Merge branch kvm-arm64/hcall-selection into kvmarm-master/next

* kvm-arm64/hcall-selection:
  : .
  : Introduce a new set of virtual sysregs for userspace to
  : select the hypercalls it wants to see exposed to the guest.
  :
  : Patches courtesy of Raghavendra and Oliver.
  : .
  KVM: arm64: Fix hypercall bitmap writeback when vcpus have already run
  KVM: arm64: Hide KVM_REG_ARM_*_BMAP_BIT_COUNT from userspace
  Documentation: Fix index.rst after psci.rst renaming
  selftests: KVM: aarch64: Add the bitmap firmware registers to get-reg-list
  selftests: KVM: aarch64: Introduce hypercall ABI test
  selftests: KVM: Create helper for making SMCCC calls
  selftests: KVM: Rename psci_cpu_on_test to psci_test
  tools: Import ARM SMCCC definitions
  Docs: KVM: Add doc for the bitmap firmware registers
  Docs: KVM: Rename psci.rst to hypercalls.rst
  KVM: arm64: Add vendor hypervisor firmware register
  KVM: arm64: Add standard hypervisor firmware register
  KVM: arm64: Setup a framework for hypercall bitmap firmware registers
  KVM: arm64: Factor out firmware register handling from psci.c
Signed-off-by: Marc Zyngier <maz@kernel.org>

Documentation/virt/kvm/api.rst

@@ -2601,6 +2601,24 @@ EINVAL.
 After the vcpu's SVE configuration is finalized, further attempts to
 write this register will fail with EPERM.
 
+arm64 bitmap feature firmware pseudo-registers have the following bit pattern::
+
+  0x6030 0000 0016 <regno:16>
+
+The bitmap feature firmware registers exposes the hypercall services that
+are available for userspace to configure. The set bits corresponds to the
+services that are available for the guests to access. By default, KVM
+sets all the supported bits during VM initialization. The userspace can
+discover the available services via KVM_GET_ONE_REG, and write back the
+bitmap corresponding to the features that it wishes guests to see via
+KVM_SET_ONE_REG.
+
+Note: These registers are immutable once any of the vCPUs of the VM has
+run at least once. A KVM_SET_ONE_REG in such a scenario will return
+a -EBUSY to userspace.
+
+(See Documentation/virt/kvm/arm/hypercalls.rst for more details.)
+
 
 MIPS registers are mapped using the lower 32 bits.  The upper 16 of that is
 the register group type:

Documentation/virt/kvm/arm/psci.rst → Documentation/virt/kvm/arm/hypercalls.rst

 .. SPDX-License-Identifier: GPL-2.0
 
-=========================================
-Power State Coordination Interface (PSCI)
-=========================================
+=======================
+ARM Hypercall Interface
+=======================
 
-KVM implements the PSCI (Power State Coordination Interface)
-specification in order to provide services such as CPU on/off, reset
-and power-off to the guest.
+KVM handles the hypercall services as requested by the guests. New hypercall
+services are regularly made available by the ARM specification or by KVM (as
+vendor services) if they make sense from a virtualization point of view.
 
-The PSCI specification is regularly updated to provide new features,
-and KVM implements these updates if they make sense from a virtualization
-point of view.
-
-This means that a guest booted on two different versions of KVM can
-observe two different "firmware" revisions. This could cause issues if
-a given guest is tied to a particular PSCI revision (unlikely), or if
-a migration causes a different PSCI version to be exposed out of the
-blue to an unsuspecting guest.
+This means that a guest booted on two different versions of KVM can observe
+two different "firmware" revisions. This could cause issues if a given guest
+is tied to a particular version of a hypercall service, or if a migration
+causes a different version to be exposed out of the blue to an unsuspecting
+guest.
 
 In order to remedy this situation, KVM exposes a set of "firmware
 pseudo-registers" that can be manipulated using the GET/SET_ONE_REG
 interface. These registers can be saved/restored by userspace, and set
-to a convenient value if required.
+to a convenient value as required.
 
-The following register is defined:
+The following registers are defined:
 
 * KVM_REG_ARM_PSCI_VERSION:
 
+  KVM implements the PSCI (Power State Coordination Interface)
+  specification in order to provide services such as CPU on/off, reset
+  and power-off to the guest.
+
   - Only valid if the vcpu has the KVM_ARM_VCPU_PSCI_0_2 feature set
     (and thus has already been initialized)
   - Returns the current PSCI version on GET_ONE_REG (defaulting to the
@@ -74,4 +74,65 @@ The following register is defined:
     KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED:
       The workaround is always active on this vCPU or it is not needed.
 
+
+Bitmap Feature Firmware Registers
+---------------------------------
+
+Contrary to the above registers, the following registers exposes the
+hypercall services in the form of a feature-bitmap to the userspace. This
+bitmap is translated to the services that are available to the guest.
+There is a register defined per service call owner and can be accessed via
+GET/SET_ONE_REG interface.
+
+By default, these registers are set with the upper limit of the features
+that are supported. This way userspace can discover all the usable
+hypercall services via GET_ONE_REG. The user-space can write-back the
+desired bitmap back via SET_ONE_REG. The features for the registers that
+are untouched, probably because userspace isn't aware of them, will be
+exposed as is to the guest.
+
+Note that KVM will not allow the userspace to configure the registers
+anymore once any of the vCPUs has run at least once. Instead, it will
+return a -EBUSY.
+
+The pseudo-firmware bitmap register are as follows:
+
+* KVM_REG_ARM_STD_BMAP:
+    Controls the bitmap of the ARM Standard Secure Service Calls.
+
+  The following bits are accepted:
+
+    Bit-0: KVM_REG_ARM_STD_BIT_TRNG_V1_0:
+      The bit represents the services offered under v1.0 of ARM True Random
+      Number Generator (TRNG) specification, ARM DEN0098.
+
+* KVM_REG_ARM_STD_HYP_BMAP:
+    Controls the bitmap of the ARM Standard Hypervisor Service Calls.
+
+  The following bits are accepted:
+
+    Bit-0: KVM_REG_ARM_STD_HYP_BIT_PV_TIME:
+      The bit represents the Paravirtualized Time service as represented by
+      ARM DEN0057A.
+
+* KVM_REG_ARM_VENDOR_HYP_BMAP:
+    Controls the bitmap of the Vendor specific Hypervisor Service Calls.
+
+  The following bits are accepted:
+
+    Bit-0: KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT
+      The bit represents the ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID
+      and ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID function-ids.
+
+    Bit-1: KVM_REG_ARM_VENDOR_HYP_BIT_PTP:
+      The bit represents the Precision Time Protocol KVM service.
+
+Errors:
+
+    =======  =============================================================
+    -ENOENT   Unknown register accessed.
+    -EBUSY    Attempt a 'write' to the register after the VM has started.
+    -EINVAL   Invalid bitmap written to the register.
+    =======  =============================================================
+
 .. [1] https://developer.arm.com/-/media/developer/pdf/ARM_DEN_0070A_Firmware_interfaces_for_mitigating_CVE-2017-5715.pdf

Documentation/virt/kvm/arm/index.rst

@@ -8,6 +8,6 @@ ARM
    :maxdepth: 2
 
    hyp-abi
-   psci
+   hypercalls
    pvtime
    ptp_kvm

arch/arm64/include/asm/kvm_host.h

@@ -101,6 +101,19 @@ struct kvm_s2_mmu {
 struct kvm_arch_memory_slot {
 };
 
+/**
+ * struct kvm_smccc_features: Descriptor of the hypercall services exposed to the guests
+ *
+ * @std_bmap: Bitmap of standard secure service calls
+ * @std_hyp_bmap: Bitmap of standard hypervisor service calls
+ * @vendor_hyp_bmap: Bitmap of vendor specific hypervisor service calls
+ */
+struct kvm_smccc_features {
+	unsigned long std_bmap;
+	unsigned long std_hyp_bmap;
+	unsigned long vendor_hyp_bmap;
+};
+
 struct kvm_arch {
 	struct kvm_s2_mmu mmu;
 
@@ -150,6 +163,9 @@ struct kvm_arch {
 
 	u8 pfr0_csv2;
 	u8 pfr0_csv3;
+
+	/* Hypercall features firmware registers' descriptor */
+	struct kvm_smccc_features smccc_feat;
 };
 
 struct kvm_vcpu_fault_info {

arch/arm64/include/uapi/asm/kvm.h

@@ -332,6 +332,40 @@ struct kvm_arm_copy_mte_tags {
 #define KVM_ARM64_SVE_VLS_WORDS	\
 	((KVM_ARM64_SVE_VQ_MAX - KVM_ARM64_SVE_VQ_MIN) / 64 + 1)
 
+/* Bitmap feature firmware registers */
+#define KVM_REG_ARM_FW_FEAT_BMAP		(0x0016 << KVM_REG_ARM_COPROC_SHIFT)
+#define KVM_REG_ARM_FW_FEAT_BMAP_REG(r)		(KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \
+						KVM_REG_ARM_FW_FEAT_BMAP |	\
+						((r) & 0xffff))
+
+#define KVM_REG_ARM_STD_BMAP			KVM_REG_ARM_FW_FEAT_BMAP_REG(0)
+
+enum {
+	KVM_REG_ARM_STD_BIT_TRNG_V1_0	= 0,
+#ifdef __KERNEL__
+	KVM_REG_ARM_STD_BMAP_BIT_COUNT,
+#endif
+};
+
+#define KVM_REG_ARM_STD_HYP_BMAP		KVM_REG_ARM_FW_FEAT_BMAP_REG(1)
+
+enum {
+	KVM_REG_ARM_STD_HYP_BIT_PV_TIME	= 0,
+#ifdef __KERNEL__
+	KVM_REG_ARM_STD_HYP_BMAP_BIT_COUNT,
+#endif
+};
+
+#define KVM_REG_ARM_VENDOR_HYP_BMAP		KVM_REG_ARM_FW_FEAT_BMAP_REG(2)
+
+enum {
+	KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT	= 0,
+	KVM_REG_ARM_VENDOR_HYP_BIT_PTP		= 1,
+#ifdef __KERNEL__
+	KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_COUNT,
+#endif
+};
+
 /* Device Control API: ARM VGIC */
 #define KVM_DEV_ARM_VGIC_GRP_ADDR	0
 #define KVM_DEV_ARM_VGIC_GRP_DIST_REGS	1

arch/arm64/kvm/arm.c

@@ -156,6 +156,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 	kvm->arch.max_vcpus = kvm_arm_default_max_vcpus();
 
 	set_default_spectre(kvm);
+	kvm_arm_init_hypercalls(kvm);
 
 	return ret;
 out_free_stage2_pgd:

arch/arm64/kvm/guest.c

@@ -18,7 +18,7 @@
 #include <linux/string.h>
 #include <linux/vmalloc.h>
 #include <linux/fs.h>
-#include <kvm/arm_psci.h>
+#include <kvm/arm_hypercalls.h>
 #include <asm/cputype.h>
 #include <linux/uaccess.h>
 #include <asm/fpsimd.h>
@@ -756,7 +756,9 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 
 	switch (reg->id & KVM_REG_ARM_COPROC_MASK) {
 	case KVM_REG_ARM_CORE:	return get_core_reg(vcpu, reg);
-	case KVM_REG_ARM_FW:	return kvm_arm_get_fw_reg(vcpu, reg);
+	case KVM_REG_ARM_FW:
+	case KVM_REG_ARM_FW_FEAT_BMAP:
+		return kvm_arm_get_fw_reg(vcpu, reg);
 	case KVM_REG_ARM64_SVE:	return get_sve_reg(vcpu, reg);
 	}
 
@@ -774,7 +776,9 @@ int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 
 	switch (reg->id & KVM_REG_ARM_COPROC_MASK) {
 	case KVM_REG_ARM_CORE:	return set_core_reg(vcpu, reg);
-	case KVM_REG_ARM_FW:	return kvm_arm_set_fw_reg(vcpu, reg);
+	case KVM_REG_ARM_FW:
+	case KVM_REG_ARM_FW_FEAT_BMAP:
+		return kvm_arm_set_fw_reg(vcpu, reg);
 	case KVM_REG_ARM64_SVE:	return set_sve_reg(vcpu, reg);
 	}
 

arch/arm64/kvm/psci.c

@@ -437,186 +437,3 @@ int kvm_psci_call(struct kvm_vcpu *vcpu)
 		return -EINVAL;
 	}
 }
-
-int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
-{
-	return 4;		/* PSCI version and three workaround registers */
-}
-
-int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
-{
-	if (put_user(KVM_REG_ARM_PSCI_VERSION, uindices++))
-		return -EFAULT;
-
-	if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1, uindices++))
-		return -EFAULT;
-
-	if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2, uindices++))
-		return -EFAULT;
-
-	if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3, uindices++))
-		return -EFAULT;
-
-	return 0;
-}
-
-#define KVM_REG_FEATURE_LEVEL_WIDTH	4
-#define KVM_REG_FEATURE_LEVEL_MASK	(BIT(KVM_REG_FEATURE_LEVEL_WIDTH) - 1)
-
-/*
- * 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)
-{
-	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;
-	default:
-		return -ENOENT;
-	}
-
-	if (copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)))
-		return -EFAULT;
-
-	return 0;
-}
-
-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;
-	default:
-		return -ENOENT;
-	}
-
-	return -EINVAL;
-}

include/kvm/arm_hypercalls.h

@@ -40,4 +40,12 @@ static inline void smccc_set_retval(struct kvm_vcpu *vcpu,
 	vcpu_set_reg(vcpu, 3, a3);
 }
 
+struct kvm_one_reg;
+
+void kvm_arm_init_hypercalls(struct kvm *kvm);
+int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu);
+int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices);
+int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
+int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
+
 #endif

include/kvm/arm_psci.h

@@ -39,11 +39,4 @@ static inline int kvm_psci_version(struct kvm_vcpu *vcpu)
 
 int kvm_psci_call(struct kvm_vcpu *vcpu);
 
-struct kvm_one_reg;
-
-int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu);
-int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices);
-int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
-int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg);
-
 #endif /* __KVM_ARM_PSCI_H__ */

tools/include/linux/arm-smccc.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2015, Linaro Limited
+ */
+#ifndef __LINUX_ARM_SMCCC_H
+#define __LINUX_ARM_SMCCC_H
+
+#include <linux/const.h>
+
+/*
+ * This file provides common defines for ARM SMC Calling Convention as
+ * specified in
+ * https://developer.arm.com/docs/den0028/latest
+ *
+ * This code is up-to-date with version DEN 0028 C
+ */
+
+#define ARM_SMCCC_STD_CALL	        _AC(0,U)
+#define ARM_SMCCC_FAST_CALL	        _AC(1,U)
+#define ARM_SMCCC_TYPE_SHIFT		31
+
+#define ARM_SMCCC_SMC_32		0
+#define ARM_SMCCC_SMC_64		1
+#define ARM_SMCCC_CALL_CONV_SHIFT	30
+
+#define ARM_SMCCC_OWNER_MASK		0x3F
+#define ARM_SMCCC_OWNER_SHIFT		24
+
+#define ARM_SMCCC_FUNC_MASK		0xFFFF
+
+#define ARM_SMCCC_IS_FAST_CALL(smc_val)	\
+	((smc_val) & (ARM_SMCCC_FAST_CALL << ARM_SMCCC_TYPE_SHIFT))
+#define ARM_SMCCC_IS_64(smc_val) \
+	((smc_val) & (ARM_SMCCC_SMC_64 << ARM_SMCCC_CALL_CONV_SHIFT))
+#define ARM_SMCCC_FUNC_NUM(smc_val)	((smc_val) & ARM_SMCCC_FUNC_MASK)
+#define ARM_SMCCC_OWNER_NUM(smc_val) \
+	(((smc_val) >> ARM_SMCCC_OWNER_SHIFT) & ARM_SMCCC_OWNER_MASK)
+
+#define ARM_SMCCC_CALL_VAL(type, calling_convention, owner, func_num) \
+	(((type) << ARM_SMCCC_TYPE_SHIFT) | \
+	((calling_convention) << ARM_SMCCC_CALL_CONV_SHIFT) | \
+	(((owner) & ARM_SMCCC_OWNER_MASK) << ARM_SMCCC_OWNER_SHIFT) | \
+	((func_num) & ARM_SMCCC_FUNC_MASK))
+
+#define ARM_SMCCC_OWNER_ARCH		0
+#define ARM_SMCCC_OWNER_CPU		1
+#define ARM_SMCCC_OWNER_SIP		2
+#define ARM_SMCCC_OWNER_OEM		3
+#define ARM_SMCCC_OWNER_STANDARD	4
+#define ARM_SMCCC_OWNER_STANDARD_HYP	5
+#define ARM_SMCCC_OWNER_VENDOR_HYP	6
+#define ARM_SMCCC_OWNER_TRUSTED_APP	48
+#define ARM_SMCCC_OWNER_TRUSTED_APP_END	49
+#define ARM_SMCCC_OWNER_TRUSTED_OS	50
+#define ARM_SMCCC_OWNER_TRUSTED_OS_END	63
+
+#define ARM_SMCCC_FUNC_QUERY_CALL_UID  0xff01
+
+#define ARM_SMCCC_QUIRK_NONE		0
+#define ARM_SMCCC_QUIRK_QCOM_A6		1 /* Save/restore register a6 */
+
+#define ARM_SMCCC_VERSION_1_0		0x10000
+#define ARM_SMCCC_VERSION_1_1		0x10001
+#define ARM_SMCCC_VERSION_1_2		0x10002
+#define ARM_SMCCC_VERSION_1_3		0x10003
+
+#define ARM_SMCCC_1_3_SVE_HINT		0x10000
+
+#define ARM_SMCCC_VERSION_FUNC_ID					\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
+			   ARM_SMCCC_SMC_32,				\
+			   0, 0)
+
+#define ARM_SMCCC_ARCH_FEATURES_FUNC_ID					\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
+			   ARM_SMCCC_SMC_32,				\
+			   0, 1)
+
+#define ARM_SMCCC_ARCH_SOC_ID						\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
+			   ARM_SMCCC_SMC_32,				\
+			   0, 2)
+
+#define ARM_SMCCC_ARCH_WORKAROUND_1					\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
+			   ARM_SMCCC_SMC_32,				\
+			   0, 0x8000)
+
+#define ARM_SMCCC_ARCH_WORKAROUND_2					\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
+			   ARM_SMCCC_SMC_32,				\
+			   0, 0x7fff)
+
+#define ARM_SMCCC_ARCH_WORKAROUND_3					\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
+			   ARM_SMCCC_SMC_32,				\
+			   0, 0x3fff)
+
+#define ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID				\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
+			   ARM_SMCCC_SMC_32,				\
+			   ARM_SMCCC_OWNER_VENDOR_HYP,			\
+			   ARM_SMCCC_FUNC_QUERY_CALL_UID)
+
+/* KVM UID value: 28b46fb6-2ec5-11e9-a9ca-4b564d003a74 */
+#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0	0xb66fb428U
+#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1	0xe911c52eU
+#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2	0x564bcaa9U
+#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3	0x743a004dU
+
+/* KVM "vendor specific" services */
+#define ARM_SMCCC_KVM_FUNC_FEATURES		0
+#define ARM_SMCCC_KVM_FUNC_PTP			1
+#define ARM_SMCCC_KVM_FUNC_FEATURES_2		127
+#define ARM_SMCCC_KVM_NUM_FUNCS			128
+
+#define ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID			\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
+			   ARM_SMCCC_SMC_32,				\
+			   ARM_SMCCC_OWNER_VENDOR_HYP,			\
+			   ARM_SMCCC_KVM_FUNC_FEATURES)
+
+#define SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED	1
+
+/*
+ * ptp_kvm is a feature used for time sync between vm and host.
+ * ptp_kvm module in guest kernel will get service from host using
+ * this hypercall ID.
+ */
+#define ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID				\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
+			   ARM_SMCCC_SMC_32,				\
+			   ARM_SMCCC_OWNER_VENDOR_HYP,			\
+			   ARM_SMCCC_KVM_FUNC_PTP)
+
+/* ptp_kvm counter type ID */
+#define KVM_PTP_VIRT_COUNTER			0
+#define KVM_PTP_PHYS_COUNTER			1
+
+/* Paravirtualised time calls (defined by ARM DEN0057A) */
+#define ARM_SMCCC_HV_PV_TIME_FEATURES				\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\
+			   ARM_SMCCC_SMC_64,			\
+			   ARM_SMCCC_OWNER_STANDARD_HYP,	\
+			   0x20)
+
+#define ARM_SMCCC_HV_PV_TIME_ST					\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\
+			   ARM_SMCCC_SMC_64,			\
+			   ARM_SMCCC_OWNER_STANDARD_HYP,	\
+			   0x21)
+
+/* TRNG entropy source calls (defined by ARM DEN0098) */
+#define ARM_SMCCC_TRNG_VERSION					\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\
+			   ARM_SMCCC_SMC_32,			\
+			   ARM_SMCCC_OWNER_STANDARD,		\
+			   0x50)
+
+#define ARM_SMCCC_TRNG_FEATURES					\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\
+			   ARM_SMCCC_SMC_32,			\
+			   ARM_SMCCC_OWNER_STANDARD,		\
+			   0x51)
+
+#define ARM_SMCCC_TRNG_GET_UUID					\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\
+			   ARM_SMCCC_SMC_32,			\
+			   ARM_SMCCC_OWNER_STANDARD,		\
+			   0x52)
+
+#define ARM_SMCCC_TRNG_RND32					\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\
+			   ARM_SMCCC_SMC_32,			\
+			   ARM_SMCCC_OWNER_STANDARD,		\
+			   0x53)
+
+#define ARM_SMCCC_TRNG_RND64					\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\
+			   ARM_SMCCC_SMC_64,			\
+			   ARM_SMCCC_OWNER_STANDARD,		\
+			   0x53)
+
+/*
+ * Return codes defined in ARM DEN 0070A
+ * ARM DEN 0070A is now merged/consolidated into ARM DEN 0028 C
+ */
+#define SMCCC_RET_SUCCESS			0
+#define SMCCC_RET_NOT_SUPPORTED			-1
+#define SMCCC_RET_NOT_REQUIRED			-2
+#define SMCCC_RET_INVALID_PARAMETER		-3
+
+#endif /*__LINUX_ARM_SMCCC_H*/

tools/testing/selftests/kvm/.gitignore

@@ -2,7 +2,8 @@
 /aarch64/arch_timer
 /aarch64/debug-exceptions
 /aarch64/get-reg-list
-/aarch64/psci_cpu_on_test
+/aarch64/hypercalls
+/aarch64/psci_test
 /aarch64/vcpu_width_config
 /aarch64/vgic_init
 /aarch64/vgic_irq

tools/testing/selftests/kvm/Makefile

@@ -105,7 +105,8 @@ TEST_GEN_PROGS_x86_64 += system_counter_offset_test
 TEST_GEN_PROGS_aarch64 += aarch64/arch_timer
 TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions
 TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list
-TEST_GEN_PROGS_aarch64 += aarch64/psci_cpu_on_test
+TEST_GEN_PROGS_aarch64 += aarch64/hypercalls
+TEST_GEN_PROGS_aarch64 += aarch64/psci_test
 TEST_GEN_PROGS_aarch64 += aarch64/vcpu_width_config
 TEST_GEN_PROGS_aarch64 += aarch64/vgic_init
 TEST_GEN_PROGS_aarch64 += aarch64/vgic_irq

tools/testing/selftests/kvm/aarch64/get-reg-list.c

@@ -294,6 +294,11 @@ static void print_reg(struct vcpu_config *c, __u64 id)
 			    "%s: Unexpected bits set in FW reg id: 0x%llx", config_name(c), id);
 		printf("\tKVM_REG_ARM_FW_REG(%lld),\n", id & 0xffff);
 		break;
+	case KVM_REG_ARM_FW_FEAT_BMAP:
+		TEST_ASSERT(id == KVM_REG_ARM_FW_FEAT_BMAP_REG(id & 0xffff),
+			    "%s: Unexpected bits set in the bitmap feature FW reg id: 0x%llx", config_name(c), id);
+		printf("\tKVM_REG_ARM_FW_FEAT_BMAP_REG(%lld),\n", id & 0xffff);
+		break;
 	case KVM_REG_ARM64_SVE:
 		if (has_cap(c, KVM_CAP_ARM_SVE))
 			printf("\t%s,\n", sve_id_to_str(c, id));
@@ -692,6 +697,9 @@ static __u64 base_regs[] = {
 	KVM_REG_ARM_FW_REG(1),		/* KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1 */
 	KVM_REG_ARM_FW_REG(2),		/* KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2 */
 	KVM_REG_ARM_FW_REG(3),		/* KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3 */
+	KVM_REG_ARM_FW_FEAT_BMAP_REG(0),	/* KVM_REG_ARM_STD_BMAP */
+	KVM_REG_ARM_FW_FEAT_BMAP_REG(1),	/* KVM_REG_ARM_STD_HYP_BMAP */
+	KVM_REG_ARM_FW_FEAT_BMAP_REG(2),	/* KVM_REG_ARM_VENDOR_HYP_BMAP */
 	ARM64_SYS_REG(3, 3, 14, 3, 1),	/* CNTV_CTL_EL0 */
 	ARM64_SYS_REG(3, 3, 14, 3, 2),	/* CNTV_CVAL_EL0 */
 	ARM64_SYS_REG(3, 3, 14, 0, 2),

tools/testing/selftests/kvm/aarch64/hypercalls.c

+// SPDX-License-Identifier: GPL-2.0-only
+
+/* hypercalls: Check the ARM64's psuedo-firmware bitmap register interface.
+ *
+ * The test validates the basic hypercall functionalities that are exposed
+ * via the psuedo-firmware bitmap register. This includes the registers'
+ * read/write behavior before and after the VM has started, and if the
+ * hypercalls are properly masked or unmasked to the guest when disabled or
+ * enabled from the KVM userspace, respectively.
+ */
+
+#include <errno.h>
+#include <linux/arm-smccc.h>
+#include <asm/kvm.h>
+#include <kvm_util.h>
+
+#include "processor.h"
+
+#define FW_REG_ULIMIT_VAL(max_feat_bit) (GENMASK(max_feat_bit, 0))
+
+/* 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_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX	1
+
+struct kvm_fw_reg_info {
+	uint64_t reg;		/* Register definition */
+	uint64_t max_feat_bit;	/* Bit that represents the upper limit of the feature-map */
+};
+
+#define FW_REG_INFO(r)			\
+	{					\
+		.reg = r,			\
+		.max_feat_bit = r##_BIT_MAX,	\
+	}
+
+static const struct kvm_fw_reg_info fw_reg_info[] = {
+	FW_REG_INFO(KVM_REG_ARM_STD_BMAP),
+	FW_REG_INFO(KVM_REG_ARM_STD_HYP_BMAP),
+	FW_REG_INFO(KVM_REG_ARM_VENDOR_HYP_BMAP),
+};
+
+enum test_stage {
+	TEST_STAGE_REG_IFACE,
+	TEST_STAGE_HVC_IFACE_FEAT_DISABLED,
+	TEST_STAGE_HVC_IFACE_FEAT_ENABLED,
+	TEST_STAGE_HVC_IFACE_FALSE_INFO,
+	TEST_STAGE_END,
+};
+
+static int stage = TEST_STAGE_REG_IFACE;
+
+struct test_hvc_info {
+	uint32_t func_id;
+	uint64_t arg1;
+};
+
+#define TEST_HVC_INFO(f, a1)	\
+	{			\
+		.func_id = f,	\
+		.arg1 = a1,	\
+	}
+
+static const struct test_hvc_info hvc_info[] = {
+	/* KVM_REG_ARM_STD_BMAP */
+	TEST_HVC_INFO(ARM_SMCCC_TRNG_VERSION, 0),
+	TEST_HVC_INFO(ARM_SMCCC_TRNG_FEATURES, ARM_SMCCC_TRNG_RND64),
+	TEST_HVC_INFO(ARM_SMCCC_TRNG_GET_UUID, 0),
+	TEST_HVC_INFO(ARM_SMCCC_TRNG_RND32, 0),
+	TEST_HVC_INFO(ARM_SMCCC_TRNG_RND64, 0),
+
+	/* KVM_REG_ARM_STD_HYP_BMAP */
+	TEST_HVC_INFO(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, ARM_SMCCC_HV_PV_TIME_FEATURES),
+	TEST_HVC_INFO(ARM_SMCCC_HV_PV_TIME_FEATURES, ARM_SMCCC_HV_PV_TIME_ST),
+	TEST_HVC_INFO(ARM_SMCCC_HV_PV_TIME_ST, 0),
+
+	/* KVM_REG_ARM_VENDOR_HYP_BMAP */
+	TEST_HVC_INFO(ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID,
+			ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID),
+	TEST_HVC_INFO(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, 0),
+	TEST_HVC_INFO(ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID, KVM_PTP_VIRT_COUNTER),
+};
+
+/* Feed false hypercall info to test the KVM behavior */
+static const struct test_hvc_info false_hvc_info[] = {
+	/* Feature support check against a different family of hypercalls */
+	TEST_HVC_INFO(ARM_SMCCC_TRNG_FEATURES, ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID),
+	TEST_HVC_INFO(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, ARM_SMCCC_TRNG_RND64),
+	TEST_HVC_INFO(ARM_SMCCC_HV_PV_TIME_FEATURES, ARM_SMCCC_TRNG_RND64),
+};
+
+static void guest_test_hvc(const struct test_hvc_info *hc_info)
+{
+	unsigned int i;
+	struct arm_smccc_res res;
+	unsigned int hvc_info_arr_sz;
+
+	hvc_info_arr_sz =
+	hc_info == hvc_info ? ARRAY_SIZE(hvc_info) : ARRAY_SIZE(false_hvc_info);
+
+	for (i = 0; i < hvc_info_arr_sz; i++, hc_info++) {
+		memset(&res, 0, sizeof(res));
+		smccc_hvc(hc_info->func_id, hc_info->arg1, 0, 0, 0, 0, 0, 0, &res);
+
+		switch (stage) {
+		case TEST_STAGE_HVC_IFACE_FEAT_DISABLED:
+		case TEST_STAGE_HVC_IFACE_FALSE_INFO:
+			GUEST_ASSERT_3(res.a0 == SMCCC_RET_NOT_SUPPORTED,
+					res.a0, hc_info->func_id, hc_info->arg1);
+			break;
+		case TEST_STAGE_HVC_IFACE_FEAT_ENABLED:
+			GUEST_ASSERT_3(res.a0 != SMCCC_RET_NOT_SUPPORTED,
+					res.a0, hc_info->func_id, hc_info->arg1);
+			break;
+		default:
+			GUEST_ASSERT_1(0, stage);
+		}
+	}
+}
+
+static void guest_code(void)
+{
+	while (stage != TEST_STAGE_END) {
+		switch (stage) {
+		case TEST_STAGE_REG_IFACE:
+			break;
+		case TEST_STAGE_HVC_IFACE_FEAT_DISABLED:
+		case TEST_STAGE_HVC_IFACE_FEAT_ENABLED:
+			guest_test_hvc(hvc_info);
+			break;
+		case TEST_STAGE_HVC_IFACE_FALSE_INFO:
+			guest_test_hvc(false_hvc_info);
+			break;
+		default:
+			GUEST_ASSERT_1(0, stage);
+		}
+
+		GUEST_SYNC(stage);
+	}
+
+	GUEST_DONE();
+}
+
+static int set_fw_reg(struct kvm_vm *vm, uint64_t id, uint64_t val)
+{
+	struct kvm_one_reg reg = {
+		.id = id,
+		.addr = (uint64_t)&val,
+	};
+
+	return _vcpu_ioctl(vm, 0, KVM_SET_ONE_REG, &reg);
+}
+
+static void get_fw_reg(struct kvm_vm *vm, uint64_t id, uint64_t *addr)
+{
+	struct kvm_one_reg reg = {
+		.id = id,
+		.addr = (uint64_t)addr,
+	};
+
+	vcpu_ioctl(vm, 0, KVM_GET_ONE_REG, &reg);
+}
+
+struct st_time {
+	uint32_t rev;
+	uint32_t attr;
+	uint64_t st_time;
+};
+
+#define STEAL_TIME_SIZE		((sizeof(struct st_time) + 63) & ~63)
+#define ST_GPA_BASE		(1 << 30)
+
+static void steal_time_init(struct kvm_vm *vm)
+{
+	uint64_t st_ipa = (ulong)ST_GPA_BASE;
+	unsigned int gpages;
+	struct kvm_device_attr dev = {
+		.group = KVM_ARM_VCPU_PVTIME_CTRL,
+		.attr = KVM_ARM_VCPU_PVTIME_IPA,
+		.addr = (uint64_t)&st_ipa,
+	};
+
+	gpages = vm_calc_num_guest_pages(VM_MODE_DEFAULT, STEAL_TIME_SIZE);
+	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, ST_GPA_BASE, 1, gpages, 0);
+
+	vcpu_ioctl(vm, 0, KVM_SET_DEVICE_ATTR, &dev);
+}
+
+static void test_fw_regs_before_vm_start(struct kvm_vm *vm)
+{
+	uint64_t val;
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < ARRAY_SIZE(fw_reg_info); i++) {
+		const struct kvm_fw_reg_info *reg_info = &fw_reg_info[i];
+
+		/* First 'read' should be an upper limit of the features supported */
+		get_fw_reg(vm, reg_info->reg, &val);
+		TEST_ASSERT(val == FW_REG_ULIMIT_VAL(reg_info->max_feat_bit),
+			"Expected all the features to be set for reg: 0x%lx; expected: 0x%lx; read: 0x%lx\n",
+			reg_info->reg, FW_REG_ULIMIT_VAL(reg_info->max_feat_bit), val);
+
+		/* Test a 'write' by disabling all the features of the register map */
+		ret = set_fw_reg(vm, reg_info->reg, 0);
+		TEST_ASSERT(ret == 0,
+			"Failed to clear all the features of reg: 0x%lx; ret: %d\n",
+			reg_info->reg, errno);
+
+		get_fw_reg(vm, reg_info->reg, &val);
+		TEST_ASSERT(val == 0,
+			"Expected all the features to be cleared for reg: 0x%lx\n", reg_info->reg);
+
+		/*
+		 * Test enabling a feature that's not supported.
+		 * Avoid this check if all the bits are occupied.
+		 */
+		if (reg_info->max_feat_bit < 63) {
+			ret = set_fw_reg(vm, reg_info->reg, BIT(reg_info->max_feat_bit + 1));
+			TEST_ASSERT(ret != 0 && errno == EINVAL,
+			"Unexpected behavior or return value (%d) while setting an unsupported feature for reg: 0x%lx\n",
+			errno, reg_info->reg);
+		}
+	}
+}
+
+static void test_fw_regs_after_vm_start(struct kvm_vm *vm)
+{
+	uint64_t val;
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < ARRAY_SIZE(fw_reg_info); i++) {
+		const struct kvm_fw_reg_info *reg_info = &fw_reg_info[i];
+
+		/*
+		 * Before starting the VM, the test clears all the bits.
+		 * Check if that's still the case.
+		 */
+		get_fw_reg(vm, reg_info->reg, &val);
+		TEST_ASSERT(val == 0,
+			"Expected all the features to be cleared for reg: 0x%lx\n",
+			reg_info->reg);
+
+		/*
+		 * Since the VM has run at least once, KVM shouldn't allow modification of
+		 * the registers and should return EBUSY. Set the registers and check for
+		 * the expected errno.
+		 */
+		ret = set_fw_reg(vm, reg_info->reg, FW_REG_ULIMIT_VAL(reg_info->max_feat_bit));
+		TEST_ASSERT(ret != 0 && errno == EBUSY,
+		"Unexpected behavior or return value (%d) while setting a feature while VM is running for reg: 0x%lx\n",
+		errno, reg_info->reg);
+	}
+}
+
+static struct kvm_vm *test_vm_create(void)
+{
+	struct kvm_vm *vm;
+
+	vm = vm_create_default(0, 0, guest_code);
+
+	ucall_init(vm, NULL);
+	steal_time_init(vm);
+
+	return vm;
+}
+
+static struct kvm_vm *test_guest_stage(struct kvm_vm *vm)
+{
+	struct kvm_vm *ret_vm = vm;
+
+	pr_debug("Stage: %d\n", stage);
+
+	switch (stage) {
+	case TEST_STAGE_REG_IFACE:
+		test_fw_regs_after_vm_start(vm);
+		break;
+	case TEST_STAGE_HVC_IFACE_FEAT_DISABLED:
+		/* Start a new VM so that all the features are now enabled by default */
+		kvm_vm_free(vm);
+		ret_vm = test_vm_create();
+		break;
+	case TEST_STAGE_HVC_IFACE_FEAT_ENABLED:
+	case TEST_STAGE_HVC_IFACE_FALSE_INFO:
+		break;
+	default:
+		TEST_FAIL("Unknown test stage: %d\n", stage);
+	}
+
+	stage++;
+	sync_global_to_guest(vm, stage);
+
+	return ret_vm;
+}
+
+static void test_run(void)
+{
+	struct kvm_vm *vm;
+	struct ucall uc;
+	bool guest_done = false;
+
+	vm = test_vm_create();
+
+	test_fw_regs_before_vm_start(vm);
+
+	while (!guest_done) {
+		vcpu_run(vm, 0);
+
+		switch (get_ucall(vm, 0, &uc)) {
+		case UCALL_SYNC:
+			vm = test_guest_stage(vm);
+			break;
+		case UCALL_DONE:
+			guest_done = true;
+			break;
+		case UCALL_ABORT:
+			TEST_FAIL("%s at %s:%ld\n\tvalues: 0x%lx, 0x%lx; 0x%lx, stage: %u",
+			(const char *)uc.args[0], __FILE__, uc.args[1],
+			uc.args[2], uc.args[3], uc.args[4], stage);
+			break;
+		default:
+			TEST_FAIL("Unexpected guest exit\n");
+		}
+	}
+
+	kvm_vm_free(vm);
+}
+
+int main(void)
+{
+	setbuf(stdout, NULL);
+
+	test_run();
+	return 0;
+}

tools/testing/selftests/kvm/aarch64/psci_cpu_on_test.c → tools/testing/selftests/kvm/aarch64/psci_test.c

@@ -26,32 +26,23 @@
 static uint64_t psci_cpu_on(uint64_t target_cpu, uint64_t entry_addr,
 			    uint64_t context_id)
 {
-	register uint64_t x0 asm("x0") = PSCI_0_2_FN64_CPU_ON;
-	register uint64_t x1 asm("x1") = target_cpu;
-	register uint64_t x2 asm("x2") = entry_addr;
-	register uint64_t x3 asm("x3") = context_id;
+	struct arm_smccc_res res;
 
-	asm("hvc #0"
-	    : "=r"(x0)
-	    : "r"(x0), "r"(x1), "r"(x2), "r"(x3)
-	    : "memory");
+	smccc_hvc(PSCI_0_2_FN64_CPU_ON, target_cpu, entry_addr, context_id,
+		  0, 0, 0, 0, &res);
 
-	return x0;
+	return res.a0;
 }
 
 static uint64_t psci_affinity_info(uint64_t target_affinity,
 				   uint64_t lowest_affinity_level)
 {
-	register uint64_t x0 asm("x0") = PSCI_0_2_FN64_AFFINITY_INFO;
-	register uint64_t x1 asm("x1") = target_affinity;
-	register uint64_t x2 asm("x2") = lowest_affinity_level;
+	struct arm_smccc_res res;
 
-	asm("hvc #0"
-	    : "=r"(x0)
-	    : "r"(x0), "r"(x1), "r"(x2)
-	    : "memory");
+	smccc_hvc(PSCI_0_2_FN64_AFFINITY_INFO, target_affinity, lowest_affinity_level,
+		  0, 0, 0, 0, 0, &res);
 
-	return x0;
+	return res.a0;
 }
 
 static void guest_main(uint64_t target_cpu)

tools/testing/selftests/kvm/include/aarch64/processor.h

@@ -185,4 +185,26 @@ static inline void local_irq_disable(void)
 	asm volatile("msr daifset, #3" : : : "memory");
 }
 
+/**
+ * struct arm_smccc_res - Result from SMC/HVC call
+ * @a0-a3 result values from registers 0 to 3
+ */
+struct arm_smccc_res {
+	unsigned long a0;
+	unsigned long a1;
+	unsigned long a2;
+	unsigned long a3;
+};
+
+/**
+ * smccc_hvc - Invoke a SMCCC function using the hvc conduit
+ * @function_id: the SMCCC function to be called
+ * @arg0-arg6: SMCCC function arguments, corresponding to registers x1-x7
+ * @res: pointer to write the return values from registers x0-x3
+ *
+ */
+void smccc_hvc(uint32_t function_id, uint64_t arg0, uint64_t arg1,
+	       uint64_t arg2, uint64_t arg3, uint64_t arg4, uint64_t arg5,
+	       uint64_t arg6, struct arm_smccc_res *res);
+
 #endif /* SELFTEST_KVM_PROCESSOR_H */

tools/testing/selftests/kvm/lib/aarch64/processor.c

@@ -500,3 +500,28 @@ void __attribute__((constructor)) init_guest_modes(void)
 {
        guest_modes_append_default();
 }
+
+void smccc_hvc(uint32_t function_id, uint64_t arg0, uint64_t arg1,
+	       uint64_t arg2, uint64_t arg3, uint64_t arg4, uint64_t arg5,
+	       uint64_t arg6, struct arm_smccc_res *res)
+{
+	asm volatile("mov   w0, %w[function_id]\n"
+		     "mov   x1, %[arg0]\n"
+		     "mov   x2, %[arg1]\n"
+		     "mov   x3, %[arg2]\n"
+		     "mov   x4, %[arg3]\n"
+		     "mov   x5, %[arg4]\n"
+		     "mov   x6, %[arg5]\n"
+		     "mov   x7, %[arg6]\n"
+		     "hvc   #0\n"
+		     "mov   %[res0], x0\n"
+		     "mov   %[res1], x1\n"
+		     "mov   %[res2], x2\n"
+		     "mov   %[res3], x3\n"
+		     : [res0] "=r"(res->a0), [res1] "=r"(res->a1),
+		       [res2] "=r"(res->a2), [res3] "=r"(res->a3)
+		     : [function_id] "r"(function_id), [arg0] "r"(arg0),
+		       [arg1] "r"(arg1), [arg2] "r"(arg2), [arg3] "r"(arg3),
+		       [arg4] "r"(arg4), [arg5] "r"(arg5), [arg6] "r"(arg6)
+		     : "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7");
+}

tools/testing/selftests/kvm/steal_time.c

@@ -118,17 +118,10 @@ struct st_time {
 
 static int64_t smccc(uint32_t func, uint64_t arg)
 {
-	unsigned long ret;
+	struct arm_smccc_res res;
 
-	asm volatile(
-		"mov	w0, %w1\n"
-		"mov	x1, %2\n"
-		"hvc	#0\n"
-		"mov	%0, x0\n"
-	: "=r" (ret) : "r" (func), "r" (arg) :
-	  "x0", "x1", "x2", "x3");
-
-	return ret;
+	smccc_hvc(func, arg, 0, 0, 0, 0, 0, 0, &res);
+	return res.a0;
 }
 
 static void check_status(struct st_time *st)