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 <drjones@xxxxxxxxxx>
Signed-off-by: Oliver Upton <oupton@xxxxxxxxxx>
---
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 <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;
--
2.33.0.rc1.237.g0d66db33f3-goog
