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drm/xe/pf: Clear all LMTT pages on alloc

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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: b1d2040582 ("drm/xe/pf: Introduce Local Memory Translation Table")
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Lukasz Laguna <lukasz.laguna@intel.com>
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Link: https://lore.kernel.org/r/20250701220052.1612-1-michal.wajdeczko@intel.com
This commit is contained in:
Michal Wajdeczko 2025-07-02 00:00:52 +02:00
parent b9329f5167
commit 3fae6918a3
1 changed files with 11 additions and 0 deletions
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11
drivers/gpu/drm/xe/xe_lmtt.c
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@ -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 @@ 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: