On Tue, Sep 14, 2021 at 03:04:59PM +1000, Dave Airlie wrote:
On Tue, 14 Sept 2021 at 14:55, Matthew Brost matthew.brost@intel.com wrote:
From: Venkata Sandeep Dhanalakota venkata.s.dhanalakota@intel.com
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?
I believe this function is only called during driver load (inherently one thread) or during a GT reset (protected by reset mutex) so at most 1 thread can be executing this code at once, thus it is safe to use a global dummy vma in this function.
Matt
Dave.
Cc: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Signed-off-by: Venkata Sandeep Dhanalakota venkata.s.dhanalakota@intel.com Signed-off-by: Matthew Brost matthew.brost@intel.com Reviewed-by: Matthew Brost matthew.brost@intel.com
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