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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 53532C021B2 for ; Thu, 20 Feb 2025 16:48:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=2phGq1PASew3t0QitT+lz7mcsTOMpz4L7ee8QirsuZU=; b=3wrT9TCv4TrMQYa73zghpOxOg2 kmBf+o1x4sJW+jethiN+olv7rC8epiTHyCUBDlYz2X/OQe+hhyHt4MKdBEzlpkFFer0JdjIER5H30 H/3zwkeoZJIAKwyWM1639ksBvy73RfSqsS00PIunQLtMD1ZTsUcRTHAsdzqvPCsd+Iah4ycf8YSjC eMtA45JE7NNZ+bcAFKPfnQUrraQDNIwrl174PZ7eF0w5Op8rGCiPsdhiSI+2LQgsAIkrDb568Ar4i XW/DSGL98VJmoO6VPe8gg0/YQrupWJ3uS9eeU8mxwoZTItmv/sP0ScCflvrNL5xorYi11eQtTxWf0 1O9b0H3A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tl9iJ-00000001x3z-0Xpd; Thu, 20 Feb 2025 16:47:51 +0000 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tl9f7-00000001w6p-3Vvd; Thu, 20 Feb 2025 16:44:34 +0000 Received: from pps.filterd (m0360083.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 51KBld33001689; Thu, 20 Feb 2025 16:43:55 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to; s=pp1; bh=2phGq1PASew3t0QitT+lz7mcsTOMpz 4L7ee8QirsuZU=; b=Fg2ZdEdZwarsWS57pS+/6IXcUxTrTtCLnhG9CBGZ/7HGWi 4zAWb3M539K8KPS0Ajmb/PEzTqkGG38Ai+zL1gYVY4anEms/XTxHY28EJ4xlx/AF IUn+cXfqtcI5hv4hzHC4AL7ugPq0hKMuYbyTtcKHIbdd6lb7tMPr95gbVbiNVJH+ yzBsnvN0hGYuWJxvHvbXddPIPPhMLHzGJxo+0NEWCwpR/A6b6JLE7YAgE1qftFmU X8qdol1P5giI4dqT57n6qb3N89dOmr8ZV58kAi7tkbB+YnfIhyNfQnGQOLkoz4M2 sXSo3k/o/GFXMpo2IP6vEkxcgwZaMd1wbjpTThkQ== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 44wtfa4552-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 20 Feb 2025 16:43:55 +0000 (GMT) Received: from m0360083.ppops.net (m0360083.ppops.net [127.0.0.1]) by pps.reinject (8.18.0.8/8.18.0.8) with ESMTP id 51KGhsmH028733; Thu, 20 Feb 2025 16:43:54 GMT Received: from ppma13.dal12v.mail.ibm.com (dd.9e.1632.ip4.static.sl-reverse.com [50.22.158.221]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 44wtfa454x-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 20 Feb 2025 16:43:54 +0000 (GMT) Received: from pps.filterd (ppma13.dal12v.mail.ibm.com [127.0.0.1]) by ppma13.dal12v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 51KF7PST027113; Thu, 20 Feb 2025 16:43:53 GMT Received: from smtprelay04.fra02v.mail.ibm.com ([9.218.2.228]) by ppma13.dal12v.mail.ibm.com (PPS) with ESMTPS id 44w025b1sh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 20 Feb 2025 16:43:53 +0000 Received: from smtpav04.fra02v.mail.ibm.com (smtpav04.fra02v.mail.ibm.com [10.20.54.103]) by smtprelay04.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 51KGhnA118088388 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 20 Feb 2025 16:43:49 GMT Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A8F0820043; Thu, 20 Feb 2025 16:43:49 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4888520040; Thu, 20 Feb 2025 16:43:49 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTPS; Thu, 20 Feb 2025 16:43:49 +0000 (GMT) Date: Thu, 20 Feb 2025 17:43:48 +0100 From: Alexander Gordeev To: Dave Young Cc: Alexander Graf , Mike Rapoport , linux-kernel@vger.kernel.org, Andrew Morton , Andy Lutomirski , Anthony Yznaga , Arnd Bergmann , Ashish Kalra , Benjamin Herrenschmidt , Borislav Petkov , Catalin Marinas , Dave Hansen , David Woodhouse , Eric Biederman , Ingo Molnar , James Gowans , Jonathan Corbet , Krzysztof Kozlowski , Mark Rutland , Paolo Bonzini , Pasha Tatashin , "H. Peter Anvin" , Peter Zijlstra , Pratyush Yadav , Rob Herring , Rob Herring , Saravana Kannan , Stanislav Kinsburskii , Steven Rostedt , Thomas Gleixner , Tom Lendacky , Usama Arif , Will Deacon , devicetree@vger.kernel.org, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, Philipp Rudo , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , linux-s390@vger.kernel.org Subject: Re: [PATCH v4 00/14] kexec: introduce Kexec HandOver (KHO) Message-ID: References: <20250206132754.2596694-1-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 02CmlzRAvH6gUhNjDul_d5grRXN4j5Cf X-Proofpoint-GUID: vqtrf0KyRdj5sNl93G5J7u-LcnzQFqNz X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-02-20_07,2025-02-20_02,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1011 suspectscore=0 impostorscore=0 lowpriorityscore=0 priorityscore=1501 mlxlogscore=660 bulkscore=0 phishscore=0 malwarescore=0 mlxscore=0 adultscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2502100000 definitions=main-2502200116 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250220_084433_876924_660B71FD X-CRM114-Status: GOOD ( 33.07 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Feb 20, 2025 at 09:49:52AM +0800, Dave Young wrote: > On Wed, 19 Feb 2025 at 21:55, Alexander Graf wrote: > > >>> What architecture exactly does this KHO work fine? Device Tree > > >>> should be ok on arm*, x86 and power*, but how about s390? > > >> KHO does not use device tree as the boot protocol, it uses FDT as a data > > >> structure and adds architecture specific bits to the boot structures to > > >> point to that data, very similar to how IMA_KEXEC works. > > >> > > >> Currently KHO is implemented on arm64 and x86, but there is no fundamental > > >> reason why it wouldn't work on any architecture that supports kexec. > > > Well, the problem is whether there is a way to add dtb in the early > > > boot path, for X86 it is added via setup_data, if there is no such > > > way I'm not sure if it is doable especially for passing some info for > > > early boot use. Then the KHO will be only for limited use cases. > > > > > > Every architecture has a platform specific way of passing data into the > > kernel so it can find its command line and initrd. S390x for example has > > struct parmarea. To enable s390x, you would remove some of its padding > > and replace it with a KHO base addr + size, so that the new kernel can > > find the KHO state tree. > > Ok, thanks for the info, I cced s390 people maybe they can provide inputs. If I understand correctly, the parmarea would be used for passing the FDT address - which appears to be fine. However, s390 does not implement early_memremap()/early_memunmap(), which KHO needs. Thanks, Dave!