int nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu, bool from_vmentry)
{
	struct vcpu_vmx *vmx = to_vmx(vcpu);
	struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
	bool evaluate_pending_interrupts;
	u32 exit_reason = EXIT_REASON_INVALID_STATE;
	u32 exit_qual;

	evaluate_pending_interrupts = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL) &
		(CPU_BASED_VIRTUAL_INTR_PENDING | CPU_BASED_VIRTUAL_NMI_PENDING);
	if (likely(!evaluate_pending_interrupts) && kvm_vcpu_apicv_active(vcpu))
		evaluate_pending_interrupts |= vmx_has_apicv_interrupt(vcpu);

	if (!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS))
		vmx->nested.vmcs01_debugctl = vmcs_read64(GUEST_IA32_DEBUGCTL);
	if (kvm_mpx_supported() &&
		!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS))
		vmx->nested.vmcs01_guest_bndcfgs = vmcs_read64(GUEST_BNDCFGS);

	vmx_switch_vmcs(vcpu, &vmx->nested.vmcs02);

	prepare_vmcs02_early(vmx, vmcs12);

	if (from_vmentry) {
		nested_get_vmcs12_pages(vcpu);

		if (nested_vmx_check_vmentry_hw(vcpu)) {
			vmx_switch_vmcs(vcpu, &vmx->vmcs01);
			return -1;
		}

		if (nested_vmx_check_vmentry_postreqs(vcpu, vmcs12, &exit_qual))
			goto vmentry_fail_vmexit;
	}

	enter_guest_mode(vcpu);
	if (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETING)
		vcpu->arch.tsc_offset += vmcs12->tsc_offset;

	if (prepare_vmcs02(vcpu, vmcs12, &exit_qual))
		goto vmentry_fail_vmexit_guest_mode;

	if (from_vmentry) {
		exit_reason = EXIT_REASON_MSR_LOAD_FAIL;
		exit_qual = nested_vmx_load_msr(vcpu,
						vmcs12->vm_entry_msr_load_addr,
						vmcs12->vm_entry_msr_load_count);
		if (exit_qual)
			goto vmentry_fail_vmexit_guest_mode;
	} else {
		/*
		 * The MMU is not initialized to point at the right entities yet and
		 * "get pages" would need to read data from the guest (i.e. we will
		 * need to perform gpa to hpa translation). Request a call
		 * to nested_get_vmcs12_pages before the next VM-entry.  The MSRs
		 * have already been set at vmentry time and should not be reset.
		 */
		kvm_make_request(KVM_REQ_GET_VMCS12_PAGES, vcpu);
	}

	/*
	 * If L1 had a pending IRQ/NMI until it executed
	 * VMLAUNCH/VMRESUME which wasn't delivered because it was
	 * disallowed (e.g. interrupts disabled), L0 needs to
	 * evaluate if this pending event should cause an exit from L2
	 * to L1 or delivered directly to L2 (e.g. In case L1 don't
	 * intercept EXTERNAL_INTERRUPT).
	 *
	 * Usually this would be handled by the processor noticing an
	 * IRQ/NMI window request, or checking RVI during evaluation of
	 * pending virtual interrupts.  However, this setting was done
	 * on VMCS01 and now VMCS02 is active instead. Thus, we force L0
	 * to perform pending event evaluation by requesting a KVM_REQ_EVENT.
	 */
	if (unlikely(evaluate_pending_interrupts))
		kvm_make_request(KVM_REQ_EVENT, vcpu);

	/*
	 * Do not start the preemption timer hrtimer until after we know
	 * we are successful, so that only nested_vmx_vmexit needs to cancel
	 * the timer.
	 */
	vmx->nested.preemption_timer_expired = false;
	if (nested_cpu_has_preemption_timer(vmcs12))
		vmx_start_preemption_timer(vcpu);

	/*
	 * Note no nested_vmx_succeed or nested_vmx_fail here. At this point
	 * we are no longer running L1, and VMLAUNCH/VMRESUME has not yet
	 * returned as far as L1 is concerned. It will only return (and set
	 * the success flag) when L2 exits (see nested_vmx_vmexit()).
	 */
	return 0;

	/*
	 * A failed consistency check that leads to a VMExit during L1's
	 * VMEnter to L2 is a variation of a normal VMexit, as explained in
	 * 26.7 "VM-entry failures during or after loading guest state".
	 */
vmentry_fail_vmexit_guest_mode:
	if (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETING)
		vcpu->arch.tsc_offset -= vmcs12->tsc_offset;
	leave_guest_mode(vcpu);

vmentry_fail_vmexit:
	vmx_switch_vmcs(vcpu, &vmx->vmcs01);

	if (!from_vmentry)
		return 1;

	load_vmcs12_host_state(vcpu, vmcs12);
	vmcs12->vm_exit_reason = exit_reason | VMX_EXIT_REASONS_FAILED_VMENTRY;
	vmcs12->exit_qualification = exit_qual;
	if (enable_shadow_vmcs || vmx->nested.hv_evmcs)
		vmx->nested.need_vmcs12_sync = true;
	return 1;
}
Unknown