Re: [PATCH] drm/radeon/kms: forbid big bo allocation (fdo 31708) v2

On Fre, 2010-11-19 at 16:34 -0500, jglisse@redhat.com wrote:

From: Jerome Glisse jglisse@redhat.com

Forbid allocating buffer bigger than visible VRAM or GTT, also properly set lpfn field.

v2 - use max macro

• silence warning

Signed-off-by: Jerome Glisse jglisse@redhat.com

drivers/gpu/drm/radeon/radeon_object.c | 34 ++++++++++++++++++++++++++----- 1 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c index 1d06774..c2fa64c 100644 --- a/drivers/gpu/drm/radeon/radeon_object.c +++ b/drivers/gpu/drm/radeon/radeon_object.c @@ -69,18 +69,28 @@ void radeon_ttm_placement_from_domain(struct radeon_bo *rbo, u32 domain) u32 c = 0;

rbo->placement.fpfn = 0;

• rbo->placement.lpfn = rbo->rdev->mc.active_vram_size >> PAGE_SHIFT;

• rbo->placement.lpfn = 0; rbo->placement.placement = rbo->placements; rbo->placement.busy_placement = rbo->placements;

• if (domain & RADEON_GEM_DOMAIN_VRAM)

• if (domain & RADEON_GEM_DOMAIN_VRAM) {

• rbo->placement.lpfn = max((unsigned)rbo->placement.lpfn, (unsigned)rbo->rdev->mc.active_vram_size >> PAGE_SHIFT);
  

  rbo->placements[c++] = TTM_PL_FLAG_WC | TTM_PL_FLAG_UNCACHED | TTM_PL_FLAG_VRAM;

• if (domain & RADEON_GEM_DOMAIN_GTT)

• }
• if (domain & RADEON_GEM_DOMAIN_GTT) {

• rbo->placement.lpfn = max((unsigned)rbo->placement.lpfn, (unsigned)rbo->rdev->mc.gtt_size >> PAGE_SHIFT);
  

  rbo->placements[c++] = TTM_PL_MASK_CACHING | TTM_PL_FLAG_TT;

• if (domain & RADEON_GEM_DOMAIN_CPU)

• }
• if (domain & RADEON_GEM_DOMAIN_CPU) {

• /* 4G limit for CPU domain */
  

• rbo->placement.lpfn = max(rbo->placement.lpfn, 0xFFFFFFFF >> PAGE_SHIFT);
  

  rbo->placements[c++] = TTM_PL_MASK_CACHING | TTM_PL_FLAG_SYSTEM;

• if (!c)

• }
• if (!c) {

• /* 4G limit for CPU domain */
  

• rbo->placement.lpfn = max(rbo->placement.lpfn, 0xFFFFFFFF >> PAGE_SHIFT);
  

  rbo->placements[c++] = TTM_PL_MASK_CACHING | TTM_PL_FLAG_SYSTEM;
• }

I don't think taxing the maximum is the right thing to do: If domain is (RADEON_GEM_DOMAIN_VRAM | RADEON_GEM_DOMAIN_GTT) and VRAM doesn't happen to be the same size as GTT, lpfn will end up larger than one of them.

AFAICT radeon_ttm_placement_from_domain() should just set lpfn to 0 (i.e. unrestricted), the callers that need it to be non-0 already set it afterwards.

Out of curiosity, where does the 4G limit come from?

@@ -104,6 +115,17 @@ int radeon_bo_create(struct radeon_device *rdev, struct drm_gem_object *gobj, } *bo_ptr = NULL;

• /* maximun bo size is the minimun btw visible vram and gtt size */
• max_size = rdev->mc.visible_vram_size;
• if (max_size > rdev->mc.gtt_size) {

• max_size = rdev->mc.gtt_size;
  

• }

max_size = min(rdev->mc.visible_vram_size, rdev->mc.gtt_size);

Except I think this should actually be max(...).

• if ((page_align << PAGE_SHIFT) >= max_size) {

• printk(KERN_WARNING "%s:%d alloc size %ldM bigger than %ldMb limit\n",
  

• 	__func__, __LINE__, page_align  >> (20 - PAGE_SHIFT), max_size >> 20);
  

• return -ENOMEM;
  

• }

Maybe this should be rate-limited, or userspace can spam dmesg.