Commit 705a412a authored by Michal Wajdeczko's avatar Michal Wajdeczko Committed by Lucas De Marchi
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drm/xe/pf: Clear all LMTT pages on alloc 



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: b1d20405 ("drm/xe/pf: Introduce Local Memory Translation Table")
Signed-off-by: default avatarMichal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Lukasz Laguna <lukasz.laguna@intel.com>
Reviewed-by: default avatarMichał Winiarski <michal.winiarski@intel.com>
Reviewed-by: default avatarPiotr Piórkowski <piotr.piorkowski@intel.com>
Link: https://lore.kernel.org/r/20250701220052.1612-1-michal.wajdeczko@intel.com


(cherry picked from commit 3fae6918)
Signed-off-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
parent d7b8f8e2

drivers/gpu/drm/xe/xe_lmtt.c

+11 −0
Original line number Diff line number Diff line
@@ -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, bo->size);



	pt->level = level;

	pt->bo = bo;
@@ -91,6 +94,9 @@ static struct xe_lmtt_pt *lmtt_pt_alloc(struct xe_lmtt *lmtt, unsigned int level 


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: