176 lines
4.1 KiB
C
176 lines
4.1 KiB
C
/*
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* gtests/tests/vmx_tsc_adjust_test.c
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*
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* Copyright (C) 2018, Google LLC.
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*
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* This work is licensed under the terms of the GNU GPL, version 2.
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*
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*
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* IA32_TSC_ADJUST test
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*
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* According to the SDM, "if an execution of WRMSR to the
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* IA32_TIME_STAMP_COUNTER MSR adds (or subtracts) value X from the TSC,
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* the logical processor also adds (or subtracts) value X from the
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* IA32_TSC_ADJUST MSR.
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*
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* Note that when L1 doesn't intercept writes to IA32_TSC, a
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* WRMSR(IA32_TSC) from L2 sets L1's TSC value, not L2's perceived TSC
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* value.
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*
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* This test verifies that this unusual case is handled correctly.
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*/
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#include "test_util.h"
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#include "kvm_util.h"
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#include "x86.h"
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#include "vmx.h"
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#include <string.h>
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#include <sys/ioctl.h>
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#include "../kselftest.h"
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#ifndef MSR_IA32_TSC_ADJUST
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#define MSR_IA32_TSC_ADJUST 0x3b
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#endif
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#define PAGE_SIZE 4096
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#define VCPU_ID 5
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#define TSC_ADJUST_VALUE (1ll << 32)
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#define TSC_OFFSET_VALUE -(1ll << 48)
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enum {
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PORT_ABORT = 0x1000,
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PORT_REPORT,
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PORT_DONE,
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};
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enum {
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VMXON_PAGE = 0,
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VMCS_PAGE,
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MSR_BITMAP_PAGE,
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NUM_VMX_PAGES,
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};
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struct kvm_single_msr {
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struct kvm_msrs header;
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struct kvm_msr_entry entry;
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} __attribute__((packed));
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/* The virtual machine object. */
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static struct kvm_vm *vm;
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static void check_ia32_tsc_adjust(int64_t max)
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{
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int64_t adjust;
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adjust = rdmsr(MSR_IA32_TSC_ADJUST);
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GUEST_SYNC(adjust);
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GUEST_ASSERT(adjust <= max);
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}
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static void l2_guest_code(void)
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{
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uint64_t l1_tsc = rdtsc() - TSC_OFFSET_VALUE;
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wrmsr(MSR_IA32_TSC, l1_tsc - TSC_ADJUST_VALUE);
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check_ia32_tsc_adjust(-2 * TSC_ADJUST_VALUE);
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/* Exit to L1 */
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__asm__ __volatile__("vmcall");
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}
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static void l1_guest_code(struct vmx_pages *vmx_pages)
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{
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#define L2_GUEST_STACK_SIZE 64
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unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
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uint32_t control;
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uintptr_t save_cr3;
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GUEST_ASSERT(rdtsc() < TSC_ADJUST_VALUE);
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wrmsr(MSR_IA32_TSC, rdtsc() - TSC_ADJUST_VALUE);
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check_ia32_tsc_adjust(-1 * TSC_ADJUST_VALUE);
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GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
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/* Prepare the VMCS for L2 execution. */
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prepare_vmcs(vmx_pages, l2_guest_code,
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&l2_guest_stack[L2_GUEST_STACK_SIZE]);
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control = vmreadz(CPU_BASED_VM_EXEC_CONTROL);
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control |= CPU_BASED_USE_MSR_BITMAPS | CPU_BASED_USE_TSC_OFFSETING;
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vmwrite(CPU_BASED_VM_EXEC_CONTROL, control);
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vmwrite(TSC_OFFSET, TSC_OFFSET_VALUE);
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/* Jump into L2. First, test failure to load guest CR3. */
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save_cr3 = vmreadz(GUEST_CR3);
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vmwrite(GUEST_CR3, -1ull);
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GUEST_ASSERT(!vmlaunch());
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GUEST_ASSERT(vmreadz(VM_EXIT_REASON) ==
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(EXIT_REASON_FAILED_VMENTRY | EXIT_REASON_INVALID_STATE));
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check_ia32_tsc_adjust(-1 * TSC_ADJUST_VALUE);
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vmwrite(GUEST_CR3, save_cr3);
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GUEST_ASSERT(!vmlaunch());
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GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
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check_ia32_tsc_adjust(-2 * TSC_ADJUST_VALUE);
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GUEST_DONE();
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}
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void report(int64_t val)
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{
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printf("IA32_TSC_ADJUST is %ld (%lld * TSC_ADJUST_VALUE + %lld).\n",
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val, val / TSC_ADJUST_VALUE, val % TSC_ADJUST_VALUE);
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}
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int main(int argc, char *argv[])
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{
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struct vmx_pages *vmx_pages;
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vm_vaddr_t vmx_pages_gva;
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struct kvm_cpuid_entry2 *entry = kvm_get_supported_cpuid_entry(1);
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if (!(entry->ecx & CPUID_VMX)) {
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fprintf(stderr, "nested VMX not enabled, skipping test\n");
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exit(KSFT_SKIP);
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}
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vm = vm_create_default(VCPU_ID, 0, (void *) l1_guest_code);
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vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
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/* Allocate VMX pages and shared descriptors (vmx_pages). */
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vmx_pages = vcpu_alloc_vmx(vm, &vmx_pages_gva);
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vcpu_args_set(vm, VCPU_ID, 1, vmx_pages_gva);
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for (;;) {
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volatile struct kvm_run *run = vcpu_state(vm, VCPU_ID);
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struct guest_args args;
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vcpu_run(vm, VCPU_ID);
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guest_args_read(vm, VCPU_ID, &args);
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TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
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"Got exit_reason other than KVM_EXIT_IO: %u (%s)\n",
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run->exit_reason,
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exit_reason_str(run->exit_reason));
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switch (args.port) {
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case GUEST_PORT_ABORT:
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TEST_ASSERT(false, "%s", (const char *) args.arg0);
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/* NOT REACHED */
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case GUEST_PORT_SYNC:
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report(args.arg1);
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break;
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case GUEST_PORT_DONE:
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goto done;
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default:
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TEST_ASSERT(false, "Unknown port 0x%x.", args.port);
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}
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}
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kvm_vm_free(vm);
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done:
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return 0;
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}
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