From nobody Sun Feb 8 15:46:45 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; 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 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1565945482; cv=none; d=zoho.com; s=zohoarc; b=BGRlZdm8gq1Rw8Pbf7ahMhCttBGC1YErKN3SneflSa4QiUWIjJKBCN2SPjEjWZ92GH52WJlZy+4o3FooBL+/rcupiwJeVhji8MYpC2KglqYsKuy+zxESySY8Gu5slGn5CDSkHUCZgNIvOApEG/qdGLCTKFp1+Wm61l4aYz6mbeQ= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1565945482; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To:ARC-Authentication-Results; bh=9oVRSWQeoFQCYF6peXpPD4lH7mkb+nuz18OVuwnch+I=; b=gKznjSIQEadatxzNOmnPEOfCTHf8v8cSQ7Tt2uJ5QhZKb7YZIJxi435+xT1ZzPNqKQk2NXz83ERmVMi4RP6HorddMeK5OQejh4k/W+hHbL7Gp1ti2pW8pHCQEyXHEb7muyEHPmT6vd4UoYHKZ+E6EYRYVctqNseFV/3SvLu+yK0= ARC-Authentication-Results: i=1; mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 15659454820100.24212728588327082; Fri, 16 Aug 2019 01:51:22 -0700 (PDT) Received: from localhost ([::1]:51932 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1hyXxA-0003ti-JP for importer@patchew.org; Fri, 16 Aug 2019 04:51:20 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:52117) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1hyXtR-0007Fc-5v for qemu-devel@nongnu.org; Fri, 16 Aug 2019 04:47:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hyXtO-00042N-M1 for qemu-devel@nongnu.org; Fri, 16 Aug 2019 04:47:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35828) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hyXtO-00041D-1x; Fri, 16 Aug 2019 04:47:26 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 529953082B40; Fri, 16 Aug 2019 08:47:25 +0000 (UTC) Received: from t460s.redhat.com (ovpn-116-249.ams2.redhat.com [10.36.116.249]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5670543FE2; Fri, 16 Aug 2019 08:47:23 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Date: Fri, 16 Aug 2019 10:47:07 +0200 Message-Id: <20190816084708.602-6-david@redhat.com> In-Reply-To: <20190816084708.602-1-david@redhat.com> References: <20190816084708.602-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Fri, 16 Aug 2019 08:47:25 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v3 5/6] s390x/mmu: Better storage key reference and change bit handling X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Huth , Janosch Frank , David Hildenbrand , Cornelia Huck , Halil Pasic , Christian Borntraeger , qemu-s390x@nongnu.org, =?UTF-8?q?Alex=20Benn=C3=A9e?= , Richard Henderson Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" Any access sets the reference bit. In case we have a read-fault, we should not allow writes to the TLB entry if the change bit was not already set. This is a preparation for proper storage-key reference/change bit handling in TCG and a fix for KVM whereby read accesses would set the change bit (old KVM versions without the ioctl to carry out the translation). Reviewed-by: Cornelia Huck Signed-off-by: David Hildenbrand --- target/s390x/mmu_helper.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) diff --git a/target/s390x/mmu_helper.c b/target/s390x/mmu_helper.c index d22c6b9c81..6cc81a29b6 100644 --- a/target/s390x/mmu_helper.c +++ b/target/s390x/mmu_helper.c @@ -420,14 +420,28 @@ nodat: return 0; } =20 - if (*flags & PAGE_READ) { - key |=3D SK_R; - } - - if (*flags & PAGE_WRITE) { + switch (rw) { + case MMU_DATA_LOAD: + case MMU_INST_FETCH: + /* + * The TLB entry has to remain write-protected on read-faults = if + * the storage key does not indicate a change already. Otherwi= se + * we might miss setting the change bit on write accesses. + */ + if (!(key & SK_C)) { + *flags &=3D ~PAGE_WRITE; + } + break; + case MMU_DATA_STORE: key |=3D SK_C; + break; + default: + g_assert_not_reached(); } =20 + /* Any store/fetch sets the reference bit */ + key |=3D SK_R; + r =3D skeyclass->set_skeys(ss, *raddr / TARGET_PAGE_SIZE, 1, &key); if (r) { trace_set_skeys_nonzero(r); --=20 2.21.0