From cb97cf95c44021278b7637731bc0928026bc29ab Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 18 Aug 2021 20:21:33 +0000 Subject: [PATCH] selftests: KVM: Introduce psci_cpu_on_test Introduce a test for aarch64 that ensures CPU resets induced by PSCI are reflected in the target vCPU's state, even if the target is never run again. This is a regression test for a race between vCPU migration and PSCI. Reviewed-by: Andrew Jones Signed-off-by: Oliver Upton Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210818202133.1106786-5-oupton@google.com --- tools/testing/selftests/kvm/.gitignore | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/aarch64/psci_cpu_on_test.c | 121 ++++++++++++++++++ .../selftests/kvm/include/aarch64/processor.h | 3 + 4 files changed, 126 insertions(+) create mode 100644 tools/testing/selftests/kvm/aarch64/psci_cpu_on_test.c diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore index 0709af0144c8..98053d3afbda 100644 --- a/tools/testing/selftests/kvm/.gitignore +++ b/tools/testing/selftests/kvm/.gitignore @@ -1,6 +1,7 @@ # SPDX-License-Identifier: GPL-2.0-only /aarch64/debug-exceptions /aarch64/get-reg-list +/aarch64/psci_cpu_on_test /aarch64/vgic_init /s390x/memop /s390x/resets diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 5832f510a16c..5d05801ab816 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -86,6 +86,7 @@ TEST_GEN_PROGS_x86_64 += kvm_binary_stats_test 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/vgic_init TEST_GEN_PROGS_aarch64 += demand_paging_test TEST_GEN_PROGS_aarch64 += dirty_log_test diff --git a/tools/testing/selftests/kvm/aarch64/psci_cpu_on_test.c b/tools/testing/selftests/kvm/aarch64/psci_cpu_on_test.c new file mode 100644 index 000000000000..018c269990e1 --- /dev/null +++ b/tools/testing/selftests/kvm/aarch64/psci_cpu_on_test.c @@ -0,0 +1,121 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * psci_cpu_on_test - Test that the observable state of a vCPU targeted by the + * CPU_ON PSCI call matches what the caller requested. + * + * Copyright (c) 2021 Google LLC. + * + * This is a regression test for a race between KVM servicing the PSCI call and + * userspace reading the vCPUs registers. + */ + +#define _GNU_SOURCE + +#include + +#include "kvm_util.h" +#include "processor.h" +#include "test_util.h" + +#define VCPU_ID_SOURCE 0 +#define VCPU_ID_TARGET 1 + +#define CPU_ON_ENTRY_ADDR 0xfeedf00dul +#define CPU_ON_CONTEXT_ID 0xdeadc0deul + +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; + + asm("hvc #0" + : "=r"(x0) + : "r"(x0), "r"(x1), "r"(x2), "r"(x3) + : "memory"); + + return x0; +} + +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; + + asm("hvc #0" + : "=r"(x0) + : "r"(x0), "r"(x1), "r"(x2) + : "memory"); + + return x0; +} + +static void guest_main(uint64_t target_cpu) +{ + GUEST_ASSERT(!psci_cpu_on(target_cpu, CPU_ON_ENTRY_ADDR, CPU_ON_CONTEXT_ID)); + uint64_t target_state; + + do { + target_state = psci_affinity_info(target_cpu, 0); + + GUEST_ASSERT((target_state == PSCI_0_2_AFFINITY_LEVEL_ON) || + (target_state == PSCI_0_2_AFFINITY_LEVEL_OFF)); + } while (target_state != PSCI_0_2_AFFINITY_LEVEL_ON); + + GUEST_DONE(); +} + +int main(void) +{ + uint64_t target_mpidr, obs_pc, obs_x0; + struct kvm_vcpu_init init; + struct kvm_vm *vm; + struct ucall uc; + + vm = vm_create(VM_MODE_DEFAULT, DEFAULT_GUEST_PHY_PAGES, O_RDWR); + kvm_vm_elf_load(vm, program_invocation_name); + ucall_init(vm, NULL); + + vm_ioctl(vm, KVM_ARM_PREFERRED_TARGET, &init); + init.features[0] |= (1 << KVM_ARM_VCPU_PSCI_0_2); + + aarch64_vcpu_add_default(vm, VCPU_ID_SOURCE, &init, guest_main); + + /* + * make sure the target is already off when executing the test. + */ + init.features[0] |= (1 << KVM_ARM_VCPU_POWER_OFF); + aarch64_vcpu_add_default(vm, VCPU_ID_TARGET, &init, guest_main); + + get_reg(vm, VCPU_ID_TARGET, ARM64_SYS_REG(MPIDR_EL1), &target_mpidr); + vcpu_args_set(vm, VCPU_ID_SOURCE, 1, target_mpidr & MPIDR_HWID_BITMASK); + vcpu_run(vm, VCPU_ID_SOURCE); + + switch (get_ucall(vm, VCPU_ID_SOURCE, &uc)) { + case UCALL_DONE: + break; + case UCALL_ABORT: + TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0], __FILE__, + uc.args[1]); + break; + default: + TEST_FAIL("Unhandled ucall: %lu", uc.cmd); + } + + get_reg(vm, VCPU_ID_TARGET, ARM64_CORE_REG(regs.pc), &obs_pc); + get_reg(vm, VCPU_ID_TARGET, ARM64_CORE_REG(regs.regs[0]), &obs_x0); + + TEST_ASSERT(obs_pc == CPU_ON_ENTRY_ADDR, + "unexpected target cpu pc: %lx (expected: %lx)", + obs_pc, CPU_ON_ENTRY_ADDR); + TEST_ASSERT(obs_x0 == CPU_ON_CONTEXT_ID, + "unexpected target context id: %lx (expected: %lx)", + obs_x0, CPU_ON_CONTEXT_ID); + + kvm_vm_free(vm); + return 0; +} diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h index 27dc5c2e56b9..c0273aefa63d 100644 --- a/tools/testing/selftests/kvm/include/aarch64/processor.h +++ b/tools/testing/selftests/kvm/include/aarch64/processor.h @@ -17,6 +17,7 @@ #define CPACR_EL1 3, 0, 1, 0, 2 #define TCR_EL1 3, 0, 2, 0, 2 #define MAIR_EL1 3, 0, 10, 2, 0 +#define MPIDR_EL1 3, 0, 0, 0, 5 #define TTBR0_EL1 3, 0, 2, 0, 0 #define SCTLR_EL1 3, 0, 1, 0, 0 #define VBAR_EL1 3, 0, 12, 0, 0 @@ -40,6 +41,8 @@ (0xfful << (4 * 8)) | \ (0xbbul << (5 * 8))) +#define MPIDR_HWID_BITMASK (0xff00fffffful) + static inline void get_reg(struct kvm_vm *vm, uint32_t vcpuid, uint64_t id, uint64_t *addr) { struct kvm_one_reg reg;