Add a selftest to verify the support for pointer authentication in KVM
guest.
Signed-off-by: Jing Zhang <jingzhangos@xxxxxxxxxx>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/aarch64/pauth_test.c | 143 ++++++++++++++++++
.../selftests/kvm/include/aarch64/processor.h | 2 +
3 files changed, 146 insertions(+)
create mode 100644 tools/testing/selftests/kvm/aarch64/pauth_test.c
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index c692cc86e7da..9bac5aecd66d 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -143,6 +143,7 @@ TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions
TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list
TEST_GEN_PROGS_aarch64 += aarch64/hypercalls
TEST_GEN_PROGS_aarch64 += aarch64/page_fault_test
+TEST_GEN_PROGS_aarch64 += aarch64/pauth_test
TEST_GEN_PROGS_aarch64 += aarch64/psci_test
TEST_GEN_PROGS_aarch64 += aarch64/smccc_filter
TEST_GEN_PROGS_aarch64 += aarch64/vcpu_width_config
diff --git a/tools/testing/selftests/kvm/aarch64/pauth_test.c b/tools/testing/selftests/kvm/aarch64/pauth_test.c
new file mode 100644
index 000000000000..d5f982da8891
--- /dev/null
+++ b/tools/testing/selftests/kvm/aarch64/pauth_test.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * pauth_test - Test for KVM guest pointer authentication.
+ *
+ * Copyright (c) 2023 Google LLC.
+ *
+ */
+
+#define _GNU_SOURCE
+
+#include <sched.h>
+
+#include "kvm_util.h"
+#include "processor.h"
+#include "test_util.h"
+
+enum uc_args {
+ WAIT_MIGRATION,
+ PASS,
+ FAIL,
+ FAIL_KVM,
+ FAIL_INSTR,
+};
+
+static noinline void pac_corruptor(void)
+{
+ __asm__ __volatile__(
+ "paciasp\n"
+ "eor lr, lr, #1 << 53\n"
+ );
+
+ /* Migrate guest to another physical CPU before authentication */
+ GUEST_SYNC(WAIT_MIGRATION);
+ __asm__ __volatile__("autiasp\n");
+}
+
+static void guest_code(void)
+{
+ uint64_t sctlr = read_sysreg(sctlr_el1);
+
+ /* Enable PAuth */
+ sctlr |= SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | SCTLR_ELx_ENDA | SCTLR_ELx_ENDB;
+ write_sysreg(sctlr, sctlr_el1);
+ isb();
+
+ pac_corruptor();
+
+ /* Shouldn't be here unless the pac_corruptor didn't do its work */
+ GUEST_SYNC(FAIL);
+ GUEST_DONE();
+}
+
+/* Guest will get an unknown exception if KVM doesn't support guest PAuth */
+static void guest_unknown_handler(struct ex_regs *regs)
+{
+ GUEST_SYNC(FAIL_KVM);
+ GUEST_DONE();
+}
+
+/* Guest will get a FPAC exception if KVM support guest PAuth */
+static void guest_fpac_handler(struct ex_regs *regs)
+{
+ GUEST_SYNC(PASS);
+ GUEST_DONE();
+}
+
+/* Guest will get an instruction abort exception if the PAuth instructions have
+ * no effect (or PAuth not enabled in guest), which would cause guest to fetch
+ * an invalid instruction due to the corrupted LR.
+ */
+static void guest_iabt_handler(struct ex_regs *regs)
+{
+ GUEST_SYNC(FAIL_INSTR);
+ GUEST_DONE();
+}
+
+int main(void)
+{
+ struct kvm_vcpu_init init;
+ struct kvm_vcpu *vcpu;
+ struct kvm_vm *vm;
+ struct ucall uc;
+ cpu_set_t cpu_mask;
+
+ TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_PTRAUTH_ADDRESS));
+ TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_PTRAUTH_GENERIC));
+
+ vm = vm_create(1);
+
+ vm_ioctl(vm, KVM_ARM_PREFERRED_TARGET, &init);
+ init.features[0] |= ((1 << KVM_ARM_VCPU_PTRAUTH_ADDRESS) |
+ (1 << KVM_ARM_VCPU_PTRAUTH_GENERIC));
+
+ vcpu = aarch64_vcpu_add(vm, 0, &init, guest_code);
+
+ vm_init_descriptor_tables(vm);
+ vcpu_init_descriptor_tables(vcpu);
+
+ vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
+ ESR_EC_UNKNOWN, guest_unknown_handler);
+ vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
+ ESR_EC_FPAC, guest_fpac_handler);
+ vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
+ ESR_EC_IABT, guest_iabt_handler);
+
+ while (1) {
+ vcpu_run(vcpu);
+
+ switch (get_ucall(vcpu, &uc)) {
+ case UCALL_ABORT:
+ REPORT_GUEST_ASSERT(uc);
+ break;
+ case UCALL_SYNC:
+ switch (uc.args[1]) {
+ case PASS:
+ /* KVM guest PAuth works! */
+ break;
+ case WAIT_MIGRATION:
+ sched_getaffinity(0, sizeof(cpu_mask), &cpu_mask);
+ CPU_CLR(sched_getcpu(), &cpu_mask);
+ sched_setaffinity(0, sizeof(cpu_mask), &cpu_mask);
+ break;
+ case FAIL:
+ TEST_FAIL("Guest corruptor code doesn't work!\n");
+ break;
+ case FAIL_KVM:
+ TEST_FAIL("KVM doesn't support guest PAuth!\n");
+ break;
+ case FAIL_INSTR:
+ TEST_FAIL("Guest PAuth instructions don't work!\n");
+ break;
+ }
+ break;
+ case UCALL_DONE:
+ goto done;
+ default:
+ TEST_FAIL("Unexpected ucall: %lu", uc.cmd);
+ }
+ }
+
+done:
+ kvm_vm_free(vm);
+}
diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h
index cb537253a6b9..f8d541af9c06 100644
--- a/tools/testing/selftests/kvm/include/aarch64/processor.h
+++ b/tools/testing/selftests/kvm/include/aarch64/processor.h
@@ -104,7 +104,9 @@ enum {
#define ESR_EC_SHIFT 26
#define ESR_EC_MASK (ESR_EC_NUM - 1)
+#define ESR_EC_UNKNOWN 0x00
#define ESR_EC_SVC64 0x15
+#define ESR_EC_FPAC 0x1c
#define ESR_EC_IABT 0x21
#define ESR_EC_DABT 0x25
#define ESR_EC_HW_BP_CURRENT 0x31
base-commit: 6eaae198076080886b9e7d57f4ae06fa782f90ef
--
2.41.0.487.g6d72f3e995-goog
