Messages in this thread | | | Subject | Re: [PATCH v3 4/6] iommu/io-pgtable-arm: add support for non-strict mode | From | "Leizhen (ThunderTown)" <> | Date | Thu, 26 Jul 2018 15:20:08 +0800 |
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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 <thunder.leizhen@huawei.com> >> --- >> 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?
> > 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, >> > > . >
-- Thanks! BestRegards
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