From 3fae6918a3e27cce20ded2551f863fb05d4bef8d Mon Sep 17 00:00:00 2001 From: Michal Wajdeczko Date: Wed, 2 Jul 2025 00:00:52 +0200 Subject: [PATCH] drm/xe/pf: Clear all LMTT pages on alloc MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Our LMEM buffer objects are not cleared by default on alloc and during VF provisioning we only setup LMTT PTEs for the actually provisioned LMEM range. But beyond that valid range we might leave some stale data that could either point to some other VFs allocations or even to the PF pages. Explicitly clear all new LMTT page to avoid the risk that a malicious VF would try to exploit that gap. While around add asserts to catch any undesired PTE overwrites and low-level debug traces to track LMTT PT life-cycle. Fixes: b1d204058218 ("drm/xe/pf: Introduce Local Memory Translation Table") Signed-off-by: Michal Wajdeczko Cc: Michał Winiarski Cc: Lukasz Laguna Reviewed-by: Michał Winiarski Reviewed-by: Piotr Piórkowski Link: https://lore.kernel.org/r/20250701220052.1612-1-michal.wajdeczko@intel.com --- drivers/gpu/drm/xe/xe_lmtt.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/gpu/drm/xe/xe_lmtt.c b/drivers/gpu/drm/xe/xe_lmtt.c index b56437a816e42..381f576036d0d 100644 --- a/drivers/gpu/drm/xe/xe_lmtt.c +++ b/drivers/gpu/drm/xe/xe_lmtt.c @@ -78,6 +78,9 @@ static struct xe_lmtt_pt *lmtt_pt_alloc(struct xe_lmtt *lmtt, unsigned int level } lmtt_assert(lmtt, xe_bo_is_vram(bo)); + lmtt_debug(lmtt, "level=%u addr=%#llx\n", level, (u64)xe_bo_main_addr(bo, XE_PAGE_SIZE)); + + xe_map_memset(lmtt_to_xe(lmtt), &bo->vmap, 0, 0, xe_bo_size(bo)); pt->level = level; pt->bo = bo; @@ -91,6 +94,9 @@ out: static void lmtt_pt_free(struct xe_lmtt_pt *pt) { + lmtt_debug(&pt->bo->tile->sriov.pf.lmtt, "level=%u addr=%llx\n", + pt->level, (u64)xe_bo_main_addr(pt->bo, XE_PAGE_SIZE)); + xe_bo_unpin_map_no_vm(pt->bo); kfree(pt); } @@ -226,9 +232,14 @@ static void lmtt_write_pte(struct xe_lmtt *lmtt, struct xe_lmtt_pt *pt, switch (lmtt->ops->lmtt_pte_size(level)) { case sizeof(u32): + lmtt_assert(lmtt, !overflows_type(pte, u32)); + lmtt_assert(lmtt, !pte || !iosys_map_rd(&pt->bo->vmap, idx * sizeof(u32), u32)); + xe_map_wr(lmtt_to_xe(lmtt), &pt->bo->vmap, idx * sizeof(u32), u32, pte); break; case sizeof(u64): + lmtt_assert(lmtt, !pte || !iosys_map_rd(&pt->bo->vmap, idx * sizeof(u64), u64)); + xe_map_wr(lmtt_to_xe(lmtt), &pt->bo->vmap, idx * sizeof(u64), u64, pte); break; default: -- 2.47.2