LXR linux/tools/testing/selftests/kvm/x86_64/vmx_apic_access

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * vmx_apic_access_test
   4 *
   5 * Copyright (C) 2020, Google LLC.
   6 *
   7 * This work is licensed under the terms of the GNU GPL, version 2.
   8 *
   9 * The first subtest simply checks to see that an L2 guest can be
  10 * launched with a valid APIC-access address that is backed by a
  11 * page of L1 physical memory.
  12 *
  13 * The second subtest sets the APIC-access address to a (valid) L1
  14 * physical address that is not backed by memory. KVM can't handle
  15 * this situation, so resuming L2 should result in a KVM exit for
  16 * internal error (emulation). This is not an architectural
  17 * requirement. It is just a shortcoming of KVM. The internal error
  18 * is unfortunate, but it's better than what used to happen!
  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#define VCPU_ID         0
  32
  33/* The virtual machine object. */
  34static struct kvm_vm *vm;
  35
  36static void l2_guest_code(void)
  37{
  38        /* Exit to L1 */
  39        __asm__ __volatile__("vmcall");
  40}
  41
  42static void l1_guest_code(struct vmx_pages *vmx_pages, unsigned long high_gpa)
  43{
  44#define L2_GUEST_STACK_SIZE 64
  45        unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
  46        uint32_t control;
  47
  48        GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
  49        GUEST_ASSERT(load_vmcs(vmx_pages));
  50
  51        /* Prepare the VMCS for L2 execution. */
  52        prepare_vmcs(vmx_pages, l2_guest_code,
  53                     &l2_guest_stack[L2_GUEST_STACK_SIZE]);
  54        control = vmreadz(CPU_BASED_VM_EXEC_CONTROL);
  55        control |= CPU_BASED_ACTIVATE_SECONDARY_CONTROLS;
  56        vmwrite(CPU_BASED_VM_EXEC_CONTROL, control);
  57        control = vmreadz(SECONDARY_VM_EXEC_CONTROL);
  58        control |= SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
  59        vmwrite(SECONDARY_VM_EXEC_CONTROL, control);
  60        vmwrite(APIC_ACCESS_ADDR, vmx_pages->apic_access_gpa);
  61
  62        /* Try to launch L2 with the memory-backed APIC-access address. */
  63        GUEST_SYNC(vmreadz(APIC_ACCESS_ADDR));
  64        GUEST_ASSERT(!vmlaunch());
  65        GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
  66
  67        vmwrite(APIC_ACCESS_ADDR, high_gpa);
  68
  69        /* Try to resume L2 with the unbacked APIC-access address. */
  70        GUEST_SYNC(vmreadz(APIC_ACCESS_ADDR));
  71        GUEST_ASSERT(!vmresume());
  72        GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
  73
  74        GUEST_DONE();
  75}
  76
  77int main(int argc, char *argv[])
  78{
  79        unsigned long apic_access_addr = ~0ul;
  80        unsigned int paddr_width;
  81        unsigned int vaddr_width;
  82        vm_vaddr_t vmx_pages_gva;
  83        unsigned long high_gpa;
  84        struct vmx_pages *vmx;
  85        bool done = false;
  86
  87        nested_vmx_check_supported();
  88
  89        vm = vm_create_default(VCPU_ID, 0, (void *) l1_guest_code);
  90
  91        kvm_get_cpu_address_width(&paddr_width, &vaddr_width);
  92        high_gpa = (1ul << paddr_width) - getpagesize();
  93        if ((unsigned long)DEFAULT_GUEST_PHY_PAGES * getpagesize() > high_gpa) {
  94                print_skip("No unbacked physical page available");
  95                exit(KSFT_SKIP);
  96        }
  97
  98        vmx = vcpu_alloc_vmx(vm, &vmx_pages_gva);
  99        prepare_virtualize_apic_accesses(vmx, vm);
 100        vcpu_args_set(vm, VCPU_ID, 2, vmx_pages_gva, high_gpa);
 101
 102        while (!done) {
 103                volatile struct kvm_run *run = vcpu_state(vm, VCPU_ID);
 104                struct ucall uc;
 105
 106                vcpu_run(vm, VCPU_ID);
 107                if (apic_access_addr == high_gpa) {
 108                        TEST_ASSERT(run->exit_reason ==
 109                                    KVM_EXIT_INTERNAL_ERROR,
 110                                    "Got exit reason other than KVM_EXIT_INTERNAL_ERROR: %u (%s)\n",
 111                                    run->exit_reason,
 112                                    exit_reason_str(run->exit_reason));
 113                        TEST_ASSERT(run->internal.suberror ==
 114                                    KVM_INTERNAL_ERROR_EMULATION,
 115                                    "Got internal suberror other than KVM_INTERNAL_ERROR_EMULATION: %u\n",
 116                                    run->internal.suberror);
 117                        break;
 118                }
 119                TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
 120                            "Got exit_reason other than KVM_EXIT_IO: %u (%s)\n",
 121                            run->exit_reason,
 122                            exit_reason_str(run->exit_reason));
 123
 124                switch (get_ucall(vm, VCPU_ID, &uc)) {
 125                case UCALL_ABORT:
 126                        TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0],
 127                                  __FILE__, uc.args[1]);
 128                        /* NOT REACHED */
 129                case UCALL_SYNC:
 130                        apic_access_addr = uc.args[1];
 131                        break;
 132                case UCALL_DONE:
 133                        done = true;
 134                        break;
 135                default:
 136                        TEST_ASSERT(false, "Unknown ucall %lu", uc.cmd);
 137                }
 138        }
 139        kvm_vm_free(vm);
 140        return 0;
 141}
 142