On 2018-07-26 8:20 AM, Leizhen (ThunderTown) wrote:
On 2018/7/25 6:25, Robin Murphy wrote:On 2018-07-12 7:18 AM, Zhen Lei wrote:To support the non-strict mode, now we only tlbi and sync for the strict mode. But for the non-leaf case, always follow strict mode.Use the lowest bit of the iova parameter to pass the strict mode: 0, IOMMU_STRICT; 1, IOMMU_NON_STRICT; Treat 0 as IOMMU_STRICT, so that the unmap operation can compatible with other IOMMUs which still use strict mode. Signed-off-by: Zhen Lei <[email protected]> --- drivers/iommu/io-pgtable-arm.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c index 010a254..9234db3 100644 --- a/drivers/iommu/io-pgtable-arm.c +++ b/drivers/iommu/io-pgtable-arm.c @@ -292,7 +292,7 @@ static void __arm_lpae_set_pte(arm_lpae_iopte *ptep, arm_lpae_iopte pte, static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data, unsigned long iova, size_t size, int lvl, - arm_lpae_iopte *ptep); + arm_lpae_iopte *ptep, int strict); static void __arm_lpae_init_pte(struct arm_lpae_io_pgtable *data, phys_addr_t paddr, arm_lpae_iopte prot, @@ -334,7 +334,7 @@ static int arm_lpae_init_pte(struct arm_lpae_io_pgtable *data, size_t sz = ARM_LPAE_BLOCK_SIZE(lvl, data); tblp = ptep - ARM_LPAE_LVL_IDX(iova, lvl, data); - if (WARN_ON(__arm_lpae_unmap(data, iova, sz, lvl, tblp) != sz)) + if (WARN_ON(__arm_lpae_unmap(data, iova, sz, lvl, tblp, IOMMU_STRICT) != sz)) return -EINVAL; } @@ -531,7 +531,7 @@ static void arm_lpae_free_pgtable(struct io_pgtable *iop) static size_t arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data, unsigned long iova, size_t size, arm_lpae_iopte blk_pte, int lvl, - arm_lpae_iopte *ptep) + arm_lpae_iopte *ptep, int strict)DMA code should never ever be splitting blocks anyway, and frankly the TLB maintenance here is dodgy enough (since we can't reasonably do break-before make as VMSA says we should) that I *really* don't want to introduce any possibility of making it more asynchronous. I'd much rather just hard-code the expectation of strict == true for this.OK, I will hard-code strict=true for it. But since it never ever be happened, why did not give a warning at the beginning?
Because DMA code is not the only caller of iommu_map/unmap. It's perfectly legal in the IOMMU API to partially unmap a previous mapping such that a block entry needs to be split. The DMA API, however, is a lot more constrined, and thus by construction the iommu-dma layer will never generate a block-splitting iommu_unmap() except as a result of illegal DMA API usage, and we obviously do not need to optimise for that (you will get a warning about mismatched unmaps under dma-debug, but it's a bit too expensive to police in the general case).
Robin.
{ struct io_pgtable_cfg *cfg = &data->iop.cfg; arm_lpae_iopte pte, *tablep; @@ -576,15 +576,18 @@ static size_t arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data, } if (unmap_idx < 0) - return __arm_lpae_unmap(data, iova, size, lvl, tablep); + return __arm_lpae_unmap(data, iova, size, lvl, tablep, strict); io_pgtable_tlb_add_flush(&data->iop, iova, size, size, true); + if (!strict) + io_pgtable_tlb_sync(&data->iop); + return size; } static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data, unsigned long iova, size_t size, int lvl, - arm_lpae_iopte *ptep) + arm_lpae_iopte *ptep, int strict) { arm_lpae_iopte pte; struct io_pgtable *iop = &data->iop; @@ -609,7 +612,7 @@ static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data, io_pgtable_tlb_sync(iop); ptep = iopte_deref(pte, data); __arm_lpae_free_pgtable(data, lvl + 1, ptep); - } else { + } else if (strict) { io_pgtable_tlb_add_flush(iop, iova, size, size, true); } @@ -620,25 +623,27 @@ static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data, * minus the part we want to unmap */ return arm_lpae_split_blk_unmap(data, iova, size, pte, - lvl + 1, ptep); + lvl + 1, ptep, strict); } /* Keep on walkin' */ ptep = iopte_deref(pte, data); - return __arm_lpae_unmap(data, iova, size, lvl + 1, ptep); + return __arm_lpae_unmap(data, iova, size, lvl + 1, ptep, strict); } static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova, size_t size) { + int strict = ((iova & IOMMU_STRICT_MODE_MASK) == IOMMU_STRICT); struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops); arm_lpae_iopte *ptep = data->pgd; int lvl = ARM_LPAE_START_LVL(data); + iova &= ~IOMMU_STRICT_MODE_MASK; if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias))) return 0; - return __arm_lpae_unmap(data, iova, size, lvl, ptep); + return __arm_lpae_unmap(data, iova, size, lvl, ptep, strict); } static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,.
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