On 2021-06-18 03:51, Sai Prakash Ranjan wrote:
Add a quirk IO_PGTABLE_QUIRK_TLB_INV_ALL to invalidate entire context with tlb_flush_all() callback in partial walk flush to improve unmap performance on select few platforms where the cost of over-invalidation is less than the unmap latency.
I still think this doesn't belong anywhere near io-pgtable at all. It's a driver-internal decision how exactly it implements a non-leaf invalidation, and that may be more complex than a predetermined boolean decision. For example, I've just realised for SMMUv3 we can't invalidate multiple levels of table at once with a range command, since if we assume the whole thing is mapped at worst-case page granularity we may fail to invalidate any parts which are mapped as intermediate-level blocks. If invalidating a 1GB region (with 4KB granule) means having to fall back to 256K non-range commands, we may not want to invalidate by VA then, even though doing so for a 2MB region is still optimal.
It's also quite feasible that drivers might want to do this for leaf invalidations too - if you don't like issuing 512 commands to invalidate 2MB, do you like issuing 511 commands to invalidate 2044KB? - and at that point the logic really has to be in the driver anyway.
Robin.
Signed-off-by: Sai Prakash Ranjan <saiprakash.ran...@codeaurora.org> --- drivers/iommu/io-pgtable-arm.c | 3 ++- include/linux/io-pgtable.h | 5 +++++ 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c index 87def58e79b5..5d362f2214bd 100644 --- a/drivers/iommu/io-pgtable-arm.c +++ b/drivers/iommu/io-pgtable-arm.c @@ -768,7 +768,8 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie) if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS | IO_PGTABLE_QUIRK_NON_STRICT | IO_PGTABLE_QUIRK_ARM_TTBR1 | - IO_PGTABLE_QUIRK_ARM_OUTER_WBWA)) + IO_PGTABLE_QUIRK_ARM_OUTER_WBWA | + IO_PGTABLE_QUIRK_TLB_INV_ALL)) return NULL;data = arm_lpae_alloc_pgtable(cfg);diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h index 4d40dfa75b55..45441592a0e6 100644 --- a/include/linux/io-pgtable.h +++ b/include/linux/io-pgtable.h @@ -82,6 +82,10 @@ struct io_pgtable_cfg { * * IO_PGTABLE_QUIRK_ARM_OUTER_WBWA: Override the outer-cacheability * attributes set in the TCR for a non-coherent page-table walker. + * + * IO_PGTABLE_QUIRK_TLB_INV_ALL: Use TLBIALL/TLBIASID to invalidate + * entire context for partial walk flush to increase unmap + * performance on select few platforms. */ #define IO_PGTABLE_QUIRK_ARM_NS BIT(0) #define IO_PGTABLE_QUIRK_NO_PERMS BIT(1) @@ -89,6 +93,7 @@ struct io_pgtable_cfg { #define IO_PGTABLE_QUIRK_NON_STRICT BIT(4) #define IO_PGTABLE_QUIRK_ARM_TTBR1 BIT(5) #define IO_PGTABLE_QUIRK_ARM_OUTER_WBWA BIT(6) + #define IO_PGTABLE_QUIRK_TLB_INV_ALL BIT(7) unsigned long quirks; unsigned long pgsize_bitmap; unsigned int ias;
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