KVM: SVM: nested: Don't allocate VMCB structures on stack (6ccbd29a) · Commits · 戴 / test

arch/x86/kvm/svm/nested.c

+33 −14

Original line number	Diff line number	Diff line
		@@ -1060,10 +1060,14 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
		struct vmcb *hsave = svm->nested.hsave;
		struct vmcb __user user_vmcb = (struct vmcb __user )
		&user_kvm_nested_state->data.svm[0];
		struct vmcb_control_area ctl;
		struct vmcb_save_area save;
		struct vmcb_control_area *ctl;
		struct vmcb_save_area *save;
		int ret;
		u32 cr0;

		BUILD_BUG_ON(sizeof(struct vmcb_control_area) + sizeof(struct vmcb_save_area) >
		KVM_STATE_NESTED_SVM_VMCB_SIZE);

		if (kvm_state->format != KVM_STATE_NESTED_FORMAT_SVM)
		return -EINVAL;

		@@ -1095,13 +1099,22 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
		return -EINVAL;
		if (kvm_state->size < sizeof(*kvm_state) + KVM_STATE_NESTED_SVM_VMCB_SIZE)
		return -EINVAL;
		if (copy_from_user(&ctl, &user_vmcb->control, sizeof(ctl)))
		return -EFAULT;
		if (copy_from_user(&save, &user_vmcb->save, sizeof(save)))
		return -EFAULT;

		if (!nested_vmcb_check_controls(&ctl))
		return -EINVAL;
		ret = -ENOMEM;
		ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
		save = kzalloc(sizeof(*save), GFP_KERNEL);
		if (!ctl \|\| !save)
		goto out_free;

		ret = -EFAULT;
		if (copy_from_user(ctl, &user_vmcb->control, sizeof(*ctl)))
		goto out_free;
		if (copy_from_user(save, &user_vmcb->save, sizeof(*save)))
		goto out_free;

		ret = -EINVAL;
		if (!nested_vmcb_check_controls(ctl))
		goto out_free;

		/*
		* Processor state contains L2 state. Check that it is
		@@ -1109,15 +1122,15 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
		*/
		cr0 = kvm_read_cr0(vcpu);
		if (((cr0 & X86_CR0_CD) == 0) && (cr0 & X86_CR0_NW))
		return -EINVAL;
		goto out_free;

		/*
		* Validate host state saved from before VMRUN (see
		* nested_svm_check_permissions).
		* TODO: validate reserved bits for all saved state.
		*/
		if (!(save.cr0 & X86_CR0_PG))
		return -EINVAL;
		if (!(save->cr0 & X86_CR0_PG))
		goto out_free;

		/*
		* All checks done, we can enter guest mode. L1 control fields
		@@ -1126,15 +1139,21 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
		* contains saved L1 state.
		*/
		copy_vmcb_control_area(&hsave->control, &svm->vmcb->control);
		hsave->save = save;
		hsave->save = *save;

		svm->nested.vmcb = kvm_state->hdr.svm.vmcb_pa;
		load_nested_vmcb_control(svm, &ctl);
		load_nested_vmcb_control(svm, ctl);
		nested_prepare_vmcb_control(svm);

		out_set_gif:
		svm_set_gif(svm, !!(kvm_state->flags & KVM_STATE_NESTED_GIF_SET));
		return 0;

		ret = 0;
		out_free:
		kfree(save);
		kfree(ctl);

		return ret;
		}

		struct kvm_x86_nested_ops svm_nested_ops = {

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