diff options
Diffstat (limited to 'tools/testing/selftests/kvm/x86/nested_tsc_adjust_test.c')
| -rw-r--r-- | tools/testing/selftests/kvm/x86/nested_tsc_adjust_test.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/x86/nested_tsc_adjust_test.c b/tools/testing/selftests/kvm/x86/nested_tsc_adjust_test.c new file mode 100644 index 000000000000..2839f650e5c9 --- /dev/null +++ b/tools/testing/selftests/kvm/x86/nested_tsc_adjust_test.c @@ -0,0 +1,165 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2018, Google LLC. + * + * IA32_TSC_ADJUST test + * + * According to the SDM, "if an execution of WRMSR to the + * IA32_TIME_STAMP_COUNTER MSR adds (or subtracts) value X from the TSC, + * the logical processor also adds (or subtracts) value X from the + * IA32_TSC_ADJUST MSR. + * + * Note that when L1 doesn't intercept writes to IA32_TSC, a + * WRMSR(IA32_TSC) from L2 sets L1's TSC value, not L2's perceived TSC + * value. + * + * This test verifies that this unusual case is handled correctly. + */ + +#include "test_util.h" +#include "kvm_util.h" +#include "processor.h" +#include "vmx.h" +#include "svm_util.h" + +#include <string.h> +#include <sys/ioctl.h> + +#include "kselftest.h" + +#ifndef MSR_IA32_TSC_ADJUST +#define MSR_IA32_TSC_ADJUST 0x3b +#endif + +#define TSC_ADJUST_VALUE (1ll << 32) +#define TSC_OFFSET_VALUE -(1ll << 48) + +#define L2_GUEST_STACK_SIZE 64 + +enum { + PORT_ABORT = 0x1000, + PORT_REPORT, + PORT_DONE, +}; + +enum { + VMXON_PAGE = 0, + VMCS_PAGE, + MSR_BITMAP_PAGE, + + NUM_VMX_PAGES, +}; + +/* The virtual machine object. */ +static struct kvm_vm *vm; + +static void check_ia32_tsc_adjust(int64_t max) +{ + int64_t adjust; + + adjust = rdmsr(MSR_IA32_TSC_ADJUST); + GUEST_SYNC(adjust); + GUEST_ASSERT(adjust <= max); +} + +static void l2_guest_code(void) +{ + uint64_t l1_tsc = rdtsc() - TSC_OFFSET_VALUE; + + wrmsr(MSR_IA32_TSC, l1_tsc - TSC_ADJUST_VALUE); + check_ia32_tsc_adjust(-2 * TSC_ADJUST_VALUE); + + /* Exit to L1 */ + __asm__ __volatile__("vmcall"); +} + +static void l1_guest_code(void *data) +{ + unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE]; + + /* Set TSC from L1 and make sure TSC_ADJUST is updated correctly */ + GUEST_ASSERT(rdtsc() < TSC_ADJUST_VALUE); + wrmsr(MSR_IA32_TSC, rdtsc() - TSC_ADJUST_VALUE); + check_ia32_tsc_adjust(-1 * TSC_ADJUST_VALUE); + + /* + * Run L2 with TSC_OFFSET. L2 will write to TSC, and L1 is not + * intercepting the write so it should update L1's TSC_ADJUST. + */ + if (this_cpu_has(X86_FEATURE_VMX)) { + struct vmx_pages *vmx_pages = data; + uint32_t control; + + GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages)); + GUEST_ASSERT(load_vmcs(vmx_pages)); + + prepare_vmcs(vmx_pages, l2_guest_code, + &l2_guest_stack[L2_GUEST_STACK_SIZE]); + control = vmreadz(CPU_BASED_VM_EXEC_CONTROL); + control |= CPU_BASED_USE_MSR_BITMAPS | CPU_BASED_USE_TSC_OFFSETTING; + vmwrite(CPU_BASED_VM_EXEC_CONTROL, control); + vmwrite(TSC_OFFSET, TSC_OFFSET_VALUE); + + GUEST_ASSERT(!vmlaunch()); + GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL); + } else { + struct svm_test_data *svm = data; + + generic_svm_setup(svm, l2_guest_code, + &l2_guest_stack[L2_GUEST_STACK_SIZE]); + + svm->vmcb->control.tsc_offset = TSC_OFFSET_VALUE; + run_guest(svm->vmcb, svm->vmcb_gpa); + GUEST_ASSERT(svm->vmcb->control.exit_code == SVM_EXIT_VMMCALL); + } + + check_ia32_tsc_adjust(-2 * TSC_ADJUST_VALUE); + GUEST_DONE(); +} + +static void report(int64_t val) +{ + pr_info("IA32_TSC_ADJUST is %ld (%lld * TSC_ADJUST_VALUE + %lld).\n", + val, val / TSC_ADJUST_VALUE, val % TSC_ADJUST_VALUE); +} + +int main(int argc, char *argv[]) +{ + vm_vaddr_t nested_gva; + struct kvm_vcpu *vcpu; + + TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX) || + kvm_cpu_has(X86_FEATURE_SVM)); + + vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code); + if (kvm_cpu_has(X86_FEATURE_VMX)) + vcpu_alloc_vmx(vm, &nested_gva); + else + vcpu_alloc_svm(vm, &nested_gva); + + vcpu_args_set(vcpu, 1, nested_gva); + + for (;;) { + struct ucall uc; + + vcpu_run(vcpu); + TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO); + + switch (get_ucall(vcpu, &uc)) { + case UCALL_ABORT: + REPORT_GUEST_ASSERT(uc); + /* NOT REACHED */ + case UCALL_SYNC: + report(uc.args[1]); + break; + case UCALL_DONE: + goto done; + default: + TEST_FAIL("Unknown ucall %lu", uc.cmd); + } + } + +done: + kvm_vm_free(vm); + return 0; +} |