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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B101BCFD2F6 for ; Thu, 27 Nov 2025 05:05:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1816C6B0022; Thu, 27 Nov 2025 00:05:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 158C86B0023; Thu, 27 Nov 2025 00:05:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 096016B0024; Thu, 27 Nov 2025 00:05:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id ECB5C6B0022 for ; Thu, 27 Nov 2025 00:05:50 -0500 (EST) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 34BBF13BDB0 for ; Thu, 27 Nov 2025 05:05:50 +0000 (UTC) X-FDA: 84155199660.11.0BA6653 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf28.hostedemail.com (Postfix) with ESMTP id A2F6AC0009 for ; Thu, 27 Nov 2025 05:05:48 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=H4jAdZwu; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf28.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1764219948; a=rsa-sha256; cv=none; b=Czz51vFSBnEivx8ndQRPXOmU+LDx8+yg2j1MV7iquBduQTXswz0a63YAhlc5ZXThWPC/iZ 2tlxva/fpJB1Y9bm0hvNHtthJRkGhaDA+PI3CERWOSJVngA/63vjFhXEyGC7v0U0XRvD0q af8NkKkFjIOWDgJ1e7uOuk16fC/LdIo= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=H4jAdZwu; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf28.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1764219948; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=ysL48WmHMu6ZVfYX+/EYpRVkz/nBDb/kZFPfAI4Ic1I=; b=tZKycJvqURVmX6scAgdC9e8fu5Tvho3qP30H6l2uUI1aeaQMjCO48vaWFqrTF2V8Iw4xi6 ZRYLZBv//A+2fmYhqS5zbtVA3cNklYcBllmYk+3/JwK8T4CLBFFPBMYyH70BBkJkpOSDQ9 e8kSoRmhgg+Xp8/6CsZBZgcud/WpYNg= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 330DE60182; Thu, 27 Nov 2025 05:05:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0A0DEC4CEF8; Thu, 27 Nov 2025 05:05:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764219947; bh=Nl9RwO91yTa5covY+c2/N9Gq4s0OvI/oEAchPUaaHrI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=H4jAdZwu3Sd4OjszEkHlJtz4SnzwWGXrgyaOCalfAVVClCU29XQXAC0JKogFFq9sq zfgHOpWN+oVfBr555kCBzeAzfAliqANmAe++un6WB8Y+mQrKzT4hnA6Qa70HJJfMeK HRqfMJRPLFbLVti/I2v4I3InHPGzVtf5Nk4mlbdxVdU4vBr+VA+q+U233XhVyKEcvy 4pPBwgFCPs8W3b3DDj1JrtQXgL4RIZDYN2/MohtkNtNmhQSjjqNEdgRWJDAjyaCCxn 3d3gNFgh07WSRkNajVcF4mcWMFN0cgepD2nu7HJzgcVbgkp5heeYUNsq1PtZm+pO7c VSh9U+RbFsZbA== Date: Thu, 27 Nov 2025 07:05:40 +0200 From: Mike Rapoport To: Usama Arif Cc: Andrew Morton , changyuanl@google.com, graf@amazon.com, leitao@debian.org, thevlad@meta.com, pratyush@kernel.org, dave.hansen@linux.intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH] mm/memblock: only mark/clear KHO scratch memory when needed Message-ID: References: <20251126072051.546700-1-usamaarif642@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251126072051.546700-1-usamaarif642@gmail.com> X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: A2F6AC0009 X-Stat-Signature: 1tgter3xrirrba3esdd7ekosmesqk7n3 X-Rspam-User: X-HE-Tag: 1764219948-370856 X-HE-Meta: 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 ARdtrK/I klieagu3hPjqHlRmvpfJ/M2iwtvH6VcesrMeBr56YuZlxfkCRrqwEIqrk0HVuDJsuOOWCQEpoXDX5nQq6YMCvsfbA6jArWUeGke68Iuk9NoL6dbetb8G1wchteGwCeRRAudGoaeTgz5FNfo5QEw2T8Kh1f62gSUl0Y3jtxzJn9OCdAUKxTHzppJ8brQx+fxaFiCn/3HcivqmKD5dGHAcojvZMobbQBuT+i5VjHIX/QJt6nVXE6rjn22gntcanwNaHrlzn+yC5+hVpHIMXBFeISgzBV/a70Nuo/pGakF9MTa5+wfmXB2yRuYBoJ4ny/KVEQzhDDeAMbv67G9DMK2DYjPREbw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Nov 26, 2025 at 07:20:51AM +0000, Usama Arif wrote: > The scratch memory for kexec handover is used to bootstrap the > kexec'ed kernel. It is only needed when CONFIG_MEMBLOCK_KHO_SCRATCH > is enabled (selected by KHO) and if it is a KHO boot. Add checks > to prevent marking a KHO scratch region unless needed. > > kexec_handover.h is now unconditionally included for is_kho_boot. > > Fixes: a2daf83e10378 ("x86/e820: temporarily enable KHO scratch for memory below 1M") > Reported-by: Vlad Poenaru > Signed-off-by: Usama Arif > --- > mm/memblock.c | 16 +++++++++++----- > 1 file changed, 11 insertions(+), 5 deletions(-) > > diff --git a/mm/memblock.c b/mm/memblock.c > index e23e16618e9b3..5c85d575bb61c 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -20,8 +20,8 @@ > > #ifdef CONFIG_KEXEC_HANDOVER > #include > -#include > #endif /* CONFIG_KEXEC_HANDOVER */ > +#include > > #include > #include > @@ -1126,8 +1126,11 @@ int __init_memblock memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t > */ > __init int memblock_mark_kho_scratch(phys_addr_t base, phys_addr_t size) > { > - return memblock_setclr_flag(&memblock.memory, base, size, 1, > - MEMBLOCK_KHO_SCRATCH); > + if (IS_ENABLED(CONFIG_MEMBLOCK_KHO_SCRATCH) && is_kho_boot()) > + return memblock_setclr_flag(&memblock.memory, base, size, 1, > + MEMBLOCK_KHO_SCRATCH); > + else else is not needed. > + return 0; > } > > /** > @@ -1140,8 +1143,11 @@ __init int memblock_mark_kho_scratch(phys_addr_t base, phys_addr_t size) > */ > __init int memblock_clear_kho_scratch(phys_addr_t base, phys_addr_t size) > { > - return memblock_setclr_flag(&memblock.memory, base, size, 0, > - MEMBLOCK_KHO_SCRATCH); > + if (IS_ENABLED(CONFIG_MEMBLOCK_KHO_SCRATCH) && is_kho_boot()) > + return memblock_setclr_flag(&memblock.memory, base, size, 0, > + MEMBLOCK_KHO_SCRATCH); > + else Ditto. > + return 0; > } > > static bool should_skip_region(struct memblock_type *type, > -- > 2.47.3 > -- Sincerely yours, Mike.