// 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;
}