// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2018, Red Hat, Inc.
 *
 * Tests for Enlightened VMCS, including nested guest state.
 */
#define _GNU_SOURCE /* for program_invocation_short_name */
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>

#include "test_util.h"

#include "kvm_util.h"

#include "vmx.h"

#define VCPU_ID         5
#define NMI_VECTOR      2

static int ud_count;

static void guest_ud_handler(struct ex_regs *regs)
{
        ud_count++;
        regs->rip += 3; /* VMLAUNCH */
}

static void guest_nmi_handler(struct ex_regs *regs)
{
}

void l2_guest_code(void)
{
        GUEST_SYNC(7);

        GUEST_SYNC(8);

        /* Forced exit to L1 upon restore */
        GUEST_SYNC(9);

        /* Done, exit to L1 and never come back.  */
        vmcall();
}

void guest_code(struct vmx_pages *vmx_pages)
{
#define L2_GUEST_STACK_SIZE 64
        unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];

        x2apic_enable();

        GUEST_SYNC(1);
        GUEST_SYNC(2);

        enable_vp_assist(vmx_pages->vp_assist_gpa, vmx_pages->vp_assist);

        GUEST_ASSERT(vmx_pages->vmcs_gpa);
        GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
        GUEST_SYNC(3);
        GUEST_ASSERT(load_vmcs(vmx_pages));
        GUEST_ASSERT(vmptrstz() == vmx_pages->enlightened_vmcs_gpa);

        GUEST_SYNC(4);
        GUEST_ASSERT(vmptrstz() == vmx_pages->enlightened_vmcs_gpa);

        prepare_vmcs(vmx_pages, l2_guest_code,
                     &l2_guest_stack[L2_GUEST_STACK_SIZE]);

        GUEST_SYNC(5);
        GUEST_ASSERT(vmptrstz() == vmx_pages->enlightened_vmcs_gpa);
        current_evmcs->revision_id = -1u;
        GUEST_ASSERT(vmlaunch());
        current_evmcs->revision_id = EVMCS_VERSION;
        GUEST_SYNC(6);

        current_evmcs->pin_based_vm_exec_control |=
                PIN_BASED_NMI_EXITING;
        GUEST_ASSERT(!vmlaunch());
        GUEST_ASSERT(vmptrstz() == vmx_pages->enlightened_vmcs_gpa);

        /*
         * NMI forces L2->L1 exit, resuming L2 and hope that EVMCS is
         * up-to-date (RIP points where it should and not at the beginning
         * of l2_guest_code(). GUEST_SYNC(9) checkes that.
         */
        GUEST_ASSERT(!vmresume());

        GUEST_SYNC(10);

        GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
        GUEST_SYNC(11);

        /* Try enlightened vmptrld with an incorrect GPA */
        evmcs_vmptrld(0xdeadbeef, vmx_pages->enlightened_vmcs);
        GUEST_ASSERT(vmlaunch());
        GUEST_ASSERT(ud_count == 1);
        GUEST_DONE();
}

void inject_nmi(struct kvm_vm *vm)
{
        struct kvm_vcpu_events events;

        vcpu_events_get(vm, VCPU_ID, &events);

        events.nmi.pending = 1;
        events.flags |= KVM_VCPUEVENT_VALID_NMI_PENDING;

        vcpu_events_set(vm, VCPU_ID, &events);
}

static void save_restore_vm(struct kvm_vm *vm)
{
        struct kvm_regs regs1, regs2;
        struct kvm_x86_state *state;

        state = vcpu_save_state(vm, VCPU_ID);
        memset(&regs1, 0, sizeof(regs1));
        vcpu_regs_get(vm, VCPU_ID, &regs1);

        kvm_vm_release(vm);

        /* Restore state in a new VM.  */
        kvm_vm_restart(vm, O_RDWR);
        vm_vcpu_add(vm, VCPU_ID);
        vcpu_set_hv_cpuid(vm, VCPU_ID);
        vcpu_enable_evmcs(vm, VCPU_ID);
        vcpu_load_state(vm, VCPU_ID, state);
        free(state);

        memset(&regs2, 0, sizeof(regs2));
        vcpu_regs_get(vm, VCPU_ID, &regs2);
        TEST_ASSERT(!memcmp(&regs1, &regs2, sizeof(regs2)),
                    "Unexpected register values after vcpu_load_state; rdi: %lx rsi: %lx",
                    (ulong) regs2.rdi, (ulong) regs2.rsi);
}

int main(int argc, char *argv[])
{
        vm_vaddr_t vmx_pages_gva = 0;

        struct kvm_vm *vm;
        struct kvm_run *run;
        struct ucall uc;
        int stage;

        /* Create VM */
        vm = vm_create_default(VCPU_ID, 0, guest_code);

        if (!nested_vmx_supported() ||
            !kvm_check_cap(KVM_CAP_NESTED_STATE) ||
            !kvm_check_cap(KVM_CAP_HYPERV_ENLIGHTENED_VMCS)) {
                print_skip("Enlightened VMCS is unsupported");
                exit(KSFT_SKIP);
        }

        vcpu_set_hv_cpuid(vm, VCPU_ID);
        vcpu_enable_evmcs(vm, VCPU_ID);

        vcpu_alloc_vmx(vm, &vmx_pages_gva);
        vcpu_args_set(vm, VCPU_ID, 1, vmx_pages_gva);

        vm_init_descriptor_tables(vm);
        vcpu_init_descriptor_tables(vm, VCPU_ID);
        vm_install_exception_handler(vm, UD_VECTOR, guest_ud_handler);
        vm_install_exception_handler(vm, NMI_VECTOR, guest_nmi_handler);

        pr_info("Running L1 which uses EVMCS to run L2\n");

        for (stage = 1;; stage++) {
                run = vcpu_state(vm, VCPU_ID);
                _vcpu_run(vm, VCPU_ID);
                TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
                            "Stage %d: unexpected exit reason: %u (%s),\n",
                            stage, run->exit_reason,
                            exit_reason_str(run->exit_reason));

                switch (get_ucall(vm, VCPU_ID, &uc)) {
                case UCALL_ABORT:
                        TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0],
                                  __FILE__, uc.args[1]);
                        /* NOT REACHED */
                case UCALL_SYNC:
                        break;
                case UCALL_DONE:
                        goto done;
                default:
                        TEST_FAIL("Unknown ucall %lu", uc.cmd);
                }

                /* UCALL_SYNC is handled here.  */
                TEST_ASSERT(!strcmp((const char *)uc.args[0], "hello") &&
                            uc.args[1] == stage, "Stage %d: Unexpected register values vmexit, got %lx",
                            stage, (ulong)uc.args[1]);

                save_restore_vm(vm);

                /* Force immediate L2->L1 exit before resuming */
                if (stage == 8) {
                        pr_info("Injecting NMI into L1 before L2 had a chance to run after restore\n");
                        inject_nmi(vm);
                }

                /*
                 * Do KVM_GET_NESTED_STATE/KVM_SET_NESTED_STATE for a freshly
                 * restored VM (before the first KVM_RUN) to check that
                 * KVM_STATE_NESTED_EVMCS is not lost.
                 */
                if (stage == 9) {
                        pr_info("Trying extra KVM_GET_NESTED_STATE/KVM_SET_NESTED_STATE cycle\n");
                        save_restore_vm(vm);
                }
        }

done:
        kvm_vm_free(vm);
}