tools/testing/selftests/kvm/x86_64/vmx_apic_access_test.c

   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. */
  34 static struct kvm_vm *vm;
  35
  36 static void l2_guest_code(void)
  37 {
  38         /* Exit to L1 */
  39         __asm__ __volatile__("vmcall");
  40 }
  41
  42 static 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
  77 int 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, 0);
 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 }