[PATCH v8 12/25] iommu/arm-smmu-v3-kvm: Probe SMMU HW

[Mostafa Saleh]

Probe SMMU features from the IDR register space. Most of
the logic is common with the kernel.

The hypervisor enforces 2 extra requirements:
- Cache coherency.
- Nested translation support.

Signed-off-by: Mostafa Saleh <smostafa at google.com>
---
 .../arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h    |  4 ++
 .../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c  | 47 +++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
index 17b9454dab85..91177f00fa97 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
@@ -11,6 +11,9 @@
  *
  * Other members are filled and used at runtime by the SMMU driver.
  * @base		Virtual address of SMMU registers
+ * @oas			PA size
+ * @pgsize_bitmap	Supported page sizes
+ * @sid_bits		Max number of SID bits supported
  */
 struct hyp_arm_smmu_v3_device {
 	phys_addr_t		mmio_addr;
@@ -20,6 +23,7 @@ struct hyp_arm_smmu_v3_device {
 	u32			options;
 	unsigned long		oas;
 	unsigned long		pgsize_bitmap;
+	unsigned int		sid_bits;
 };
 
 extern size_t kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count);
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index 7022d38e75c4..f8b7c5406017 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -29,6 +29,47 @@ static void smmu_deinit_device(struct hyp_arm_smmu_v3_device *smmu)
 	smmu->base = NULL;
 }
 
+/*
+ * Mini-probe and validation for the hypervisor.
+ */
+static int smmu_probe(struct hyp_arm_smmu_v3_device *smmu)
+{
+	u32 reg;
+
+	if (!(smmu->features & ARM_SMMU_FEAT_COHERENCY))
+		return -EINVAL;
+
+	reg = arm_smmu_idr0_probe(smmu);
+
+	if (!(FIELD_GET(IDR0_TTF, reg) & IDR0_TTF_AARCH64))
+		return -ENXIO;
+
+	if (!(smmu->features & (ARM_SMMU_FEAT_TT_LE | ARM_SMMU_FEAT_TT_BE)))
+		return -ENXIO;
+
+	reg = readl_relaxed(smmu->base + ARM_SMMU_IDR1);
+	if (reg & (IDR1_TABLES_PRESET | IDR1_QUEUES_PRESET | IDR1_REL))
+		return -EINVAL;
+
+	smmu->sid_bits = FIELD_GET(IDR1_SIDSIZE, reg);
+	/* Follows the kernel logic */
+	if (smmu->sid_bits <= STRTAB_SPLIT)
+		smmu->features &= ~ARM_SMMU_FEAT_2_LVL_STRTAB;
+
+	arm_smmu_idr3_probe(smmu);
+
+	arm_smmu_idr5_probe(smmu);
+	if (!smmu->oas)
+		smmu->oas = 48;
+
+	arm_smmu_device_iidr_probe(smmu);
+
+	if (!(smmu->features & ARM_SMMU_FEAT_NESTING))
+		return -ENXIO;
+
+	return 0;
+}
+
 static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
 {
 	unsigned long haddr;
@@ -43,8 +84,14 @@ static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
 		return ret;
 
 	smmu->base = (void __iomem *)haddr;
+	ret = smmu_probe(smmu);
+	if (ret)
+		goto out_ret;
 
 	return 0;
+out_ret:
+	smmu_deinit_device(smmu);
+	return ret;
 }
 
 /* Called while is the host is still trusted. */
-- 
2.55.0.1082.g2b9226bbc0-goog