From nobody Sun Dec 28 23:14:59 2025 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 F37EFC10DCE for ; Tue, 5 Dec 2023 00:46:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346429AbjLEAqd (ORCPT ); Mon, 4 Dec 2023 19:46:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60388 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234828AbjLEApg (ORCPT ); Mon, 4 Dec 2023 19:45:36 -0500 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38CAF116 for ; Mon, 4 Dec 2023 16:45:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1701737138; x=1733273138; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=YaJcwdfsbT/u6tJs5uRbj4NUFmy4HkVgm/EwY5jjC6U=; b=F6IQpxEkhFTBIwCR8svjMWMRi3APMIdb3u1bGxLya4UaflqAsfoIwTWs 0fWnVzogu0i0zGjdrhB/RCXbmo9vuEEeAm0iuzSEihLybW4fnXewhrjSu 8/rQe8a1C1a/Y6D0jab+W9r9RieutvmvtoEozr7ItlN6lw4Di1nWjKy11 j5wXnkXAFHUfi2mdW4NftVNY8N7gQs14ViJb9BRbw4ALYfOuGUlbmwoZz PtSA0nvato+30k5YddLkckoog08DdLI3yUdddB7DqtrbvtObnPp4FY6PB HiZwF8dthXvVRQx33zWQyb3uOpgi9ZqnIgc48FNZqSoF8L5hKMNyZk2oG w==; X-IronPort-AV: E=McAfee;i="6600,9927,10914"; a="392688743" X-IronPort-AV: E=Sophos;i="6.04,251,1695711600"; d="scan'208";a="392688743" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Dec 2023 16:45:36 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10914"; a="944067956" X-IronPort-AV: E=Sophos;i="6.04,251,1695711600"; d="scan'208";a="944067956" Received: from abijaz-mobl2.ger.corp.intel.com (HELO box.shutemov.name) ([10.252.61.240]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Dec 2023 16:45:30 -0800 Received: by box.shutemov.name (Postfix, from userid 1000) id 9FC0810A44E; Tue, 5 Dec 2023 03:45:20 +0300 (+03) From: "Kirill A. Shutemov" To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org Cc: "Rafael J. Wysocki" , Peter Zijlstra , Adrian Hunter , Kuppuswamy Sathyanarayanan , Elena Reshetova , Jun Nakajima , Rick Edgecombe , Tom Lendacky , "Kalra, Ashish" , Sean Christopherson , "Huang, Kai" , Baoquan He , kexec@lists.infradead.org, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCHv4 11/14] x86/mm: Make e820_end_ram_pfn() cover E820_TYPE_ACPI ranges Date: Tue, 5 Dec 2023 03:45:07 +0300 Message-ID: <20231205004510.27164-12-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231205004510.27164-1-kirill.shutemov@linux.intel.com> References: <20231205004510.27164-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" e820__end_of_ram_pfn() is used to calculate max_pfn which, among other things, guides where direct mapping ends. Any memory above max_pfn is not going to be present in the direct mapping. e820__end_of_ram_pfn() finds the end of the ram based on the highest E820_TYPE_RAM range. But it doesn't includes E820_TYPE_ACPI ranges into calculation. Despite the name, E820_TYPE_ACPI covers not only ACPI data, but also EFI tables and might be required by kernel to function properly. Usually the problem is hidden because there is some E820_TYPE_RAM memory above E820_TYPE_ACPI. But crashkernel only presents pre-allocated crash memory as E820_TYPE_RAM on boot. If the preallocated range is small, it can fit under the last E820_TYPE_ACPI range. Modify e820__end_of_ram_pfn() and e820__end_of_low_ram_pfn() to cover E820_TYPE_ACPI memory. The problem was discovered during debugging kexec for TDX guest. TDX guest uses E820_TYPE_ACPI to store the unaccepted memory bitmap and pass it between the kernels on kexec. Signed-off-by: Kirill A. Shutemov --- arch/x86/kernel/e820.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index fb8cf953380d..99c80680dc9e 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -827,7 +827,7 @@ u64 __init e820__memblock_alloc_reserved(u64 size, u64 = align) /* * Find the highest page frame number we have available */ -static unsigned long __init e820_end_pfn(unsigned long limit_pfn, enum e82= 0_type type) +static unsigned long __init e820_end_ram_pfn(unsigned long limit_pfn) { int i; unsigned long last_pfn =3D 0; @@ -838,7 +838,8 @@ static unsigned long __init e820_end_pfn(unsigned long = limit_pfn, enum e820_type unsigned long start_pfn; unsigned long end_pfn; =20 - if (entry->type !=3D type) + if (entry->type !=3D E820_TYPE_RAM && + entry->type !=3D E820_TYPE_ACPI) continue; =20 start_pfn =3D entry->addr >> PAGE_SHIFT; @@ -864,12 +865,12 @@ static unsigned long __init e820_end_pfn(unsigned lon= g limit_pfn, enum e820_type =20 unsigned long __init e820__end_of_ram_pfn(void) { - return e820_end_pfn(MAX_ARCH_PFN, E820_TYPE_RAM); + return e820_end_ram_pfn(MAX_ARCH_PFN); } =20 unsigned long __init e820__end_of_low_ram_pfn(void) { - return e820_end_pfn(1UL << (32 - PAGE_SHIFT), E820_TYPE_RAM); + return e820_end_ram_pfn(1UL << (32 - PAGE_SHIFT)); } =20 static void __init early_panic(char *msg) --=20 2.41.0