From: Nikunj A Dadhania nikunj@amd.com
Add a test case to verify the Bus Lock exit feature
The main thing that the selftest verifies is that when a Buslock is generated in the guest context, the KVM_EXIT_X86_BUS_LOCK is triggered for SVM or VMX when the KVM capability KVM_CAP_X86_BUS_LOCK_EXIT is enabled.
This test case also verifies the Bus Lock exit in nested scenario.
Signed-off-by: Nikunj A Dadhania nikunj@amd.com Co-developed-by: Manali Shukla manali.shukla@amd.com Signed-off-by: Manali Shukla manali.shukla@amd.com --- tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/x86_64/kvm_buslock_test.c | 130 ++++++++++++++++++ 2 files changed, 131 insertions(+) create mode 100644 tools/testing/selftests/kvm/x86_64/kvm_buslock_test.c
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 960cf6a77198..b2de61e4a213 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -81,6 +81,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/hyperv_svm_test TEST_GEN_PROGS_x86_64 += x86_64/hyperv_tlb_flush TEST_GEN_PROGS_x86_64 += x86_64/kvm_clock_test TEST_GEN_PROGS_x86_64 += x86_64/kvm_pv_test +TEST_GEN_PROGS_x86_64 += x86_64/kvm_buslock_test TEST_GEN_PROGS_x86_64 += x86_64/monitor_mwait_test TEST_GEN_PROGS_x86_64 += x86_64/nested_exceptions_test TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test diff --git a/tools/testing/selftests/kvm/x86_64/kvm_buslock_test.c b/tools/testing/selftests/kvm/x86_64/kvm_buslock_test.c new file mode 100644 index 000000000000..82693520485c --- /dev/null +++ b/tools/testing/selftests/kvm/x86_64/kvm_buslock_test.c @@ -0,0 +1,130 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2024 Advanced Micro Devices, Inc. + */ + +#include "test_util.h" +#include "kvm_util.h" +#include "processor.h" +#include "svm_util.h" +#include "vmx.h" + +#define NR_ITERATIONS 100 +#define L2_GUEST_STACK_SIZE 64 + +struct buslock_test { + unsigned char pad[PAGE_SIZE - 2]; + atomic_long_t val; +} __packed; + +struct buslock_test test __aligned(PAGE_SIZE); + +static __always_inline void buslock_atomic_add(int i, atomic_long_t *v) +{ + asm volatile(LOCK_PREFIX "addl %1,%0" + : "+m" (v->counter) + : "ir" (i) : "memory"); +} + +static void buslock_add(void) +{ + /* + * Increment a page unaligned variable atomically. + * This should generate a bus lock exit. + */ + for (int i = 0; i < NR_ITERATIONS; i++) + buslock_atomic_add(2, &test.val); +} + +static void l2_guest_code(void) +{ + buslock_add(); + GUEST_DONE(); +} + +static void l1_svm_code(struct svm_test_data *svm) +{ + unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE]; + struct vmcb *vmcb = svm->vmcb; + + generic_svm_setup(svm, l2_guest_code, + &l2_guest_stack[L2_GUEST_STACK_SIZE]); + run_guest(vmcb, svm->vmcb_gpa); + GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL); + GUEST_DONE(); +} + +static void l1_vmx_code(struct vmx_pages *vmx) +{ + unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE]; + + GUEST_ASSERT_EQ(prepare_for_vmx_operation(vmx), true); + GUEST_ASSERT_EQ(load_vmcs(vmx), true); + + prepare_vmcs(vmx, NULL, &l2_guest_stack[L2_GUEST_STACK_SIZE]); + + GUEST_ASSERT(!vmwrite(GUEST_RIP, (u64)l2_guest_code)); + GUEST_ASSERT(!vmlaunch()); + + GUEST_ASSERT_EQ(vmreadz(VM_EXIT_REASON), EXIT_REASON_VMCALL); + GUEST_DONE(); +} + +static void guest_code(void *test_data) +{ + buslock_add(); + + if (this_cpu_has(X86_FEATURE_SVM)) + l1_svm_code(test_data); + else + l1_vmx_code(test_data); +} + +int main(int argc, char *argv[]) +{ + struct kvm_vcpu *vcpu; + struct kvm_run *run; + struct kvm_vm *vm; + vm_vaddr_t nested_test_data_gva; + + TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_SVM) || kvm_cpu_has(X86_FEATURE_VMX)); + TEST_REQUIRE(kvm_has_cap(KVM_CAP_X86_BUS_LOCK_EXIT)); + + vm = vm_create(1); + vm_enable_cap(vm, KVM_CAP_X86_BUS_LOCK_EXIT, KVM_BUS_LOCK_DETECTION_EXIT); + vcpu = vm_vcpu_add(vm, 0, guest_code); + + if (kvm_cpu_has(X86_FEATURE_SVM)) + vcpu_alloc_svm(vm, &nested_test_data_gva); + else + vcpu_alloc_vmx(vm, &nested_test_data_gva); + + vcpu_args_set(vcpu, 1, nested_test_data_gva); + + run = vcpu->run; + + for (;;) { + struct ucall uc; + + vcpu_run(vcpu); + + if (run->exit_reason == KVM_EXIT_IO) { + switch (get_ucall(vcpu, &uc)) { + case UCALL_ABORT: + REPORT_GUEST_ASSERT(uc); + /* NOT REACHED */ + case UCALL_SYNC: + continue; + case UCALL_DONE: + goto done; + default: + TEST_FAIL("Unknown ucall 0x%lx.", uc.cmd); + } + } + + TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_X86_BUS_LOCK); + } +done: + kvm_vm_free(vm); + return 0; +}