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Fri, 6 Mar 2026 10:52:57 GMT Received: from smtprelay05.dal12v.mail.ibm.com ([172.16.1.7]) by ppma12.dal12v.mail.ibm.com (PPS) with ESMTPS id 4cmapsfm9g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 06 Mar 2026 10:52:57 +0000 Received: from smtpav01.wdc07v.mail.ibm.com (smtpav01.wdc07v.mail.ibm.com [10.39.53.228]) by smtprelay05.dal12v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 626AquTR8978994 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 6 Mar 2026 10:52:57 GMT Received: from smtpav01.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B2E4558055; Fri, 6 Mar 2026 10:52:56 +0000 (GMT) Received: from smtpav01.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4966D58063; Fri, 6 Mar 2026 10:52:56 +0000 (GMT) Received: from ltc.linux.ibm.com (unknown [9.5.196.140]) by smtpav01.wdc07v.mail.ibm.com (Postfix) with ESMTP; Fri, 6 Mar 2026 10:52:56 +0000 (GMT) MIME-Version: 1.0 Date: Fri, 06 Mar 2026 16:22:55 +0530 From: Misbah Anjum N To: qemu-ppc@nongnu.org Cc: qemu-devel@nongnu.org, anisinha@redhat.com, pbonzini@redhat.com Subject: [BUG] [powerpc] KVM guest boot failure - hangs on startup after commit 98884e0c Message-ID: X-Sender: misanjum@linux.ibm.com Organization: IBM Content-Type: text/plain; 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envelope-from=misanjum@linux.ibm.com; helo=mx0b-001b2d01.pphosted.com X-Spam_score_int: 18 X-Spam_score: 1.8 X-Spam_bar: + X-Spam_report: (1.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, HEXHASH_WORD=2.999, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.892, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.622, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Hi, I'm reporting a critical regression on ppc64le that causes all KVM guests to hang immediately during startup. Git bisect identified commit 98884e0cc10997a17ce9abfd6ff10be19224ca6a as the first bad commit. The commit completely breaks KVM functionality on ppc64le. Regression Details: Working Version: QEMU 10.2.50 (v10.2.0-1669-gffcf1a7981) Broken Version: QEMU 10.2.50 (v10.2.0-1816-g3fb456e9a0) Bad Commit: 98884e0cc10997a17ce9abfd6ff10be19224ca6a "accel/kvm: add changes required to support KVM VM file descriptor change" Commit Link: https://gitlab.com/qemu-project/qemu/-/commit/98884e0cc10997a17ce9abfd6ff10be19224ca6a Environment: Host: Fedora 42, Kernel 7.0.0-rc2, Power11 (ppc64le) Libvirt: 12.1.0 Guest: Fedora 42, Kernel 7.0.0-rc2 Machine Type: pseries with KVM acceleration Build Configuration: git clone https://gitlab.com/qemu-project/qemu.git cd qemu git submodule init git submodule update --recursive ./configure --target-list=ppc64-softmmu --disable-tcg --prefix=/usr make && make install Reproduction: Using virt-install: /usr/bin/virt-install --connect=qemu:///system --hvm --accelerate --name 'avocado-vt-vm1' --machine pseries --memory=32768 --vcpu=32,sockets=1,cores=32,threads=1 --import --nographics --os-variant rhel8.0 --serial pty --memballoon model=virtio --controller type=scsi,model=virtio-scsi --disk path=/home/kvmci/tests/data/avocado-vt/images/rhel8.0devel-ppc64le.qcow2,bus=scsi,size=10,format=qcow2 --network=bridge=virbr0,model=virtio --boot emulator=/usr/bin/qemu-system-ppc64 Result: Starting install... Using direct QEMU command: /usr/bin/qemu-system-ppc64 -name avocado-vt-vm1 -machine pseries,accel=kvm -enable-kvm -m 32768 -smp 32,sockets=1,cores=32,threads=1 -nographic -serial pty -device virtio-balloon -device virtio-scsi-pci,id=scsi0 -drive file=/home/kvmci/tests/data/avocado-vt/images/rhel8.0devel-ppc64le.qcow2,if=none,id=drive-scsi0-0-0,format=qcow2 -device scsi-hd,bus=scsi0.0,drive=drive-scsi0-0-0 -netdev bridge,id=net0,br=virbr0 -device virtio-net-pci,netdev=net0 Result: Analysis: The commit introduces VM file descriptor change support with architecture-specific hooks. I attempted the following fixes without success: 1. Changed abort() to return 0; in stubs/kvm.c 2. Added early return in kvm_reset_vmfd() when kvm_arch_supports_vmfd_change() returns false Git Bisect Log: # git bisect bad 98884e0cc10997a17ce9abfd6ff10be19224ca6a is the first bad commit commit 98884e0cc10997a17ce9abfd6ff10be19224ca6a (HEAD) Author: Ani Sinha Date: Wed Feb 25 09:19:10 2026 +0530 accel/kvm: add changes required to support KVM VM file descriptor change This change adds common kvm specific support to handle KVM VM file descriptor change. KVM VM file descriptor can change as a part of confidential guest reset mechanism. A new function api kvm_arch_on_vmfd_change() per architecture platform is added in order to implement architecture specific changes required to support it. A subsequent patch will add x86 specific implementation for kvm_arch_on_vmfd_change() as currently only x86 supports confidential guest reset. Signed-off-by: Ani Sinha Link: https://lore.kernel.org/r/20260225035000.385950-6-anisinha@redhat.com Signed-off-by: Paolo Bonzini MAINTAINERS | 6 ++++++ accel/kvm/kvm-all.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--- accel/kvm/trace-events | 1 + include/system/kvm.h | 3 +++ stubs/kvm.c | 22 ++++++++++++++++++++++ stubs/meson.build | 1 + target/i386/kvm/kvm.c | 10 ++++++++++ 7 files changed, 128 insertions(+), 3 deletions(-) create mode 100644 stubs/kvm.c # git bisect log git bisect start git bisect good ffcf1a7981793973ffbd8100a7c3c6042d02ae23 git bisect bad 3fb456e9a0e9eef6a71d9b49bfff596a0f0046e9 git bisect bad e76c30bb13ecb9dc716fa629954bfb6253056ce2 git bisect good 9bdc612a18588975f5776ee4e562df607fea1b2c git bisect bad 40c015e96942fd2a3e4d5ace6063b3333a3dd372 git bisect good df8df3cb6b743372ebb335bd8404bc3d748da350 git bisect bad 0f53f021ad1ede28dc8944686544e496cab02e5e git bisect bad 9f0c2b3032639315faf141010a2603b0dbf56230 git bisect bad 98884e0cc10997a17ce9abfd6ff10be19224ca6a first bad commit: [98884e0cc10997a17ce9abfd6ff10be19224ca6a] Thanks, Misbah Anjum N