From nobody Mon Feb 9 10:28:27 2026 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6A6EA60ECB for ; Mon, 18 Mar 2024 23:34:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710804851; cv=none; b=nKNj1+41QY/2/m2XI2+93DIjPI6iM5WuyzZwi9zpwlG5P1YIVh7r4zheh3PKRPGxgUmBpWx8i40BJTLyhyhDuXT6Z8Sc8Rh9glz4SbBAvGxCgdJIGe+/e0x4jIoLPbnwunMW9xheFUTOKA8O9kxahuzlCeUHWVixeKjBeomhvIA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710804851; c=relaxed/simple; bh=3UZOWxvel2gxNTwrPzBwKutiH6HW6UJXahf+TYTu8Rk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=jwoJS213fGdF8ocq8x930t41HUYIMJ0CIgILqel2kdvSRnQZEdwmrJPHweoXJ65Gfs/KFblFWzgVBund/3POYhDZajNZv5N4KItZSiQVEgwK3fO6GWDwz3veEYvjYZhmJJfdj6l10jsTPWSRfvxUJLFpOjY7YgkMO4BhRQeoji0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=aPALtLQf; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="aPALtLQf" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1710804847; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+IyuuUxiGnoaxGNnwqcPQ8aX2JAcsb4DAgIo+w+cUTM=; b=aPALtLQfLWvVMUTCUwXF7F/WEhYqF1yciWGySGYUsF+JhbMylTuMDvWrJLd0Xpc9twuiJy QIw+nJGrWH90uAR0aB/w4iB/4viAXeXgZwOADjUO9UpxQGrK4EDeauqnEUAPccQFtyLTOI xcODa1JUMfydGj6JR2XdpuT50gSLARc= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-644-1cbqT6GUM0qzkcQ9oKbrTg-1; Mon, 18 Mar 2024 19:33:54 -0400 X-MC-Unique: 1cbqT6GUM0qzkcQ9oKbrTg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6E1D13C02451; Mon, 18 Mar 2024 23:33:54 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 474331121312; Mon, 18 Mar 2024 23:33:54 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: michael.roth@amd.com, isaku.yamahata@intel.com, seanjc@google.com Subject: [PATCH v4 03/15] KVM: x86: use u64_to_user_addr() Date: Mon, 18 Mar 2024 19:33:40 -0400 Message-ID: <20240318233352.2728327-4-pbonzini@redhat.com> In-Reply-To: <20240318233352.2728327-1-pbonzini@redhat.com> References: <20240318233352.2728327-1-pbonzini@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.3 Content-Type: text/plain; charset="utf-8" There is no danger to the kernel if 32-bit userspace provides a 64-bit value that has the high bits set, but for whatever reason happens to resolve to an address that has something mapped there. KVM uses the checked version of get_user() and put_user(), so any faults are caught properly. Suggested-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 24 +++--------------------- 1 file changed, 3 insertions(+), 21 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 47d9f03b7778..3d2029402513 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4842,25 +4842,13 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, l= ong ext) return r; } =20 -static inline void __user *kvm_get_attr_addr(struct kvm_device_attr *attr) -{ - void __user *uaddr =3D (void __user*)(unsigned long)attr->addr; - - if ((u64)(unsigned long)uaddr !=3D attr->addr) - return ERR_PTR_USR(-EFAULT); - return uaddr; -} - static int kvm_x86_dev_get_attr(struct kvm_device_attr *attr) { - u64 __user *uaddr =3D kvm_get_attr_addr(attr); + u64 __user *uaddr =3D u64_to_user_ptr(attr->addr); =20 if (attr->group) return -ENXIO; =20 - if (IS_ERR(uaddr)) - return PTR_ERR(uaddr); - switch (attr->attr) { case KVM_X86_XCOMP_GUEST_SUPP: if (put_user(kvm_caps.supported_xcr0, uaddr)) @@ -5712,12 +5700,9 @@ static int kvm_arch_tsc_has_attr(struct kvm_vcpu *vc= pu, static int kvm_arch_tsc_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr) { - u64 __user *uaddr =3D kvm_get_attr_addr(attr); + u64 __user *uaddr =3D u64_to_user_ptr(attr->addr); int r; =20 - if (IS_ERR(uaddr)) - return PTR_ERR(uaddr); - switch (attr->attr) { case KVM_VCPU_TSC_OFFSET: r =3D -EFAULT; @@ -5735,13 +5720,10 @@ static int kvm_arch_tsc_get_attr(struct kvm_vcpu *v= cpu, static int kvm_arch_tsc_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr) { - u64 __user *uaddr =3D kvm_get_attr_addr(attr); + u64 __user *uaddr =3D u64_to_user_ptr(attr->addr); struct kvm *kvm =3D vcpu->kvm; int r; =20 - if (IS_ERR(uaddr)) - return PTR_ERR(uaddr); - switch (attr->attr) { case KVM_VCPU_TSC_OFFSET: { u64 offset, tsc, ns; --=20 2.43.0