From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8EFA5188936; Thu, 12 Sep 2024 05:21:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726118519; cv=none; b=gE1xNhFOUTFHs/31Q6ovM5uj8Ws9ooEoonWoecInBN9qexxnrybuTEsR+08285D6msU/yVbydTa0Pc3ZoAMMuSuO5F5cv4QXNsvJTGFlJjxrgR+z80c3O+8QEg0PcxtFjT+Lo4+5a9H6RZ/mR+pvHFeVZptKmUmJTMFlG7p/Byg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726118519; c=relaxed/simple; bh=2VP9K8A4lQ+kKZ4u3aFFAQdAmskII642zMj1HvDJd+c=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HPR/mzVNtGFVmPpNS4BqyENdR9FlGv38vmaqLQvuhfS2dYOcDqhjmKUyjQ0VSBcocFy1HLXpNA+ZmKQ86/trtuapfZHyQebEOZzXWi0TMy27ATgqZ7YStj2aMkRsvSU6nOuS7vuRLRtu/tqeSd7khofSKEwLTmIOHdSFqN3KCgY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=X7KNatHA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="X7KNatHA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 41E51C4CEC3; Thu, 12 Sep 2024 05:21:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1726118518; bh=2VP9K8A4lQ+kKZ4u3aFFAQdAmskII642zMj1HvDJd+c=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=X7KNatHA46rb30Quk/me3P7g7WSPNaN3Zj/jCzS4xdfPvJ6PzZocT3PfkvFYh9JXC 7dFTJeAzkNw+q5QOTD1t1RdIStAZmk0ohtt1kkT527YBHzywtn1+yTbOIozV1kELsx qO/D8Yu7XQn8ynAx4X2MfyRQ43YG27TG72Ax8gR8= Date: Thu, 12 Sep 2024 07:21:55 +0200 From: Greg KH To: Niels Dettenbach Cc: linux-arch@vger.kernel.org, stable@vger.kernel.org, trivial@kernel.org Subject: Re: [PATCH 1/1] x86: SMT broken on Xen PV DomU since 6.9 (updated) Message-ID: <2024091258-quickness-clapping-7418@gregkh> References: <4242435.1IzOArtZ34@gongov> <3301863.oiGErgHkdL@gongov> Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3301863.oiGErgHkdL@gongov> On Wed, Sep 11, 2024 at 05:49:46PM +0200, Niels Dettenbach wrote: > Am Mittwoch, 11. September 2024, 10:53:30 schrieb Niels Dettenbach: > > virtual machines under Xen Hypervisor (DomU) running in Xen PV mode use a > > special, nonstandard synthetized CPU topology which "just works" under > > kernels 6.9.x while newer kernels assuming a "crash kernel" and disable > > SMT (reducing to one CPU core) because the newer topology implementation > > produces a wrong error "[Firmware Bug]: APIC enumeration order not > > specification compliant" after new topology checks which are improper for > > Xen PV platform. As a result, the kernel disables SMT and activates just > > one CPU core within the VM (DomU). > > > > The patch disables the regarding checks if it is running in Xen PV > > mode (only) and bring back SMT / all CPUs as in the past to such DomU > > VMs. > > > > Signed-off-by: Niels Dettenbach > > > > Signed-off-by: Niels Dettenbach > --- > > A reworked proposal patch which substitutes my initial proposed patch: > > > --- linux/arch/x86/kernel/cpu/topology.c 2024-09-11 17:42:42.699278317 +0200 > +++ linux/arch/x86/kernel/cpu/topology.c.orig 2024-09-11 09:53:16.194095250 +0200 Please submit this to the proper developers and maintainers for this code, as the get_maintainers script will tell you as the documentation states. As it is, this isn't going anywhere as you did not include them properly. good luck! greg k-h