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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 16840C4332F for ; Fri, 18 Mar 2022 15:22:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237920AbiCRPXp convert rfc822-to-8bit (ORCPT ); Fri, 18 Mar 2022 11:23:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43832 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237139AbiCRPXm (ORCPT ); Fri, 18 Mar 2022 11:23:42 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.85.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 8D39B262411 for ; Fri, 18 Mar 2022 08:22:23 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-150-J-EB7TRUPCa955UakG2Ikg-1; Fri, 18 Mar 2022 15:22:20 +0000 X-MC-Unique: J-EB7TRUPCa955UakG2Ikg-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.32; Fri, 18 Mar 2022 15:22:20 +0000 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.033; Fri, 18 Mar 2022 15:22:20 +0000 From: David Laight To: 'Juergen Gross' , "xen-devel@lists.xenproject.org" , "platform-driver-x86@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Dell.Client.Kernel@dell.com" CC: Stuart Hayes , Hans de Goede , Mark Gross , "stable@vger.kernel.org" Subject: RE: [PATCH] platform/x86/dell: add buffer allocation/free functions for SMI calls Thread-Topic: [PATCH] platform/x86/dell: add buffer allocation/free functions for SMI calls Thread-Index: AQHYOto/hyLOp/NEJ0S+JLWvPC30KazFQPKg Date: Fri, 18 Mar 2022 15:22:19 +0000 Message-ID: References: <20220318150950.16843-1-jgross@suse.com> In-Reply-To: <20220318150950.16843-1-jgross@suse.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Juergen Gross > Sent: 18 March 2022 15:10 > > The dcdbas driver is used to call SMI handlers for both, dcdbas and > dell-smbios-smm. Both drivers allocate a buffer for communicating > with the SMI handler. The physical buffer address is then passed to > the called SMI handler via %ebx. > > Unfortunately this doesn't work when running in Xen dom0, as the > physical address obtained via virt_to_phys() is only a guest physical > address, and not a machine physical address as needed by SMI. The physical address from virt_to_phy() is always wrong. That is the physical address the cpu has for the memory. What you want is the address the dma master interface needs to use. That can be different for a physical system - no need for virtualisation. On x86 they do usually match, but anything with a full iommu will need completely different addresses. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)