From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, T_DKIMWL_WL_HIGH,UNPARSEABLE_RELAY autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 129C4ECDE5F for ; Mon, 23 Jul 2018 15:04:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B520320852 for ; Mon, 23 Jul 2018 15:04:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="xR9xwQfa" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B520320852 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388211AbeGWQFx (ORCPT ); Mon, 23 Jul 2018 12:05:53 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:35232 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388047AbeGWQFx (ORCPT ); Mon, 23 Jul 2018 12:05:53 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w6NEwrHH024923; Mon, 23 Jul 2018 15:03:46 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=oVxKBhOYTL0Pz+6RlFamxs+O4YVfyefRs/fm6lLxe3I=; b=xR9xwQfaHHmSkkN7TfatkVQjQYnO1OdTV6dD+9TA0SLqVMnnzJMzuCuDfnx5wMo1rKrQ kJIZZRqmr7nyKBlGY0nlXiMnL/MI/+dQR6PCpTCg0bjdOUcmfwRQPYmuPyU//ksFRPwO W2VCDKaSYC1ZmICKpu2BbfOORYG7CCsvr0ZNfk4eMmmfztDjMG2DAhbwBJMpgoyZggjx 5qhtSMwqIMS8U57LRWAe8rhhGQtwYFwNDif9wBbw4h4U+f5kaUOtuOOp9bIFYNKWX7LY qUHO44sDGdi6u6UAelKofUOvTvL8W0f7VfvjF/eKM4EDJlid9d33dRkaTFhthhVKuI2W QA== Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp2120.oracle.com with ESMTP id 2kbwfpmwss-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 23 Jul 2018 15:03:46 +0000 Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w6NF3ibW002383 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 23 Jul 2018 15:03:44 GMT Received: from abhmp0008.oracle.com (abhmp0008.oracle.com [141.146.116.14]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w6NF3gAX015700; Mon, 23 Jul 2018 15:03:42 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 ; Mon, 23 Jul 2018 08:03:42 -0700 Subject: Re: [PATCH 2/2] xen/pv: Call get_cpu_address_sizes to set x86_virt/phys_bits To: "M. Vefa Bicakci" , linux-kernel@vger.kernel.org Cc: "Kirill A. Shutemov" , 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> <20180721194909.23903-2-m.v.b@runbox.com> <90bc371d-a296-51b3-8b78-62106c9690de@oracle.com> <13b774d7-bc8c-039a-fbc0-52318f535883@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: <8c17dccf-d382-0ba4-612c-8c674f5dd9e0@oracle.com> Date: Mon, 23 Jul 2018 11:04:09 -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: <13b774d7-bc8c-039a-fbc0-52318f535883@runbox.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8962 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=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1806210000 definitions=main-1807230171 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/22/2018 11:57 AM, M. Vefa Bicakci wrote: > On 07/21/2018 07:17 PM, M. Vefa Bicakci wrote: >> On 07/21/2018 05:25 PM, Boris Ostrovsky wrote: >>> On 07/21/2018 03:49 PM, M. Vefa Bicakci wrote: >>>> diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c >>>> index 439a94bf89ad..87afb000142a 100644 >>>> --- a/arch/x86/xen/enlighten_pv.c >>>> +++ b/arch/x86/xen/enlighten_pv.c >>>> @@ -1257,6 +1257,7 @@ asmlinkage __visible void __init >>>> xen_start_kernel(void) >>>>       /* Work out if we support NX */ >>>>       get_cpu_cap(&boot_cpu_data); >>>> +    get_cpu_address_sizes(&boot_cpu_data); >>>>       x86_configure_nx(); >>> >>> >>> Have you observed any problems without this call? get_cpu_cap() is only >>> called here to set X86_FEATURE_NX, and is then called again, together >>> with get_cpu_address_sizes(), from early_identify_cpu(). >> >> Thank you for the reviews! Without the call to get_cpu_address_sizes, >> paravirtualized virtual machines do not boot up kernels with versions >> 4.17 and up at all; this includes dom0 and domU. No domU logs are >> generated in dom0's /var/log/xen/console/ directory either, despite >> having earlyprintk=xen on the kernel command line for my test domU. > > Hello Boris, > > I debugged this further with a debugging version of Xen (so that I can > get early kernel print-outs via the "xen_raw_console_write" function), > and I found the root cause of the boot up failure. > > In summary, the issue is due to the following call path in version > 4.17 (and higher, I assume), which the kernel goes through /only/ when > CONFIG_DEBUG_VIRTUAL is enabled: > > enlighten_pv.c::xen_start_kernel >   mmu_pv.c::xen_reserve_special_pages >     page.h::__pa >       physaddr.c::__phys_addr >         physaddr.h::phys_addr_valid // uses boot_cpu_data.x86_phys_bits > > The return value of phys_addr_valid is used with the VIRTUAL_BUG_ON > macro, > which evaluates to BUG_ON in case CONFIG_DEBUG_VIRTUAL is enabled. Ah, that's why it hasn't been detected. > > It looks like the call to get_cpu_address_size is required in the > xen_start_kernel function. Perhaps there is a more elegant way to > resolve this issue as well. > > Another approach could be to check in the phys_addr_valid function > whether > boot_cpu_data.x86_phys_bits has been initialized or not, I think, but > I am > not sure about the correctness of this approach. No, I think your patch is good. The only thing I'd suggest is to move the call a few lines down. The way it is placed now may create impression that we are calling get_cpu_address_sizes() to figure out NX support. -boris