The VMID16 (8.1) extension to SMMUv2 added a 16-bit VMID16 field to the CBA2R registers. Unfortunately, if software writes this field as zero after setting an 8-bit VMID in a stage-2 CBAR, then the VMID may also be overwritten with zero on some early implementations (the architecture was later updated to fix this issue).
This patch ensures that we initialise CBA2R before CBAR, therefore ensuring that the VMID is set correctly. Tested-by: Manish Jaggi <[email protected]> Signed-off-by: Will Deacon <[email protected]> --- drivers/iommu/arm-smmu.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index fc13dd56953e..4abb831e24f0 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -730,6 +730,20 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain, stage1 = cfg->cbar != CBAR_TYPE_S2_TRANS; cb_base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, cfg->cbndx); + if (smmu->version > ARM_SMMU_V1) { + /* + * CBA2R. + * *Must* be initialised before CBAR thanks to VMID16 + * architectural oversight affected some implementations. + */ +#ifdef CONFIG_64BIT + reg = CBA2R_RW64_64BIT; +#else + reg = CBA2R_RW64_32BIT; +#endif + writel_relaxed(reg, gr1_base + ARM_SMMU_GR1_CBA2R(cfg->cbndx)); + } + /* CBAR */ reg = cfg->cbar; if (smmu->version == ARM_SMMU_V1) @@ -747,16 +761,6 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain, } writel_relaxed(reg, gr1_base + ARM_SMMU_GR1_CBAR(cfg->cbndx)); - if (smmu->version > ARM_SMMU_V1) { - /* CBA2R */ -#ifdef CONFIG_64BIT - reg = CBA2R_RW64_64BIT; -#else - reg = CBA2R_RW64_32BIT; -#endif - writel_relaxed(reg, gr1_base + ARM_SMMU_GR1_CBA2R(cfg->cbndx)); - } - /* TTBRs */ if (stage1) { reg = pgtbl_cfg->arm_lpae_s1_cfg.ttbr[0]; -- 2.1.4 _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
