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a=ed25519-sha256; c=relaxed/relaxed; t=1794332395; s=strato-dkim-0003; d=xenosoft.de; h=In-Reply-To:Date:Message-ID:From:References:Cc:To:Subject:Cc:Date: From:Subject:Sender; bh=TfBLrrNXwj9PDzJLXqf9MPbdj5kOF5LdyfVsHqX5orE=; b=VWAHcmuNxt67l+OLByVVf+oFGjQtveIzuLDwfhBm1q6T8SQVIrRFp5+/mNaXrkO/4y sThiQYB6+1Kvk6HG+/Ag== X-RZG-AUTH: ":L2QefEenb+UdBJSdRCXu93KJ1bmSGnhMdmOod1DhGN0rBVhd9dFr4thIFiqT9BURIC+l5Bzg" Received: from void-ppc.a-eon.tld by smtp.strato.de (RZmta 55.6.3 DYNA|AUTH) with ESMTPSA id e825d92AAHdrhx0 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Tue, 10 Nov 2026 18:39:53 +0100 (CET) Subject: Re: [PATCH v2 0/3] KVM: PPC: BookE: Fix boot hang on preemptible kernels To: Shrikanth Hegde , maddy@linux.ibm.com, linuxppc-dev@lists.ozlabs.org Cc: mpe@ellerman.id.au, npiggin@gmail.com, christophe.leroy@csgroup.eu, linux-kernel@vger.kernel.org, msuchanek@suse.de, ritesh.list@gmail.com, harshpb@linux.ibm.com, gautam@linux.ibm.com, amachhiw@linux.ibm.com, venkat88@linux.ibm.com, nnmlinux@linux.ibm.com, mkchauras@gmail.com, "R.T.Dickinson" , mad skateman , Damien Stewart , Christian Zigotzky References: <20261110053238.3794500-1-sshegde@linux.ibm.com> From: Christian Zigotzky Organization: A-EON Open Source Message-ID: <519cb2b2-5c3d-a75e-6919-d5d0784bae63@xenosoft.de> Date: Tue, 10 Nov 2026 18:39:52 +0100 X-Mailer: BrassMonkey/35.0.2 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , Precedence: list X-Archived-By: MIME-Version: 1.0 In-Reply-To: <20261110053238.3794500-1-sshegde@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 10/11/26 06:32, Shrikanth Hegde wrote: > Christian Zigotzky had reported that preemptible kernels don't boot on > his FSL Cyrus+ board. The board freezes on running either full/lazy > preemption and has been an issue for a while now (years!). > > https://lore.kernel.org/all/b897b0fd-90f2-4215-bcd4-3714e497d773@xenosoft.de/#t > > After 7.0, there is only preempt=full/lazy which removed the > preempt=none/voluntary workaround used to mask the issue. There was > challenge is getting the console logs which made the fixes difficult since > one couldn't know where the issue is. > > Thanks to Michal for helping in getting the logs. That pointed at few > places where the issue could be. This series is an attempt at fixing > those. > > Christian, I haven't taken the tested-by tag since patches have > changed quite a bit. > Please help in *testing* the patches again. > > v1->v2: > - Re-order to avoid preempt count dance (Narayana Murty N) > - Do only hard_irq_disable on PPC64 to avoid second warning. On PPC32 > use local_irq_disable to acheive the same. (Ritesh Harjani) > > v1: https://lore.kernel.org/all/20260928110411.844582-1-sshegde@linux.ibm.com/ > > New API ppc_hard_irq_disable could potentially be used in other places. > There is similar pattern of doing both local and hard irq disable and > likely not all callsites need both. But it is a larger effort and due to > my time limit, it will be taken up subsequently. > > Shrikanth Hegde (3): > powerpc/irq: Add ppc_hard_irq_disable() > KVM: PPC: BookE: Load FP and Altivec before enabling the interrupts > KVM: PPC: Use ppc_hard_irq_disable before guest entry > > arch/powerpc/include/asm/hw_irq.h | 17 +++++++++++++++++ > arch/powerpc/kvm/booke.c | 7 +++++-- > arch/powerpc/kvm/powerpc.c | 14 +++----------- > 3 files changed, 25 insertions(+), 13 deletions(-) > I patched the RC2 of kernel 7.4 with these three new patches and compiled it again [1]. The patched RC2 preempt kernel works with KVM HV without any problems. Tested-by: Christian Zigotzky Thanks a lot for your help! :-) [1] https://github.com/chzigotzky/kernels/releases/tag/v7.4.0-rc2-2 -- Sent with BrassMonkey 35.0.2 (https://github.com/chzigotzky/Web-Browsers-and-Suites-for-Linux-PPC/releases/tag/BrassMonkey_35.0.2)