search for: 7f466032dc9e

Hi all: This series try to fix several issues introduced by meta data accelreation series. Please review. Jason Wang (6): vhost: don't set uaddr for invalid address vhost: validate MMU notifier registration vhost: fix vhost map leak vhost: reset invalidate_count in vhost_set_vring_num_addr() vhost: mark dirty pages during map uninit vhost: don't do synchronize_rcu() in

Hi all: This series try to fix several issues introduced by meta data accelreation series. Please review. Changes from V4: - switch to use spinlock synchronize MMU notifier with accessors 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

Hi all: This series try to fix several issues introduced by meta data accelreation series. Please review. Changes from V4: - switch to use spinlock synchronize MMU notifier with accessors 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

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

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):

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

...ts packed virtqueues which were described >> at [1]. In this version we try to address the performance regression >> saw by V2. The root cause is packed virtqueue need more times of >> userspace memory accesssing which turns out to be very >> expensive. Thanks to the help of 7f466032dc9e ("vhost: access vq >> metadata through kernel virtual address"), such overhead cold be >> eliminated. So in this version, we can see about 2% improvement for >> packed virtqueue on PPS. > Great job, thanks! > Pls allow a bit more review time than usual as this is a...

...t 03:57:17AM -0400, Jason Wang wrote: > We don't mark dirty pages if the map was teared down outside MMU > notifier. This will lead untracked dirty pages. Fixing by marking > dirty pages during map uninit. > > Reported-by: Michael S. Tsirkin <mst at redhat.com> > Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address") > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/vhost/vhost.c | 22 ++++++++++++++++------ > 1 file changed, 16 insertions(+), 6 deletions(-) > > diff --git a/drivers/vhost/vhost.c...

...t 03:57:17AM -0400, Jason Wang wrote: > We don't mark dirty pages if the map was teared down outside MMU > notifier. This will lead untracked dirty pages. Fixing by marking > dirty pages during map uninit. > > Reported-by: Michael S. Tsirkin <mst at redhat.com> > Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address") > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/vhost/vhost.c | 22 ++++++++++++++++------ > 1 file changed, 16 insertions(+), 6 deletions(-) > > diff --git a/drivers/vhost/vhost.c...

...idate_count after the un-registering of MMU notifier, the > invalidate_cont will run out of sync (e.g never reach zero). This will > in fact disable the fast accessor path. Fixing by reset the count to > zero. > > Reported-by: Michael S. Tsirkin <mst at redhat.com> > Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address") > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/vhost/vhost.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 0...

...g of MMU notifier, the > invalidate_cont will run out of sync (e.g never reach zero). This will > in fact disable the fast accessor path. Fixing by reset the count to > zero. > > Reported-by: Michael S. Tsirkin <mst at redhat.com> Did Michael report this as well? > Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address") > Signed-off-by: Jason Wang <jasowang at redhat.com> > drivers/vhost/vhost.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 2a31549762...

...g of MMU notifier, the > invalidate_cont will run out of sync (e.g never reach zero). This will > in fact disable the fast accessor path. Fixing by reset the count to > zero. > > Reported-by: Michael S. Tsirkin <mst at redhat.com> Did Michael report this as well? > Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address") > Signed-off-by: Jason Wang <jasowang at redhat.com> > drivers/vhost/vhost.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 2a31549762...

..._vq_maps() > since we've already serialized with readers (memory accessors). This > also avoid the possible userspace DOS through ioctl() because of the > possible high latency caused by synchronize_rcu(). > > Reported-by: Michael S. Tsirkin <mst at redhat.com> > Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address") > Signed-off-by: Jason Wang <jasowang at redhat.com> I agree synchronize_rcu in both mmu notifiers and ioctl is a problem we must fix. > --- > drivers/vhost/vhost.c | 4 +++- > 1 file changed, 3 insertions(+...

...hanks, Stefano On Wed, Jul 31, 2019 at 04:46:55AM -0400, Jason Wang wrote: > Instead of returning -EAGAIN unconditionally, we'd better do that only > we're sure the range is overlapped with the metadata area. > > Reported-by: Jason Gunthorpe <jgg at ziepe.ca> > Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address") > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/vhost/vhost.c | 32 +++++++++++++++++++------------- > 1 file changed, 19 insertions(+), 13 deletions(-) > > diff --git a/drivers/vho...

...en it was odd, it means > there's a reader we need to wait it to be even again then we are > synchronized. Consider the read critical section is pretty small the > synchronization should be done very fast. > > Reported-by: Michael S. Tsirkin <mst at redhat.com> > Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address") > Signed-off-by: Jason Wang <jasowang at redhat.com> > drivers/vhost/vhost.c | 141 ++++++++++++++++++++++++++---------------- > drivers/vhost/vhost.h | 7 ++- > 2 files changed, 90 insertions(+), 58 deletio...

...en it was odd, it means > there's a reader we need to wait it to be even again then we are > synchronized. Consider the read critical section is pretty small the > synchronization should be done very fast. > > Reported-by: Michael S. Tsirkin <mst at redhat.com> > Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address") > Signed-off-by: Jason Wang <jasowang at redhat.com> > drivers/vhost/vhost.c | 141 ++++++++++++++++++++++++++---------------- > drivers/vhost/vhost.h | 7 ++- > 2 files changed, 90 insertions(+), 58 deletio...

...between mm > and MMU notifier thus a double free. To solve this, introduce a > boolean flag to track whether MMU notifier is registered and only do > unregistering when it was true. > > Reported-and-tested-by: > syzbot+e58112d71f77113ddb7b at syzkaller.appspotmail.com > Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address") > Signed-off-by: Jason Wang <jasowang at redhat.com> Right. This fixes the bug. But it's not great that simple things like setting vq address put pressure on memory allocator. Also, if we get a single during proces...

...ynchronization in vhost_uninit_vq_maps() since we've already serialized with readers (memory accessors). This also avoid the possible userspace DOS through ioctl() because of the possible high latency caused by synchronize_rcu(). Reported-by: Michael S. Tsirkin <mst at redhat.com> Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address") Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/vhost/vhost.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 5b8821d00fe4..a17df1f...

We don't mark dirty pages if the map was teared down outside MMU notifier. This will lead untracked dirty pages. Fixing by marking dirty pages during map uninit. Reported-by: Michael S. Tsirkin <mst at redhat.com> Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address") Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/vhost/vhost.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index...