[PATCH v5 03/10] KVM: arm64: Add standard hypervisor firmware register

[Raghavendra Rao Ananta <rananta@google.com>]

Introduce the firmware register to hold the standard hypervisor
service calls (owner value 5) as a bitmap. The bitmap represents
the features that'll be enabled for the guest, as configured by
the user-space. Currently, this includes support only for
Paravirtualized time, represented by bit-0.

Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
---
 arch/arm64/include/asm/kvm_host.h |  2 ++
 arch/arm64/include/uapi/asm/kvm.h |  3 +++
 arch/arm64/kvm/hypercalls.c       | 21 ++++++++++++++++++---
 include/kvm/arm_hypercalls.h      |  4 ++++
 4 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 6e663383d7b4..20165242ebd9 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -105,9 +105,11 @@ struct kvm_arch_memory_slot {
  * struct kvm_smccc_features: Descriptor the hypercall services exposed to the guests
  *
  * @std_bmap: Bitmap of standard secure service calls
+ * @std_hyp_bmap: Bitmap of standard hypervisor service calls
  */
 struct kvm_smccc_features {
 	u64 std_bmap;
+	u64 std_hyp_bmap;
 };
 
 struct kvm_arch {
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 56e4bc58a355..67353bf4e69d 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -341,6 +341,9 @@ struct kvm_arm_copy_mte_tags {
 #define KVM_REG_ARM_STD_BMAP			KVM_REG_ARM_FW_FEAT_BMAP_REG(0)
 #define KVM_REG_ARM_STD_BIT_TRNG_V1_0		BIT(0)
 
+#define KVM_REG_ARM_STD_HYP_BMAP		KVM_REG_ARM_FW_FEAT_BMAP_REG(1)
+#define KVM_REG_ARM_STD_HYP_BIT_PV_TIME		BIT(0)
+
 /* Device Control API: ARM VGIC */
 #define KVM_DEV_ARM_VGIC_GRP_ADDR	0
 #define KVM_DEV_ARM_VGIC_GRP_DIST_REGS	1
diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
index cf04b5ee5f56..64ae6c7e7145 100644
--- a/arch/arm64/kvm/hypercalls.c
+++ b/arch/arm64/kvm/hypercalls.c
@@ -65,8 +65,6 @@ static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val)
 static const u32 hvc_func_default_allowed_list[] = {
 	ARM_SMCCC_VERSION_FUNC_ID,
 	ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
-	ARM_SMCCC_HV_PV_TIME_FEATURES,
-	ARM_SMCCC_HV_PV_TIME_ST,
 	ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID,
 	ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID,
 	ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID,
@@ -100,6 +98,10 @@ static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)
 	case ARM_SMCCC_TRNG_RND64:
 		return kvm_arm_fw_reg_feat_enabled(smccc_feat->std_bmap,
 						KVM_REG_ARM_STD_BIT_TRNG_V1_0);
+	case ARM_SMCCC_HV_PV_TIME_FEATURES:
+	case ARM_SMCCC_HV_PV_TIME_ST:
+		return kvm_arm_fw_reg_feat_enabled(smccc_feat->std_hyp_bmap,
+					KVM_REG_ARM_STD_HYP_BIT_PV_TIME);
 	default:
 		return kvm_hvc_call_default_allowed(vcpu, func_id);
 	}
@@ -107,6 +109,7 @@ static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)
 
 int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
 {
+	struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;
 	u32 func_id = smccc_get_function(vcpu);
 	u64 val[4] = {SMCCC_RET_NOT_SUPPORTED};
 	u32 feature;
@@ -170,7 +173,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
 			}
 			break;
 		case ARM_SMCCC_HV_PV_TIME_FEATURES:
-			val[0] = SMCCC_RET_SUCCESS;
+			if (kvm_arm_fw_reg_feat_enabled(smccc_feat->std_hyp_bmap,
+					KVM_REG_ARM_STD_HYP_BIT_PV_TIME))
+				val[0] = SMCCC_RET_SUCCESS;
 			break;
 		}
 		break;
@@ -216,6 +221,7 @@ static const u64 kvm_arm_fw_reg_ids[] = {
 	KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2,
 	KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3,
 	KVM_REG_ARM_STD_BMAP,
+	KVM_REG_ARM_STD_HYP_BMAP,
 };
 
 void kvm_arm_init_hypercalls(struct kvm *kvm)
@@ -223,6 +229,7 @@ void kvm_arm_init_hypercalls(struct kvm *kvm)
 	struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat;
 
 	smccc_feat->std_bmap = KVM_ARM_SMCCC_STD_FEATURES;
+	smccc_feat->std_hyp_bmap = KVM_ARM_SMCCC_STD_HYP_FEATURES;
 }
 
 int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
@@ -312,6 +319,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	case KVM_REG_ARM_STD_BMAP:
 		val = READ_ONCE(smccc_feat->std_bmap);
 		break;
+	case KVM_REG_ARM_STD_HYP_BMAP:
+		val = READ_ONCE(smccc_feat->std_hyp_bmap);
+		break;
 	default:
 		return -ENOENT;
 	}
@@ -334,6 +344,10 @@ static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val)
 		fw_reg_bmap = &smccc_feat->std_bmap;
 		fw_reg_features = KVM_ARM_SMCCC_STD_FEATURES;
 		break;
+	case KVM_REG_ARM_STD_HYP_BMAP:
+		fw_reg_bmap = &smccc_feat->std_hyp_bmap;
+		fw_reg_features = KVM_ARM_SMCCC_STD_HYP_FEATURES;
+		break;
 	default:
 		return -ENOENT;
 	}
@@ -438,6 +452,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 
 		return 0;
 	case KVM_REG_ARM_STD_BMAP:
+	case KVM_REG_ARM_STD_HYP_BMAP:
 		return kvm_arm_set_fw_reg_bmap(vcpu, reg->id, val);
 	default:
 		return -ENOENT;
diff --git a/include/kvm/arm_hypercalls.h b/include/kvm/arm_hypercalls.h
index fd3ff350ee9d..b0915d8c5b81 100644
--- a/include/kvm/arm_hypercalls.h
+++ b/include/kvm/arm_hypercalls.h
@@ -8,10 +8,14 @@
 
 /* Last valid bits of the bitmapped firmware registers */
 #define KVM_REG_ARM_STD_BMAP_BIT_MAX		0
+#define KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX	0
 
 #define KVM_ARM_SMCCC_STD_FEATURES \
 	GENMASK_ULL(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0)
 
+#define KVM_ARM_SMCCC_STD_HYP_FEATURES \
+	GENMASK_ULL(KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX, 0)
+
 int kvm_hvc_call_handler(struct kvm_vcpu *vcpu);
 
 static inline u32 smccc_get_function(struct kvm_vcpu *vcpu)
-- 
2.35.1.1094.g7c7d902a7c-goog

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