1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * vmx_tsc_adjust_test 4 * 5 * Copyright (C) 2018, Google LLC. 6 * 7 * IA32_TSC_ADJUST test 8 * 9 * According to the SDM, "if an execution of WRMSR to the 10 * IA32_TIME_STAMP_COUNTER MSR adds (or subtracts) value X from the TSC, 11 * the logical processor also adds (or subtracts) value X from the 12 * IA32_TSC_ADJUST MSR. 13 * 14 * Note that when L1 doesn't intercept writes to IA32_TSC, a 15 * WRMSR(IA32_TSC) from L2 sets L1's TSC value, not L2's perceived TSC 16 * value. 17 * 18 * This test verifies that this unusual case is handled correctly. 19 */ 20 21 #include "test_util.h" 22 #include "kvm_util.h" 23 #include "processor.h" 24 #include "vmx.h" 25 26 #include <string.h> 27 #include <sys/ioctl.h> 28 29 #include "kselftest.h" 30 31 #ifndef MSR_IA32_TSC_ADJUST 32 #define MSR_IA32_TSC_ADJUST 0x3b 33 #endif 34 35 #define VCPU_ID 5 36 37 #define TSC_ADJUST_VALUE (1ll << 32) 38 #define TSC_OFFSET_VALUE -(1ll << 48) 39 40 enum { 41 PORT_ABORT = 0x1000, 42 PORT_REPORT, 43 PORT_DONE, 44 }; 45 46 enum { 47 VMXON_PAGE = 0, 48 VMCS_PAGE, 49 MSR_BITMAP_PAGE, 50 51 NUM_VMX_PAGES, 52 }; 53 54 struct kvm_single_msr { 55 struct kvm_msrs header; 56 struct kvm_msr_entry entry; 57 } __attribute__((packed)); 58 59 /* The virtual machine object. */ 60 static struct kvm_vm *vm; 61 62 static void check_ia32_tsc_adjust(int64_t max) 63 { 64 int64_t adjust; 65 66 adjust = rdmsr(MSR_IA32_TSC_ADJUST); 67 GUEST_SYNC(adjust); 68 GUEST_ASSERT(adjust <= max); 69 } 70 71 static void l2_guest_code(void) 72 { 73 uint64_t l1_tsc = rdtsc() - TSC_OFFSET_VALUE; 74 75 wrmsr(MSR_IA32_TSC, l1_tsc - TSC_ADJUST_VALUE); 76 check_ia32_tsc_adjust(-2 * TSC_ADJUST_VALUE); 77 78 /* Exit to L1 */ 79 __asm__ __volatile__("vmcall"); 80 } 81 82 static void l1_guest_code(struct vmx_pages *vmx_pages) 83 { 84 #define L2_GUEST_STACK_SIZE 64 85 unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE]; 86 uint32_t control; 87 uintptr_t save_cr3; 88 89 GUEST_ASSERT(rdtsc() < TSC_ADJUST_VALUE); 90 wrmsr(MSR_IA32_TSC, rdtsc() - TSC_ADJUST_VALUE); 91 check_ia32_tsc_adjust(-1 * TSC_ADJUST_VALUE); 92 93 GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages)); 94 GUEST_ASSERT(load_vmcs(vmx_pages)); 95 96 /* Prepare the VMCS for L2 execution. */ 97 prepare_vmcs(vmx_pages, l2_guest_code, 98 &l2_guest_stack[L2_GUEST_STACK_SIZE]); 99 control = vmreadz(CPU_BASED_VM_EXEC_CONTROL); 100 control |= CPU_BASED_USE_MSR_BITMAPS | CPU_BASED_USE_TSC_OFFSETTING; 101 vmwrite(CPU_BASED_VM_EXEC_CONTROL, control); 102 vmwrite(TSC_OFFSET, TSC_OFFSET_VALUE); 103 104 /* Jump into L2. First, test failure to load guest CR3. */ 105 save_cr3 = vmreadz(GUEST_CR3); 106 vmwrite(GUEST_CR3, -1ull); 107 GUEST_ASSERT(!vmlaunch()); 108 GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == 109 (EXIT_REASON_FAILED_VMENTRY | EXIT_REASON_INVALID_STATE)); 110 check_ia32_tsc_adjust(-1 * TSC_ADJUST_VALUE); 111 vmwrite(GUEST_CR3, save_cr3); 112 113 GUEST_ASSERT(!vmlaunch()); 114 GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL); 115 116 check_ia32_tsc_adjust(-2 * TSC_ADJUST_VALUE); 117 118 GUEST_DONE(); 119 } 120 121 static void report(int64_t val) 122 { 123 pr_info("IA32_TSC_ADJUST is %ld (%lld * TSC_ADJUST_VALUE + %lld).\n", 124 val, val / TSC_ADJUST_VALUE, val % TSC_ADJUST_VALUE); 125 } 126 127 int main(int argc, char *argv[]) 128 { 129 vm_vaddr_t vmx_pages_gva; 130 131 nested_vmx_check_supported(); 132 133 vm = vm_create_default(VCPU_ID, 0, (void *) l1_guest_code); 134 135 /* Allocate VMX pages and shared descriptors (vmx_pages). */ 136 vcpu_alloc_vmx(vm, &vmx_pages_gva); 137 vcpu_args_set(vm, VCPU_ID, 1, vmx_pages_gva); 138 139 for (;;) { 140 volatile struct kvm_run *run = vcpu_state(vm, VCPU_ID); 141 struct ucall uc; 142 143 vcpu_run(vm, VCPU_ID); 144 TEST_ASSERT(run->exit_reason == KVM_EXIT_IO, 145 "Got exit_reason other than KVM_EXIT_IO: %u (%s)\n", 146 run->exit_reason, 147 exit_reason_str(run->exit_reason)); 148 149 switch (get_ucall(vm, VCPU_ID, &uc)) { 150 case UCALL_ABORT: 151 TEST_FAIL("%s", (const char *)uc.args[0]); 152 /* NOT REACHED */ 153 case UCALL_SYNC: 154 report(uc.args[1]); 155 break; 156 case UCALL_DONE: 157 goto done; 158 default: 159 TEST_FAIL("Unknown ucall %lu", uc.cmd); 160 } 161 } 162 163 done: 164 kvm_vm_free(vm); 165 return 0; 166 } 167