From: Dave Airlie <[email protected]> When NVK enabled large pages userspace tests were seeing fault reports at a valid address.
There was a case where an address moving from 64k page to 4k pages could expose a race between unmapping the 4k page, mapping the 64k page and unref the 4k pages. Unref 4k pages would cause the dual-page table handling to always set the LPTE entry to SPARSE or INVALID, but if we'd mapped a valid LPTE in the meantime, it would get trashed. Keep track of when a valid LPTE has been referenced, and don't reset in that case. The SPTES field is fine at 31 limit, so just steal a bit from it. Cc: [email protected] Link: https://gitlab.freedesktop.org/mesa/mesa/-/issues/14610 Signed-off-by: Dave Airlie <[email protected]> --- drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c | 33 ++++++++++++++----- drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.h | 3 +- 2 files changed, 27 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c index f95c58b67633..73141dda4728 100644 --- a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c @@ -242,14 +242,17 @@ nvkm_vmm_unref_sptes(struct nvkm_vmm_iter *it, struct nvkm_vmm_pt *pgt, if (pgt->pte[pteb] & NVKM_VMM_PTE_SPARSE) { TRA(it, "LPTE %05x: U -> S %d PTEs", pteb, ptes); pair->func->sparse(vmm, pgt->pt[0], pteb, ptes); - } else - if (pair->func->invalid) { - /* If the MMU supports it, restore the LPTE to the - * INVALID state to tell the MMU there is no point - * trying to fetch the corresponding SPTEs. - */ - TRA(it, "LPTE %05x: U -> I %d PTEs", pteb, ptes); - pair->func->invalid(vmm, pgt->pt[0], pteb, ptes); + } else if (!(pgt->pte[pteb] & NVKM_VMM_PTE_BIG_VALID)) { + if (pair->func->invalid) { + /* If the MMU supports it, restore the LPTE to the + * INVALID state to tell the MMU there is no point + * trying to fetch the corresponding SPTEs. + */ + TRA(it, "LPTE %05x: U -> I %d PTEs", pteb, ptes); + pair->func->invalid(vmm, pgt->pt[0], pteb, ptes); + } + } else { + TRA(it, "LPTE %05x: V %d PTEs", pteb, ptes); } } } @@ -280,6 +283,13 @@ nvkm_vmm_unref_ptes(struct nvkm_vmm_iter *it, bool pfn, u32 ptei, u32 ptes) if (desc->type == SPT && (pgt->refs[0] || pgt->refs[1])) nvkm_vmm_unref_sptes(it, pgt, desc, ptei, ptes); + if (desc->type == LPT && (pgt->refs[0] || pgt->refs[1])) { + for (u32 lpti = ptei; ptes; lpti++) { + pgt->pte[lpti] &= ~NVKM_VMM_PTE_BIG_VALID; + ptes--; + } + } + /* PT no longer needed? Destroy it. */ if (!pgt->refs[type]) { it->lvl++; @@ -374,6 +384,13 @@ nvkm_vmm_ref_ptes(struct nvkm_vmm_iter *it, bool pfn, u32 ptei, u32 ptes) if (desc->type == SPT) nvkm_vmm_ref_sptes(it, pgt, desc, ptei, ptes); + if (desc->type == LPT) { + for (u32 lpti = ptei; ptes; lpti++) { + pgt->pte[lpti] |= NVKM_VMM_PTE_BIG_VALID; + ptes--; + } + } + return true; } diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.h b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.h index 4586a425dbe4..1fe7915b8e87 100644 --- a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.h +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.h @@ -46,7 +46,8 @@ struct nvkm_vmm_pt { */ #define NVKM_VMM_PTE_SPARSE 0x80 #define NVKM_VMM_PTE_VALID 0x40 -#define NVKM_VMM_PTE_SPTES 0x3f +#define NVKM_VMM_PTE_BIG_VALID 0x20 +#define NVKM_VMM_PTE_SPTES 0x1f u8 pte[]; }; -- 2.52.0
