1 files changed, 336 insertions, 3 deletions

diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
index 30da78f72b3b..c9f401fa01a9 100644
--- a/arch/arm64/kvm/hypercalls.c
+++ b/arch/arm64/kvm/hypercalls.c
@@ -9,6 +9,13 @@
 #include <kvm/arm_hypercalls.h>
 #include <kvm/arm_psci.h>
 
+#define KVM_ARM_SMCCC_STD_FEATURES				\
+	GENMASK(KVM_REG_ARM_STD_BMAP_BIT_COUNT - 1, 0)
+#define KVM_ARM_SMCCC_STD_HYP_FEATURES				\
+	GENMASK(KVM_REG_ARM_STD_HYP_BMAP_BIT_COUNT - 1, 0)
+#define KVM_ARM_SMCCC_VENDOR_HYP_FEATURES			\
+	GENMASK(KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_COUNT - 1, 0)
+
 static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val)
 {
 	struct system_time_snapshot systime_snapshot;
@@ -58,13 +65,73 @@ static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val)
 	val[3] = lower_32_bits(cycles);
 }
 
+static bool kvm_hvc_call_default_allowed(u32 func_id)
+{
+	switch (func_id) {
+	/*
+	 * List of function-ids that are not gated with the bitmapped
+	 * feature firmware registers, and are to be allowed for
+	 * servicing the call by default.
+	 */
+	case ARM_SMCCC_VERSION_FUNC_ID:
+	case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
+		return true;
+	default:
+		/* PSCI 0.2 and up is in the 0:0x1f range */
+		if (ARM_SMCCC_OWNER_NUM(func_id) == ARM_SMCCC_OWNER_STANDARD &&
+		    ARM_SMCCC_FUNC_NUM(func_id) <= 0x1f)
+			return true;
+
+		/*
+		 * KVM's PSCI 0.1 doesn't comply with SMCCC, and has
+		 * its own function-id base and range
+		 */
+		if (func_id >= KVM_PSCI_FN(0) && func_id <= KVM_PSCI_FN(3))
+			return true;
+
+		return false;
+	}
+}
+
+static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)
+{
+	struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;
+
+	switch (func_id) {
+	case ARM_SMCCC_TRNG_VERSION:
+	case ARM_SMCCC_TRNG_FEATURES:
+	case ARM_SMCCC_TRNG_GET_UUID:
+	case ARM_SMCCC_TRNG_RND32:
+	case ARM_SMCCC_TRNG_RND64:
+		return test_bit(KVM_REG_ARM_STD_BIT_TRNG_V1_0,
+				&smccc_feat->std_bmap);
+	case ARM_SMCCC_HV_PV_TIME_FEATURES:
+	case ARM_SMCCC_HV_PV_TIME_ST:
+		return test_bit(KVM_REG_ARM_STD_HYP_BIT_PV_TIME,
+				&smccc_feat->std_hyp_bmap);
+	case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
+	case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID:
+		return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT,
+				&smccc_feat->vendor_hyp_bmap);
+	case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
+		return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_PTP,
+				&smccc_feat->vendor_hyp_bmap);
+	default:
+		return kvm_hvc_call_default_allowed(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;
 	gpa_t gpa;
 
+	if (!kvm_hvc_call_allowed(vcpu, func_id))
+		goto out;
+
 	switch (func_id) {
 	case ARM_SMCCC_VERSION_FUNC_ID:
 		val[0] = ARM_SMCCC_VERSION_1_1;
@@ -107,8 +174,22 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
 				break;
 			}
 			break;
+		case ARM_SMCCC_ARCH_WORKAROUND_3:
+			switch (arm64_get_spectre_bhb_state()) {
+			case SPECTRE_VULNERABLE:
+				break;
+			case SPECTRE_MITIGATED:
+				val[0] = SMCCC_RET_SUCCESS;
+				break;
+			case SPECTRE_UNAFFECTED:
+				val[0] = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
+				break;
+			}
+			break;
 		case ARM_SMCCC_HV_PV_TIME_FEATURES:
-			val[0] = SMCCC_RET_SUCCESS;
+			if (test_bit(KVM_REG_ARM_STD_HYP_BIT_PV_TIME,
+				     &smccc_feat->std_hyp_bmap))
+				val[0] = SMCCC_RET_SUCCESS;
 			break;
 		}
 		break;
@@ -127,8 +208,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
 		val[3] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3;
 		break;
 	case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
-		val[0] = BIT(ARM_SMCCC_KVM_FUNC_FEATURES);
-		val[0] |= BIT(ARM_SMCCC_KVM_FUNC_PTP);
+		val[0] = smccc_feat->vendor_hyp_bmap;
 		break;
 	case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
 		kvm_ptp_get_time(vcpu, val);
@@ -143,6 +223,259 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
 		return kvm_psci_call(vcpu);
 	}
 
+out:
 	smccc_set_retval(vcpu, val[0], val[1], val[2], val[3]);
 	return 1;
 }
+
+static const u64 kvm_arm_fw_reg_ids[] = {
+	KVM_REG_ARM_PSCI_VERSION,
+	KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1,
+	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,
+	KVM_REG_ARM_VENDOR_HYP_BMAP,
+};
+
+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;
+	smccc_feat->vendor_hyp_bmap = KVM_ARM_SMCCC_VENDOR_HYP_FEATURES;
+}
+
+int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
+{
+	return ARRAY_SIZE(kvm_arm_fw_reg_ids);
+}
+
+int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(kvm_arm_fw_reg_ids); i++) {
+		if (put_user(kvm_arm_fw_reg_ids[i], uindices++))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+#define KVM_REG_FEATURE_LEVEL_MASK	GENMASK(3, 0)
+
+/*
+ * Convert the workaround level into an easy-to-compare number, where higher
+ * values mean better protection.
+ */
+static int get_kernel_wa_level(u64 regid)
+{
+	switch (regid) {
+	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
+		switch (arm64_get_spectre_v2_state()) {
+		case SPECTRE_VULNERABLE:
+			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
+		case SPECTRE_MITIGATED:
+			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_AVAIL;
+		case SPECTRE_UNAFFECTED:
+			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_REQUIRED;
+		}
+		return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
+	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
+		switch (arm64_get_spectre_v4_state()) {
+		case SPECTRE_MITIGATED:
+			/*
+			 * As for the hypercall discovery, we pretend we
+			 * don't have any FW mitigation if SSBS is there at
+			 * all times.
+			 */
+			if (cpus_have_final_cap(ARM64_SSBS))
+				return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
+			fallthrough;
+		case SPECTRE_UNAFFECTED:
+			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
+		case SPECTRE_VULNERABLE:
+			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
+		}
+		break;
+	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
+		switch (arm64_get_spectre_bhb_state()) {
+		case SPECTRE_VULNERABLE:
+			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL;
+		case SPECTRE_MITIGATED:
+			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_AVAIL;
+		case SPECTRE_UNAFFECTED:
+			return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_REQUIRED;
+		}
+		return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL;
+	}
+
+	return -EINVAL;
+}
+
+int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+	struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;
+	void __user *uaddr = (void __user *)(long)reg->addr;
+	u64 val;
+
+	switch (reg->id) {
+	case KVM_REG_ARM_PSCI_VERSION:
+		val = kvm_psci_version(vcpu);
+		break;
+	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
+	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
+	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
+		val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK;
+		break;
+	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;
+	case KVM_REG_ARM_VENDOR_HYP_BMAP:
+		val = READ_ONCE(smccc_feat->vendor_hyp_bmap);
+		break;
+	default:
+		return -ENOENT;
+	}
+
+	if (copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val)
+{
+	int ret = 0;
+	struct kvm *kvm = vcpu->kvm;
+	struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat;
+	unsigned long *fw_reg_bmap, fw_reg_features;
+
+	switch (reg_id) {
+	case KVM_REG_ARM_STD_BMAP:
+		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;
+	case KVM_REG_ARM_VENDOR_HYP_BMAP:
+		fw_reg_bmap = &smccc_feat->vendor_hyp_bmap;
+		fw_reg_features = KVM_ARM_SMCCC_VENDOR_HYP_FEATURES;
+		break;
+	default:
+		return -ENOENT;
+	}
+
+	/* Check for unsupported bit */
+	if (val & ~fw_reg_features)
+		return -EINVAL;
+
+	mutex_lock(&kvm->lock);
+
+	if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &kvm->arch.flags) &&
+	    val != *fw_reg_bmap) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	WRITE_ONCE(*fw_reg_bmap, val);
+out:
+	mutex_unlock(&kvm->lock);
+	return ret;
+}
+
+int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+	void __user *uaddr = (void __user *)(long)reg->addr;
+	u64 val;
+	int wa_level;
+
+	if (copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id)))
+		return -EFAULT;
+
+	switch (reg->id) {
+	case KVM_REG_ARM_PSCI_VERSION:
+	{
+		bool wants_02;
+
+		wants_02 = test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features);
+
+		switch (val) {
+		case KVM_ARM_PSCI_0_1:
+			if (wants_02)
+				return -EINVAL;
+			vcpu->kvm->arch.psci_version = val;
+			return 0;
+		case KVM_ARM_PSCI_0_2:
+		case KVM_ARM_PSCI_1_0:
+		case KVM_ARM_PSCI_1_1:
+			if (!wants_02)
+				return -EINVAL;
+			vcpu->kvm->arch.psci_version = val;
+			return 0;
+		}
+		break;
+	}
+
+	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
+	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
+		if (val & ~KVM_REG_FEATURE_LEVEL_MASK)
+			return -EINVAL;
+
+		if (get_kernel_wa_level(reg->id) < val)
+			return -EINVAL;
+
+		return 0;
+
+	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
+		if (val & ~(KVM_REG_FEATURE_LEVEL_MASK |
+			    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED))
+			return -EINVAL;
+
+		/* The enabled bit must not be set unless the level is AVAIL. */
+		if ((val & KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED) &&
+		    (val & KVM_REG_FEATURE_LEVEL_MASK) != KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL)
+			return -EINVAL;
+
+		/*
+		 * Map all the possible incoming states to the only two we
+		 * really want to deal with.
+		 */
+		switch (val & KVM_REG_FEATURE_LEVEL_MASK) {
+		case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL:
+		case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN:
+			wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
+			break;
+		case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL:
+		case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED:
+			wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		/*
+		 * We can deal with NOT_AVAIL on NOT_REQUIRED, but not the
+		 * other way around.
+		 */
+		if (get_kernel_wa_level(reg->id) < wa_level)
+			return -EINVAL;
+
+		return 0;
+	case KVM_REG_ARM_STD_BMAP:
+	case KVM_REG_ARM_STD_HYP_BMAP:
+	case KVM_REG_ARM_VENDOR_HYP_BMAP:
+		return kvm_arm_set_fw_reg_bmap(vcpu, reg->id, val);
+	default:
+		return -ENOENT;
+	}
+
+	return -EINVAL;
+}