Messages in this thread Patch in this message | | | Date | Tue, 22 Aug 2023 16:04:10 -0700 | From | Nicolin Chen <> | Subject | Re: [PATCH 3/3] iommu/arm-smmu-v3: Add a max_tlbi_ops for __arm_smmu_tlb_inv_range() |
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Hi Robin,
On Tue, Aug 22, 2023 at 09:32:26AM -0700, Nicolin Chen wrote: > On Tue, Aug 22, 2023 at 10:30:35AM +0100, Robin Murphy wrote: > > > > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > > > index d6c647e1eb01..3f0db30932bd 100644 > > > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > > > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > > > @@ -1897,7 +1897,14 @@ static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd, > > > if (!size) > > > return; > > > > > > - if (smmu->features & ARM_SMMU_FEAT_RANGE_INV) { > > > + if (!(smmu->features & ARM_SMMU_FEAT_RANGE_INV)) { > > > + /* > > > + * When the size reaches a threshold, replace per-granule TLBI > > > + * commands with one single per-asid or per-vmid TLBI command. > > > + */ > > > + if (size >= granule * smmu_domain->max_tlbi_ops) > > > + return arm_smmu_tlb_inv_domain(smmu_domain); > > > > This looks like it's at the wrong level - we should have figured this > > out before we got as far as low-level command-building. I'd have thought > > it would be a case of short-circuiting directly from > > arm_smmu_tlb_inv_range_domain() to arm_smmu_tlb_inv_context(). > > OK, I could do that. We would have copies of this same routine > though. Also, the shortcut applies to !ARM_SMMU_FEAT_RANGE_INV > cases only, so this function feels convenient to me.
I was trying to say that we would need the same piece in both arm_smmu_tlb_inv_range_domain() and arm_smmu_tlb_inv_range_asid(), though the latter one only needs to call arm_smmu_tlb_inv_asid().
Also, arm_smmu_tlb_inv_context() does a full range ATC invalidation instead of a given range like what arm_smmu_tlb_inv_range_domain() currently does. So, it might be a bit overkill.
Combining all your comments, we'd have something like this:
------------------------------------------------------------------- diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c index 7614739ea2c1..2967a6634c7c 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -1937,12 +1937,22 @@ static void arm_smmu_tlb_inv_range_domain(unsigned long iova, size_t size, size_t granule, bool leaf, struct arm_smmu_domain *smmu_domain) { + struct io_pgtable_cfg *cfg = + &io_pgtable_ops_to_pgtable(smmu_domain->pgtbl_ops)->cfg; struct arm_smmu_cmdq_ent cmd = { .tlbi = { .leaf = leaf, }, }; + /* + * If the given size is too large that would end up with too many TLBI + * commands in CMDQ, short circuit directly to a full invalidation + */ + if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_RANGE_INV) && + size >= granule * (1UL << cfg->bits_per_level)) + return arm_smmu_tlb_inv_context(smmu_domain); + if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) { cmd.opcode = smmu_domain->smmu->features & ARM_SMMU_FEAT_E2H ? CMDQ_OP_TLBI_EL2_VA : CMDQ_OP_TLBI_NH_VA; @@ -1964,6 +1974,8 @@ void arm_smmu_tlb_inv_range_asid(unsigned long iova, size_t size, int asid, size_t granule, bool leaf, struct arm_smmu_domain *smmu_domain) { + struct io_pgtable_cfg *cfg = + &io_pgtable_ops_to_pgtable(smmu_domain->pgtbl_ops)->cfg; struct arm_smmu_cmdq_ent cmd = { .opcode = smmu_domain->smmu->features & ARM_SMMU_FEAT_E2H ? CMDQ_OP_TLBI_EL2_VA : CMDQ_OP_TLBI_NH_VA, @@ -1973,6 +1985,14 @@ void arm_smmu_tlb_inv_range_asid(unsigned long iova, size_t size, int asid, }, }; + /* + * If the given size is too large that would end up with too many TLBI + * commands in CMDQ, short circuit directly to a full invalidation + */ + if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_RANGE_INV) && + size >= granule * (1UL << cfg->bits_per_level)) + return arm_smmu_tlb_inv_asid(smmu_domain->smmu, asid); + __arm_smmu_tlb_inv_range(&cmd, iova, size, granule, smmu_domain); } ------------------------------------------------------------------- You're sure that you prefer this, right?
Thanks Nicolin
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