search for: kthread_use_mm

Some architectures like arm64 and s390 require USER_DS to be set for kernel threads to access user address space, which is the whole purpose of kthread_use_mm, but other like x86 don't. That has lead to a huge mess where some callers are fixed up once they are tested on said architectures, while others linger around and yet other like io_uring try to do "clever" optimizations for what usually is just a trivial asignment to a member in the...

Some architectures like arm64 and s390 require USER_DS to be set for kernel threads to access user address space, which is the whole purpose of kthread_use_mm, but other like x86 don't. That has lead to a huge mess where some callers are fixed up once they are tested on said architectures, while others linger around and yet other like io_uring try to do "clever" optimizations for what usually is just a trivial asignment to a member in the...

.../drm/amd/amdgpu/amdgpu_amdkfd.h @@ -192,9 +192,9 @@ uint8_t amdgpu_amdkfd_get_xgmi_hops_count(struct kgd_dev *dst, struct kgd_dev *s if ((mmptr) == current->mm) { \ valid = !get_user((dst), (wptr)); \ } else if (current->flags & PF_KTHREAD) { \ - use_mm(mmptr); \ + kthread_use_mm(mmptr); \ valid = !get_user((dst), (wptr)); \ - unuse_mm(mmptr); \ + kthread_unuse_mm(mmptr); \ } \ pagefault_enable(); \ } \ diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index dee01c371bf5..92e9b340dbc2 100644 --- a/drive...

...drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h @@ -192,9 +192,9 @@ uint8_t amdgpu_amdkfd_get_xgmi_hops_count(struct kgd_dev *dst, struct kgd_dev *s if ((mmptr) == current->mm) { \ valid = !get_user((dst), (wptr)); \ } else if (current->mm == NULL) { \ - use_mm(mmptr); \ + kthread_use_mm(mmptr); \ valid = !get_user((dst), (wptr)); \ - unuse_mm(mmptr); \ + kthread_unuse_mm(mmptr); \ } \ pagefault_enable(); \ } \ diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index ca1dd6e6f395..f2927575b793 100644 --- a/drive...

Hi all, this series improves the use_mm / unuse_mm interface by better documenting the assumptions, and my taking the set_fs manipulations spread over the callers into the core API.

Hi all, this series improves the use_mm / unuse_mm interface by better documenting the assumptions, and my taking the set_fs manipulations spread over the callers into the core API.

Hi all, this series improves the use_mm / unuse_mm interface by better documenting the assumptions, and my taking the set_fs manipulations spread over the callers into the core API. Changes since v1: - drop a few patches - fix a comment typo - cover the newly merged use_mm/unuse_mm caller in vfio

Hi all, this series improves the use_mm / unuse_mm interface by better documenting the assumptions, and my taking the set_fs manipulations spread over the callers into the core API. Changes since v1: - drop a few patches - fix a comment typo - cover the newly merged use_mm/unuse_mm caller in vfio

...een 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. > > Signed-off-by:...

...een 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. I wonder if everything wo...

...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. > &...

...> >> >> >> 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 >> >>...

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 ++-

...; + > +static void vdpasim_mm_work_fn(struct kthread_work *work) > +{ > + struct vdpasim_mm_work *mm_work = > + container_of(work, struct vdpasim_mm_work, work); > + > + mm_work->ret = 0; > + > + if (mm_work->bind) { > + kthread_use_mm(mm_work->mm); > + //TODO: should we attach the cgroup of the mm owner? > + } else { > + kthread_unuse_mm(mm_work->mm); > + } > +} > + > +static void vdpasim_worker_queue_mm(struct vdpasim *vdpasim, > +...

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

v2: - rebased on Linus' tree, commit ae3419fbac84 ("vc_screen: don't clobber return value in vcs_read") - removed `struct task_struct *owner` param (unused for now, maybe ?useful to support cgroups) [Jason] - add unbind_mm callback [Jason] - call the new unbind_mm callback during the release [Jason] - avoid to call bind_mm callback after the reset, since the device ?is not