| Message ID | 20221130235805.221010-4-andi.shyti@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add guard padding around i915_vma | expand |
On 30/11/2022 23:58, Andi Shyti wrote: > From: Chris Wilson <chris@chris-wilson.co.uk> > > Introduce the concept of padding the i915_vma with guard pages before > and after. The major consequence is that all ordinary uses of i915_vma > must use i915_vma_offset/i915_vma_size and not i915_vma.node.start/size > directly, as the drm_mm_node will include the guard pages that surround > our object. > > The biggest connundrum is how exactly to mix requesting a fixed address > with guard pages, particularly through the existing uABI. The user does > not know about guard pages, so such must be transparent to the user, and > so the execobj.offset must be that of the object itself excluding the > guard. So a PIN_OFFSET_FIXED must then be exclusive of the guard pages. > The caveat is that some placements will be impossible with guard pages, > as wrap arounds need to be avoided, and the vma itself will require a > larger node. We must not report EINVAL but ENOSPC as these are unavailable > locations within the GTT rather than conflicting user requirements. > > In the next patch, we start using guard pages for scanout objects. While > these are limited to GGTT vma, on a few platforms these vma (or at least > an alias of the vma) is shared with userspace, so we may leak the > existence of such guards if we are not careful to ensure that the > execobj.offset is transparent and excludes the guards. (On such platforms > like ivb, without full-ppgtt, userspace has to use relocations so the > presence of more untouchable regions within its GTT such be of no further > issue.) > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > Signed-off-by: Tejas Upadhyay <tejaskumarx.surendrakumar.upadhyay@intel.com> > Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> > Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com> > --- > drivers/gpu/drm/i915/gt/intel_ggtt.c | 14 ++++++--- > drivers/gpu/drm/i915/i915_gem_gtt.h | 3 +- > drivers/gpu/drm/i915/i915_vma.c | 40 +++++++++++++++++++----- > drivers/gpu/drm/i915/i915_vma.h | 5 +-- > drivers/gpu/drm/i915/i915_vma_resource.c | 4 +-- > drivers/gpu/drm/i915/i915_vma_resource.h | 7 ++++- > drivers/gpu/drm/i915/i915_vma_types.h | 1 + > 7 files changed, 57 insertions(+), 17 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c > index 7644738b9cdbe..784d4a8c43ba9 100644 > --- a/drivers/gpu/drm/i915/gt/intel_ggtt.c > +++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c > @@ -296,8 +296,11 @@ static void gen8_ggtt_insert_entries(struct i915_address_space *vm, > */ > > gte = (gen8_pte_t __iomem *)ggtt->gsm; > - gte += vma_res->start / I915_GTT_PAGE_SIZE; > - end = gte + vma_res->node_size / I915_GTT_PAGE_SIZE; > + gte += (vma_res->start - vma_res->guard) / I915_GTT_PAGE_SIZE; > + end = gte + vma_res->guard / I915_GTT_PAGE_SIZE; > + while (gte < end) > + gen8_set_pte(gte++, vm->scratch[0]->encode); > + end += (vma_res->node_size + vma_res->guard) / I915_GTT_PAGE_SIZE; > > for_each_sgt_daddr(addr, iter, vma_res->bi.pages) > gen8_set_pte(gte++, pte_encode | addr); > @@ -347,9 +350,12 @@ static void gen6_ggtt_insert_entries(struct i915_address_space *vm, > dma_addr_t addr; > > gte = (gen6_pte_t __iomem *)ggtt->gsm; > - gte += vma_res->start / I915_GTT_PAGE_SIZE; > - end = gte + vma_res->node_size / I915_GTT_PAGE_SIZE; > + gte += (vma_res->start - vma_res->guard) / I915_GTT_PAGE_SIZE; > > + end = gte + vma_res->guard / I915_GTT_PAGE_SIZE; > + while (gte < end) > + iowrite32(vm->scratch[0]->encode, gte++); > + end += (vma_res->node_size + vma_res->guard) / I915_GTT_PAGE_SIZE; > for_each_sgt_daddr(addr, iter, vma_res->bi.pages) > iowrite32(vm->pte_encode(addr, level, flags), gte++); > GEM_BUG_ON(gte > end); > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h > index 8c2f57eb5ddaa..2434197830523 100644 > --- a/drivers/gpu/drm/i915/i915_gem_gtt.h > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.h > @@ -44,7 +44,8 @@ int i915_gem_gtt_insert(struct i915_address_space *vm, > #define PIN_HIGH BIT_ULL(5) > #define PIN_OFFSET_BIAS BIT_ULL(6) > #define PIN_OFFSET_FIXED BIT_ULL(7) > -#define PIN_VALIDATE BIT_ULL(8) /* validate placement only, no need to call unpin() */ > +#define PIN_OFFSET_GUARD BIT_ULL(8) > +#define PIN_VALIDATE BIT_ULL(9) /* validate placement only, no need to call unpin() */ > > #define PIN_GLOBAL BIT_ULL(10) /* I915_VMA_GLOBAL_BIND */ > #define PIN_USER BIT_ULL(11) /* I915_VMA_LOCAL_BIND */ > diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c > index fefee5fef38d3..3877847179710 100644 > --- a/drivers/gpu/drm/i915/i915_vma.c > +++ b/drivers/gpu/drm/i915/i915_vma.c > @@ -419,7 +419,7 @@ i915_vma_resource_init_from_vma(struct i915_vma_resource *vma_res, > obj->mm.rsgt, i915_gem_object_is_readonly(obj), > i915_gem_object_is_lmem(obj), obj->mm.region, > vma->ops, vma->private, __i915_vma_offset(vma), > - __i915_vma_size(vma), vma->size); > + __i915_vma_size(vma), vma->size, vma->guard); > } > > /** > @@ -677,6 +677,10 @@ bool i915_vma_misplaced(const struct i915_vma *vma, > i915_vma_offset(vma) != (flags & PIN_OFFSET_MASK)) > return true; > > + if (flags & PIN_OFFSET_GUARD && > + vma->guard < (flags & PIN_OFFSET_MASK)) > + return true; > + > return false; > } > > @@ -749,15 +753,16 @@ static int > i915_vma_insert(struct i915_vma *vma, struct i915_gem_ww_ctx *ww, > u64 size, u64 alignment, u64 flags) > { > - unsigned long color; > + unsigned long color, guard; > u64 start, end; > int ret; > > GEM_BUG_ON(i915_vma_is_bound(vma, I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND)); > GEM_BUG_ON(drm_mm_node_allocated(&vma->node)); > + GEM_BUG_ON(hweight64(flags & (PIN_OFFSET_GUARD | PIN_OFFSET_FIXED | PIN_OFFSET_BIAS)) > 1); > > size = max(size, vma->size); > - alignment = max(alignment, vma->display_alignment); > + alignment = max_t(typeof(alignment), alignment, vma->display_alignment); > if (flags & PIN_MAPPABLE) { > size = max_t(typeof(size), size, vma->fence_size); > alignment = max_t(typeof(alignment), > @@ -768,8 +773,17 @@ i915_vma_insert(struct i915_vma *vma, struct i915_gem_ww_ctx *ww, > GEM_BUG_ON(!IS_ALIGNED(alignment, I915_GTT_MIN_ALIGNMENT)); > GEM_BUG_ON(!is_power_of_2(alignment)); > > + guard = vma->guard; /* retain guard across rebinds */ > + if (flags & PIN_OFFSET_GUARD) { > + GEM_BUG_ON(overflows_type(flags & PIN_OFFSET_MASK, u32)); > + guard = max_t(u32, guard, flags & PIN_OFFSET_MASK); > + } > + roundup(guard, BIT(vma->vm->scratch_order + PAGE_SHIFT)); roundup = ? Lets have a comment here as well. /* * Be efficient with PTE use by using the native size for the guard. */ Would that be accurate? > + > start = flags & PIN_OFFSET_BIAS ? flags & PIN_OFFSET_MASK : 0; > GEM_BUG_ON(!IS_ALIGNED(start, I915_GTT_PAGE_SIZE)); > + /* We need to be sure we do not ecceed the va area */ > + GEM_BUG_ON(2 * guard > end); "exceed" but haven't we said this is not needed? Regards, Tvrtko > > end = vma->vm->total; > if (flags & PIN_MAPPABLE) > @@ -780,11 +794,12 @@ i915_vma_insert(struct i915_vma *vma, struct i915_gem_ww_ctx *ww, > > alignment = max(alignment, i915_vm_obj_min_alignment(vma->vm, vma->obj)); > > - /* If binding the object/GGTT view requires more space than the entire > + /* > + * If binding the object/GGTT view requires more space than the entire > * aperture has, reject it early before evicting everything in a vain > * attempt to find space. > */ > - if (size > end) { > + if (size > end - 2 * guard) { > drm_dbg(&to_i915(vma->obj->base.dev)->drm, > "Attempting to bind an object larger than the aperture: request=%llu > %s aperture=%llu\n", > size, flags & PIN_MAPPABLE ? "mappable" : "total", end); > @@ -801,13 +816,23 @@ i915_vma_insert(struct i915_vma *vma, struct i915_gem_ww_ctx *ww, > if (!IS_ALIGNED(offset, alignment) || > range_overflows(offset, size, end)) > return -EINVAL; > + /* > + * The caller knows not of the guard added by others and > + * requests for the offset of the start of its buffer > + * to be fixed, which may not be the same as the position > + * of the vma->node due to the guard pages. > + */ > + if (offset < guard || offset + size > end - guard) > + return -ENOSPC; > > ret = i915_gem_gtt_reserve(vma->vm, ww, &vma->node, > - size, offset, color, > - flags); > + size + 2 * guard, > + offset - guard, > + color, flags); > if (ret) > return ret; > } else { > + size += 2 * guard; > /* > * We only support huge gtt pages through the 48b PPGTT, > * however we also don't want to force any alignment for > @@ -855,6 +880,7 @@ i915_vma_insert(struct i915_vma *vma, struct i915_gem_ww_ctx *ww, > GEM_BUG_ON(!i915_gem_valid_gtt_space(vma, color)); > > list_move_tail(&vma->vm_link, &vma->vm->bound_list); > + vma->guard = guard; > > return 0; > } > diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h > index 3fd4512b1f65f..ed5c9d682a1b2 100644 > --- a/drivers/gpu/drm/i915/i915_vma.h > +++ b/drivers/gpu/drm/i915/i915_vma.h > @@ -128,7 +128,7 @@ static inline bool i915_vma_is_closed(const struct i915_vma *vma) > /* Internal use only. */ > static inline u64 __i915_vma_size(const struct i915_vma *vma) > { > - return vma->node.size; > + return vma->node.size - 2 * vma->guard; > } > > /** > @@ -150,7 +150,8 @@ static inline u64 i915_vma_size(const struct i915_vma *vma) > /* Internal use only. */ > static inline u64 __i915_vma_offset(const struct i915_vma *vma) > { > - return vma->node.start; > + /* The actual start of the vma->pages is after the guard pages. */ > + return vma->node.start + vma->guard; > } > > /** > diff --git a/drivers/gpu/drm/i915/i915_vma_resource.c b/drivers/gpu/drm/i915/i915_vma_resource.c > index de1342dbfa128..6ba7a7feceba1 100644 > --- a/drivers/gpu/drm/i915/i915_vma_resource.c > +++ b/drivers/gpu/drm/i915/i915_vma_resource.c > @@ -34,8 +34,8 @@ static struct kmem_cache *slab_vma_resources; > * and removal of fences increases as O(ln(pending_unbinds)) instead of > * O(1) for a single fence without interval tree. > */ > -#define VMA_RES_START(_node) ((_node)->start) > -#define VMA_RES_LAST(_node) ((_node)->start + (_node)->node_size - 1) > +#define VMA_RES_START(_node) ((_node)->start - (_node)->guard) > +#define VMA_RES_LAST(_node) ((_node)->start + (_node)->node_size + (_node)->guard - 1) > INTERVAL_TREE_DEFINE(struct i915_vma_resource, rb, > u64, __subtree_last, > VMA_RES_START, VMA_RES_LAST, static, vma_res_itree); > diff --git a/drivers/gpu/drm/i915/i915_vma_resource.h b/drivers/gpu/drm/i915/i915_vma_resource.h > index 54edf3739ca0b..c1864e3d0b43e 100644 > --- a/drivers/gpu/drm/i915/i915_vma_resource.h > +++ b/drivers/gpu/drm/i915/i915_vma_resource.h > @@ -57,6 +57,7 @@ struct i915_page_sizes { > * @node_size: Size of the allocated range manager node with padding > * subtracted. > * @vma_size: Bind size. > + * @guard: The size of guard area preceding and trailing the bind. > * @page_sizes_gtt: Resulting page sizes from the bind operation. > * @bound_flags: Flags indicating binding status. > * @allocated: Backend private data. TODO: Should move into @private. > @@ -115,6 +116,7 @@ struct i915_vma_resource { > u64 start; > u64 node_size; > u64 vma_size; > + u32 guard; > u32 page_sizes_gtt; > > u32 bound_flags; > @@ -179,6 +181,7 @@ static inline void i915_vma_resource_put(struct i915_vma_resource *vma_res) > * @start: Offset into the address space of bind range start after padding. > * @node_size: Size of the allocated range manager node minus padding. > * @size: Bind size. > + * @guard: The size of the guard area preceding and trailing the bind. > * > * Initializes a vma resource allocated using i915_vma_resource_alloc(). > * The reason for having separate allocate and initialize function is that > @@ -197,7 +200,8 @@ static inline void i915_vma_resource_init(struct i915_vma_resource *vma_res, > void *private, > u64 start, > u64 node_size, > - u64 size) > + u64 size, > + u32 guard) > { > __i915_vma_resource_init(vma_res); > vma_res->vm = vm; > @@ -215,6 +219,7 @@ static inline void i915_vma_resource_init(struct i915_vma_resource *vma_res, > vma_res->start = start; > vma_res->node_size = node_size; > vma_res->vma_size = size; > + vma_res->guard = guard; > } > > static inline void i915_vma_resource_fini(struct i915_vma_resource *vma_res) > diff --git a/drivers/gpu/drm/i915/i915_vma_types.h b/drivers/gpu/drm/i915/i915_vma_types.h > index 0375812792b9c..77fda2244d161 100644 > --- a/drivers/gpu/drm/i915/i915_vma_types.h > +++ b/drivers/gpu/drm/i915/i915_vma_types.h > @@ -202,6 +202,7 @@ struct i915_vma { > /* mmap-offset associated with fencing for this vma */ > struct i915_mmap_offset *mmo; > > + u32 guard; /* padding allocated around vma->pages within the node */ > u32 fence_size; > u32 fence_alignment; > u32 display_alignment;
Hi Tvrtko, [...] > > @@ -768,8 +773,17 @@ i915_vma_insert(struct i915_vma *vma, struct i915_gem_ww_ctx *ww, > > GEM_BUG_ON(!IS_ALIGNED(alignment, I915_GTT_MIN_ALIGNMENT)); > > GEM_BUG_ON(!is_power_of_2(alignment)); > > + guard = vma->guard; /* retain guard across rebinds */ > > + if (flags & PIN_OFFSET_GUARD) { > > + GEM_BUG_ON(overflows_type(flags & PIN_OFFSET_MASK, u32)); > > + guard = max_t(u32, guard, flags & PIN_OFFSET_MASK); > > + } > > + roundup(guard, BIT(vma->vm->scratch_order + PAGE_SHIFT)); > > roundup = ? ehehe... yes, please ignore, that's some copy/paste error during the rebase... > Lets have a comment here as well. > > /* > * Be efficient with PTE use by using the native size for the guard. > */ > > Would that be accurate? and I also forgot the update of my previous comment... yours is quite accurate. > > + > > start = flags & PIN_OFFSET_BIAS ? flags & PIN_OFFSET_MASK : 0; > > GEM_BUG_ON(!IS_ALIGNED(start, I915_GTT_PAGE_SIZE)); > > + /* We need to be sure we do not ecceed the va area */ > > + GEM_BUG_ON(2 * guard > end); > > "exceed" but haven't we said this is not needed? I wrote it in the cover letter. I had an offline chat with Chris and he was keen to have this check not only for overflow protection but also for a documentation purpose so that the reader knows better about the size and usage of the guard. Does it make sense? Thanks a lot! Andi
On 01/12/2022 10:45, Andi Shyti wrote: > Hi Tvrtko, > > [...] > >>> @@ -768,8 +773,17 @@ i915_vma_insert(struct i915_vma *vma, struct i915_gem_ww_ctx *ww, >>> GEM_BUG_ON(!IS_ALIGNED(alignment, I915_GTT_MIN_ALIGNMENT)); >>> GEM_BUG_ON(!is_power_of_2(alignment)); >>> + guard = vma->guard; /* retain guard across rebinds */ >>> + if (flags & PIN_OFFSET_GUARD) { >>> + GEM_BUG_ON(overflows_type(flags & PIN_OFFSET_MASK, u32)); >>> + guard = max_t(u32, guard, flags & PIN_OFFSET_MASK); >>> + } >>> + roundup(guard, BIT(vma->vm->scratch_order + PAGE_SHIFT)); >> >> roundup = ? > > ehehe... yes, please ignore, that's some copy/paste error during > the rebase... > >> Lets have a comment here as well. >> >> /* >> * Be efficient with PTE use by using the native size for the guard. >> */ >> >> Would that be accurate? > > and I also forgot the update of my previous comment... yours is > quite accurate. > >>> + >>> start = flags & PIN_OFFSET_BIAS ? flags & PIN_OFFSET_MASK : 0; >>> GEM_BUG_ON(!IS_ALIGNED(start, I915_GTT_PAGE_SIZE)); >>> + /* We need to be sure we do not ecceed the va area */ >>> + GEM_BUG_ON(2 * guard > end); >> >> "exceed" but haven't we said this is not needed? > > I wrote it in the cover letter. I had an offline chat with Chris > and he was keen to have this check not only for overflow > protection but also for a documentation purpose so that the > reader knows better about the size and usage of the guard. > > Does it make sense? Not to me really, I have no idea how could anyone ever end up with guard size of half+ of GGTT. And the total 2 * guard + size is checked and rejected already. So I have no idea what it is supposed to be documenting. GEM_BUG_ON suggests really bad things would happen if that was passed in, like something would be incorrectly calculated. If that is not the case and things would just safely fail then it is just confusing to have it. Regards, Tvrtko
diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c index 7644738b9cdbe..784d4a8c43ba9 100644 --- a/drivers/gpu/drm/i915/gt/intel_ggtt.c +++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c @@ -296,8 +296,11 @@ static void gen8_ggtt_insert_entries(struct i915_address_space *vm, */ gte = (gen8_pte_t __iomem *)ggtt->gsm; - gte += vma_res->start / I915_GTT_PAGE_SIZE; - end = gte + vma_res->node_size / I915_GTT_PAGE_SIZE; + gte += (vma_res->start - vma_res->guard) / I915_GTT_PAGE_SIZE; + end = gte + vma_res->guard / I915_GTT_PAGE_SIZE; + while (gte < end) + gen8_set_pte(gte++, vm->scratch[0]->encode); + end += (vma_res->node_size + vma_res->guard) / I915_GTT_PAGE_SIZE; for_each_sgt_daddr(addr, iter, vma_res->bi.pages) gen8_set_pte(gte++, pte_encode | addr); @@ -347,9 +350,12 @@ static void gen6_ggtt_insert_entries(struct i915_address_space *vm, dma_addr_t addr; gte = (gen6_pte_t __iomem *)ggtt->gsm; - gte += vma_res->start / I915_GTT_PAGE_SIZE; - end = gte + vma_res->node_size / I915_GTT_PAGE_SIZE; + gte += (vma_res->start - vma_res->guard) / I915_GTT_PAGE_SIZE; + end = gte + vma_res->guard / I915_GTT_PAGE_SIZE; + while (gte < end) + iowrite32(vm->scratch[0]->encode, gte++); + end += (vma_res->node_size + vma_res->guard) / I915_GTT_PAGE_SIZE; for_each_sgt_daddr(addr, iter, vma_res->bi.pages) iowrite32(vm->pte_encode(addr, level, flags), gte++); GEM_BUG_ON(gte > end); diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h index 8c2f57eb5ddaa..2434197830523 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.h +++ b/drivers/gpu/drm/i915/i915_gem_gtt.h @@ -44,7 +44,8 @@ int i915_gem_gtt_insert(struct i915_address_space *vm, #define PIN_HIGH BIT_ULL(5) #define PIN_OFFSET_BIAS BIT_ULL(6) #define PIN_OFFSET_FIXED BIT_ULL(7) -#define PIN_VALIDATE BIT_ULL(8) /* validate placement only, no need to call unpin() */ +#define PIN_OFFSET_GUARD BIT_ULL(8) +#define PIN_VALIDATE BIT_ULL(9) /* validate placement only, no need to call unpin() */ #define PIN_GLOBAL BIT_ULL(10) /* I915_VMA_GLOBAL_BIND */ #define PIN_USER BIT_ULL(11) /* I915_VMA_LOCAL_BIND */ diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index fefee5fef38d3..3877847179710 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -419,7 +419,7 @@ i915_vma_resource_init_from_vma(struct i915_vma_resource *vma_res, obj->mm.rsgt, i915_gem_object_is_readonly(obj), i915_gem_object_is_lmem(obj), obj->mm.region, vma->ops, vma->private, __i915_vma_offset(vma), - __i915_vma_size(vma), vma->size); + __i915_vma_size(vma), vma->size, vma->guard); } /** @@ -677,6 +677,10 @@ bool i915_vma_misplaced(const struct i915_vma *vma, i915_vma_offset(vma) != (flags & PIN_OFFSET_MASK)) return true; + if (flags & PIN_OFFSET_GUARD && + vma->guard < (flags & PIN_OFFSET_MASK)) + return true; + return false; } @@ -749,15 +753,16 @@ static int i915_vma_insert(struct i915_vma *vma, struct i915_gem_ww_ctx *ww, u64 size, u64 alignment, u64 flags) { - unsigned long color; + unsigned long color, guard; u64 start, end; int ret; GEM_BUG_ON(i915_vma_is_bound(vma, I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND)); GEM_BUG_ON(drm_mm_node_allocated(&vma->node)); + GEM_BUG_ON(hweight64(flags & (PIN_OFFSET_GUARD | PIN_OFFSET_FIXED | PIN_OFFSET_BIAS)) > 1); size = max(size, vma->size); - alignment = max(alignment, vma->display_alignment); + alignment = max_t(typeof(alignment), alignment, vma->display_alignment); if (flags & PIN_MAPPABLE) { size = max_t(typeof(size), size, vma->fence_size); alignment = max_t(typeof(alignment), @@ -768,8 +773,17 @@ i915_vma_insert(struct i915_vma *vma, struct i915_gem_ww_ctx *ww, GEM_BUG_ON(!IS_ALIGNED(alignment, I915_GTT_MIN_ALIGNMENT)); GEM_BUG_ON(!is_power_of_2(alignment)); + guard = vma->guard; /* retain guard across rebinds */ + if (flags & PIN_OFFSET_GUARD) { + GEM_BUG_ON(overflows_type(flags & PIN_OFFSET_MASK, u32)); + guard = max_t(u32, guard, flags & PIN_OFFSET_MASK); + } + roundup(guard, BIT(vma->vm->scratch_order + PAGE_SHIFT)); + start = flags & PIN_OFFSET_BIAS ? flags & PIN_OFFSET_MASK : 0; GEM_BUG_ON(!IS_ALIGNED(start, I915_GTT_PAGE_SIZE)); + /* We need to be sure we do not ecceed the va area */ + GEM_BUG_ON(2 * guard > end); end = vma->vm->total; if (flags & PIN_MAPPABLE) @@ -780,11 +794,12 @@ i915_vma_insert(struct i915_vma *vma, struct i915_gem_ww_ctx *ww, alignment = max(alignment, i915_vm_obj_min_alignment(vma->vm, vma->obj)); - /* If binding the object/GGTT view requires more space than the entire + /* + * If binding the object/GGTT view requires more space than the entire * aperture has, reject it early before evicting everything in a vain * attempt to find space. */ - if (size > end) { + if (size > end - 2 * guard) { drm_dbg(&to_i915(vma->obj->base.dev)->drm, "Attempting to bind an object larger than the aperture: request=%llu > %s aperture=%llu\n", size, flags & PIN_MAPPABLE ? "mappable" : "total", end); @@ -801,13 +816,23 @@ i915_vma_insert(struct i915_vma *vma, struct i915_gem_ww_ctx *ww, if (!IS_ALIGNED(offset, alignment) || range_overflows(offset, size, end)) return -EINVAL; + /* + * The caller knows not of the guard added by others and + * requests for the offset of the start of its buffer + * to be fixed, which may not be the same as the position + * of the vma->node due to the guard pages. + */ + if (offset < guard || offset + size > end - guard) + return -ENOSPC; ret = i915_gem_gtt_reserve(vma->vm, ww, &vma->node, - size, offset, color, - flags); + size + 2 * guard, + offset - guard, + color, flags); if (ret) return ret; } else { + size += 2 * guard; /* * We only support huge gtt pages through the 48b PPGTT, * however we also don't want to force any alignment for @@ -855,6 +880,7 @@ i915_vma_insert(struct i915_vma *vma, struct i915_gem_ww_ctx *ww, GEM_BUG_ON(!i915_gem_valid_gtt_space(vma, color)); list_move_tail(&vma->vm_link, &vma->vm->bound_list); + vma->guard = guard; return 0; } diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h index 3fd4512b1f65f..ed5c9d682a1b2 100644 --- a/drivers/gpu/drm/i915/i915_vma.h +++ b/drivers/gpu/drm/i915/i915_vma.h @@ -128,7 +128,7 @@ static inline bool i915_vma_is_closed(const struct i915_vma *vma) /* Internal use only. */ static inline u64 __i915_vma_size(const struct i915_vma *vma) { - return vma->node.size; + return vma->node.size - 2 * vma->guard; } /** @@ -150,7 +150,8 @@ static inline u64 i915_vma_size(const struct i915_vma *vma) /* Internal use only. */ static inline u64 __i915_vma_offset(const struct i915_vma *vma) { - return vma->node.start; + /* The actual start of the vma->pages is after the guard pages. */ + return vma->node.start + vma->guard; } /** diff --git a/drivers/gpu/drm/i915/i915_vma_resource.c b/drivers/gpu/drm/i915/i915_vma_resource.c index de1342dbfa128..6ba7a7feceba1 100644 --- a/drivers/gpu/drm/i915/i915_vma_resource.c +++ b/drivers/gpu/drm/i915/i915_vma_resource.c @@ -34,8 +34,8 @@ static struct kmem_cache *slab_vma_resources; * and removal of fences increases as O(ln(pending_unbinds)) instead of * O(1) for a single fence without interval tree. */ -#define VMA_RES_START(_node) ((_node)->start) -#define VMA_RES_LAST(_node) ((_node)->start + (_node)->node_size - 1) +#define VMA_RES_START(_node) ((_node)->start - (_node)->guard) +#define VMA_RES_LAST(_node) ((_node)->start + (_node)->node_size + (_node)->guard - 1) INTERVAL_TREE_DEFINE(struct i915_vma_resource, rb, u64, __subtree_last, VMA_RES_START, VMA_RES_LAST, static, vma_res_itree); diff --git a/drivers/gpu/drm/i915/i915_vma_resource.h b/drivers/gpu/drm/i915/i915_vma_resource.h index 54edf3739ca0b..c1864e3d0b43e 100644 --- a/drivers/gpu/drm/i915/i915_vma_resource.h +++ b/drivers/gpu/drm/i915/i915_vma_resource.h @@ -57,6 +57,7 @@ struct i915_page_sizes { * @node_size: Size of the allocated range manager node with padding * subtracted. * @vma_size: Bind size. + * @guard: The size of guard area preceding and trailing the bind. * @page_sizes_gtt: Resulting page sizes from the bind operation. * @bound_flags: Flags indicating binding status. * @allocated: Backend private data. TODO: Should move into @private. @@ -115,6 +116,7 @@ struct i915_vma_resource { u64 start; u64 node_size; u64 vma_size; + u32 guard; u32 page_sizes_gtt; u32 bound_flags; @@ -179,6 +181,7 @@ static inline void i915_vma_resource_put(struct i915_vma_resource *vma_res) * @start: Offset into the address space of bind range start after padding. * @node_size: Size of the allocated range manager node minus padding. * @size: Bind size. + * @guard: The size of the guard area preceding and trailing the bind. * * Initializes a vma resource allocated using i915_vma_resource_alloc(). * The reason for having separate allocate and initialize function is that @@ -197,7 +200,8 @@ static inline void i915_vma_resource_init(struct i915_vma_resource *vma_res, void *private, u64 start, u64 node_size, - u64 size) + u64 size, + u32 guard) { __i915_vma_resource_init(vma_res); vma_res->vm = vm; @@ -215,6 +219,7 @@ static inline void i915_vma_resource_init(struct i915_vma_resource *vma_res, vma_res->start = start; vma_res->node_size = node_size; vma_res->vma_size = size; + vma_res->guard = guard; } static inline void i915_vma_resource_fini(struct i915_vma_resource *vma_res) diff --git a/drivers/gpu/drm/i915/i915_vma_types.h b/drivers/gpu/drm/i915/i915_vma_types.h index 0375812792b9c..77fda2244d161 100644 --- a/drivers/gpu/drm/i915/i915_vma_types.h +++ b/drivers/gpu/drm/i915/i915_vma_types.h @@ -202,6 +202,7 @@ struct i915_vma { /* mmap-offset associated with fencing for this vma */ struct i915_mmap_offset *mmo; + u32 guard; /* padding allocated around vma->pages within the node */ u32 fence_size; u32 fence_alignment; u32 display_alignment;