From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga04.intel.com (mga04.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 29E2E2F5F for ; Thu, 1 Dec 2022 13:47:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1669902476; x=1701438476; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=mTaZIIv3uUc9JYNMsjX+rfZMzd1G+Dsj8zGp0aHQgQI=; b=EnaOgte25qubhv2XEuGM5FKgJ1yCdOvew2AfNGfNbYv2R5TDYaZdJ5eW cLjpyszi7k+qPIN6/Ke/24WjEwna2zJyxYSy0zIoUFkNSnFQiDnkp5uB6 aav2M/Ba0SjIzTozhbo/WBGdYyTgFlWA8xfvM8ORIT8fJWlgmOKEkv9vw dJJhDiSQ/JjmlO3ePR86sYefTKgRog082LAKOkxtgbjB/1m9OKtcxYTUP 0dZt865uOrYXtETPEcgCLVP156LxltRN8wNNZg8EFhpobUmqq741/AskC T7ToeuU+TLHPPCo0BZPLf8Srot4CelvouilNvXkKcpmvf9fiiOVRNHkr/ w==; X-IronPort-AV: E=McAfee;i="6500,9779,10548"; a="314385106" X-IronPort-AV: E=Sophos;i="5.96,209,1665471600"; d="scan'208";a="314385106" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Dec 2022 05:47:55 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10548"; a="677219981" X-IronPort-AV: E=Sophos;i="5.96,209,1665471600"; d="scan'208";a="677219981" Received: from ichepiga-mobl1.ger.corp.intel.com (HELO box.shutemov.name) ([10.252.55.59]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Dec 2022 05:47:47 -0800 Received: by box.shutemov.name (Postfix, from userid 1000) id CD4AA109781; Thu, 1 Dec 2022 16:47:44 +0300 (+03) Date: Thu, 1 Dec 2022 16:47:44 +0300 From: "Kirill A. Shutemov" To: Mike Rapoport Cc: "Kirill A. Shutemov" , Borislav Petkov , Andy Lutomirski , Sean Christopherson , Andrew Morton , Joerg Roedel , Ard Biesheuvel , Andi Kleen , Kuppuswamy Sathyanarayanan , David Rientjes , Vlastimil Babka , Tom Lendacky , Thomas Gleixner , Peter Zijlstra , Paolo Bonzini , Ingo Molnar , Varad Gautam , Dario Faggioli , Dave Hansen , David Hildenbrand , marcelo.cerri@canonical.com, tim.gardner@canonical.com, khalid.elmously@canonical.com, philip.cox@canonical.com, x86@kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, Mike Rapoport Subject: Re: [PATCHv7 08/14] x86/mm: Reserve unaccepted memory bitmap Message-ID: <20221201134744.7p3lgw6buv4oqwyn@box.shutemov.name> References: <20220614120231.48165-1-kirill.shutemov@linux.intel.com> <20220614120231.48165-9-kirill.shutemov@linux.intel.com> <20221130012840.sf4rvddzc4ev7bj5@box.shutemov.name> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Dec 01, 2022 at 11:37:10AM +0200, Mike Rapoport wrote: > On Wed, Nov 30, 2022 at 04:28:40AM +0300, Kirill A. Shutemov wrote: > > On Tue, Jul 26, 2022 at 11:07:14AM +0200, Borislav Petkov wrote: > > > On Tue, Jun 14, 2022 at 03:02:25PM +0300, Kirill A. Shutemov wrote: > > > > diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c > > > > index f267205f2d5a..22d1fe48dcba 100644 > > > > --- a/arch/x86/kernel/e820.c > > > > +++ b/arch/x86/kernel/e820.c > > > > @@ -1316,6 +1316,16 @@ void __init e820__memblock_setup(void) > > > > int i; > > > > u64 end; > > > > > > > > + /* Mark unaccepted memory bitmap reserved */ > > > > + if (boot_params.unaccepted_memory) { > > > > + unsigned long size; > > > > + > > > > + /* One bit per 2MB */ > > > > + size = DIV_ROUND_UP(e820__end_of_ram_pfn() * PAGE_SIZE, > > > > + PMD_SIZE * BITS_PER_BYTE); > > > > + memblock_reserve(boot_params.unaccepted_memory, size); > > > > + } > > > > + > > > > > > Hmm, I don't like how this is dropped right in the middle of a unrelated > > > function. > > > > > > You're adding arch/x86/mm/unaccepted_memory.c later. Why don't you put > > > that chunk in a function there which is called by early_reserve_memory() > > > which does exactly what you want - reserve memory early, before memblock > > > allocations? > > > > early_reserve_memory() specifically called before e820__memory_setup() > > (see comment in setup_arch()), so we don't have e820_table finalized and > > we need it to get correct RAM size from e820__end_of_ram_pfn(). > > > > I guess we can hide the chunk in a function in unaccepted_memory.c and > > call it from here, but it would require #ifdeffery in a header file as the > > .c is only compiled for CONFIG_UNACCEPTED_MEMORY=y. > > > > Looks like an overkill to me, no? > > Agree. Can we just extend the comment to explain why we reserve the bitmap > at e820__memblock_setup() rather than in early_reserve_memory(), pretty > much with the explanation above? Okay, I will do this: diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index 49b5164a4cba..62068956bb76 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -1316,7 +1316,14 @@ void __init e820__memblock_setup(void) int i; u64 end; - /* Mark unaccepted memory bitmap reserved */ + /* + * Mark unaccepted memory bitmap reserved. + * + * This kind of reservation usually done from early_reserve_memory(), + * but early_reserve_memory() called before e820__memory_setup(), so + * e820_table is not finalized and e820__end_of_ram_pfn() cannot be + * used to get correct RAM size. + */ if (boot_params.unaccepted_memory) { unsigned long size; -- Kiryl Shutsemau / Kirill A. Shutemov