From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.alien8.de (mail.alien8.de [65.109.113.108]) (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 B87858405D for ; Mon, 29 Jul 2024 07:37:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=65.109.113.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722238642; cv=none; b=NV2SpBy6lTtSYp2JVxA8xYzktN+aDme1Fe2/KoNtqH6sSWI6yd9y1fus0HA7PCkmcHkvvaPQeDZwxOJ1lNXYijbgHzthQvBT0mIEVBiawz/FoBrPp0Ryx98rnSaOBShOF8tgDWIjelWlQu5mJA8n+uurGvuPxpJ4hHhiTKHCHHU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722238642; c=relaxed/simple; bh=xh35lWVybpfb50jbud+d9GoOn8NzNc1b7hY3gmkMAhY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=maYJRlYT5umNPo/in/FV3UWY7cIw8qu1cU76h37zjwZ83u/kFyyuUj7huq88TUeeKyNZw1RC784BG/KNmj5N0jJ6eu4fXh2squp0vuV2b4jE136Ad905TNB7N93NC/Ntdxv5DAL/UpLlQ/f8C/TeKXWfwK+2kmBgwMPxvhi/Ov4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de; spf=pass smtp.mailfrom=alien8.de; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b=M5JVOAhn; arc=none smtp.client-ip=65.109.113.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=alien8.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b="M5JVOAhn" Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTP id 2732740E01CD; Mon, 29 Jul 2024 07:37:12 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mail.alien8.de Received: from mail.alien8.de ([127.0.0.1]) by localhost (mail.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id omumRzOIxJFO; Mon, 29 Jul 2024 07:37:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=alien8; t=1722238628; bh=8M2kh7pb9zb2h2r+Zlz6AdOcPVeXs0BRF+Vy8SM5Gaw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=M5JVOAhn6ZGXN6HNTF/2k8lSwSK/HG/NvMU9DEeW65T/9ZsdhOKLiOtaSX4jFHbg9 F82qPA8U3AfMTqtDohYvLCmlDsxo8RJjxD5VJeKylRP7Nq2e1gaM2bKgjctoB3J7FV dKwvUOSNL0uiVNuJHmp8ivIubxnGnJjvvEWrTFJKasAb79CG9yvKw21tvSplzSFKRl p/jYtbgHlRHoNDmOB76tDBYGJQZaFgbNCKQNRrSRZ0TM39XzPC2kiLS/wfZ2rFTQpE wbjWa7PGv0F+gyHdrwO7w8mj8m8A1IYf6nt2v+OVNIdk0OJP0vQYVAdzT7Cyy6XiUX Ho4surnrimTzC0I+iUoiWx/ApbBEUhLuFy+EJ6GRnwWDjhAAFGIBvjDJJR3V3NNYIJ zzbjk3BsI9cagfvyOLVUXb8yVulcV7KklJpzsDe1PLHy5IqrZ2TxROyQVPJ1biGLu/ CPFBFoL6pZiH+cIUFEOAj/noRtYOfusNeNtLL57PUf6uEs04P13ZF7XdbafKsMPnPD KuDcKHe43t//GLT4iVXKfRd0bunOXydIeTM8IJxdc5jXwxiv4ajJHIuY8CNbWB3dnX Drqe9MWlWodwkD5fRWvoSW014QKwU4MuGhOtjTeOYqWoJd/E/1TG9oetLzJfibR/EY T7sMWvH03n/lzNgSQmVFOP54= Received: from zn.tnic (p5de8ee85.dip0.t-ipconnect.de [93.232.238.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 2C32940E00F4; Mon, 29 Jul 2024 07:36:58 +0000 (UTC) Date: Mon, 29 Jul 2024 09:36:51 +0200 From: Borislav Petkov To: Thomas Gleixner Cc: Rob , Christian Heusel , regressions@lists.linux.dev, x86@kernel.org, Joerg Roedel , Tony Luck , LKML , Paul Menzel , Lyude Paul Subject: Re: [PATCH] x86/apic: Remove logical destination mode for 64-bit Message-ID: <20240729073651.GAZqdGk97FQzkGCPS8@fat_crate.local> References: <5e08cab0-c6b5-4169-8d42-ddb0ffb4a6c9@heusel.eu> <20240725105029.GAZqIt9aLsIaG7JqN5@fat_crate.local> <12df8b45-6100-4c8b-b82a-a6a75bed2e05@heusel.eu> <87a5i4whoz.ffs@tglx> <8734nvuvrs.ffs@tglx> <87cymyua9j.ffs@tglx> <877cd5u671.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <877cd5u671.ffs@tglx> On Sun, Jul 28, 2024 at 01:06:10PM +0200, Thomas Gleixner wrote: > Logical destination mode of the local APIC is used for systems with up to > 8 CPUs. It has an advantage over physical destination mode as it allows to > target multiple CPUs at once with IPIs. > > That advantage was definitely worth it when systems with up to 8 CPUs > were state of the art for servers and workstations, but that's history. > > Aside of that there are systems which fail to work with logical destination > mode as the ACPI/DMI quirks show and there are AMD Zen1 systems out there > which fail when interrupt remapping is enabled. The latter can be cured by > firmware updates, but not all OEMs distribute the required changes. > > Physical destination mode is guaranteed to work because it is the only way > to get a CPU up and running via the INIT/INIT/STARTUP sequence. > > As the number of CPUs keeps increasing, logical destination mode becomes a > less used code path so there is no real good reason to keep it around. > > Therefore remove logical destination mode support for 64-bit and default to > physical destination mode. > > Signed-off-by: Thomas Gleixner > --- > arch/x86/include/asm/apic.h | 8 -- > arch/x86/kernel/apic/apic_flat_64.c | 119 ++---------------------------------- > 2 files changed, 7 insertions(+), 120 deletions(-) Boots on my Zen1 but then again, it never had those Zen1 client problems to begin with... Anyway Tested-by: Borislav Petkov (AMD) Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette