1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * psci_cpu_on_test - Test that the observable state of a vCPU targeted by the
4  * CPU_ON PSCI call matches what the caller requested.
5  *
6  * Copyright (c) 2021 Google LLC.
7  *
8  * This is a regression test for a race between KVM servicing the PSCI call and
9  * userspace reading the vCPUs registers.
10  */
11 
12 #define _GNU_SOURCE
13 
14 #include <linux/psci.h>
15 
16 #include "kvm_util.h"
17 #include "processor.h"
18 #include "test_util.h"
19 
20 #define VCPU_ID_SOURCE 0
21 #define VCPU_ID_TARGET 1
22 
23 #define CPU_ON_ENTRY_ADDR 0xfeedf00dul
24 #define CPU_ON_CONTEXT_ID 0xdeadc0deul
25 
26 static uint64_t psci_cpu_on(uint64_t target_cpu, uint64_t entry_addr,
27 			    uint64_t context_id)
28 {
29 	struct arm_smccc_res res;
30 
31 	smccc_hvc(PSCI_0_2_FN64_CPU_ON, target_cpu, entry_addr, context_id,
32 		  0, 0, 0, 0, &res);
33 
34 	return res.a0;
35 }
36 
37 static uint64_t psci_affinity_info(uint64_t target_affinity,
38 				   uint64_t lowest_affinity_level)
39 {
40 	struct arm_smccc_res res;
41 
42 	smccc_hvc(PSCI_0_2_FN64_AFFINITY_INFO, target_affinity, lowest_affinity_level,
43 		  0, 0, 0, 0, 0, &res);
44 
45 	return res.a0;
46 }
47 
48 static void guest_main(uint64_t target_cpu)
49 {
50 	GUEST_ASSERT(!psci_cpu_on(target_cpu, CPU_ON_ENTRY_ADDR, CPU_ON_CONTEXT_ID));
51 	uint64_t target_state;
52 
53 	do {
54 		target_state = psci_affinity_info(target_cpu, 0);
55 
56 		GUEST_ASSERT((target_state == PSCI_0_2_AFFINITY_LEVEL_ON) ||
57 			     (target_state == PSCI_0_2_AFFINITY_LEVEL_OFF));
58 	} while (target_state != PSCI_0_2_AFFINITY_LEVEL_ON);
59 
60 	GUEST_DONE();
61 }
62 
63 int main(void)
64 {
65 	uint64_t target_mpidr, obs_pc, obs_x0;
66 	struct kvm_vcpu_init init;
67 	struct kvm_vm *vm;
68 	struct ucall uc;
69 
70 	vm = vm_create(VM_MODE_DEFAULT, DEFAULT_GUEST_PHY_PAGES, O_RDWR);
71 	kvm_vm_elf_load(vm, program_invocation_name);
72 	ucall_init(vm, NULL);
73 
74 	vm_ioctl(vm, KVM_ARM_PREFERRED_TARGET, &init);
75 	init.features[0] |= (1 << KVM_ARM_VCPU_PSCI_0_2);
76 
77 	aarch64_vcpu_add_default(vm, VCPU_ID_SOURCE, &init, guest_main);
78 
79 	/*
80 	 * make sure the target is already off when executing the test.
81 	 */
82 	init.features[0] |= (1 << KVM_ARM_VCPU_POWER_OFF);
83 	aarch64_vcpu_add_default(vm, VCPU_ID_TARGET, &init, guest_main);
84 
85 	get_reg(vm, VCPU_ID_TARGET, KVM_ARM64_SYS_REG(SYS_MPIDR_EL1), &target_mpidr);
86 	vcpu_args_set(vm, VCPU_ID_SOURCE, 1, target_mpidr & MPIDR_HWID_BITMASK);
87 	vcpu_run(vm, VCPU_ID_SOURCE);
88 
89 	switch (get_ucall(vm, VCPU_ID_SOURCE, &uc)) {
90 	case UCALL_DONE:
91 		break;
92 	case UCALL_ABORT:
93 		TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0], __FILE__,
94 			  uc.args[1]);
95 		break;
96 	default:
97 		TEST_FAIL("Unhandled ucall: %lu", uc.cmd);
98 	}
99 
100 	get_reg(vm, VCPU_ID_TARGET, ARM64_CORE_REG(regs.pc), &obs_pc);
101 	get_reg(vm, VCPU_ID_TARGET, ARM64_CORE_REG(regs.regs[0]), &obs_x0);
102 
103 	TEST_ASSERT(obs_pc == CPU_ON_ENTRY_ADDR,
104 		    "unexpected target cpu pc: %lx (expected: %lx)",
105 		    obs_pc, CPU_ON_ENTRY_ADDR);
106 	TEST_ASSERT(obs_x0 == CPU_ON_CONTEXT_ID,
107 		    "unexpected target context id: %lx (expected: %lx)",
108 		    obs_x0, CPU_ON_CONTEXT_ID);
109 
110 	kvm_vm_free(vm);
111 	return 0;
112 }
113