Re: [PATCH v4 3/5] iommu/io-pgtable-arm: add support for non-strict mode

From: Leizhen (ThunderTown)
Date: Thu Aug 09 2018 - 07:21:02 EST



On 2018/8/9 18:54, Robin Murphy wrote:
> On 06/08/18 13:27, 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.
>>
>> Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
>> ---
>> drivers/iommu/io-pgtable-arm.c | 27 ++++++++++++++++++---------
>> drivers/iommu/io-pgtable.h | 3 +++
>> 2 files changed, 21 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
>> index 010a254..bb61bef 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, bool strict);
>>
>> static void __arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
>> phys_addr_t paddr, arm_lpae_iopte prot,
>> @@ -319,6 +319,7 @@ static int arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
>> arm_lpae_iopte prot, int lvl,
>> arm_lpae_iopte *ptep)
>> {
>> + size_t unmapped;
>> arm_lpae_iopte pte = *ptep;
>>
>> if (iopte_leaf(pte, lvl)) {
>> @@ -334,7 +335,8 @@ 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))
>> + unmapped = __arm_lpae_unmap(data, iova, sz, lvl, tblp, true);
>> + if (WARN_ON(unmapped != sz))
>
> What's the extra local variable for?

in order to remove the warning: more than 80 characters a line

>
>> return -EINVAL;
>> }
>>
>> @@ -576,15 +578,17 @@ 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, true);
>>
>> io_pgtable_tlb_add_flush(&data->iop, iova, size, size, true);
>> + 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, bool strict)
>> {
>> arm_lpae_iopte pte;
>> struct io_pgtable *iop = &data->iop;
>> @@ -609,7 +613,7 @@ 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) {
>
> Since this is the only place we ever actually evaluate "strict", can't we just test iop->cfg.quirks directly at this point instead of playing pass-the-parcel with the extra argument?

Wonderful, you're right!

>
> Robin.
>
>> io_pgtable_tlb_add_flush(iop, iova, size, size, true);
>> }
>>
>> @@ -625,12 +629,13 @@ static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
>>
>> /* 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)
>> {
>> + bool 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);
>> @@ -638,7 +643,9 @@ static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
>> if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias)))
>> return 0;
>>
>> - return __arm_lpae_unmap(data, iova, size, lvl, ptep);
>> + strict = !(data->iop.cfg.quirks & IO_PGTABLE_QUIRK_NON_STRICT);
>> +
>> + return __arm_lpae_unmap(data, iova, size, lvl, ptep, strict);
>> }
>>
>> static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
>> @@ -771,7 +778,8 @@ static void arm_lpae_restrict_pgsizes(struct io_pgtable_cfg *cfg)
>> u64 reg;
>> struct arm_lpae_io_pgtable *data;
>>
>> - if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS | IO_PGTABLE_QUIRK_NO_DMA))
>> + if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS | IO_PGTABLE_QUIRK_NO_DMA |
>> + IO_PGTABLE_QUIRK_NON_STRICT))
>> return NULL;
>>
>> data = arm_lpae_alloc_pgtable(cfg);
>> @@ -863,7 +871,8 @@ static void arm_lpae_restrict_pgsizes(struct io_pgtable_cfg *cfg)
>> struct arm_lpae_io_pgtable *data;
>>
>> /* The NS quirk doesn't apply at stage 2 */
>> - if (cfg->quirks & ~IO_PGTABLE_QUIRK_NO_DMA)
>> + if (cfg->quirks & ~(IO_PGTABLE_QUIRK_NO_DMA |
>> + IO_PGTABLE_QUIRK_NON_STRICT))
>> return NULL;
>>
>> data = arm_lpae_alloc_pgtable(cfg);
>> diff --git a/drivers/iommu/io-pgtable.h b/drivers/iommu/io-pgtable.h
>> index 2df7909..beb14a3 100644
>> --- a/drivers/iommu/io-pgtable.h
>> +++ b/drivers/iommu/io-pgtable.h
>> @@ -71,12 +71,15 @@ struct io_pgtable_cfg {
>> * be accessed by a fully cache-coherent IOMMU or CPU (e.g. for a
>> * software-emulated IOMMU), such that pagetable updates need not
>> * be treated as explicit DMA data.
>> + * IO_PGTABLE_QUIRK_NON_STRICT: Put off TLBs invalidation and release
>> + * memory first.
>> */
>> #define IO_PGTABLE_QUIRK_ARM_NS BIT(0)
>> #define IO_PGTABLE_QUIRK_NO_PERMS BIT(1)
>> #define IO_PGTABLE_QUIRK_TLBI_ON_MAP BIT(2)
>> #define IO_PGTABLE_QUIRK_ARM_MTK_4GB BIT(3)
>> #define IO_PGTABLE_QUIRK_NO_DMA BIT(4)
>> + #define IO_PGTABLE_QUIRK_NON_STRICT BIT(5)
>> unsigned long quirks;
>> unsigned long pgsize_bitmap;
>> unsigned int ias;
>> --
>> 1.8.3
>>
>>
>
> .
>

--
Thanks!
BestRegards