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 static void l2_guest_code(void)
  32 {
  33         /* Exit to L1 */
  34         __asm__ __volatile__("vmcall");
  35 }
  36
  37 static void l1_guest_code(struct vmx_pages *vmx_pages, unsigned long high_gpa)
  38 {
  39 #define L2_GUEST_STACK_SIZE 64
  40         unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
  41         uint32_t control;
  42
  43         GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
  44         GUEST_ASSERT(load_vmcs(vmx_pages));
  45
  46         /* Prepare the VMCS for L2 execution. */
  47         prepare_vmcs(vmx_pages, l2_guest_code,
  48                      &l2_guest_stack[L2_GUEST_STACK_SIZE]);
  49         control = vmreadz(CPU_BASED_VM_EXEC_CONTROL);
  50         control |= CPU_BASED_ACTIVATE_SECONDARY_CONTROLS;
  51         vmwrite(CPU_BASED_VM_EXEC_CONTROL, control);
  52         control = vmreadz(SECONDARY_VM_EXEC_CONTROL);
  53         control |= SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
  54         vmwrite(SECONDARY_VM_EXEC_CONTROL, control);
  55         vmwrite(APIC_ACCESS_ADDR, vmx_pages->apic_access_gpa);
  56
  57         /* Try to launch L2 with the memory-backed APIC-access address. */
  58         GUEST_SYNC(vmreadz(APIC_ACCESS_ADDR));
  59         GUEST_ASSERT(!vmlaunch());
  60         GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
  61
  62         vmwrite(APIC_ACCESS_ADDR, high_gpa);
  63
  64         /* Try to resume L2 with the unbacked APIC-access address. */
  65         GUEST_SYNC(vmreadz(APIC_ACCESS_ADDR));
  66         GUEST_ASSERT(!vmresume());
  67         GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
  68
  69         GUEST_DONE();
  70 }
  71
  72 int main(int argc, char *argv[])
  73 {
  74         unsigned long apic_access_addr = ~0ul;
  75         vm_vaddr_t vmx_pages_gva;
  76         unsigned long high_gpa;
  77         struct vmx_pages *vmx;
  78         bool done = false;
  79
  80         struct kvm_vcpu *vcpu;
  81         struct kvm_vm *vm;
  82
  83         TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX));
  84
  85         vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code);
  86
  87         high_gpa = (vm->max_gfn - 1) << vm->page_shift;
  88
  89         vmx = vcpu_alloc_vmx(vm, &vmx_pages_gva);
  90         prepare_virtualize_apic_accesses(vmx, vm);
  91         vcpu_args_set(vcpu, 2, vmx_pages_gva, high_gpa);
  92
  93         while (!done) {
  94                 volatile struct kvm_run *run = vcpu->run;
  95                 struct ucall uc;
  96
  97                 vcpu_run(vcpu);
  98                 if (apic_access_addr == high_gpa) {
  99                         TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_INTERNAL_ERROR);
 100                         TEST_ASSERT(run->internal.suberror ==
 101                                     KVM_INTERNAL_ERROR_EMULATION,
 102                                     "Got internal suberror other than KVM_INTERNAL_ERROR_EMULATION: %u\n",
 103                                     run->internal.suberror);
 104                         break;
 105                 }
 106                 TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
 107
 108                 switch (get_ucall(vcpu, &uc)) {
 109                 case UCALL_ABORT:
 110                         REPORT_GUEST_ASSERT(uc);
 111                         /* NOT REACHED */
 112                 case UCALL_SYNC:
 113                         apic_access_addr = uc.args[1];
 114                         break;
 115                 case UCALL_DONE:
 116                         done = true;
 117                         break;
 118                 default:
 119                         TEST_ASSERT(false, "Unknown ucall %lu", uc.cmd);
 120                 }
 121         }
 122         kvm_vm_free(vm);
 123         return 0;
 124 }