Received: by 2002:ac0:a5b6:0:0:0:0:0 with SMTP id m51-v6csp4058694imm; Mon, 18 Jun 2018 08:29:34 -0700 (PDT) X-Google-Smtp-Source: ADUXVKJnccKiDRJZndBSO6AymdXkj+B24/W+8psSgc5fQ5Da1FVqELten6o98YdlErGJbD1oEfJ+ X-Received: by 2002:a63:9902:: with SMTP id d2-v6mr11663218pge.166.1529335774710; Mon, 18 Jun 2018 08:29:34 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1529335774; cv=none; d=google.com; s=arc-20160816; b=qgJ77MWkW0jiLkmkxlHZLbyKTOp3I6uPxlClHvUds4f4zYadGR74F5YUG4mRTE6gu0 tuCBGxupF5FpedrwPMWOtCdzQFXpJk67w1lF+OYAjClRZTAEZ22Xe1zlkHkf/b1knSLL EK7P5DEQF6bkEfv+9oc4fjuKFG7iDixY7q6W3FyWGbvNH7SOf/aVXedVhsAcj3CbENrP CRu3+M1rSFcc93fdDD66oDI1iH5WGPe4GXSVXLA0BpJvdbya9QEt57uwiw1ooBVEX6Ab ioJm2CFF0YINu/0V52lV6dpxwBDCZg4l8R8lWGE8f1EZgC4Ytc4OrCFXb1ZX1YZyEM30 TVWQ== 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:to:subject :dkim-signature:arc-authentication-results; bh=9D6kQ2A6QHYn16VraSF6MaPqiJRQnidkvZ5SqkMYlNc=; b=Il6qfqXhVJM/fhru/LdlmqX+8jrWmLIK8+2Nk4OUTP74PT3Eog81ES2HcWYjUFC0pg po7oZPFVOr660jWp8ZZ+W6WRtt1Pd9T+UCa+m3BuWcTQvlRFThQeOrgn8FKcvEjKpIFR 348jAmdX6FYCANX75YMeYuqu3P8kFF4BTElX4aAvw+oMgBZcORdHe1NkJ4NPAfp6YgoY wB3jLTtsGdow+67E9PiRVkOkNXohU8L1LTFcFHniFo6QWkE+Gfb+BFBK0oi/2HwfEnXQ kBw7anDVKpMwD1pyE+zq0jA+EqGYBcywdcefrrWnHBQOOMFMnPzefgxncVIxK3pX0RGR CdQA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2017-10-26 header.b=wK7Qichk; 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 g61-v6si15229976plb.169.2018.06.18.08.29.20; Mon, 18 Jun 2018 08:29:34 -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-2017-10-26 header.b=wK7Qichk; 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 S1755221AbeFRP12 (ORCPT + 99 others); Mon, 18 Jun 2018 11:27:28 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:58280 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754563AbeFRP10 (ORCPT ); Mon, 18 Jun 2018 11:27:26 -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 w5IFJU6w016979; Mon, 18 Jun 2018 15:27:21 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2017-10-26; bh=9D6kQ2A6QHYn16VraSF6MaPqiJRQnidkvZ5SqkMYlNc=; b=wK7Qichkzz9FTTOuCI+XqTKIiSL3tR6rYQ+htcOYV5TicfzA4RWfWRv6nkg+6Ct9De2Y lcvNlGHFdFE4W4c26HTjXS+txIrqcqUnf8wBQO+p8yAK+iLdjVV9xo5xz6x06lW8RB+d fluL2G7WVpzAhA/eYf7izDUa6d/1lRLSkBBaoQGeFS2TgTPszZZ/R8bUVcZkMtzH0hCP 5EIkgvkJv8j5Un9pdwlVrTrolxvCqG4BmgETHMup66vtD+wMSMN9LwHbG+AQF425b2PV 0jTTAETLyLpb8U8HXLzPPWVLGVakehWgUDt8dzKDEKzPJgZbiijftqmzE30CFDa8bne0 6Q== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by userp2120.oracle.com with ESMTP id 2jmu6xmhn1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 18 Jun 2018 15:27:21 +0000 Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w5IFRKM0022027 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 18 Jun 2018 15:27:21 GMT Received: from abhmp0005.oracle.com (abhmp0005.oracle.com [141.146.116.11]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w5IFRKel031591; Mon, 18 Jun 2018 15:27:20 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, 18 Jun 2018 08:27:20 -0700 Subject: Re: [PATCH v2] xen: add new hypercall buffer mapping device To: Juergen Gross , linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org References: <20180618073639.26066-1-jgross@suse.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: <5b48b1ae-bcfe-e92d-1f74-ea4e7a9a7f56@oracle.com> Date: Mon, 18 Jun 2018 11:27:05 -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: <20180618073639.26066-1-jgross@suse.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=8927 signatures=668702 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=8.0.1-1805220000 definitions=main-1806180180 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/18/2018 03:36 AM, Juergen Gross wrote: > For passing arbitrary data from user land to the Xen hypervisor the > Xen tools today are using mlock()ed buffers. Unfortunately the kernel > might change access rights of such buffers for brief periods of time > e.g. for page migration or compaction, leading to access faults in the > hypervisor, as the hypervisor can't use the locks of the kernel. > > In order to solve this problem add a new device node to the Xen privcmd > driver to easily allocate hypercall buffers via mmap(). The memory is > allocated in the kernel and just mapped into user space. Marked as > VM_IO the user mapping will not be subject to page migration et al. > > Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky