diff options
| -rw-r--r-- | arch/arm64/kvm/arm.c | 8 | ||||
| -rw-r--r-- | arch/arm64/kvm/psci.c | 15 | ||||
| -rw-r--r-- | arch/arm64/kvm/reset.c | 16 | ||||
| -rw-r--r-- | tools/testing/selftests/kvm/.gitignore | 1 | ||||
| -rw-r--r-- | tools/testing/selftests/kvm/Makefile | 1 | ||||
| -rw-r--r-- | tools/testing/selftests/kvm/aarch64/psci_cpu_on_test.c | 121 | ||||
| -rw-r--r-- | tools/testing/selftests/kvm/include/aarch64/processor.h | 3 |
7 files changed, 156 insertions, 9 deletions
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index fd9a6bcf797f..1decdec70102 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1216,6 +1216,14 @@ long kvm_arch_vcpu_ioctl(struct file *filp, if (copy_from_user(®, argp, sizeof(reg))) break; + /* + * We could owe a reset due to PSCI. Handle the pending reset + * here to ensure userspace register accesses are ordered after + * the reset. + */ + if (kvm_check_request(KVM_REQ_VCPU_RESET, vcpu)) + kvm_reset_vcpu(vcpu); + if (ioctl == KVM_SET_ONE_REG) r = kvm_arm_set_reg(vcpu, ®); else diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c index db4056ecccfd..74c47d420253 100644 --- a/arch/arm64/kvm/psci.c +++ b/arch/arm64/kvm/psci.c @@ -59,6 +59,12 @@ static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu) kvm_vcpu_kick(vcpu); } +static inline bool kvm_psci_valid_affinity(struct kvm_vcpu *vcpu, + unsigned long affinity) +{ + return !(affinity & ~MPIDR_HWID_BITMASK); +} + static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu) { struct vcpu_reset_state *reset_state; @@ -66,9 +72,9 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu) struct kvm_vcpu *vcpu = NULL; unsigned long cpu_id; - cpu_id = smccc_get_arg1(source_vcpu) & MPIDR_HWID_BITMASK; - if (vcpu_mode_is_32bit(source_vcpu)) - cpu_id &= ~((u32) 0); + cpu_id = smccc_get_arg1(source_vcpu); + if (!kvm_psci_valid_affinity(source_vcpu, cpu_id)) + return PSCI_RET_INVALID_PARAMS; vcpu = kvm_mpidr_to_vcpu(kvm, cpu_id); @@ -126,6 +132,9 @@ static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu) target_affinity = smccc_get_arg1(vcpu); lowest_affinity_level = smccc_get_arg2(vcpu); + if (!kvm_psci_valid_affinity(vcpu, target_affinity)) + return PSCI_RET_INVALID_PARAMS; + /* Determine target affinity mask */ target_affinity_mask = psci_affinity_mask(lowest_affinity_level); if (!target_affinity_mask) diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index 08fd487d5f95..5ce36b0a3343 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -210,10 +210,16 @@ static bool vcpu_allowed_register_width(struct kvm_vcpu *vcpu) */ int kvm_reset_vcpu(struct kvm_vcpu *vcpu) { + struct vcpu_reset_state reset_state; int ret; bool loaded; u32 pstate; + mutex_lock(&vcpu->kvm->lock); + reset_state = vcpu->arch.reset_state; + WRITE_ONCE(vcpu->arch.reset_state.reset, false); + mutex_unlock(&vcpu->kvm->lock); + /* Reset PMU outside of the non-preemptible section */ kvm_pmu_vcpu_reset(vcpu); @@ -276,8 +282,8 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu) * Additional reset state handling that PSCI may have imposed on us. * Must be done after all the sys_reg reset. */ - if (vcpu->arch.reset_state.reset) { - unsigned long target_pc = vcpu->arch.reset_state.pc; + if (reset_state.reset) { + unsigned long target_pc = reset_state.pc; /* Gracefully handle Thumb2 entry point */ if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) { @@ -286,13 +292,11 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu) } /* Propagate caller endianness */ - if (vcpu->arch.reset_state.be) + if (reset_state.be) kvm_vcpu_set_be(vcpu); *vcpu_pc(vcpu) = target_pc; - vcpu_set_reg(vcpu, 0, vcpu->arch.reset_state.r0); - - vcpu->arch.reset_state.reset = false; + vcpu_set_reg(vcpu, 0, reset_state.r0); } /* Reset timer */ 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 <linux/psci.h> + +#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; |