From: Brian Nguyen Date: Thu, 5 Mar 2026 17:15:48 +0000 (+0000) Subject: drm/xe: Skip over non leaf pte for PRL generation X-Git-Tag: v7.0-rc5~14^2^2~4 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=38b8dcde231641f00eee977d245dbfe5f6b06e11;p=thirdparty%2Flinux.git drm/xe: Skip over non leaf pte for PRL generation The check using xe_child->base.children was insufficient in determining if a pte was a leaf node. So explicitly skip over every non-leaf pt and conditionally abort if there is a scenario where a non-leaf pt is interleaved between leaf pt, which results in the page walker skipping over some leaf pt. Note that the behavior being targeted for abort is PD[0] = 2M PTE PD[1] = PT -> 512 4K PTEs PD[2] = 2M PTE results in abort, page walker won't descend PD[1]. With new abort, ensuring valid PRL before handling a second abort. v2: - Revert to previous assert. - Revised non-leaf handling for interleaf child pt and leaf pte. - Update comments to specifications. (Stuart) - Remove unnecessary XE_PTE_PS64. (Matthew B) v3: - Modify secondary abort to only check non-leaf PTEs. (Matthew B) Fixes: b912138df299 ("drm/xe: Create page reclaim list on unbind") Signed-off-by: Brian Nguyen Reviewed-by: Matthew Brost Cc: Stuart Summers Link: https://patch.msgid.link/20260305171546.67691-6-brian3.nguyen@intel.com Signed-off-by: Matt Roper (cherry picked from commit 1d123587525db86cc8f0d2beb35d9e33ca3ade83) Signed-off-by: Thomas Hellström --- diff --git a/drivers/gpu/drm/xe/xe_pt.c b/drivers/gpu/drm/xe/xe_pt.c index 13b355fadd58..2d9ce2c4cb4f 100644 --- a/drivers/gpu/drm/xe/xe_pt.c +++ b/drivers/gpu/drm/xe/xe_pt.c @@ -1655,14 +1655,35 @@ static int xe_pt_stage_unbind_entry(struct xe_ptw *parent, pgoff_t offset, XE_WARN_ON(!level); /* Check for leaf node */ if (xe_walk->prl && xe_page_reclaim_list_valid(xe_walk->prl) && - (!xe_child->base.children || !xe_child->base.children[first])) { + xe_child->level <= MAX_HUGEPTE_LEVEL) { struct iosys_map *leaf_map = &xe_child->bo->vmap; pgoff_t count = xe_pt_num_entries(addr, next, xe_child->level, walk); for (pgoff_t i = 0; i < count; i++) { - u64 pte = xe_map_rd(xe, leaf_map, (first + i) * sizeof(u64), u64); + u64 pte; int ret; + /* + * If not a leaf pt, skip unless non-leaf pt is interleaved between + * leaf ptes which causes the page walk to skip over the child leaves + */ + if (xe_child->base.children && xe_child->base.children[first + i]) { + u64 pt_size = 1ULL << walk->shifts[xe_child->level]; + bool edge_pt = (i == 0 && !IS_ALIGNED(addr, pt_size)) || + (i == count - 1 && !IS_ALIGNED(next, pt_size)); + + if (!edge_pt) { + xe_page_reclaim_list_abort(xe_walk->tile->primary_gt, + xe_walk->prl, + "PT is skipped by walk at level=%u offset=%lu", + xe_child->level, first + i); + break; + } + continue; + } + + pte = xe_map_rd(xe, leaf_map, (first + i) * sizeof(u64), u64); + /* * In rare scenarios, pte may not be written yet due to racy conditions. * In such cases, invalidate the PRL and fallback to full PPC invalidation. @@ -1674,9 +1695,8 @@ static int xe_pt_stage_unbind_entry(struct xe_ptw *parent, pgoff_t offset, } /* Ensure it is a defined page */ - xe_tile_assert(xe_walk->tile, - xe_child->level == 0 || - (pte & (XE_PTE_PS64 | XE_PDE_PS_2M | XE_PDPE_PS_1G))); + xe_tile_assert(xe_walk->tile, xe_child->level == 0 || + (pte & (XE_PDE_PS_2M | XE_PDPE_PS_1G))); /* An entry should be added for 64KB but contigious 4K have XE_PTE_PS64 */ if (pte & XE_PTE_PS64) @@ -1701,11 +1721,11 @@ static int xe_pt_stage_unbind_entry(struct xe_ptw *parent, pgoff_t offset, killed = xe_pt_check_kill(addr, next, level - 1, xe_child, action, walk); /* - * Verify PRL is active and if entry is not a leaf pte (base.children conditions), - * there is a potential need to invalidate the PRL if any PTE (num_live) are dropped. + * Verify if any PTE are potentially dropped at non-leaf levels, either from being + * killed or the page walk covers the region. */ - if (xe_walk->prl && level > 1 && xe_child->num_live && - xe_child->base.children && xe_child->base.children[first]) { + if (xe_walk->prl && xe_page_reclaim_list_valid(xe_walk->prl) && + xe_child->level > MAX_HUGEPTE_LEVEL && xe_child->num_live) { bool covered = xe_pt_covers(addr, next, xe_child->level, &xe_walk->base); /*