| Summary: |
kernel 6.14 -> 6.15 regression: kvm fails to launch - "guest CPU doesn't match specification: missing features: sbpb,ibpb-brtype" |
| Product: |
[Fedora] Fedora
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Reporter: |
pgnd <pgnd> |
| Component: |
kernel | Assignee: |
Kernel Maintainer List <kernel-maint> |
| Status: |
CLOSED
CURRENTRELEASE
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QA Contact: |
Fedora Extras Quality Assurance <extras-qa> |
| Severity: |
urgent
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Docs Contact: |
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| Priority: |
unspecified
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| Version: |
42 | CC: |
acaringi, adscvr, airlied, hdegoede, hpa, josef, jpoimboe, kernel-maint, linville, masami256, mchehab, pgnd, ptalbert, steved, suraj.ghimire7
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| Target Milestone: |
--- | Keywords: |
Regression |
| Target Release: |
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| Hardware: |
x86_64 | |
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| OS: |
Linux | |
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Fixed In Version:
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Doc Type:
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Doc Text:
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Story Points:
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Environment:
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Last Closed:
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2025-07-16 18:44:05 UTC
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Type:
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Regression:
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Documentation:
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CRM:
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Verified Versions:
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Category:
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oVirt Team:
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RHEL 7.3 requirements from Atomic Host:
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Cloudforms Team:
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Target Upstream Version:
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Embargoed:
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on several similarly-config'd machines running distro Name: Fedora Linux 42 (Adams) Version: 42 Codename: with rpm -qa | grep kernel-6 kernel-6.15.3-200.fc42.x86_64 kernel-6.15.4-200.fc42.x86_64 kernel-6.15.5-200.fc42.x86_64 on AMD cpu, cat /proc/cpuinfo | grep -E "model name|flags" | head -n2 model name : AMD Ryzen 5 5600G with Radeon Graphics flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nopl xtopology nonstop_tsc cpuid extd_apicid aperfmperf rapl pni pclmulqdq monitor ssse3 fma cx16 sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt tce topoext perfctr_core perfctr_nb bpext perfctr_llc mwaitx cpb cat_l3 cdp_l3 hw_pstate ssbd mba ibrs ibpb stibp vmmcall fsgsbase bmi1 avx2 smep bmi2 erms invpcid cqm rdt_a rdseed adx smap clflushopt clwb sha_ni xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local user_shstk clzero irperf xsaveerptr rdpru wbnoinvd cppc arat npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold avic v_vmsave_vmload vgif v_spec_ctrl umip pku ospke vaes vpclmulqdq rdpid overflow_recov succor smca fsrm debug_swap when booted to either of uname -rm 6.15.3-200.fc42.x86_64 x86_64 uname -rm 6.15.4-200.fc42.x86_64 x86_64 KVM guests launche without issue; e.g. virsh list Id Name State ---------------------- 1 f01 running virsh dominfo f01 Id: 1 Name: f01 UUID: f... OS Type: hvm State: running CPU(s): 4 CPU time: 44.1s Max memory: 8388608 KiB Used memory: 8388608 KiB Persistent: yes Autostart: enable Managed save: no Security model: none Security DOI: 0 on switch to uname -rm 6.15.5-200.fc42.x86_64 x86_64 , with no other changes, kvm guest fails to launch Jul 13 16:17:26 mach virtqemud[1831]: internal error: Failed to autostart VM 'f01': operation failed: guest CPU doesn't match specification: missing features: sbpb,ibpb-brtype reboot, switch to 6.15.3-200.fc42.x86_64 x86_64 or, 6.15.4-200.fc42.x86_64 x86_64 all's good again. here, rpm -q --whatprovides `which virtqemud` libvirt-daemon-driver-qemu-11.0.0-3.fc42.x86_64 rpm -q --queryformat '%{installtime:date}\n' kernel-6.15.5-200.fc42.x86_64 libvirt-daemon-driver-qemu Sun 13 Jul 2025 12:19:01 PM EDT Tue 24 Jun 2025 07:33:57 PM EDT digging re: sbpb & ibpb speculative exec barriers, i note @ 6.15 AMD-related changes Linux 6.15 Adds AMD Zen 5 SRSO Mitigation For KVM, Preps For Attack Vector Controls https://www.phoronix.com/news/Linux-6.15-x86-bugs checking cd /etc/libvirt/ grep -E "cpu mode|sbpb|ibpb" `find . | grep xml` ./qemu/autostart/f01.xml: <cpu mode='custom' match='exact' check='full'> ./qemu/autostart/f01.xml: <feature policy='require' name='sbpb'/> ./qemu/autostart/f01.xml: <feature policy='require' name='ibpb-brtype'/> ./qemu/f01.xml: <cpu mode='custom' match='exact' check='full'> ./qemu/f01.xml: <feature policy='require' name='sbpb'/> ./qemu/f01.xml: <feature policy='require' name='ibpb-brtype'/> Reproducible: Always