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=-5.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 51A79C2D0D3 for ; Mon, 30 Dec 2019 10:49:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 27DB52080A for ; Mon, 30 Dec 2019 10:49:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hF+1q6+3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727273AbfL3Ktj (ORCPT ); Mon, 30 Dec 2019 05:49:39 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:42248 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726196AbfL3Kti (ORCPT ); Mon, 30 Dec 2019 05:49:38 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1577702976; 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=hJa72CmFrQq4gAWpDR2+FRwRpYQu3hnMmC9EZDd2GoY=; b=hF+1q6+3vxI0Q17MyLCmfQhORkqzB4jfKO5uo0TDETUD6YtNy/fLpdM74GweQ1WDLHw3jW FGAmaz8jlln3iZQ4/1r1v62QjgpskQ0UI+CXoChN/5bpo94w1Aa4ObXD3tqp05ydUu8Erc RQmqjcwzqHUTw62Rgu4vV8ePQoiIbpk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-258-UW4dviq2Pt-WxMvgbk182w-1; Mon, 30 Dec 2019 05:49:33 -0500 X-MC-Unique: UW4dviq2Pt-WxMvgbk182w-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1229F8024CD; Mon, 30 Dec 2019 10:49:31 +0000 (UTC) Received: from dhcp-128-65.nay.redhat.com (ovpn-12-231.pek2.redhat.com [10.72.12.231]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B37095C1B5; Mon, 30 Dec 2019 10:49:25 +0000 (UTC) Date: Mon, 30 Dec 2019 18:49:21 +0800 From: Dave Young To: Dan Williams Cc: Dan Williams , linux-efi , X86 ML , Linux Kernel Mailing List , Michael Weiser , Ard Biesheuvel , kexec@lists.infradead.org, Ingo Molnar , Borislav Petkov , "Eric W. Biederman" , "H. Peter Anvin" , Thomas Gleixner Subject: Re: [PATCH] x86/efi: update e820 about reserved EFI boot services data to fix kexec breakage Message-ID: <20191230104921.GA16888@dhcp-128-65.nay.redhat.com> References: <20191204075233.GA10520@dhcp-128-65.nay.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org On 12/30/19 at 01:42am, Dan Williams wrote: > On Sat, Dec 28, 2019 at 10:13 PM Dan Williams wrote: > > > > On Sat, Dec 28, 2019 at 12:54 PM Dan Williams > > wrote: > > > > > > On Tue, Dec 3, 2019 at 11:53 PM Dave Young wrote: > > > > > > > > Michael Weiser reported he got below error during a kexec rebooting: > > > > esrt: Unsupported ESRT version 2904149718861218184. > > > > > > > > The ESRT memory stays in EFI boot services data, and it was reserved > > > > in kernel via efi_mem_reserve(). The initial purpose of the reservation > > > > is to reuse the EFI boot services data across kexec reboot. For example > > > > the BGRT image data and some ESRT memory like Michael reported. > > > > > > > > But although the memory is reserved it is not updated in X86 e820 table. > > > > And kexec_file_load iterate system ram in io resource list to find places > > > > for kernel, initramfs and other stuff. In Michael's case the kexec loaded > > > > initramfs overwritten the ESRT memory and then the failure happened. > > > > > > > > Since kexec_file_load depends on the e820 to be updated, just fix this > > > > by updating the reserved EFI boot services memory as reserved type in e820. > > > > > > > > Originally any memory descriptors with EFI_MEMORY_RUNTIME attribute are > > > > bypassed in the reservation code path because they are assumed as reserved. > > > > But the reservation is still needed for multiple kexec reboot. > > > > And it is the only possible case we come here thus just drop the code > > > > chunk then everything works without side effects. > > > > > > > > On my machine the ESRT memory sits in an EFI runtime data range, it does > > > > not trigger the problem, but I successfully tested with BGRT instead. > > > > both kexec_load and kexec_file_load work and kdump works as well. > > > > > > > > Signed-off-by: Dave Young > > > > --- > > > > arch/x86/platform/efi/quirks.c | 6 ++---- > > > > 1 file changed, 2 insertions(+), 4 deletions(-) > > > > > > > > --- linux-x86.orig/arch/x86/platform/efi/quirks.c > > > > +++ linux-x86/arch/x86/platform/efi/quirks.c > > > > @@ -260,10 +260,6 @@ void __init efi_arch_mem_reserve(phys_ad > > > > return; > > > > } > > > > > > > > - /* No need to reserve regions that will never be freed. */ > > > > - if (md.attribute & EFI_MEMORY_RUNTIME) > > > > - return; > > > > - > > > > size += addr % EFI_PAGE_SIZE; > > > > size = round_up(size, EFI_PAGE_SIZE); > > > > addr = round_down(addr, EFI_PAGE_SIZE); > > > > @@ -293,6 +289,8 @@ void __init efi_arch_mem_reserve(phys_ad > > > > early_memunmap(new, new_size); > > > > > > > > efi_memmap_install(new_phys, num_entries); > > > > + e820__range_update(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED); > > > > + e820__update_table(e820_table); > > > > } > > > > > > > > /* > > > > > > > > > > Bisect says this change (commit af1648984828) is triggering a > > > regression, likely not urgent, in my testing of the new efi_fake_mem= > > > facility to allow memory to be marked "soft reserved" via the kernel > > > command line (commit 199c84717612 x86/efi: Add efi_fake_mem support > > > for EFI_MEMORY_SP). The following command line triggers the crash > > > signature below: > > > > > > efi_fake_mem=4G@9G:0x40000,4G@13G:0x40000 > > > > > > However, this command line works ok: > > > > > > efi_fake_mem=8G@9G:0x40000 > > > > > > So, something about multiple efi_fake_mem statements interacts badly > > > with this change. Nothing obvious occurs to me at the moment, I'll > > > keep debugging, but wanted to highlight this in the meantime in case > > > someone else sees a deeper issue or the root cause. > > > > Still looking, but this failure does not seem to be specific to the > > "soft reservation" changes. Any update to the efi memmap that pushes > > it over a page boundary triggers this failure. I.e. I can fix the > > problem by over-allocating the efi memmap and then page aligning the > > result. __early_ioremap "should" be handling this case, but it appears > > something else is messing this up. > > Found it. Neither this patch nor the soft reservation changes are at > fault, they are just helping to trigger a long standing bug in > efi_fake_memmap(). Its usage of efi_memmap_split_count() can over > count the number of splits needed for new entries. Consider the case > of 2 contiguous fake entries intersecting the end of a single entry. > The first call to efi_memmap_split_count() determines the resulting > split will be (old1, new1, old2), the second call determines (old1, > new2). The result is 2 splits when only 1 is needed to get a result of > (old1, new1, new2) and the new map ends up with an empty entry. > efi_memmap_install() interprets an empty entry as start = 0 end = > 0xffffffffffffffff and attempts an extra split / copy past the end of > the new map. > > I'll send a patch to fix up efi_fake_memmap(). > Cool, I also noticed if two of fake mem used, we only get one md with "SP" attribute in print_efi_memmap, that is the root cause. Thanks Dave