start(struct vhost_virtqueue *vq, + int index, + unsign...