[PATCH v3 2/5] iommu/arm-smmu: Add support for split pagetables

Jordan Crouse
2019-12-16T16:38:08Z

Add support to enable split pagetables (TTBR1) if the supporting driver
requests it via the DOMAIN_ATTR_SPLIT_TABLES flag. When enabled, the driver
will set up the TTBR0 and TTBR1 regions and program the default domain
pagetable on TTBR1.

After attaching the device, the value of he domain attribute can
be queried to see if the split pagetables were successfully programmed.
Furthermore the domain geometry will be updated so that the caller can
determine the active region for the pagetable that was programmed.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
---

drivers/iommu/arm-smmu.c | 40 +++++++++++++++++++++++++++++++++++-----
drivers/iommu/arm-smmu.h | 45 +++++++++++++++++++++++++++++++++++++++------
2 files changed, 74 insertions(+), 11 deletions(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index c106406..7b59116 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -538,9 +538,17 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
cb->ttbr[0] = pgtbl_cfg->arm_v7s_cfg.ttbr;
cb->ttbr[1] = 0;
} else {
- cb->ttbr[0] = pgtbl_cfg->arm_lpae_s1_cfg.ttbr;
- cb->ttbr[0] |= FIELD_PREP(TTBRn_ASID, cfg->asid);
- cb->ttbr[1] = FIELD_PREP(TTBRn_ASID, cfg->asid);
+ if (pgtbl_cfg->quirks & IO_PGTABLE_QUIRK_ARM_TTBR1) {
+ cb->ttbr[0] = FIELD_PREP(TTBRn_ASID, cfg->asid);
+ cb->ttbr[1] = pgtbl_cfg->arm_lpae_s1_cfg.ttbr;
+ cb->ttbr[1] |=
+ FIELD_PREP(TTBRn_ASID, cfg->asid);
+ } else {
+ cb->ttbr[0] = pgtbl_cfg->arm_lpae_s1_cfg.ttbr;
+ cb->ttbr[0] |=
+ FIELD_PREP(TTBRn_ASID, cfg->asid);
+ cb->ttbr[1] = FIELD_PREP(TTBRn_ASID, cfg->asid);
+ }
}
} else {
cb->ttbr[0] = pgtbl_cfg->arm_lpae_s2_cfg.vttbr;
@@ -651,6 +659,7 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
enum io_pgtable_fmt fmt;
struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
+ u32 quirks = 0;

mutex_lock(&smmu_domain->init_mutex);
if (smmu_domain->smmu)
@@ -719,6 +728,8 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
oas = smmu->ipa_size;
if (cfg->fmt == ARM_SMMU_CTX_FMT_AARCH64) {
fmt = ARM_64_LPAE_S1;
+ if (smmu_domain->split_pagetables)
+ 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);
@@ -788,6 +799,7 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
.coherent_walk = smmu->features & ARM_SMMU_FEAT_COHERENT_WALK,
.tlb = smmu_domain->flush_ops,
.iommu_dev = smmu->dev,
+ .quirks = quirks,
};

if (smmu_domain->non_strict)
@@ -801,8 +813,15 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,

/* Update the domain's page sizes to reflect the page table format */
domain->pgsize_bitmap = pgtbl_cfg.pgsize_bitmap;
- domain->geometry.aperture_end = (1UL << ias) - 1;
- domain->geometry.force_aperture = true;
+
+ if (pgtbl_cfg.quirks & IO_PGTABLE_QUIRK_ARM_TTBR1) {
+ domain->geometry.aperture_start = ~((1ULL << ias) - 1);
+ domain->geometry.aperture_end = ~0UL;
+ } else {
+ domain->geometry.aperture_end = (1UL << ias) - 1;
+ domain->geometry.force_aperture = true;
+ smmu_domain->split_pagetables = false;
+ }

/* Initialise the context bank with our page table cfg */
arm_smmu_init_context_bank(smmu_domain, &pgtbl_cfg);
@@ -1484,6 +1503,9 @@ static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
case DOMAIN_ATTR_NESTING:
*(int *)data = (smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED);
return 0;
+ case DOMAIN_ATTR_SPLIT_TABLES:
+ *(int *)data = smmu_domain->split_pagetables;
+ return 0;
default:
return -ENODEV;
}
@@ -1524,6 +1546,14 @@ static int arm_smmu_domain_set_attr(struct iommu_domain *domain,
else
smmu_domain->stage = ARM_SMMU_DOMAIN_S1;
break;
+ case DOMAIN_ATTR_SPLIT_TABLES:
+ if (smmu_domain->smmu) {
+ ret = -EPERM;
+ goto out_unlock;
+ }
+ if (*(int *)data)
+ smmu_domain->split_pagetables = true;
+ break;
default:
ret = -ENODEV;
}
diff --git a/drivers/iommu/arm-smmu.h b/drivers/iommu/arm-smmu.h
index afab9de..68526cc 100644
--- a/drivers/iommu/arm-smmu.h
+++ b/drivers/iommu/arm-smmu.h
@@ -177,6 +177,16 @@ enum arm_smmu_cbar_type {
#define TCR_IRGN0 GENMASK(9, 8)
#define TCR_T0SZ GENMASK(5, 0)

+#define TCR_TG1 GENMASK(31, 30)
+
+#define TG0_4K 0
+#define TG0_64K 1
+#define TG0_16K 2
+
+#define TG1_16K 1
+#define TG1_4K 2
+#define TG1_64K 3
+
#define ARM_SMMU_CB_CONTEXTIDR 0x34
#define ARM_SMMU_CB_S1_MAIR0 0x38
#define ARM_SMMU_CB_S1_MAIR1 0x3c
@@ -329,16 +339,39 @@ struct arm_smmu_domain {
struct mutex init_mutex; /* Protects smmu pointer */
spinlock_t cb_lock; /* Serialises ATS1* ops and TLB syncs */
struct iommu_domain domain;
+ bool split_pagetables;
};

+static inline u32 arm_smmu_lpae_tcr_tg(struct io_pgtable_cfg *cfg)
+{
+ u32 val;
+
+ if (!(cfg->quirks & IO_PGTABLE_QUIRK_ARM_TTBR1))
+ return FIELD_PREP(TCR_TG0, cfg->arm_lpae_s1_cfg.tcr.tg);
+
+ val = FIELD_PREP(TCR_TG1, cfg->arm_lpae_s1_cfg.tcr.tg);
+
+ if (cfg->arm_lpae_s1_cfg.tcr.tg == TG1_4K)
+ val |= FIELD_PREP(TCR_TG0, TG0_4K);
+ else if (cfg->arm_lpae_s1_cfg.tcr.tg == TG1_16K)
+ val |= FIELD_PREP(TCR_TG0, TG0_16K);
+ else
+ val |= FIELD_PREP(TCR_TG0, TG0_64K);
+
+ return val;
+}
+
static inline u32 arm_smmu_lpae_tcr(struct io_pgtable_cfg *cfg)
{
- return TCR_EPD1 |
- FIELD_PREP(TCR_TG0, cfg->arm_lpae_s1_cfg.tcr.tg) |
- FIELD_PREP(TCR_SH0, cfg->arm_lpae_s1_cfg.tcr.sh) |
- FIELD_PREP(TCR_ORGN0, cfg->arm_lpae_s1_cfg.tcr.orgn) |
- FIELD_PREP(TCR_IRGN0, cfg->arm_lpae_s1_cfg.tcr.irgn) |
- FIELD_PREP(TCR_T0SZ, cfg->arm_lpae_s1_cfg.tcr.tsz);
+ u32 tcr = FIELD_PREP(TCR_SH0, cfg->arm_lpae_s1_cfg.tcr.sh) |
+ FIELD_PREP(TCR_ORGN0, cfg->arm_lpae_s1_cfg.tcr.orgn) |
+ FIELD_PREP(TCR_IRGN0, cfg->arm_lpae_s1_cfg.tcr.irgn) |
+ FIELD_PREP(TCR_T0SZ, cfg->arm_lpae_s1_cfg.tcr.tsz);
+
+ if (!(cfg->quirks & IO_PGTABLE_QUIRK_ARM_TTBR1))
+ return tcr | TCR_EPD1 | arm_smmu_lpae_tcr_tg(cfg);
+
+ return tcr | (tcr << 16) | arm_smmu_lpae_tcr_tg(cfg);
}

static inline u32 arm_smmu_lpae_tcr2(struct io_pgtable_cfg *cfg)
--
2.7.4