From nobody Sat Dec 27 07:14:04 2025 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9445441206 for ; Fri, 22 Dec 2023 23:52:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="JNvimOwO" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1703289150; x=1734825150; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=YaJcwdfsbT/u6tJs5uRbj4NUFmy4HkVgm/EwY5jjC6U=; b=JNvimOwOEnMhGi4Kn6oPnmeIzsgVKtcYOcGPNQGYqycgVAeg8yxYlLAm HjjIZDqPyakJgy6ysV3eFeXv9n1mVpdQb/sQiTFd5YmYmPm+jSFh4fVB/ YqzNCkxY2A42TLu+i1GftVfaIdyloVoccxie0XmxU032g0NGPOSpt/P/n gF0dzqe9WCE4HOotfkYjUPIkYR9hMjeqRGH7Z4lsCqLkEgmGSw74IiwFL h1CjMzdYSoof7E/C0Rv7IYDY62/XObIcVt9sP2OrB1eSAiOd7u4Nokv7B HCsmdbCKXFXlSESlm9lJMVF0FUjmML2UWeEH53kFxstrdIeym4u2PhD9y w==; X-IronPort-AV: E=McAfee;i="6600,9927,10932"; a="395063331" X-IronPort-AV: E=Sophos;i="6.04,297,1695711600"; d="scan'208";a="395063331" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Dec 2023 15:52:28 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10932"; a="900623008" X-IronPort-AV: E=Sophos;i="6.04,297,1695711600"; d="scan'208";a="900623008" Received: from jeroenke-mobl.ger.corp.intel.com (HELO box.shutemov.name) ([10.249.35.180]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Dec 2023 15:52:22 -0800 Received: by box.shutemov.name (Postfix, from userid 1000) id 4D67210A4DD; Sat, 23 Dec 2023 02:52:12 +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: [PATCHv5 11/16] x86/mm: Make e820_end_ram_pfn() cover E820_TYPE_ACPI ranges Date: Sat, 23 Dec 2023 02:52:03 +0300 Message-ID: <20231222235209.32143-12-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231222235209.32143-1-kirill.shutemov@linux.intel.com> References: <20231222235209.32143-1-kirill.shutemov@linux.intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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