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 DC796D11185 for ; Mon, 4 Nov 2024 06:21:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=qRjTOCEwVL6GYNnP7Sc9R/ebfIqpZTNNkBQkUszDHpw=; b=C2m1wqHB54gguc xBup9MPb5+Cyxa0YxoOW6VnXu3Fu421KXZsS+RHqrYb2b+Blb1lNxiB5tJmmoAKnR9CtrmW00q49j 1t+Q3ySJpHTaYE/cazKeMzW+bjQ6hYnLn8dZd7sgWkvoRzF2NsFdJBI3/7hMyYrIg1zeT7Nu/hQYM HtJpKwJIoRvFDmcvfSTXQVI30UGrAPwwMzIVI1Blk3BVPXdWk63rek198cJFoETUUWRVtwswIBovw B1Pewjgcq93DxUnIO/CY9Y3veStOoZUOdZcf62mz9rI4YOPASsLi675g75icBvQ8h44etcnmGwt50 GDGegRuuMHIBmcwL2IxQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t7qSq-0000000CkZB-2LLf; Mon, 04 Nov 2024 06:21:24 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t7qSn-0000000CkYk-282p for kexec@lists.infradead.org; Mon, 04 Nov 2024 06:21:23 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1730701280; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=/Yt6e01JiHs6xDUFc4KUXQd8i1elq2u0nXKuucFyQGQ=; b=C5nfLtGxsFHw+kCR4Io+aPSPNXA28rScFPcj4q+oa91Snmr4y5FMvfG5XImTGPkgV284JT R2hJCqOCUjttUjZ1atgBQDsfMDmc/EIuH6Mxc2tznvZ7+0EjoPn4yht0UtiY2Z95kcWiA6 2f6EQdmcR1PKOeUcYq613TEbo3rqZMQ= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-49-b2Wj_TLPNE6Ox6N8IQMnvg-1; Mon, 04 Nov 2024 01:21:16 -0500 X-MC-Unique: b2Wj_TLPNE6Ox6N8IQMnvg-1 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A026619560B4; Mon, 4 Nov 2024 06:21:13 +0000 (UTC) Received: from localhost (unknown [10.72.112.78]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id DA7C11956052; Mon, 4 Nov 2024 06:21:10 +0000 (UTC) Date: Mon, 4 Nov 2024 14:21:06 +0800 From: Baoquan He To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-s390@vger.kernel.org, virtualization@lists.linux.dev, kvm@vger.kernel.org, linux-fsdevel@vger.kernel.org, kexec@lists.infradead.org, Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , Eugenio =?iso-8859-1?Q?P=E9rez?= , Vivek Goyal , Dave Young , Thomas Huth , Cornelia Huck , Janosch Frank , Claudio Imbrenda , Eric Farman , Andrew Morton Subject: Re: [PATCH v1 00/11] fs/proc/vmcore: kdump support for virtio-mem on s390 Message-ID: References: <20241025151134.1275575-1-david@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20241025151134.1275575-1-david@redhat.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241103_222121_649077_10B838C4 X-CRM114-Status: GOOD ( 28.06 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On 10/25/24 at 05:11pm, David Hildenbrand wrote: > This is based on "[PATCH v3 0/7] virtio-mem: s390 support" [1], which adds > virtio-mem support on s390. > > The only "different than everything else" thing about virtio-mem on s390 > is kdump: The crash (2nd) kernel allocates+prepares the elfcore hdr > during fs_init()->vmcore_init()->elfcorehdr_alloc(). Consequently, the > crash kernel must detect memory ranges of the crashed/panicked kernel to > include via PT_LOAD in the vmcore. > > On other architectures, all RAM regions (boot + hotplugged) can easily be > observed on the old (to crash) kernel (e.g., using /proc/iomem) to create > the elfcore hdr. > > On s390, information about "ordinary" memory (heh, "storage") can be > obtained by querying the hypervisor/ultravisor via SCLP/diag260, and > that information is stored early during boot in the "physmem" memblock > data structure. > > But virtio-mem memory is always detected by as device driver, which is > usually build as a module. So in the crash kernel, this memory can only be > properly detected once the virtio-mem driver started up. > > The virtio-mem driver already supports the "kdump mode", where it won't > hotplug any memory but instead queries the device to implement the > pfn_is_ram() callback, to avoid reading unplugged memory holes when reading > the vmcore. > > With this series, if the virtio-mem driver is included in the kdump > initrd -- which dracut already takes care of under Fedora/RHEL -- it will > now detect the device RAM ranges on s390 once it probes the devices, to add > them to the vmcore using the same callback mechanism we already have for > pfn_is_ram(). > > To add these device RAM ranges to the vmcore ("patch the vmcore"), we will > add new PT_LOAD entries that describe these memory ranges, and update > all offsets vmcore size so it is all consistent. > > Note that makedumfile is shaky with v6.12-rcX, I made the "obvious" things > (e.g., free page detection) work again while testing as documented in [2]. > > Creating the dumps using makedumpfile seems to work fine, and the > dump regions (PT_LOAD) are as expected. I yet have to check in more detail > if the created dumps are good (IOW, the right memory was dumped, but it > looks like makedumpfile reads the right memory when interpreting the > kernel data structures, which is promising). > > Patch #1 -- #6 are vmcore preparations and cleanups Thanks for CC-ing me, I will review the patch 1-6, vmcore part next week. _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec