| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * vmx_tsc_adjust_test |
| * |
| * 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 <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) |
| |
| 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(struct vmx_pages *vmx_pages) |
| { |
| #define L2_GUEST_STACK_SIZE 64 |
| unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE]; |
| uint32_t control; |
| uintptr_t save_cr3; |
| |
| GUEST_ASSERT(rdtsc() < TSC_ADJUST_VALUE); |
| wrmsr(MSR_IA32_TSC, rdtsc() - TSC_ADJUST_VALUE); |
| check_ia32_tsc_adjust(-1 * TSC_ADJUST_VALUE); |
| |
| GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages)); |
| GUEST_ASSERT(load_vmcs(vmx_pages)); |
| |
| /* Prepare the VMCS for L2 execution. */ |
| 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); |
| |
| /* Jump into L2. First, test failure to load guest CR3. */ |
| save_cr3 = vmreadz(GUEST_CR3); |
| vmwrite(GUEST_CR3, -1ull); |
| GUEST_ASSERT(!vmlaunch()); |
| GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == |
| (EXIT_REASON_FAILED_VMENTRY | EXIT_REASON_INVALID_STATE)); |
| check_ia32_tsc_adjust(-1 * TSC_ADJUST_VALUE); |
| vmwrite(GUEST_CR3, save_cr3); |
| |
| GUEST_ASSERT(!vmlaunch()); |
| GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL); |
| |
| 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 vmx_pages_gva; |
| struct kvm_vcpu *vcpu; |
| |
| TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX)); |
| |
| vm = vm_create_with_one_vcpu(&vcpu, (void *) l1_guest_code); |
| |
| /* Allocate VMX pages and shared descriptors (vmx_pages). */ |
| vcpu_alloc_vmx(vm, &vmx_pages_gva); |
| vcpu_args_set(vcpu, 1, vmx_pages_gva); |
| |
| for (;;) { |
| volatile struct kvm_run *run = vcpu->run; |
| struct ucall uc; |
| |
| vcpu_run(vcpu); |
| TEST_ASSERT(run->exit_reason == KVM_EXIT_IO, |
| "Got exit_reason other than KVM_EXIT_IO: %u (%s)\n", |
| run->exit_reason, |
| exit_reason_str(run->exit_reason)); |
| |
| 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; |
| } |