From beb3c6a066bff1ba412f983cb9d1a42f4cd8f76a Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 6 Jan 2017 16:27:30 +0000 Subject: [PATCH] iommu/arm-smmu-v3: Install bypass STEs for IOMMU_DOMAIN_IDENTITY domains In preparation for allowing the default domain type to be overridden, this patch adds support for IOMMU_DOMAIN_IDENTITY domains to the ARM SMMUv3 driver. An identity domain is created by placing the corresponding stream table entries into "bypass" mode, which allows transactions to flow through the SMMU without any translation. Signed-off-by: Will Deacon --- drivers/iommu/arm-smmu-v3.c | 58 +++++++++++++++++++++++-------------- 1 file changed, 37 insertions(+), 21 deletions(-) diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index 97be8de3e834..803352d78d43 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -554,9 +554,14 @@ struct arm_smmu_s2_cfg { }; struct arm_smmu_strtab_ent { - bool valid; - - bool bypass; /* Overrides s1/s2 config */ + /* + * An STE is "assigned" if the master emitting the corresponding SID + * is attached to a domain. The behaviour of an unassigned STE is + * determined by the disable_bypass parameter, whereas an assigned + * STE behaves according to s1_cfg/s2_cfg, which themselves are + * configured according to the domain type. + */ + bool assigned; struct arm_smmu_s1_cfg *s1_cfg; struct arm_smmu_s2_cfg *s2_cfg; }; @@ -632,6 +637,7 @@ enum arm_smmu_domain_stage { ARM_SMMU_DOMAIN_S1 = 0, ARM_SMMU_DOMAIN_S2, ARM_SMMU_DOMAIN_NESTED, + ARM_SMMU_DOMAIN_BYPASS, }; struct arm_smmu_domain { @@ -1005,9 +1011,9 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid, * This is hideously complicated, but we only really care about * three cases at the moment: * - * 1. Invalid (all zero) -> bypass (init) - * 2. Bypass -> translation (attach) - * 3. Translation -> bypass (detach) + * 1. Invalid (all zero) -> bypass/fault (init) + * 2. Bypass/fault -> translation/bypass (attach) + * 3. Translation/bypass -> bypass/fault (detach) * * Given that we can't update the STE atomically and the SMMU * doesn't read the thing in a defined order, that leaves us @@ -1046,11 +1052,15 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid, } /* Nuke the existing STE_0 value, as we're going to rewrite it */ - val = ste->valid ? STRTAB_STE_0_V : 0; + val = STRTAB_STE_0_V; + + /* Bypass/fault */ + if (!ste->assigned || !(ste->s1_cfg || ste->s2_cfg)) { + if (!ste->assigned && disable_bypass) + val |= STRTAB_STE_0_CFG_ABORT; + else + val |= STRTAB_STE_0_CFG_BYPASS; - if (ste->bypass) { - val |= disable_bypass ? STRTAB_STE_0_CFG_ABORT - : STRTAB_STE_0_CFG_BYPASS; dst[0] = cpu_to_le64(val); dst[1] = cpu_to_le64(STRTAB_STE_1_SHCFG_INCOMING << STRTAB_STE_1_SHCFG_SHIFT); @@ -1111,10 +1121,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid, static void arm_smmu_init_bypass_stes(u64 *strtab, unsigned int nent) { unsigned int i; - struct arm_smmu_strtab_ent ste = { - .valid = true, - .bypass = true, - }; + struct arm_smmu_strtab_ent ste = { .assigned = false }; for (i = 0; i < nent; ++i) { arm_smmu_write_strtab_ent(NULL, -1, strtab, &ste); @@ -1378,7 +1385,9 @@ static struct iommu_domain *arm_smmu_domain_alloc(unsigned type) { struct arm_smmu_domain *smmu_domain; - if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_DMA) + if (type != IOMMU_DOMAIN_UNMANAGED && + type != IOMMU_DOMAIN_DMA && + type != IOMMU_DOMAIN_IDENTITY) return NULL; /* @@ -1509,6 +1518,11 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain) struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); struct arm_smmu_device *smmu = smmu_domain->smmu; + if (domain->type == IOMMU_DOMAIN_IDENTITY) { + smmu_domain->stage = ARM_SMMU_DOMAIN_BYPASS; + return 0; + } + /* Restrict the stage to what we can actually support */ if (!(smmu->features & ARM_SMMU_FEAT_TRANS_S1)) smmu_domain->stage = ARM_SMMU_DOMAIN_S2; @@ -1597,7 +1611,7 @@ static void arm_smmu_detach_dev(struct device *dev) { struct arm_smmu_master_data *master = dev->iommu_fwspec->iommu_priv; - master->ste.bypass = true; + master->ste.assigned = false; arm_smmu_install_ste_for_dev(dev->iommu_fwspec); } @@ -1617,7 +1631,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) ste = &master->ste; /* Already attached to a different domain? */ - if (!ste->bypass) + if (ste->assigned) arm_smmu_detach_dev(dev); mutex_lock(&smmu_domain->init_mutex); @@ -1638,10 +1652,12 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) goto out_unlock; } - ste->bypass = false; - ste->valid = true; + ste->assigned = true; - if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) { + if (smmu_domain->stage == ARM_SMMU_DOMAIN_BYPASS) { + ste->s1_cfg = NULL; + ste->s2_cfg = NULL; + } else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) { ste->s1_cfg = &smmu_domain->s1_cfg; ste->s2_cfg = NULL; arm_smmu_write_ctx_desc(smmu, ste->s1_cfg); @@ -1801,7 +1817,7 @@ static void arm_smmu_remove_device(struct device *dev) master = fwspec->iommu_priv; smmu = master->smmu; - if (master && master->ste.valid) + if (master && master->ste.assigned) arm_smmu_detach_dev(dev); iommu_group_remove_device(dev); iommu_device_unlink(&smmu->iommu, dev);