Received: by 2002:ac0:a5a7:0:0:0:0:0 with SMTP id m36-v6csp4259509imm; Sat, 21 Jul 2018 14:20:51 -0700 (PDT) X-Google-Smtp-Source: AAOMgpeP6HSsyCwwzqiiRWqtmFvwDIVgtInqLCSYVjpZ+h27rb+jVHm6y6Ipz+yb74H0s4xubcQj X-Received: by 2002:a17:902:b189:: with SMTP id s9-v6mr6988004plr.188.1532208051565; Sat, 21 Jul 2018 14:20:51 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1532208051; cv=none; d=google.com; s=arc-20160816; b=fubVYDus0oT8vtE/WSi5JpvqsKQNJhFx5X06dperK/PEsNymc+YJRDOiXshAtZZcLg eJfcsRD0DXjYJGqdI+rpt7YeDdAWKQqTXDGiA9EcGnSZbMTG34aqUBKRegDjMx+iHjfg Z83rkH4f9v4mP5/rc9zSIZTJlhCbXyENjyqpRuzigOyqkUS5zCzqObtskJdsX813W7a/ MoewmZt10zwuWICZ5JCd13sg/BJT3XnHafVpFfzjwKFCp3j+geer2wr6abBuv6CH+s4S 19DljMhFd3PiSvxLjAYmonRBe+1308ZHdYULz69LakIANgFSvnGqKUBhQY6s06pdxzhr STjg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-language :content-transfer-encoding:in-reply-to:mime-version:user-agent:date :message-id:autocrypt:openpgp:from:references:cc:to:subject :dkim-signature:arc-authentication-results; bh=XZDD7fyLG8m14+nYKES/LWigAyE84VHnIzzfKTNPdvw=; b=eajTfT31qpfmwIh6WxNQRPiEtfQNSQImgZjiZ/oUp8ySFOc3fcYT+66ounOp0BOG7Y uKyzT1m13DmxqiOiLoOuLTfLm3614gpeC+ULTEYZa4U5xaIesa30YtZrSdnnwBWqrVNs sCyMK2RmkaUMbRitptsO0p10LbsVHqRWfDQDyUuRR9VVtcp1ktz/m3peGNpxyBVm9gRw BfbBdo8QOwpqzRhsEmOcHoUHCXyPpqB88bYHLOYLYbnQ5RSQGBnrfvqmi8lxjfm00tmy 6xl1bOmWCT4y8rT6981BTULoI94ysg3Gp72F2QxJwmJml6kREDkDZWOazKU8XMGzJeyw vG8Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2018-07-02 header.b=N8zEwIEg; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id 34-v6si4937601pgs.243.2018.07.21.14.20.37; Sat, 21 Jul 2018 14:20:51 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2018-07-02 header.b=N8zEwIEg; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728164AbeGUWN4 (ORCPT + 99 others); Sat, 21 Jul 2018 18:13:56 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:55854 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727838AbeGUWN4 (ORCPT ); Sat, 21 Jul 2018 18:13:56 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w6LLJ8NC047668; Sat, 21 Jul 2018 21:19:15 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=XZDD7fyLG8m14+nYKES/LWigAyE84VHnIzzfKTNPdvw=; b=N8zEwIEgitsH5ogTlYRXoYvHKMlMpBG4gSsm2t6BXV6dehQSb+YGX7GXLRWmTA1yHrUo 8TZfeZKc6aLiF2yCGZviHGtC63iwAOfrgHlUX0AmdAULqeE9xta40pCIopzJbN6lCXbz WirlgGQ17Ux7urgmV14OgOzG/ocf2cVfaWt9QkKrPnLba/DxS7Z8nftXVG+tvw27TvuK V1NCrwmIw8860BiehSXHrXzxm/eXnM95B688sg6RYov6LsdwqTzi9w5Y25ju9O53ea4q XdQgVD9G6KQCTebJKlPkZnAmp/LtcFSTRKNlTurXv5O7Naqaq67rDCkRg7tIVK842uYJ hA== Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp2130.oracle.com with ESMTP id 2kbv8ss16s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sat, 21 Jul 2018 21:19:15 +0000 Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w6LLJBIh027021 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sat, 21 Jul 2018 21:19:11 GMT Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w6LLJ9k9027532; Sat, 21 Jul 2018 21:19:10 GMT Received: from dhcp-burlington7-2nd-B-east-10-152-55-162.usdhcp.oraclecorp.com (/10.152.32.65) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sat, 21 Jul 2018 14:19:09 -0700 Subject: Re: [PATCH 1/2] x86/entry/64: Do not clear %rbx under Xen To: "M. Vefa Bicakci" , linux-kernel@vger.kernel.org Cc: Dominik Brodowski , Andy Lutomirski , Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , Juergen Gross , xen-devel@lists.xenproject.org, x86@kernel.org, stable@vger.kernel.org References: <20180721194909.23903-1-m.v.b@runbox.com> From: Boris Ostrovsky Openpgp: preference=signencrypt Autocrypt: addr=boris.ostrovsky@oracle.com; prefer-encrypt=mutual; keydata= xsFNBFH8CgsBEAC0KiOi9siOvlXatK2xX99e/J3OvApoYWjieVQ9232Eb7GzCWrItCzP8FUV PQg8rMsSd0OzIvvjbEAvaWLlbs8wa3MtVLysHY/DfqRK9Zvr/RgrsYC6ukOB7igy2PGqZd+M MDnSmVzik0sPvB6xPV7QyFsykEgpnHbvdZAUy/vyys8xgT0PVYR5hyvhyf6VIfGuvqIsvJw5 C8+P71CHI+U/IhsKrLrsiYHpAhQkw+Zvyeml6XSi5w4LXDbF+3oholKYCkPwxmGdK8MUIdkM d7iYdKqiP4W6FKQou/lC3jvOceGupEoDV9botSWEIIlKdtm6C4GfL45RD8V4B9iy24JHPlom woVWc0xBZboQguhauQqrBFooHO3roEeM1pxXjLUbDtH4t3SAI3gt4dpSyT3EvzhyNQVVIxj2 FXnIChrYxR6S0ijSqUKO0cAduenhBrpYbz9qFcB/GyxD+ZWY7OgQKHUZMWapx5bHGQ8bUZz2 SfjZwK+GETGhfkvNMf6zXbZkDq4kKB/ywaKvVPodS1Poa44+B9sxbUp1jMfFtlOJ3AYB0WDS Op3d7F2ry20CIf1Ifh0nIxkQPkTX7aX5rI92oZeu5u038dHUu/dO2EcuCjl1eDMGm5PLHDSP 0QUw5xzk1Y8MG1JQ56PtqReO33inBXG63yTIikJmUXFTw6lLJwARAQABzTNCb3JpcyBPc3Ry b3Zza3kgKFdvcmspIDxib3Jpcy5vc3Ryb3Zza3lAb3JhY2xlLmNvbT7CwXgEEwECACIFAlH8 CgsCGwMGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEIredpCGysGyasEP/j5xApopUf4g 9Fl3UxZuBx+oduuw3JHqgbGZ2siA3EA4bKwtKq8eT7ekpApn4c0HA8TWTDtgZtLSV5IdH+9z JimBDrhLkDI3Zsx2CafL4pMJvpUavhc5mEU8myp4dWCuIylHiWG65agvUeFZYK4P33fGqoaS VGx3tsQIAr7MsQxilMfRiTEoYH0WWthhE0YVQzV6kx4wj4yLGYPPBtFqnrapKKC8yFTpgjaK jImqWhU9CSUAXdNEs/oKVR1XlkDpMCFDl88vKAuJwugnixjbPFTVPyoC7+4Bm/FnL3iwlJVE qIGQRspt09r+datFzPqSbp5Fo/9m4JSvgtPp2X2+gIGgLPWp2ft1NXHHVWP19sPgEsEJXSr9 tskM8ScxEkqAUuDs6+x/ISX8wa5Pvmo65drN+JWA8EqKOHQG6LUsUdJolFM2i4Z0k40BnFU/ kjTARjrXW94LwokVy4x+ZYgImrnKWeKac6fMfMwH2aKpCQLlVxdO4qvJkv92SzZz4538az1T m+3ekJAimou89cXwXHCFb5WqJcyjDfdQF857vTn1z4qu7udYCuuV/4xDEhslUq1+GcNDjAhB nNYPzD+SvhWEsrjuXv+fDONdJtmLUpKs4Jtak3smGGhZsqpcNv8nQzUGDQZjuCSmDqW8vn2o hWwveNeRTkxh+2x1Qb3GT46uzsFNBFH8CgsBEADGC/yx5ctcLQlB9hbq7KNqCDyZNoYu1HAB Hal3MuxPfoGKObEktawQPQaSTB5vNlDxKihezLnlT/PKjcXC2R1OjSDinlu5XNGc6mnky03q yymUPyiMtWhBBftezTRxWRslPaFWlg/h/Y1iDuOcklhpr7K1h1jRPCrf1yIoxbIpDbffnuyz kuto4AahRvBU4Js4sU7f/btU+h+e0AcLVzIhTVPIz7PM+Gk2LNzZ3/on4dnEc/qd+ZZFlOQ4 KDN/hPqlwA/YJsKzAPX51L6Vv344pqTm6Z0f9M7YALB/11FO2nBB7zw7HAUYqJeHutCwxm7i BDNt0g9fhviNcJzagqJ1R7aPjtjBoYvKkbwNu5sWDpQ4idnsnck4YT6ctzN4I+6lfkU8zMzC gM2R4qqUXmxFIS4Bee+gnJi0Pc3KcBYBZsDK44FtM//5Cp9DrxRQOh19kNHBlxkmEb8kL/pw XIDcEq8MXzPBbxwHKJ3QRWRe5jPNpf8HCjnZz0XyJV0/4M1JvOua7IZftOttQ6KnM4m6WNIZ 2ydg7dBhDa6iv1oKdL7wdp/rCulVWn8R7+3cRK95SnWiJ0qKDlMbIN8oGMhHdin8cSRYdmHK kTnvSGJNlkis5a+048o0C6jI3LozQYD/W9wq7MvgChgVQw1iEOB4u/3FXDEGulRVko6xCBU4 SQARAQABwsFfBBgBAgAJBQJR/AoLAhsMAAoJEIredpCGysGyfvMQAIywR6jTqix6/fL0Ip8G jpt3uk//QNxGJE3ZkUNLX6N786vnEJvc1beCu6EwqD1ezG9fJKMl7F3SEgpYaiKEcHfoKGdh 30B3Hsq44vOoxR6zxw2B/giADjhmWTP5tWQ9548N4VhIZMYQMQCkdqaueSL+8asp8tBNP+TJ PAIIANYvJaD8xA7sYUXGTzOXDh2THWSvmEWWmzok8er/u6ZKdS1YmZkUy8cfzrll/9hiGCTj u3qcaOM6i/m4hqtvsI1cOORMVwjJF4+IkC5ZBoeRs/xW5zIBdSUoC8L+OCyj5JETWTt40+lu qoqAF/AEGsNZTrwHJYu9rbHH260C0KYCNqmxDdcROUqIzJdzDKOrDmebkEVnxVeLJBIhYZUd t3Iq9hdjpU50TA6sQ3mZxzBdfRgg+vaj2DsJqI5Xla9QGKD+xNT6v14cZuIMZzO7w0DoojM4 ByrabFsOQxGvE0w9Dch2BDSI2Xyk1zjPKxG1VNBQVx3flH37QDWpL2zlJikW29Ws86PHdthh Fm5PY8YtX576DchSP6qJC57/eAAe/9ztZdVAdesQwGb9hZHJc75B+VNm4xrh/PJO6c1THqdQ 19WVJ+7rDx3PhVncGlbAOiiiE3NOFPJ1OQYxPKtpBUukAlOTnkKE6QcA4zckFepUkfmBV1wM Jg6OxFYd01z+a+oL Message-ID: <5a21b844-36a9-8fe4-c6cd-6fade3dfa941@oracle.com> Date: Sat, 21 Jul 2018 17:19:36 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180721194909.23903-1-m.v.b@runbox.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8961 signatures=668706 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=757 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1806210000 definitions=main-1807210245 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/21/2018 03:49 PM, M. Vefa Bicakci wrote: > diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S > index c7449f377a77..96e8ff34129e 100644 > --- a/arch/x86/entry/entry_64.S > +++ b/arch/x86/entry/entry_64.S > @@ -1129,7 +1129,7 @@ ENTRY(xen_failsafe_callback) > addq $0x30, %rsp > UNWIND_HINT_IRET_REGS > pushq $-1 /* orig_ax = -1 => not a system call */ > - PUSH_AND_CLEAR_REGS > + PUSH_AND_CLEAR_REGS clear_rbx=0 Do we need this at all? We are returning from the hypervisor here. -boris > ENCODE_FRAME_POINTER > jmp error_exit > END(xen_failsafe_callback)