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Tue, 10 Nov 2026 05:32:43 +0000 (GMT) Received: from li-7bb28a4c-2dab-11b2-a85c-887b5c60d769.ibm.com.com (unknown [9.39.31.82]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTP; Tue, 10 Nov 2026 05:32:43 +0000 (GMT) From: Shrikanth Hegde To: maddy@linux.ibm.com, linuxppc-dev@lists.ozlabs.org, chzigotzky@xenosoft.de Cc: sshegde@linux.ibm.com, 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 Subject: [PATCH v2 0/3] KVM: PPC: BookE: Fix boot hang on preemptible kernels Date: Tue, 10 Nov 2026 11:02:35 +0530 Message-ID: <20261110053238.3794500-1-sshegde@linux.ibm.com> X-Mailer: git-send-email 2.54.0 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMTEwMDAyMCBTYWx0ZWRfX7SmTiYpQVO83 O9A8IiS+gqxsaxHalo5K93/qSsnbNm1bdPk4HQlUksoPQkyIi+ShV558a1mLaRsozpeb3PmW9j/ z6PpW7Ff8YwclZY9XRHGjJAKcg+RtAvgOMvRZjpHEzsbz+l5DuX1Abec9FI0gLCMWdBJfmv56fj dT1IyiDJXOWoZovX28u8e5zsxupx4sqdIrmlKwdY6InhN3wcSit6WUvvfhckU9jz54CDM9qvCqv XmG68XYvmEHxkxV4RwYYzwkvg0tLnblCmuhqcoln+5K7HO7LPUsJFB8NE36iSa4OyOh+qk8WSLR uG6KOVEXB4oidN9lkajsZYMuoVhbBCZh10NN9aqL+h2MiTrUxlETur4oYf4fpUQfa07MMn/vJl7 K45qDVwd5injYJVIXprADUZl0irdEn3xAJ5Cd+4kBRBsQDD3HijkeBqDCdFxDjVjMJv3CmATlHg Z/WrPb/MszLe6I/yweg== X-Proofpoint-ORIG-GUID: ur6jOE1MD5IweUcx091tEt4NmVkk4y-p X-Proofpoint-Spam-Info: AW1haW4tMjYxMTEwMDAyMCBTYWx0ZWRfX94sWsxKMSIVs a6rdFnryC2jFks4f1wGwp7xXas5hFd+QZSNAo/B7nC8/GPmi27srhs1ZGT3ZJ63aUaAMoMmY4+N EUU1oi5rZBmZiJ2UXqSVVR48tHDeeNM= X-Authority-Analysis: v=2.4 cv=euZKXYpX c=1 sm=1 tr=0 ts=6af2ac85 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=zJRp6_cAMcgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=TP6vnLs4_apDoI4o4IoA:9 X-Proofpoint-GUID: zblinZSGDM_-FHEVuZgq4qMDHW1n05Ja X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.138,FMLib:17.12.100.49 definitions=2026-11-10_02,2026-11-06_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 clxscore=1015 suspectscore=0 spamscore=0 priorityscore=1501 lowpriorityscore=0 bulkscore=0 impostorscore=0 adultscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2611040001 definitions=main-2611100020 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(-) -- 2.52.0