From nobody Tue Nov 4 11:11:43 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1529927853058687.6791089329815; Mon, 25 Jun 2018 04:57:33 -0700 (PDT) Received: from localhost ([::1]:45883 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fXQ7g-0001nh-Bo for importer@patchew.org; Mon, 25 Jun 2018 07:57:32 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38936) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fXQ4F-0007QQ-D0 for qemu-devel@nongnu.org; Mon, 25 Jun 2018 07:54:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fXQ4C-0001bt-UT for qemu-devel@nongnu.org; Mon, 25 Jun 2018 07:53:59 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:38552 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fXQ4C-0001bV-PC; Mon, 25 Jun 2018 07:53:56 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4A2994023336; Mon, 25 Jun 2018 11:53:56 +0000 (UTC) Received: from t460s.redhat.com (ovpn-116-226.ams2.redhat.com [10.36.116.226]) by smtp.corp.redhat.com (Postfix) with ESMTP id E914A2166B5D; Mon, 25 Jun 2018 11:53:54 +0000 (UTC) From: David Hildenbrand To: qemu-s390x@nongnu.org Date: Mon, 25 Jun 2018 13:53:44 +0200 Message-Id: <20180625115352.6889-2-david@redhat.com> In-Reply-To: <20180625115352.6889-1-david@redhat.com> References: <20180625115352.6889-1-david@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Mon, 25 Jun 2018 11:53:56 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Mon, 25 Jun 2018 11:53:56 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'david@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH v3 1/9] s390x/tcg: avoid overflows in time2tod/tod2time X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Huth , David Hildenbrand , Cornelia Huck , Alexander Graf , qemu-devel@nongnu.org, Christian Borntraeger , Richard Henderson Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Big values for the TOD/ns clock can result in some overflows that can be avoided. Not all overflows can be handled however, as the conversion either multiplies by 4.096 or divided by 4.096. Apply the trick used in the Linux kernel in arch/s390/include/asm/timex.h for tod_to_ns() and use the same trick also for the conversion in the other direction. Signed-off-by: David Hildenbrand Reviewed-by: Thomas Huth --- target/s390x/internal.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/target/s390x/internal.h b/target/s390x/internal.h index e392a02d12..6cf63340bf 100644 --- a/target/s390x/internal.h +++ b/target/s390x/internal.h @@ -243,13 +243,14 @@ enum cc_op { /* Converts ns to s390's clock format */ static inline uint64_t time2tod(uint64_t ns) { - return (ns << 9) / 125; + return (ns << 9) / 125 + (((ns & 0xff10000000000000ull) / 125) << 9); + } =20 /* Converts s390's clock format to ns */ static inline uint64_t tod2time(uint64_t t) { - return (t * 125) >> 9; + return ((t >> 9) * 125) + (((t & 0x1ff) * 125) >> 9); } =20 static inline hwaddr decode_basedisp_s(CPUS390XState *env, uint32_t ipb, --=20 2.17.1