Domains which are being set up for split pagetables usually want to be on a specific context bank for hardware reasons. Force the context bank for domains with the split-pagetable quirk to context bank 0. If context bank 0 is taken, move that context bank to another unused bank and rewrite the stream matching registers accordingly.
This is be used by [1] and [2] to leave context bank 0 open so that the Adreno GPU can program it. [1] https://lists.linuxfoundation.org/pipermail/iommu/2020-January/041438.html [2] https://lists.linuxfoundation.org/pipermail/iommu/2020-January/041444.html Signed-off-by: Jordan Crouse <jcro...@codeaurora.org> --- drivers/iommu/arm-smmu.c | 63 +++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 59 insertions(+), 4 deletions(-) diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 85a6773..799a254 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -254,6 +254,43 @@ static int __arm_smmu_alloc_bitmap(unsigned long *map, int start, int end) return idx; } +static void arm_smmu_write_s2cr(struct arm_smmu_device *smmu, int idx); + +static int __arm_smmu_alloc_cb(struct arm_smmu_device *smmu, int start, + int target) +{ + int new, i; + + /* Allocate a new context bank id */ + new = __arm_smmu_alloc_bitmap(smmu->context_map, start, + smmu->num_context_banks); + + if (new < 0) + return new; + + /* If no target is set or we actually got the bank index we wanted */ + if (target == -1 || new == target) + return new; + + /* Copy the context configuration to the new index */ + memcpy(&smmu->cbs[new], &smmu->cbs[target], sizeof(*smmu->cbs)); + smmu->cbs[new].cfg->cbndx = new; + + /* FIXME: Do we need locking here? */ + for (i = 0; i < smmu->num_mapping_groups; i++) { + if (smmu->s2crs[i].cbndx == target) { + smmu->s2crs[i].cbndx = new; + arm_smmu_write_s2cr(smmu, i); + } + } + + /* + * FIXME: Does getting here imply that 'target' is already set in the + * context_map? + */ + return target; +} + static void __arm_smmu_free_bitmap(unsigned long *map, int idx) { clear_bit(idx, map); @@ -770,6 +807,7 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); struct arm_smmu_cfg *cfg = &smmu_domain->cfg; unsigned long quirks = 0; + int forcecb = -1; mutex_lock(&smmu_domain->init_mutex); if (smmu_domain->smmu) @@ -844,8 +882,25 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, * SEP_UPSTREAM so we don't need to reduce the size of * the ias to account for the sign extension bit */ - if (smmu_domain->split_pagetables) - quirks |= IO_PGTABLE_QUIRK_ARM_TTBR1; + if (smmu_domain->split_pagetables) { + /* + * If split pagetables are enabled, assume that + * the user's intent is to use per-instance + * pagetables which, at least on a QCOM target, + * means that this domain should be on context + * bank 0. + */ + + /* + * If we can't force to context bank 0 then + * don't bother enabling split pagetables which + * then would not allow aux domains + */ + if (start == 0) { + forcecb = 0; + quirks |= IO_PGTABLE_QUIRK_ARM_TTBR1; + } + } } else if (cfg->fmt == ARM_SMMU_CTX_FMT_AARCH32_L) { fmt = ARM_32_LPAE_S1; ias = min(ias, 32UL); @@ -883,8 +938,8 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, ret = -EINVAL; goto out_unlock; } - ret = __arm_smmu_alloc_bitmap(smmu->context_map, start, - smmu->num_context_banks); + + ret = __arm_smmu_alloc_cb(smmu, start, forcecb); if (ret < 0) goto out_unlock; -- 2.7.4 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
