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SubjectRe: [PATCH v3 4/6] iommu/io-pgtable-arm: add support for non-strict mode
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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.

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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