Quelle  nested_emulation_test.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
#include "test_util.h"
#include "kvm_util.h"
#include "processor.h"
#include "vmx.h"
#include "svm_util.h"

enum {
 SVM_F,
 VMX_F,
 NR_VIRTUALIZATION_FLAVORS,
};

struct emulated_instruction {
 const char name[32];
 uint8_t opcode[15];
 uint32_t exit_reason[NR_VIRTUALIZATION_FLAVORS];
};

static struct emulated_instruction instructions[] = {
 {
  .name = "pause",
  .opcode = { 0xf3, 0x90 },
  .exit_reason = { SVM_EXIT_PAUSE,
     EXIT_REASON_PAUSE_INSTRUCTION, }
 },
 {
  .name = "hlt",
  .opcode = { 0xf4 },
  .exit_reason = { SVM_EXIT_HLT,
     EXIT_REASON_HLT, }
 },
};

static uint8_t kvm_fep[] = { 0x0f, 0x0b, 0x6b, 0x76, 0x6d }; /* ud2 ; .ascii "kvm" */
static uint8_t l2_guest_code[sizeof(kvm_fep) + 15];
static uint8_t *l2_instruction = &l2_guest_code[sizeof(kvm_fep)];

static uint32_t get_instruction_length(struct emulated_instruction *insn)
{
 uint32_t i;

 for (i = 0; i < ARRAY_SIZE(insn->opcode) && insn->opcode[i]; i++)
  ;

 return i;
}

static void guest_code(void *test_data)
{
 int f = this_cpu_has(X86_FEATURE_SVM) ? SVM_F : VMX_F;
 int i;

 memcpy(l2_guest_code, kvm_fep, sizeof(kvm_fep));

 if (f == SVM_F) {
  struct svm_test_data *svm = test_data;
  struct vmcb *vmcb = svm->vmcb;

  generic_svm_setup(svm, NULL, NULL);
  vmcb->save.idtr.limit = 0;
  vmcb->save.rip = (u64)l2_guest_code;

  vmcb->control.intercept |= BIT_ULL(INTERCEPT_SHUTDOWN) |
        BIT_ULL(INTERCEPT_PAUSE) |
        BIT_ULL(INTERCEPT_HLT);
  vmcb->control.intercept_exceptions = 0;
 } else {
  GUEST_ASSERT(prepare_for_vmx_operation(test_data));
  GUEST_ASSERT(load_vmcs(test_data));

  prepare_vmcs(test_data, NULL, NULL);
  GUEST_ASSERT(!vmwrite(GUEST_IDTR_LIMIT, 0));
  GUEST_ASSERT(!vmwrite(GUEST_RIP, (u64)l2_guest_code));
  GUEST_ASSERT(!vmwrite(EXCEPTION_BITMAP, 0));

  vmwrite(CPU_BASED_VM_EXEC_CONTROL, vmreadz(CPU_BASED_VM_EXEC_CONTROL) |
         CPU_BASED_PAUSE_EXITING |
         CPU_BASED_HLT_EXITING);
 }

 for (i = 0; i < ARRAY_SIZE(instructions); i++) {
  struct emulated_instruction *insn = &instructions[i];
  uint32_t insn_len = get_instruction_length(insn);
  uint32_t exit_insn_len;
  u32 exit_reason;

  /*
 * Copy the target instruction to the L2 code stream, and fill
 * the remaining bytes with INT3s so that a missed intercept
 * results in a consistent failure mode (SHUTDOWN).
 */
  memcpy(l2_instruction, insn->opcode, insn_len);
  memset(l2_instruction + insn_len, 0xcc, sizeof(insn->opcode) - insn_len);

  if (f == SVM_F) {
   struct svm_test_data *svm = test_data;
   struct vmcb *vmcb = svm->vmcb;

   run_guest(vmcb, svm->vmcb_gpa);
   exit_reason = vmcb->control.exit_code;
   exit_insn_len = vmcb->control.next_rip - vmcb->save.rip;
   GUEST_ASSERT_EQ(vmcb->save.rip, (u64)l2_instruction);
  } else {
   GUEST_ASSERT_EQ(i ? vmresume() : vmlaunch(), 0);
   exit_reason = vmreadz(VM_EXIT_REASON);
   exit_insn_len = vmreadz(VM_EXIT_INSTRUCTION_LEN);
   GUEST_ASSERT_EQ(vmreadz(GUEST_RIP), (u64)l2_instruction);
  }

  __GUEST_ASSERT(exit_reason == insn->exit_reason[f],
          "Wanted exit_reason '0x%x' for '%s', got '0x%x'",
          insn->exit_reason[f], insn->name, exit_reason);

  __GUEST_ASSERT(exit_insn_len == insn_len,
          "Wanted insn_len '%u' for '%s', got '%u'",
          insn_len, insn->name, exit_insn_len);
 }

 GUEST_DONE();
}

int main(int argc, char *argv[])
{
 vm_vaddr_t nested_test_data_gva;
 struct kvm_vcpu *vcpu;
 struct kvm_vm *vm;

 TEST_REQUIRE(is_forced_emulation_enabled);
 TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_SVM) || kvm_cpu_has(X86_FEATURE_VMX));

 vm = vm_create_with_one_vcpu(&vcpu, guest_code);
 vm_enable_cap(vm, KVM_CAP_EXCEPTION_PAYLOAD, -2ul);

 if (kvm_cpu_has(X86_FEATURE_SVM))
  vcpu_alloc_svm(vm, &nested_test_data_gva);
 else
  vcpu_alloc_vmx(vm, &nested_test_data_gva);

 vcpu_args_set(vcpu, 1, nested_test_data_gva);

 vcpu_run(vcpu);
 TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_DONE);

 kvm_vm_free(vm);
}