From nobody Mon Feb 9 10:12:15 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=1566482723; cv=none; d=zoho.com; s=zohoarc; b=hIwk4OFB6D6gmobAIu4NhPb6o+aiizsG3yvhoSxOYUoR5r/8sTQBqwAChikkqQ5P2GkeIDrk5QcS9ZOa6/pDTdxClHbdz+4cUdViT3SgCJF+twBHnHKhNSh5yCfwh/0UDrnl48cDDUzTJAFJU1qSxrJJkQNzjQpYkt8YLf8WBB0= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1566482723; 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=IL4ZU2OhgUfAwStO4E/EAwwIS3anb5iBenuwFJGp7+Q=; b=NkiDr0aTOIk+7+Ya+jXP5imgNSixurGW+2t+6ZakN7x3Q5b9IJdiTJXUtDfDfveTqi0Ab8gedIvWaeGmaKRnTR/LBNmlGoW8qxaakjdx1nFmR7xS9tMHv7HmaB1OV8wi7OR2VSz6mCZ2J1Kb9chX83XHEtkIr3EVbgCwUiwFc8I= 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 1566482723277723.1191210981856; Thu, 22 Aug 2019 07:05:23 -0700 (PDT) Received: from localhost ([::1]:43564 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i0niK-00066n-JZ for importer@patchew.org; Thu, 22 Aug 2019 10:05:20 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48530) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i0ncN-0000Qa-2Z for qemu-devel@nongnu.org; Thu, 22 Aug 2019 09:59:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i0ncM-0004O5-0M for qemu-devel@nongnu.org; Thu, 22 Aug 2019 09:59:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60798) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i0ncL-0004Ni-RN; Thu, 22 Aug 2019 09:59:09 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2BEC5102BB3D; Thu, 22 Aug 2019 13:59:09 +0000 (UTC) Received: from localhost (dhcp-192-222.str.redhat.com [10.33.192.222]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CD49160619; Thu, 22 Aug 2019 13:59:08 +0000 (UTC) From: Cornelia Huck To: Peter Maydell Date: Thu, 22 Aug 2019 15:58:38 +0200 Message-Id: <20190822135839.32340-8-cohuck@redhat.com> In-Reply-To: <20190822135839.32340-1-cohuck@redhat.com> References: <20190822135839.32340-1-cohuck@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.64]); Thu, 22 Aug 2019 13:59:09 +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] [PULL 6/7] 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: qemu-s390x@nongnu.org, Cornelia Huck , qemu-devel@nongnu.org, David Hildenbrand Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" From: David Hildenbrand 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 Message-Id: <20190816084708.602-6-david@redhat.com> Signed-off-by: Cornelia Huck --- 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 40b6c1fc36a9..61654e07dec8 100644 --- a/target/s390x/mmu_helper.c +++ b/target/s390x/mmu_helper.c @@ -421,14 +421,28 @@ 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 2.20.1