1 files changed, 123 insertions, 0 deletions
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
new file mode 100644
index 000000000000..6c1113059632
--- /dev/null
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Implementation of the IOMMU SVA API for the ARM SMMUv3
+ */
+
+#include <linux/mm.h>
+#include <linux/mmu_context.h>
+#include <linux/slab.h>
+
+#include "arm-smmu-v3.h"
+#include "../../io-pgtable-arm.h"
+
+static struct arm_smmu_ctx_desc *
+arm_smmu_share_asid(struct mm_struct *mm, u16 asid)
+{
+	struct arm_smmu_ctx_desc *cd;
+
+	cd = xa_load(&arm_smmu_asid_xa, asid);
+	if (!cd)
+		return NULL;
+
+	if (cd->mm) {
+		if (WARN_ON(cd->mm != mm))
+			return ERR_PTR(-EINVAL);
+		/* All devices bound to this mm use the same cd struct. */
+		refcount_inc(&cd->refs);
+		return cd;
+	}
+
+	/* Ouch, ASID is already in use for a private cd. */
+	return ERR_PTR(-EBUSY);
+}
+
+__maybe_unused
+static struct arm_smmu_ctx_desc *arm_smmu_alloc_shared_cd(struct mm_struct *mm)
+{
+	u16 asid;
+	int err = 0;
+	u64 tcr, par, reg;
+	struct arm_smmu_ctx_desc *cd;
+	struct arm_smmu_ctx_desc *ret = NULL;
+
+	asid = arm64_mm_context_get(mm);
+	if (!asid)
+		return ERR_PTR(-ESRCH);
+
+	cd = kzalloc(sizeof(*cd), GFP_KERNEL);
+	if (!cd) {
+		err = -ENOMEM;
+		goto out_put_context;
+	}
+
+	refcount_set(&cd->refs, 1);
+
+	mutex_lock(&arm_smmu_asid_lock);
+	ret = arm_smmu_share_asid(mm, asid);
+	if (ret) {
+		mutex_unlock(&arm_smmu_asid_lock);
+		goto out_free_cd;
+	}
+
+	err = xa_insert(&arm_smmu_asid_xa, asid, cd, GFP_KERNEL);
+	mutex_unlock(&arm_smmu_asid_lock);
+
+	if (err)
+		goto out_free_asid;
+
+	tcr = FIELD_PREP(CTXDESC_CD_0_TCR_T0SZ, 64ULL - vabits_actual) |
+	      FIELD_PREP(CTXDESC_CD_0_TCR_IRGN0, ARM_LPAE_TCR_RGN_WBWA) |
+	      FIELD_PREP(CTXDESC_CD_0_TCR_ORGN0, ARM_LPAE_TCR_RGN_WBWA) |
+	      FIELD_PREP(CTXDESC_CD_0_TCR_SH0, ARM_LPAE_TCR_SH_IS) |
+	      CTXDESC_CD_0_TCR_EPD1 | CTXDESC_CD_0_AA64;
+
+	switch (PAGE_SIZE) {
+	case SZ_4K:
+		tcr |= FIELD_PREP(CTXDESC_CD_0_TCR_TG0, ARM_LPAE_TCR_TG0_4K);
+		break;
+	case SZ_16K:
+		tcr |= FIELD_PREP(CTXDESC_CD_0_TCR_TG0, ARM_LPAE_TCR_TG0_16K);
+		break;
+	case SZ_64K:
+		tcr |= FIELD_PREP(CTXDESC_CD_0_TCR_TG0, ARM_LPAE_TCR_TG0_64K);
+		break;
+	default:
+		WARN_ON(1);
+		err = -EINVAL;
+		goto out_free_asid;
+	}
+
+	reg = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
+	par = cpuid_feature_extract_unsigned_field(reg, ID_AA64MMFR0_PARANGE_SHIFT);
+	tcr |= FIELD_PREP(CTXDESC_CD_0_TCR_IPS, par);
+
+	cd->ttbr = virt_to_phys(mm->pgd);
+	cd->tcr = tcr;
+	/*
+	 * MAIR value is pretty much constant and global, so we can just get it
+	 * from the current CPU register
+	 */
+	cd->mair = read_sysreg(mair_el1);
+	cd->asid = asid;
+	cd->mm = mm;
+
+	return cd;
+
+out_free_asid:
+	arm_smmu_free_asid(cd);
+out_free_cd:
+	kfree(cd);
+out_put_context:
+	arm64_mm_context_put(mm);
+	return err < 0 ? ERR_PTR(err) : ret;
+}
+
+__maybe_unused
+static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd)
+{
+	if (arm_smmu_free_asid(cd)) {
+		/* Unpin ASID */
+		arm64_mm_context_put(cd->mm);
+		kfree(cd);
+	}
+}