Commit cb9b6a1b authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

Merge branch 'kvm-fix-svm-races' into HEAD

parents 4a98623d 3c346c0c

arch/x86/kvm/svm/nested.c

+20 −12
Original line number Diff line number Diff line
@@ -272,6 +272,13 @@ static bool nested_vmcb_check_cr3_cr4(struct kvm_vcpu *vcpu, 
static bool nested_vmcb_valid_sregs(struct kvm_vcpu *vcpu,

				    struct vmcb_save_area *save)

{

	/*

	 * FIXME: these should be done after copying the fields,

	 * to avoid TOC/TOU races.  For these save area checks

	 * the possible damage is limited since kvm_set_cr0 and

	 * kvm_set_cr4 handle failure; EFER_SVME is an exception

	 * so it is force-set later in nested_prepare_vmcb_save.

	 */

	if (CC(!(save->efer & EFER_SVME)))

		return false;
@@ -291,14 +298,6 @@ static bool nested_vmcb_valid_sregs(struct kvm_vcpu *vcpu, 
	return true;

}



static bool nested_vmcb_checks(struct kvm_vcpu *vcpu, struct vmcb *vmcb12)

{

	if (!nested_vmcb_valid_sregs(vcpu, &vmcb12->save))

		return false;



	return nested_vmcb_check_controls(&vmcb12->control);

}



static void nested_load_control_from_vmcb12(struct vcpu_svm *svm,

					    struct vmcb_control_area *control)

{
@@ -449,7 +448,14 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12 
	}



	kvm_set_rflags(&svm->vcpu, vmcb12->save.rflags | X86_EFLAGS_FIXED);

	svm_set_efer(&svm->vcpu, vmcb12->save.efer);



	/*

	 * Force-set EFER_SVME even though it is checked earlier on the

	 * VMCB12, because the guest can flip the bit between the check

	 * and now.  Clearing EFER_SVME would call svm_free_nested.

	 */

	svm_set_efer(&svm->vcpu, vmcb12->save.efer | EFER_SVME);



	svm_set_cr0(&svm->vcpu, vmcb12->save.cr0);

	svm_set_cr4(&svm->vcpu, vmcb12->save.cr4);
@@ -564,7 +570,6 @@ int enter_svm_guest_mode(struct kvm_vcpu *vcpu, u64 vmcb12_gpa, 
	WARN_ON(svm->vmcb == svm->nested.vmcb02.ptr);



	nested_svm_copy_common_state(svm->vmcb01.ptr, svm->nested.vmcb02.ptr);

	nested_load_control_from_vmcb12(svm, &vmcb12->control);



	svm_switch_vmcb(svm, &svm->nested.vmcb02);

	nested_vmcb02_prepare_control(svm);
@@ -614,7 +619,10 @@ int nested_svm_vmrun(struct kvm_vcpu *vcpu) 
	if (WARN_ON_ONCE(!svm->nested.initialized))

		return -EINVAL;



	if (!nested_vmcb_checks(vcpu, vmcb12)) {

	nested_load_control_from_vmcb12(svm, &vmcb12->control);



	if (!nested_vmcb_valid_sregs(vcpu, &vmcb12->save) ||

	    !nested_vmcb_check_controls(&svm->nested.ctl)) {

		vmcb12->control.exit_code    = SVM_EXIT_ERR;

		vmcb12->control.exit_code_hi = 0;

		vmcb12->control.exit_info_1  = 0;
@@ -1251,7 +1259,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, 


	/*

	 * Processor state contains L2 state.  Check that it is

	 * valid for guest mode (see nested_vmcb_checks).

	 * valid for guest mode (see nested_vmcb_check_save).

	 */

	cr0 = kvm_read_cr0(vcpu);

        if (((cr0 & X86_CR0_CD) == 0) && (cr0 & X86_CR0_NW))