On Thu, Jul 07, 2022 at 10:14:38AM +0200, Thomas Hellström wrote:
On Wed, 2022-07-06 at 22:43 -0700, Niranjana Vishwanathapura wrote:
On Wed, Jul 06, 2022 at 06:21:03PM +0200, Thomas Hellström wrote:
> On Fri, 2022-07-01 at 15:50 -0700, Niranjana Vishwanathapura wrote:
> > Bind and unbind the mappings upon VM_BIND and VM_UNBIND calls.
> >
> > Signed-off-by: Niranjana Vishwanathapura
> > <niranjana.vishwanathapura@xxxxxxxxx>
> > Signed-off-by: Prathap Kumar Valsan
> > <prathap.kumar.valsan@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/Makefile | 1 +
> > drivers/gpu/drm/i915/gem/i915_gem_create.c | 10 +-
> > drivers/gpu/drm/i915/gem/i915_gem_object.h | 2 +
> > drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h | 38 +++
> > .../drm/i915/gem/i915_gem_vm_bind_object.c | 233
> > ++++++++++++++++++
> > drivers/gpu/drm/i915/gt/intel_gtt.c | 7 +
> > drivers/gpu/drm/i915/gt/intel_gtt.h | 9 +
> > drivers/gpu/drm/i915/i915_driver.c | 11 +-
> > drivers/gpu/drm/i915/i915_vma.c | 7 +-
> > drivers/gpu/drm/i915/i915_vma.h | 2 -
> > drivers/gpu/drm/i915/i915_vma_types.h | 8 +
> > 11 files changed, 318 insertions(+), 10 deletions(-)
> > create mode 100644 drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h
> > create mode 100644
> > drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
> >
> > diff --git a/drivers/gpu/drm/i915/Makefile
> > b/drivers/gpu/drm/i915/Makefile
> > index 522ef9b4aff3..4e1627e96c6e 100644
> > --- a/drivers/gpu/drm/i915/Makefile
> > +++ b/drivers/gpu/drm/i915/Makefile
> > @@ -165,6 +165,7 @@ gem-y += \
> > gem/i915_gem_ttm_move.o \
> > gem/i915_gem_ttm_pm.o \
> > gem/i915_gem_userptr.o \
> > + gem/i915_gem_vm_bind_object.o \
> > gem/i915_gem_wait.o \
> > gem/i915_gemfs.o
> > i915-y += \
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_create.c
> > b/drivers/gpu/drm/i915/gem/i915_gem_create.c
> > index 33673fe7ee0a..927a87e5ec59 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_create.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_create.c
> > @@ -15,10 +15,10 @@
> > #include "i915_trace.h"
> > #include "i915_user_extensions.h"
> >
> > -static u32 object_max_page_size(struct intel_memory_region
> > **placements,
> > - unsigned int n_placements)
> > +u32 i915_gem_object_max_page_size(struct intel_memory_region
> > **placements,
>
> Kerneldoc.
This is an existing function that is being modified. As I
mentioned in other thread, we probably need a prep patch early
in this series to add missing kernel-docs in i915 which this
patch series would later update.
Here we make a static function extern, which according to the patch
submission guidelines, mandates a kerneloc comment, so it's not so much
that the function is modified. We should be fine adding kerneldoc in
the patch that makes the function extern.
Ok, sounds good.
>
> > + unsigned int n_placements)
> > {
> > - u32 max_page_size = 0;
> > + u32 max_page_size = I915_GTT_PAGE_SIZE_4K;
> > int i;
> >
> > for (i = 0; i < n_placements; i++) {
> > @@ -28,7 +28,6 @@ static u32 object_max_page_size(struct
> > intel_memory_region **placements,
> > max_page_size = max_t(u32, max_page_size, mr-
> > > min_page_size);
> > }
> >
> > - GEM_BUG_ON(!max_page_size);
> > return max_page_size;
> > }
>
> Should this change be separated out? It's not immediately clear to
> a
> reviewer why it is included.
It is being removed as max_page_size now has a non-zero default
value and hence this check is not valid anymore.
But that in itself deserves an explanation in the patch commit message.
So that's why I wondered whether it wouldn't be better to separate it
out?
Yah, we can have this change in a separate patch before we introduce
VM_BIND feature.
>
> >
> > @@ -99,7 +98,8 @@ __i915_gem_object_create_user_ext(struct
> > drm_i915_private *i915, u64 size,
> >
> > i915_gem_flush_free_objects(i915);
> >
> > - size = round_up(size, object_max_page_size(placements,
> > n_placements));
> > + size = round_up(size,
> > i915_gem_object_max_page_size(placements,
> > +
> > n_placements));
> > if (size == 0)
> > return ERR_PTR(-EINVAL);
> >
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> > b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> > index 6f0a3ce35567..650de2224843 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> > @@ -47,6 +47,8 @@ static inline bool
> > i915_gem_object_size_2big(u64
> > size)
> > }
> >
> > void i915_gem_init__objects(struct drm_i915_private *i915);
> > +u32 i915_gem_object_max_page_size(struct intel_memory_region
> > **placements,
> > + unsigned int n_placements);
> >
> > void i915_objects_module_exit(void);
> > int i915_objects_module_init(void);
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h
> > b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h
> > new file mode 100644
> > index 000000000000..642cdb559f17
> > --- /dev/null
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h
> > @@ -0,0 +1,38 @@
> > +/* SPDX-License-Identifier: MIT */
> > +/*
> > + * Copyright © 2022 Intel Corporation
> > + */
> > +
> > +#ifndef __I915_GEM_VM_BIND_H
> > +#define __I915_GEM_VM_BIND_H
> > +
> > +#include "i915_drv.h"
> > +
> > +#define assert_vm_bind_held(vm) lockdep_assert_held(&(vm)-
> > > vm_bind_lock)
> > +
> > +static inline void i915_gem_vm_bind_lock(struct
> > i915_address_space
> > *vm)
> > +{
> > + mutex_lock(&vm->vm_bind_lock);
> > +}
> > +
> > +static inline int
> > +i915_gem_vm_bind_lock_interruptible(struct i915_address_space
> > *vm)
> > +{
> > + return mutex_lock_interruptible(&vm->vm_bind_lock);
> > +}
> > +
> > +static inline void i915_gem_vm_bind_unlock(struct
> > i915_address_space
> > *vm)
> > +{
> > + mutex_unlock(&vm->vm_bind_lock);
> > +}
> > +
>
> Kerneldoc for the inlines.
>
> > +struct i915_vma *
> > +i915_gem_vm_bind_lookup_vma(struct i915_address_space *vm, u64
> > va);
> > +void i915_gem_vm_bind_remove(struct i915_vma *vma, bool
> > release_obj);
> > +int i915_gem_vm_bind_obj(struct i915_address_space *vm,
> > + struct drm_i915_gem_vm_bind *va,
> > + struct drm_file *file);
> > +int i915_gem_vm_unbind_obj(struct i915_address_space *vm,
> > + struct drm_i915_gem_vm_unbind *va);
> > +
> > +#endif /* __I915_GEM_VM_BIND_H */
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
> > b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
> > new file mode 100644
> > index 000000000000..43ceb4dcca6c
> > --- /dev/null
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
> > @@ -0,0 +1,233 @@
> > +// SPDX-License-Identifier: MIT
> > +/*
> > + * Copyright © 2022 Intel Corporation
> > + */
> > +
> > +#include <linux/interval_tree_generic.h>
> > +
> > +#include "gem/i915_gem_vm_bind.h"
> > +#include "gt/gen8_engine_cs.h"
> > +
> > +#include "i915_drv.h"
> > +#include "i915_gem_gtt.h"
> > +
> > +#define START(node) ((node)->start)
> > +#define LAST(node) ((node)->last)
> > +
> > +INTERVAL_TREE_DEFINE(struct i915_vma, rb, u64, __subtree_last,
> > + START, LAST, static inline, i915_vm_bind_it)
> > +
> > +#undef START
> > +#undef LAST
> > +
> > +/**
> > + * DOC: VM_BIND/UNBIND ioctls
> > + *
> > + * DRM_I915_GEM_VM_BIND/UNBIND ioctls allows UMD to bind/unbind
> > GEM
> > buffer
> > + * objects (BOs) or sections of a BOs at specified GPU virtual
> > addresses on a
> > + * specified address space (VM). Multiple mappings can map to
> > the
> > same physical
> > + * pages of an object (aliasing). These mappings (also referred
> > to
> > as persistent
> > + * mappings) will be persistent across multiple GPU submissions
> > (execbuf calls)
> > + * issued by the UMD, without user having to provide a list of
> > all
> > required
> > + * mappings during each submission (as required by older execbuf
> > mode).
> > + *
> > + * The VM_BIND/UNBIND calls allow UMDs to request a timeline out
> > fence for
> > + * signaling the completion of bind/unbind operation.
> > + *
> > + * VM_BIND feature is advertised to user via
> > I915_PARAM_VM_BIND_VERSION.
> > + * User has to opt-in for VM_BIND mode of binding for an address
> > space (VM)
> > + * during VM creation time via I915_VM_CREATE_FLAGS_USE_VM_BIND
> > extension.
> > + *
> > + * VM_BIND/UNBIND ioctl calls executed on different CPU threads
> > concurrently
> > + * are not ordered. Furthermore, parts of the VM_BIND/UNBIND
> > operations can be
> > + * done asynchronously, when valid out fence is specified.
> > + *
> > + * VM_BIND locking order is as below.
> > + *
> > + * 1) Lock-A: A vm_bind mutex will protect vm_bind lists. This
> > lock
> > is taken in
> > + * vm_bind/vm_unbind ioctl calls, in the execbuf path and
> > while
> > releasing the
> > + * mapping.
> > + *
> > + * In future, when GPU page faults are supported, we can
> > potentially use a
> > + * rwsem instead, so that multiple page fault handlers can
> > take
> > the read
> > + * side lock to lookup the mapping and hence can run in
> > parallel.
> > + * The older execbuf mode of binding do not need this lock.
> > + *
> > + * 2) Lock-B: The object's dma-resv lock will protect i915_vma
> > state
> > and needs
> > + * to be held while binding/unbinding a vma in the async
> > worker
> > and while
> > + * updating dma-resv fence list of an object. Note that
> > private
> > BOs of a VM
> > + * will all share a dma-resv object.
> > + *
> > + * The future system allocator support will use the HMM
> > prescribed locking
> > + * instead.
>
> I don't think the last sentence is relevant for this series. Also,
> are
> there any other mentions for Locks A, B and C? If not, can we ditch
> that naming?
It is taken from design rfc :). Yah, I think better to remove it and
probably the lock names and make it more specific to the
implementation
in this patch series.
Ah, OK, if it's taken from the RFC and is an established naming in
documentation that will remain, then it's fine with me. Perhaps with a
pointer added to that doc that will help the reader.
sounds good.
>
> > + *
> > + * 3) Lock-C: Spinlock/s to protect some of the VM's lists like
> > the
> > list of
> > + * invalidated vmas (due to eviction and userptr
> > invalidation)
> > etc.
> > + */
> > +
> > +struct i915_vma *
> > +i915_gem_vm_bind_lookup_vma(struct i915_address_space *vm, u64
> > va)
>
> Kerneldoc for the extern functions.
>
>
> > +{
> > + struct i915_vma *vma, *temp;
> > +
> > + assert_vm_bind_held(vm);
> > +
> > + vma = i915_vm_bind_it_iter_first(&vm->va, va, va);
> > + /* Working around compiler error, remove later */
>
> Is this still relevant? What compiler error is seen here?
I don't remember what error it was and I am no longer seeing it.
May be it got fixed in latest kernel. We can remove this work around.
>
> > + if (vma)
> > + temp = i915_vm_bind_it_iter_next(vma, va + vma-
> > >size,
> > -1);
> > + return vma;
> > +}
> > +
> > +void i915_gem_vm_bind_remove(struct i915_vma *vma, bool
> > release_obj)
> > +{
> > + assert_vm_bind_held(vma->vm);
> > +
> > + if (!list_empty(&vma->vm_bind_link)) {
> > + list_del_init(&vma->vm_bind_link);
> > + i915_vm_bind_it_remove(vma, &vma->vm->va);
> > +
> > + /* Release object */
> > + if (release_obj)
> > + i915_vma_put(vma);
>
> i915_vma_put() here is confusing. Can we use i915_gem_object_put()
> to
> further make it clear that the persistent vmas actually take a
> reference on the object?
>
makes sense.
> > + }
> > +}
> > +
> > +int i915_gem_vm_unbind_obj(struct i915_address_space *vm,
> > + struct drm_i915_gem_vm_unbind *va)
> > +{
> > + struct drm_i915_gem_object *obj;
> > + struct i915_vma *vma;
> > + int ret;
> > +
> > + va->start = gen8_noncanonical_addr(va->start);
> > + ret = i915_gem_vm_bind_lock_interruptible(vm);
> > + if (ret)
> > + return ret;
> > +
> > + vma = i915_gem_vm_bind_lookup_vma(vm, va->start);
> > + if (!vma) {
> > + ret = -ENOENT;
> > + goto out_unlock;
> > + }
> > +
> > + if (vma->size != va->length)
> > + ret = -EINVAL;
> > + else
> > + i915_gem_vm_bind_remove(vma, false);
> > +
> > +out_unlock:
> > + i915_gem_vm_bind_unlock(vm);
> > + if (ret || !vma)
> > + return ret;
> > +
> > + /* Destroy vma and then release object */
> > + obj = vma->obj;
> > + ret = i915_gem_object_lock(obj, NULL);
> > + if (ret)
> > + return ret;
>
> This call never returns an error and we could GEM_WARN_ON(...), or
> (void) to annotate that the return value is wilfully ignored.
>
makes sense.
> > +
> > + i915_vma_destroy(vma);
> > + i915_gem_object_unlock(obj);
> > + i915_gem_object_put(obj);
> > +
> > + return 0;
> > +}
> > +
> > +static struct i915_vma *vm_bind_get_vma(struct
> > i915_address_space
> > *vm,
> > + struct
> > drm_i915_gem_object
> > *obj,
> > + struct
> > drm_i915_gem_vm_bind
> > *va)
> > +{
> > + struct i915_ggtt_view view;
> > + struct i915_vma *vma;
> > +
> > + va->start = gen8_noncanonical_addr(va->start);
> > + vma = i915_gem_vm_bind_lookup_vma(vm, va->start);
> > + if (vma)
> > + return ERR_PTR(-EEXIST);
> > +
> > + view.type = I915_GGTT_VIEW_PARTIAL;
> > + view.partial.offset = va->offset >> PAGE_SHIFT;
> > + view.partial.size = va->length >> PAGE_SHIFT;
>
> IIRC, this vma view is not handled correctly in the vma code, that
> only
> understands views for ggtt bindings.
>
This patch series extends the partial view to ppgtt also.
Yah, the naming is still i915_ggtt_view, but I am hoping we can fix
the
name in a follow up patch later.
Hmm, I somehow thought that the vma page adjustment was a NOP on ppgtt
and only done on ggtt. But that's indeed not the case. Yes, then this
is ok. We need to remember, though, that if we're going to use the
existing vma async unbinding functionality, we'd need to attach the vma
pages to the vma resource.
Yah. Given that vmas (and hence vma_resource) makes their on sg_table
from that of vma->obj (in this case through intel_partial_pages()),
the 'view' is not relavant after that. So, I think we should be good.
>
> > + vma = i915_vma_instance(obj, vm, &view);
> > + if (IS_ERR(vma))
> > + return vma;
> > +
> > + vma->start = va->start;
> > + vma->last = va->start + va->length - 1;
> > +
> > + return vma;
> > +}
> > +
> > +int i915_gem_vm_bind_obj(struct i915_address_space *vm,
> > + struct drm_i915_gem_vm_bind *va,
> > + struct drm_file *file)
> > +{
> > + struct drm_i915_gem_object *obj;
> > + struct i915_vma *vma = NULL;
> > + struct i915_gem_ww_ctx ww;
> > + u64 pin_flags;
> > + int ret = 0;
> > +
> > + if (!vm->vm_bind_mode)
> > + return -EOPNOTSUPP;
> > +
> > + obj = i915_gem_object_lookup(file, va->handle);
> > + if (!obj)
> > + return -ENOENT;
> > +
> > + if (!va->length ||
> > + !IS_ALIGNED(va->offset | va->length,
> > + i915_gem_object_max_page_size(obj-
> > > mm.placements,
> > + obj-
> > > mm.n_placements)) ||
> > + range_overflows_t(u64, va->offset, va->length, obj-
> > > base.size)) {
> > + ret = -EINVAL;
> > + goto put_obj;
> > + }
> > +
> > + ret = i915_gem_vm_bind_lock_interruptible(vm);
> > + if (ret)
> > + goto put_obj;
> > +
> > + vma = vm_bind_get_vma(vm, obj, va);
> > + if (IS_ERR(vma)) {
> > + ret = PTR_ERR(vma);
> > + goto unlock_vm;
> > + }
> > +
> > + i915_gem_ww_ctx_init(&ww, true);
> > + pin_flags = va->start | PIN_OFFSET_FIXED | PIN_USER;
> > +retry:
> > + ret = i915_gem_object_lock(vma->obj, &ww);
> > + if (ret)
> > + goto out_ww;
> > +
> > + ret = i915_vma_pin_ww(vma, &ww, 0, 0, pin_flags);
> > + if (ret)
> > + goto out_ww;
> > +
> > + /* Make it evictable */
> > + __i915_vma_unpin(vma);
>
> A considerable effort has been put into avoiding short term vma
> pins in
> i915. We should add an interface like i915_vma_bind_ww() that
> avoids
> the pin altoghether.
Currently in i915 driver VA managment and device page table bindings
are tightly coupled. i915_vma_pin_ww() does the both VA allocation
and
biding. And we also interpret VA being allocated (drm_mm node
allocated)
also as vma is bound.
Decoupling it would be ideal but I think it needs to be carefully
done
in a separate patch series to not cause any regression.
So the idea would be not to decouple these, but to just avoid pinning
the vma in the process.
Well, we need the i915_vma_insert() as well (not just the bind).
I think the best and the only option we have today is i915_vma_pin_ww().
I think that slicing it falls into the bucket of decoupling as I mentioned
above. May be we can take this on later?
Niranjana
>
> > +
> > + list_add_tail(&vma->vm_bind_link, &vm->vm_bound_list);
> > + i915_vm_bind_it_insert(vma, &vm->va);
> > +
> > + /* Hold object reference until vm_unbind */
> > + i915_gem_object_get(vma->obj);
> > +out_ww:
> > + if (ret == -EDEADLK) {
> > + ret = i915_gem_ww_ctx_backoff(&ww);
> > + if (!ret)
> > + goto retry;
> > + }
> > +
> > + if (ret)
> > + i915_vma_destroy(vma);
> > +
> > + i915_gem_ww_ctx_fini(&ww);
>
> Could use for_i915_gem_ww()?
>
Yah, I think it is a better idea to use it.
> > +unlock_vm:
> > + i915_gem_vm_bind_unlock(vm);
> > +put_obj:
> > + i915_gem_object_put(obj);
> > + return ret;
> > +}
> > diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c
> > b/drivers/gpu/drm/i915/gt/intel_gtt.c
> > index b67831833c9a..135dc4a76724 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_gtt.c
> > +++ b/drivers/gpu/drm/i915/gt/intel_gtt.c
> > @@ -176,6 +176,8 @@ int i915_vm_lock_objects(struct
> > i915_address_space *vm,
> > void i915_address_space_fini(struct i915_address_space *vm)
> > {
> > drm_mm_takedown(&vm->mm);
> > + GEM_BUG_ON(!RB_EMPTY_ROOT(&vm->va.rb_root));
> > + mutex_destroy(&vm->vm_bind_lock);
> > }
> >
> > /**
> > @@ -282,6 +284,11 @@ void i915_address_space_init(struct
> > i915_address_space *vm, int subclass)
> >
> > INIT_LIST_HEAD(&vm->bound_list);
> > INIT_LIST_HEAD(&vm->unbound_list);
> > +
> > + vm->va = RB_ROOT_CACHED;
> > + INIT_LIST_HEAD(&vm->vm_bind_list);
> > + INIT_LIST_HEAD(&vm->vm_bound_list);
> > + mutex_init(&vm->vm_bind_lock);
> > }
> >
> > void *__px_vaddr(struct drm_i915_gem_object *p)
> > diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h
> > b/drivers/gpu/drm/i915/gt/intel_gtt.h
> > index c812aa9708ae..d4a6ce65251d 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_gtt.h
> > +++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
> > @@ -259,6 +259,15 @@ struct i915_address_space {
> > */
> > struct list_head unbound_list;
> >
> > + /**
> > + * List of VM_BIND objects.
> > + */
>
> Proper kerneldoc + intel locking guidelines comments, please.
>
> > + struct mutex vm_bind_lock; /* Protects vm_bind lists */
> > + struct list_head vm_bind_list;
> > + struct list_head vm_bound_list;
> > + /* va tree of persistent vmas */
> > + struct rb_root_cached va;
> > +
> > /* Global GTT */
> > bool is_ggtt:1;
> >
> > diff --git a/drivers/gpu/drm/i915/i915_driver.c
> > b/drivers/gpu/drm/i915/i915_driver.c
> > index ccf990dfd99b..776ab7844f60 100644
> > --- a/drivers/gpu/drm/i915/i915_driver.c
> > +++ b/drivers/gpu/drm/i915/i915_driver.c
> > @@ -68,6 +68,7 @@
> > #include "gem/i915_gem_ioctls.h"
> > #include "gem/i915_gem_mman.h"
> > #include "gem/i915_gem_pm.h"
> > +#include "gem/i915_gem_vm_bind.h"
> > #include "gt/intel_gt.h"
> > #include "gt/intel_gt_pm.h"
> > #include "gt/intel_rc6.h"
> > @@ -1783,13 +1784,16 @@ static int i915_gem_vm_bind_ioctl(struct
> > drm_device *dev, void *data,
> > {
> > struct drm_i915_gem_vm_bind *args = data;
> > struct i915_address_space *vm;
> > + int ret;
> >
> > vm = i915_gem_vm_lookup(file->driver_priv, args->vm_id);
> > if (unlikely(!vm))
> > return -ENOENT;
> >
> > + ret = i915_gem_vm_bind_obj(vm, args, file);
> > +
> > i915_vm_put(vm);
> > - return -EINVAL;
> > + return ret;
> > }
> >
> > static int i915_gem_vm_unbind_ioctl(struct drm_device *dev, void
> > *data,
> > @@ -1797,13 +1801,16 @@ static int
> > i915_gem_vm_unbind_ioctl(struct
> > drm_device *dev, void *data,
> > {
> > struct drm_i915_gem_vm_unbind *args = data;
> > struct i915_address_space *vm;
> > + int ret;
> >
> > vm = i915_gem_vm_lookup(file->driver_priv, args->vm_id);
> > if (unlikely(!vm))
> > return -ENOENT;
> >
> > + ret = i915_gem_vm_unbind_obj(vm, args);
> > +
> > i915_vm_put(vm);
> > - return -EINVAL;
> > + return ret;
> > }
> >
> > static const struct drm_ioctl_desc i915_ioctls[] = {
> > diff --git a/drivers/gpu/drm/i915/i915_vma.c
> > b/drivers/gpu/drm/i915/i915_vma.c
> > index 43339ecabd73..d324e29cef0a 100644
> > --- a/drivers/gpu/drm/i915/i915_vma.c
> > +++ b/drivers/gpu/drm/i915/i915_vma.c
> > @@ -29,6 +29,7 @@
> > #include "display/intel_frontbuffer.h"
> > #include "gem/i915_gem_lmem.h"
> > #include "gem/i915_gem_tiling.h"
> > +#include "gem/i915_gem_vm_bind.h"
> > #include "gt/intel_engine.h"
> > #include "gt/intel_engine_heartbeat.h"
> > #include "gt/intel_gt.h"
> > @@ -234,6 +235,7 @@ vma_create(struct drm_i915_gem_object *obj,
> > spin_unlock(&obj->vma.lock);
> > mutex_unlock(&vm->mutex);
> >
> > + INIT_LIST_HEAD(&vma->vm_bind_link);
> > return vma;
> >
> > err_unlock:
> > @@ -290,7 +292,6 @@ i915_vma_instance(struct drm_i915_gem_object
> > *obj,
> > {
> > struct i915_vma *vma;
> >
> > - GEM_BUG_ON(view && !i915_is_ggtt_or_dpt(vm));
> > GEM_BUG_ON(!kref_read(&vm->ref));
> >
> > spin_lock(&obj->vma.lock);
> > @@ -1660,6 +1661,10 @@ static void release_references(struct
> > i915_vma
> > *vma, bool vm_ddestroy)
> >
> > spin_unlock(&obj->vma.lock);
> >
> > + i915_gem_vm_bind_lock(vma->vm);
> > + i915_gem_vm_bind_remove(vma, true);
> > + i915_gem_vm_bind_unlock(vma->vm);
> > +
>
> The vm might be destroyed at this point already.
>
Ah, due to async vma resource release...
> From what I understand we can destroy the vma from three call
> sites:
> 1) VM_UNBIND -> The vma has already been removed from the vm_bind
> address space,
> 2) object destruction -> since the vma has an object reference
> while in
> the vm_bind address space, it must also have been removed from the
> address space if called from object destruction.
> 3) vm destruction. Suggestion is to call VM_UNBIND from under the
> vm_bind lock early in vm destruction.
>
> Then the above added code can be removed and replaced with an
> assert
> that the vm_bind address space RB_NODE is indeed empty.
>
...yah, makes sense to move this code to early in VM destruction than
here.
Niranjana
>
> > spin_lock_irq(>->closed_lock);
> > __i915_vma_remove_closed(vma);
> > spin_unlock_irq(>->closed_lock);
> > diff --git a/drivers/gpu/drm/i915/i915_vma.h
> > b/drivers/gpu/drm/i915/i915_vma.h
> > index 88ca0bd9c900..dcb49f79ff7e 100644
> > --- a/drivers/gpu/drm/i915/i915_vma.h
> > +++ b/drivers/gpu/drm/i915/i915_vma.h
> > @@ -164,8 +164,6 @@ i915_vma_compare(struct i915_vma *vma,
> > {
> > ptrdiff_t cmp;
> >
> > - GEM_BUG_ON(view && !i915_is_ggtt_or_dpt(vm));
> > -
> > cmp = ptrdiff(vma->vm, vm);
> > if (cmp)
> > return cmp;
> > diff --git a/drivers/gpu/drm/i915/i915_vma_types.h
> > b/drivers/gpu/drm/i915/i915_vma_types.h
> > index be6e028c3b57..b6d179bdbfa0 100644
> > --- a/drivers/gpu/drm/i915/i915_vma_types.h
> > +++ b/drivers/gpu/drm/i915/i915_vma_types.h
> > @@ -289,6 +289,14 @@ struct i915_vma {
> > /** This object's place on the active/inactive lists */
> > struct list_head vm_link;
> >
> > + struct list_head vm_bind_link; /* Link in persistent VMA
> > list
> > */
> > +
> > + /** Interval tree structures for persistent vma */
>
> Proper kerneldoc.
>
> > + struct rb_node rb;
> > + u64 start;
> > + u64 last;
> > + u64 __subtree_last;
> > +
> > struct list_head obj_link; /* Link in the object's VMA
> > list
> > */
> > struct rb_node obj_node;
> > struct hlist_node obj_hash;
>
> Thanks,
> Thomas
>
