From 3677a649a751c8f061ba379a98c369473ccac980 Mon Sep 17 00:00:00 2001 From: Tomasz Nowicki Date: Mon, 16 Jan 2017 08:16:07 +0100 Subject: [PATCH] iommu/arm-smmu: Fix for ThunderX erratum #27704 The goal of erratum #27704 workaround was to make sure that ASIDs and VMIDs are unique across all SMMU instances on affected Cavium systems. Currently, the workaround code partitions ASIDs and VMIDs by increasing global cavium_smmu_context_count which in turn becomes the base ASID and VMID value for the given SMMU instance upon the context bank initialization. For systems with multiple SMMU instances this approach implies the risk of crossing 8-bit ASID, like for 1-socket CN88xx capable of 4 SMMUv2, 128 context banks each: SMMU_0 (0-127 ASID RANGE) SMMU_1 (127-255 ASID RANGE) SMMU_2 (256-383 ASID RANGE) <--- crossing 8-bit ASID SMMU_3 (384-511 ASID RANGE) <--- crossing 8-bit ASID Since now we use 8-bit ASID (SMMU_CBn_TCR2.AS = 0) we effectively misconfigure ASID[15:8] bits of SMMU_CBn_TTBRm register for SMMU_2/3. Moreover, we still assume non-zero ASID[15:8] bits upon context invalidation. In the end, except SMMU_0/1 devices all other devices under other SMMUs will fail on guest power off/on. Since we try to invalidate TLB with 16-bit ASID but we actually have 8-bit zero padded 16-bit entry. This patch adds 16-bit ASID support for stage-1 AArch64 contexts so that we use ASIDs consistently for all SMMU instances. Signed-off-by: Tomasz Nowicki Reviewed-by: Robin Murphy Reviewed-by: Tirumalesh Chalamarla Signed-off-by: Will Deacon --- drivers/iommu/arm-smmu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 93b9177..d01802e 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -264,6 +264,7 @@ enum arm_smmu_s2cr_privcfg { #define TTBCR2_SEP_SHIFT 15 #define TTBCR2_SEP_UPSTREAM (0x7 << TTBCR2_SEP_SHIFT) +#define TTBCR2_AS (1 << 4) #define TTBRn_ASID_SHIFT 48 @@ -783,6 +784,8 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain, reg = pgtbl_cfg->arm_lpae_s1_cfg.tcr; reg2 = pgtbl_cfg->arm_lpae_s1_cfg.tcr >> 32; reg2 |= TTBCR2_SEP_UPSTREAM; + if (cfg->fmt == ARM_SMMU_CTX_FMT_AARCH64) + reg2 |= TTBCR2_AS; } if (smmu->version > ARM_SMMU_V1) writel_relaxed(reg2, cb_base + ARM_SMMU_CB_TTBCR2); -- 2.7.4