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?
>
> 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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