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

   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         register uint64_t x0 asm("x0") = PSCI_0_2_FN64_CPU_ON;
  30         register uint64_t x1 asm("x1") = target_cpu;
  31         register uint64_t x2 asm("x2") = entry_addr;
  32         register uint64_t x3 asm("x3") = context_id;
  33
  34         asm("hvc #0"
  35             : "=r"(x0)
  36             : "r"(x0), "r"(x1), "r"(x2), "r"(x3)
  37             : "memory");
  38
  39         return x0;
  40 }
  41
  42 static uint64_t psci_affinity_info(uint64_t target_affinity,
  43                                    uint64_t lowest_affinity_level)
  44 {
  45         register uint64_t x0 asm("x0") = PSCI_0_2_FN64_AFFINITY_INFO;
  46         register uint64_t x1 asm("x1") = target_affinity;
  47         register uint64_t x2 asm("x2") = lowest_affinity_level;
  48
  49         asm("hvc #0"
  50             : "=r"(x0)
  51             : "r"(x0), "r"(x1), "r"(x2)
  52             : "memory");
  53
  54         return x0;
  55 }
  56
  57 static void guest_main(uint64_t target_cpu)
  58 {
  59         GUEST_ASSERT(!psci_cpu_on(target_cpu, CPU_ON_ENTRY_ADDR, CPU_ON_CONTEXT_ID));
  60         uint64_t target_state;
  61
  62         do {
  63                 target_state = psci_affinity_info(target_cpu, 0);
  64
  65                 GUEST_ASSERT((target_state == PSCI_0_2_AFFINITY_LEVEL_ON) ||
  66                              (target_state == PSCI_0_2_AFFINITY_LEVEL_OFF));
  67         } while (target_state != PSCI_0_2_AFFINITY_LEVEL_ON);
  68
  69         GUEST_DONE();
  70 }
  71
  72 int main(void)
  73 {
  74         uint64_t target_mpidr, obs_pc, obs_x0;
  75         struct kvm_vcpu_init init;
  76         struct kvm_vm *vm;
  77         struct ucall uc;
  78
  79         vm = vm_create(VM_MODE_DEFAULT, DEFAULT_GUEST_PHY_PAGES, O_RDWR);
  80         kvm_vm_elf_load(vm, program_invocation_name);
  81         ucall_init(vm, NULL);
  82
  83         vm_ioctl(vm, KVM_ARM_PREFERRED_TARGET, &init);
  84         init.features[0] |= (1 << KVM_ARM_VCPU_PSCI_0_2);
  85
  86         aarch64_vcpu_add_default(vm, VCPU_ID_SOURCE, &init, guest_main);
  87
  88         /*
  89          * make sure the target is already off when executing the test.
  90          */
  91         init.features[0] |= (1 << KVM_ARM_VCPU_POWER_OFF);
  92         aarch64_vcpu_add_default(vm, VCPU_ID_TARGET, &init, guest_main);
  93
  94         get_reg(vm, VCPU_ID_TARGET, ARM64_SYS_REG(MPIDR_EL1), &target_mpidr);
  95         vcpu_args_set(vm, VCPU_ID_SOURCE, 1, target_mpidr & MPIDR_HWID_BITMASK);
  96         vcpu_run(vm, VCPU_ID_SOURCE);
  97
  98         switch (get_ucall(vm, VCPU_ID_SOURCE, &uc)) {
  99         case UCALL_DONE:
 100                 break;
 101         case UCALL_ABORT:
 102                 TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0], __FILE__,
 103                           uc.args[1]);
 104                 break;
 105         default:
 106                 TEST_FAIL("Unhandled ucall: %lu", uc.cmd);
 107         }
 108
 109         get_reg(vm, VCPU_ID_TARGET, ARM64_CORE_REG(regs.pc), &obs_pc);
 110         get_reg(vm, VCPU_ID_TARGET, ARM64_CORE_REG(regs.regs[0]), &obs_x0);
 111
 112         TEST_ASSERT(obs_pc == CPU_ON_ENTRY_ADDR,
 113                     "unexpected target cpu pc: %lx (expected: %lx)",
 114                     obs_pc, CPU_ON_ENTRY_ADDR);
 115         TEST_ASSERT(obs_x0 == CPU_ON_CONTEXT_ID,
 116                     "unexpected target context id: %lx (expected: %lx)",
 117                     obs_x0, CPU_ON_CONTEXT_ID);
 118
 119         kvm_vm_free(vm);
 120         return 0;
 121 }