On Tue, 14 Sept 2021 at 14:55, Matthew Brost <matthew.brost@xxxxxxxxx> wrote:
>
> From: Venkata Sandeep Dhanalakota <venkata.s.dhanalakota@xxxxxxxxx>
>
> Defining vma on stack can cause stack overflow, if
> vma gets populated with new fields.
Is there some higher level locking stopping that from getting trashed?
or a guarantee that uc_fw_bind_ggtt is only entered by one thread at a
time?
Dave.
>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
> Signed-off-by: Venkata Sandeep Dhanalakota <venkata.s.dhanalakota@xxxxxxxxx>
> Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
> Reviewed-by: Matthew Brost <matthew.brost@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c | 18 +++++++++---------
> drivers/gpu/drm/i915/gt/uc/intel_uc_fw.h | 2 ++
> 2 files changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
> index 3a16d08608a5..f632dbd32b42 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
> @@ -413,20 +413,20 @@ static void uc_fw_bind_ggtt(struct intel_uc_fw *uc_fw)
> {
> struct drm_i915_gem_object *obj = uc_fw->obj;
> struct i915_ggtt *ggtt = __uc_fw_to_gt(uc_fw)->ggtt;
> - struct i915_vma dummy = {
> - .node.start = uc_fw_ggtt_offset(uc_fw),
> - .node.size = obj->base.size,
> - .pages = obj->mm.pages,
> - .vm = &ggtt->vm,
> - };
> + struct i915_vma *dummy = &uc_fw->dummy;
> +
> + dummy->node.start = uc_fw_ggtt_offset(uc_fw);
> + dummy->node.size = obj->base.size;
> + dummy->pages = obj->mm.pages;
> + dummy->vm = &ggtt->vm;
>
> GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
> - GEM_BUG_ON(dummy.node.size > ggtt->uc_fw.size);
> + GEM_BUG_ON(dummy->node.size > ggtt->uc_fw.size);
>
> /* uc_fw->obj cache domains were not controlled across suspend */
> - drm_clflush_sg(dummy.pages);
> + drm_clflush_sg(dummy->pages);
>
> - ggtt->vm.insert_entries(&ggtt->vm, &dummy, I915_CACHE_NONE, 0);
> + ggtt->vm.insert_entries(&ggtt->vm, dummy, I915_CACHE_NONE, 0);
> }
>
> static void uc_fw_unbind_ggtt(struct intel_uc_fw *uc_fw)
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.h b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.h
> index 99bb1fe1af66..693cc0ebcd63 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.h
> @@ -10,6 +10,7 @@
> #include "intel_uc_fw_abi.h"
> #include "intel_device_info.h"
> #include "i915_gem.h"
> +#include "i915_vma.h"
>
> struct drm_printer;
> struct drm_i915_private;
> @@ -75,6 +76,7 @@ struct intel_uc_fw {
> bool user_overridden;
> size_t size;
> struct drm_i915_gem_object *obj;
> + struct i915_vma dummy;
>
> /*
> * The firmware build process will generate a version header file with major and
> --
> 2.32.0
>
