From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (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 2DEC920C010; Tue, 29 Oct 2024 23:06:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730243222; cv=none; b=hhrrITLKFfNrvWL0RvAZ5p+Fw6tJNFmj/trs2DFfcRUWYXPcncMlujW1/kQNiiYCqOY2CAZw3LTzRG6lpx4ETO9T377XiT1emWuXGvGmJECw8K+jFO6ydZz9oKUtqKC4Slh1iFt9V7cVWIJEY1W7TbLKS4oIrmgm7O1WEeDgZPg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730243222; c=relaxed/simple; bh=SZfWRojPKRj/QMHbVbiZftAEiOO0Fj7sz5Cu5qZPY9w=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ZfXavvd1RNB1ew2ZGQ6kMV8sT9yHE7Gk2b3eL+5E0pqWdYOSub+d+nek6205pSaFy66iaC8mRtN/Q/tIS1KNGm83KGkwEff21tZCM+Uqm8l9/0ZjzFkm14f1KJgsTtoRK/ENJtxWRbnLa1JZevBelSpQmYcs/K+94IghGPflifI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b=JNg0BgvT; arc=none smtp.client-ip=198.137.202.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="JNg0BgvT" Received: from [172.27.3.244] ([76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 49TN5w1H579040 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Tue, 29 Oct 2024 16:05:59 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 49TN5w1H579040 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2024101701; t=1730243162; bh=JhctH8JV5OEarLmfDsY60GKnKpJkPqEFlwdBmGsg578=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=JNg0BgvTe5Iy1C4piQZT+QrNk7KVzqcucI2N5oTTMhPIwvuTxVXIGi8FFnuE9dkmf NtSdgtbWZNIKaAcfLeE/9sPVwXw56lu0bhlJqEqvzwmIlIQ9Zn9ND74+o5877R+npw qR/mYaooYZBsbPXHyeHTP0n3h4To82so9Ueq4T7dj8cnjtqJGk9fA+evqhMBrd6Q9H rXekf6omKcdgijjksg+KF/z8+o+o11kYVTSnecROknQKzI4+pqtDNZPJqUuMcaqcN9 rsIGwMtEhaww1qs8bFm8nNaca/UBhltEWatrsVY0TaYdwlNdvYdCjCKVu7SGe9xmvG LTbU0JTQB1hAw== Message-ID: Date: Tue, 29 Oct 2024 16:05:58 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 05/16] x86/cpu: Defer CR pinning setup until after EFI initialization To: Dave Hansen , "Luck, Tony" , "Mehta, Sohil" , Alexander Shishkin , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "x86@kernel.org" , Peter Zijlstra , Ard Biesheuvel , "Paul E. McKenney" , Josh Poimboeuf , Xiongwei Song , "Li, Xin3" , "Mike Rapoport (IBM)" , Brijesh Singh , Michael Roth , "Kirill A. Shutemov" , Alexey Kardashevskiy Cc: Jonathan Corbet , Ingo Molnar , Pawan Gupta , Daniel Sneddon , "Huang, Kai" , Sandipan Das , Breno Leitao , "Edgecombe, Rick P" , Alexei Starovoitov , Hou Tao , Juergen Gross , Vegard Nossum , Kees Cook , Eric Biggers , Jason Gunthorpe , "Masami Hiramatsu (Google)" , Andrew Morton , Luis Chamberlain , Yuntao Wang , Rasmus Villemoes , Christophe Leroy , Tejun Heo , Changbin Du , Huang Shijie , Geert Uytterhoeven , Namhyung Kim , Arnaldo Carvalho de Melo , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-efi@vger.kernel.org" References: <20241028160917.1380714-1-alexander.shishkin@linux.intel.com> <20241028160917.1380714-6-alexander.shishkin@linux.intel.com> <34dd023d-3ed5-4655-88be-14a7a300b91e@intel.com> <869c1545-8c94-4820-a861-fbc563056597@intel.com> Content-Language: en-US From: "H. Peter Anvin" In-Reply-To: <869c1545-8c94-4820-a861-fbc563056597@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 10/29/24 16:03, Dave Hansen wrote: > On 10/29/24 15:59, Luck, Tony wrote: >>> *IF* we switched things to do text poking in the upper half of the >>> address space, we'd probably want to find a completely unused PGD entry. >>> I'm not sure off the top of my head if we have a good one for that or >>> if it's worth the trouble. >> I expect that would be easy on 64-bit (no way the kernel needs all the >> PGD entries from 256..511) but hard for 32-bit (where kernel address >> space is in critically short supply on any machine with >1GB RAM). > > Yeah, I was talking about 64-bit only. On 32-bit PAE a PGD maps 1/4 of > the address space which is totally unworkable for stealing. But it is also not necessary. -hpa