search for: mmget

...start < vma->vm_start)) { > - r = -EFAULT; > - goto out; > - } > - if (unlikely((gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) && > - vma->vm_file)) { > - r = -EPERM; > - goto out; > - } > + mm = mirror->hmm->mmu_notifier.mm; > + if (!mmget_not_zero(mm)) /* Happens during process shutdown */ This works because mirror->hmm->mmu_notifier holds an mmgrab reference to the mm? So the MM will not just go away, but if the mmget refcount is 0, it means the mm is marked for destruction and shouldn't be used any more. > + ret...

...So, only when the bus supports user VA >> (e.g. vhost-vdpa). >> >> vdpasim_mm_work_fn work is used to serialize the binding to a new >> address space when the .bind_mm callback is invoked, and unbinding >> when the .unbind_mm callback is invoked. >> >> Call mmget_not_zero()/kthread_use_mm() inside the worker function >> to pin the address space only as long as needed, following the >> documentation of mmget() in include/linux/sched/mm.h: >> >> * Never use this function to pin this address space for an >> * unbounded/indefin...

...vhost-vdpa). >> >> >> >> vdpasim_mm_work_fn work is used to serialize the binding to a new >> >> address space when the .bind_mm callback is invoked, and unbinding >> >> when the .unbind_mm callback is invoked. >> >> >> >> Call mmget_not_zero()/kthread_use_mm() inside the worker function >> >> to pin the address space only as long as needed, following the >> >> documentation of mmget() in include/linux/sched/mm.h: >> >> >> >> * Never use this function to pin this address space f...

...er's mm has been bound. So, only when the bus supports user VA > (e.g. vhost-vdpa). > > vdpasim_mm_work_fn work is used to serialize the binding to a new > address space when the .bind_mm callback is invoked, and unbinding > when the .unbind_mm callback is invoked. > > Call mmget_not_zero()/kthread_use_mm() inside the worker function > to pin the address space only as long as needed, following the > documentation of mmget() in include/linux/sched/mm.h: > > * Never use this function to pin this address space for an > * unbounded/indefinite amount of time....

...er's mm has been bound. So, only when the bus supports user VA > (e.g. vhost-vdpa). > > vdpasim_mm_work_fn work is used to serialize the binding to a new > address space when the .bind_mm callback is invoked, and unbinding > when the .unbind_mm callback is invoked. > > Call mmget_not_zero()/kthread_use_mm() inside the worker function > to pin the address space only as long as needed, following the > documentation of mmget() in include/linux/sched/mm.h: > > * Never use this function to pin this address space for an > * unbounded/indefinite amount of time...

...is this important enough for a TODO comment, but not important enough to do right away? > + * release semantics on the initialization of the mmu_notifier_mm's > + * contents are provided for unlocked readers. acquire can only be > + * used while holding the mmgrab or mmget, and is safe because once > + * created the mmu_notififer_mm is not freed until the mm is > + * destroyed. As above, users holding the mmap_sem or one of the > + * mm_take_all_locks() do not need to use acquire semantics. > */ Some spaces instead of tabs her...

...* We can't race against any other mmu notifier method either * thanks to mm_take_all_locks(). * * release semantics on the initialization of the mmu_notifier_mm's * contents are provided for unlocked readers. acquire can only be * used while holding the mmgrab or mmget, and is safe because once * created the mmu_notififer_mm is not freed until the mm is * destroyed. As above, users holding the mmap_sem or one of the * mm_take_all_locks() do not need to use acquire semantics. */ if (mmu_notifier_mm) smp_store_release(&mm->mm...

...;m noto sure wake_up_q is even a function this layer should be calling. > > + * release semantics on the initialization of the mmu_notifier_mm's > > + * contents are provided for unlocked readers. acquire can only be > > + * used while holding the mmgrab or mmget, and is safe because once > > + * created the mmu_notififer_mm is not freed until the mm is > > + * destroyed. As above, users holding the mmap_sem or one of the > > + * mm_take_all_locks() do not need to use acquire semantics. > > */ > > S...

...ainst any other mmu notifier method either > * thanks to mm_take_all_locks(). > * > * release semantics on the initialization of the mmu_notifier_mm's > * contents are provided for unlocked readers. acquire can only be > * used while holding the mmgrab or mmget, and is safe because once > * created the mmu_notififer_mm is not freed until the mm is > * destroyed. As above, users holding the mmap_sem or one of the > * mm_take_all_locks() do not need to use acquire semantics. > */ > if (mmu_notifier_mm) > sm...

...lock first virtio-mem: Don't rely on implicit compiler padding for requests Guennadi Liakhovetski (1): vhost: (cosmetic) remove a superfluous variable initialisation Jason Wang (4): vhost: allow device that does not depend on vhost worker vhost: use mmgrab() instead of mmget() for non worker device vdpa: introduce get_vq_notification method vhost_vdpa: support doorbell mapping via mmap Longpeng(Mike) (3): crypto: virtio: Fix src/dst scatterlist calculation in __virtio_crypto_skcipher_do_req() crypto: virtio: Fix use-after-free in virtio_crypto_...

Let's move work management inside the vdpa_sim core. This way we can easily change how we manage the works, without having to change the devices each time. Acked-by: Eugenio P??rez Martin <eperezma at redhat.com> Acked-by: Jason Wang <jasowang at redhat.com> Signed-off-by: Stefano Garzarella <sgarzare at redhat.com> --- drivers/vdpa/vdpa_sim/vdpa_sim.h | 3 ++-

...We can't race against any other mmu notifier method either * thanks to mm_take_all_locks(). + * + * release semantics on the initialization of the mmu_notifier_mm's + * contents are provided for unlocked readers. acquire can only be + * used while holding the mmgrab or mmget, and is safe because once + * created the mmu_notififer_mm is not freed until the mm is + * destroyed. As above, users holding the mmap_sem or one of the + * mm_take_all_locks() do not need to use acquire semantics. */ if (mmu_notifier_mm) - mm->mmu_notifier_mm = m...

...not meet those requirements. So a new virtio-pci driver for vDPA bus is introduced, and I verify this with page-per-vq=on with a userspace vhost-vdpa driver in guest. Please review. Thanks Jason Wang (6): vhost: allow device that does not depend on vhost worker vhost: use mmgrab() instead of mmget() for non worker device vdpa: introduce get_vq_notification method vhost_vdpa: support doorbell mapping via mmap vdpa: introduce virtio pci driver vdpa: vp_vdpa: report doorbell location drivers/vdpa/Kconfig | 6 + drivers/vdpa/Makefile | 1 + drivers/vdpa/vp_vdpa/M...

...not meet those requirements. So a new virtio-pci driver for vDPA bus is introduced, and I verify this with page-per-vq=on with a userspace vhost-vdpa driver in guest. Please review. Thanks Jason Wang (6): vhost: allow device that does not depend on vhost worker vhost: use mmgrab() instead of mmget() for non worker device vdpa: introduce get_vq_notification method vhost_vdpa: support doorbell mapping via mmap vdpa: introduce virtio pci driver vdpa: vp_vdpa: report doorbell location drivers/vdpa/Kconfig | 6 + drivers/vdpa/Makefile | 1 + drivers/vdpa/vp_vdpa/M...

This series adds support for the use of user virtual addresses in the vDPA simulator devices. The main reason for this change is to lift the pinning of all guest memory. Especially with virtio devices implemented in software. The next step would be to generalize the code in vdpa-sim to allow the implementation of in-kernel software devices. Similar to vhost, but using vDPA so we can reuse the

.../* - * Just wait for range to be valid, safe to ignore return value as we - * will use the return value of hmm_range_fault() below under the - * mmap_sem to ascertain the validity of the range. - */ - hmm_range_wait_until_valid(&range, TIMEOUT_IN_MSEC); + if (!mmget_not_zero(mni->notifier.mm)) + return -EFAULT; again: + range.notifier_seq = mmu_interval_read_begin(&mni); down_read(&mm->mmap_sem); ret = hmm_range_fault(&range, HMM_RANGE_SNAPSHOT); if (ret) { up_read(&mm->mmap_sem); -...

...We can't race against any other mmu notifier method either * thanks to mm_take_all_locks(). + * + * release semantics on the initialization of the mmu_notifier_mm's + * contents are provided for unlocked readers. acquire can only be + * used while holding the mmgrab or mmget, and is safe because once + * created the mmu_notififer_mm is not freed until the mm is + * destroyed. As above, users holding the mmap_sem or one of the + * mm_take_all_locks() do not need to use acquire semantics. */ if (mmu_notifier_mm) - mm->mmu_notifier_mm = m...

Hi Dan, Jérôme and Jason, below is a series that cleans up the dev_pagemap interface so that it is more easily usable, which removes the need to wrap it in hmm and thus allowing to kill a lot of code Note: this series is on top of Linux 5.2-rc6 and has some minor conflicts with the hmm tree that are easy to resolve. Diffstat summary: 34 files changed, 379 insertions(+), 1016 deletions(-) Git

From: Jason Gunthorpe <jgg at mellanox.com> 8 of the mmu_notifier using drivers (i915_gem, radeon_mn, umem_odp, hfi1, scif_dma, vhost, gntdev, hmm) drivers are using a common pattern where they only use invalidate_range_start/end and immediately check the invalidating range against some driver data structure to tell if the driver is interested. Half of them use an interval_tree, the others

On 10/28/19 1:10 PM, Jason Gunthorpe wrote: ... > include/linux/mmu_notifier.h | 98 +++++++ > mm/Kconfig | 1 + > mm/mmu_notifier.c | 533 +++++++++++++++++++++++++++++++++-- > 3 files changed, 607 insertions(+), 25 deletions(-) > > diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h > index 12bd603d318ce7..51b92ba013ddce