Guest kernel crashes with kvm_pr on POWER8 When attempting to use the kvm_pr module with QEMU 2.10 on a POWER8 host, Debian and Ubuntu guests hang and show crashes. Host kernel is 4.14. Issue is observed with host kernels 4.9 and 4.13 as well; no other host kernels were tested. Is this the correct place to report a kvm_pr bug? Output from Ubuntu 17.10 guest: Quiescing Open Firmware ... Booting Linux via __start() @ 0x0000000002000000 ... [ 0.000000] Page sizes from device-tree: [ 0.000000] base_shift=12: shift=12, sllp=0x0000, avpnm=0x00000000, tlbiel=1, penc=0 [ 0.000000] base_shift=16: shift=16, sllp=0x0110, avpnm=0x00000000, tlbiel=1, penc=1 [ 0.000000] base_shift=24: shift=24, sllp=0x0100, avpnm=0x00000001, tlbiel=0, penc=0 [ 0.000000] Using 1TB segments [ 0.000000] Initializing hash mmu with SLB [ 0.000000] Linux version 4.13.0-16-generic (buildd@bos01-ppc64el-029) (gcc version 7.2.0 (Ubuntu 7.2.0-8ubuntu2)) #19-Ubuntu SMP Wed Oct 11 18:37:02 UTC 2017 (Ubuntu 4.13.0-16.19-generic 4.13.4) [ 0.000000] Found initrd at 0xc000000003b00000:0xc0000000048cf68b [ 0.000000] Using pSeries machine description [ 0.000000] bootconsole [udbg0] enabled [ 0.000000] Partition configured for 2 cpus. [ 0.000000] CPU maps initialized for 1 thread per core -> smp_release_cpus() spinning_secondaries = 1 <- smp_release_cpus() [ 0.000000] ----------------------------------------------------- [ 0.000000] ppc64_pft_size = 0x19 [ 0.000000] phys_mem_size = 0x100000000 [ 0.000000] dcache_bsize = 0x80 [ 0.000000] icache_bsize = 0x80 [ 0.000000] cpu_features = 0x077c7a6c18500249 [ 0.000000] possible = 0x5fffffff18500649 [ 0.000000] always = 0x0000000018100040 [ 0.000000] cpu_user_features = 0xdc0065c2 0xae000000 [ 0.000000] mmu_features = 0x7c006001 [ 0.000000] firmware_features = 0x00000000415a445f [ 0.000000] htab_hash_mask = 0x3ffff [ 0.000000] ----------------------------------------------------- [ 0.000000] numa: NODE_DATA [mem 0xfffd7c80-0xfffe3fff] [ 0.000000] PCI host bridge /pci@800000020000000 ranges: [ 0.000000] IO 0x0000200000000000..0x000020000000ffff -> 0x0000000000000000 [ 0.000000] MEM 0x0000200080000000..0x00002000ffffffff -> 0x0000000080000000 [ 0.000000] MEM 0x0000210000000000..0x000021ffffffffff -> 0x0000210000000000 [ 0.000000] PPC64 nvram contains 65536 bytes [ 0.000000] Zone ranges: [ 0.000000] DMA [mem 0x0000000000000000-0x00000000ffffffff] [ 0.000000] DMA32 empty [ 0.000000] Normal empty [ 0.000000] Device empty [ 0.000000] Movable zone start for each node [ 0.000000] Early memory node ranges [ 0.000000] node 0: [mem 0x0000000000000000-0x00000000ffffffff] [ 0.000000] Initmem setup node 0 [mem 0x0000000000000000-0x00000000ffffffff] [ 0.000000] percpu: Embedded 4 pages/cpu @c0000000ffe00000 s162840 r0 d99304 u524288 [ 0.000000] Built 1 zonelists in Node order, mobility grouping on. Total pages: 65472 [ 0.000000] Policy zone: DMA [ 0.000000] Kernel command line: BOOT_IMAGE=/install/vmlinux file=/cdrom/preseed/ubuntu-server.seed no_timer_check printk.time=1 --- [ 0.000000] PID hash table entries: 4096 (order: -1, 32768 bytes) [ 0.000000] Memory: 4070016K/4194304K available (12800K kernel code, 2048K rwdata, 3456K rodata, 4608K init, 3021K bss, 124288K reserved, 0K cma-reserved) [ 0.000000] random: get_random_u64 called from cache_random_seq_create+0x80/0x180 with crng_init=0 [ 0.000000] SLUB: HWalign=128, Order=0-3, MinObjects=0, CPUs=2, Nodes=1 [ 0.000000] ftrace: allocating 33631 entries in 13 pages [ 0.000000] Hierarchical RCU implementation. [ 0.000000] RCU restricting CPUs from NR_CPUS=2048 to nr_cpu_ids=2. [ 0.000000] Tasks RCU enabled. [ 0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=2 [ 0.000000] NR_IRQS: 512, nr_irqs: 512, preallocated irqs: 16 [ 0.000006] clocksource: timebase: mask: 0xffffffffffffffff max_cycles: 0x761537d007, max_idle_ns: 440795202126 ns [ 0.000696] clocksource: timebase mult[1f40000] shift[24] registered [ 0.001189] Console: colour dummy device 80x25 [ 0.001500] console [hvc0] enabled [ 0.001500] console [hvc0] enabled [ 0.001751] bootconsole [udbg0] disabled [ 0.001751] bootconsole [udbg0] disabled [ 0.002142] pid_max: default: 32768 minimum: 301 [ 0.002358] Security Framework initialized [ 0.002377] Yama: becoming mindful. [ 0.002466] AppArmor: AppArmor initialized [ 0.007008] Dentry cache hash table entries: 524288 (order: 6, 4194304 bytes) [ 0.009037] Inode-cache hash table entries: 262144 (order: 5, 2097152 bytes) [ 0.009144] Mount-cache hash table entries: 8192 (order: 0, 65536 bytes) [ 0.009282] Mountpoint-cache hash table entries: 8192 (order: 0, 65536 bytes) [ 0.011066] EEH: pSeries platform initialized [ 0.011137] POWER8 performance monitor hardware support registered [ 0.011231] Hierarchical SRCU implementation. [ 0.012560] smp: Bringing up secondary CPUs ... [ 0.014620] smp: Brought up 1 node, 2 CPUs [ 0.014669] numa: Node 0 CPUs: 0-1 [ 0.017357] devtmpfs: initialized [ 0.020796] evm: security.selinux [ 0.020816] evm: security.SMACK64 [ 0.020832] evm: security.SMACK64EXEC [ 0.020849] evm: security.SMACK64TRANSMUTE [ 0.020865] evm: security.SMACK64MMAP [ 0.020882] evm: security.ima [ 0.020898] evm: security.capability [ 0.021384] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns [ 0.021428] futex hash table entries: 512 (order: 0, 65536 bytes) [ 0.022217] NET: Registered protocol family 16 [ 0.023456] EEH: No capable adapters found [ 0.068790] KVM: Live patching for a fast VM worked [ 0.069504] cpuidle: using governor ladder [ 0.069606] cpuidle: using governor menu [ 0.070109] pstore: using zlib compression [ 0.070162] pstore: Registered nvram as persistent store backend Linux ppc64le #19-Ubuntu SMP W[ 0.073385] PCI: Probing PCI hardware [ 0.073595] PCI host bridge to bus 0000:00 [ 0.073650] pci_bus 0000:00: root bus resource [io 0x10000-0x1ffff] (bus address [0x0000-0xffff]) [ 0.073722] pci_bus 0000:00: root bus resource [mem 0x200080000000-0x2000ffffffff] (bus address [0x80000000-0xffffffff]) [ 0.073827] pci_bus 0000:00: root bus resource [mem 0x210000000000-0x21ffffffffff] [ 0.073913] pci_bus 0000:00: root bus resource [bus 00-ff] [ 0.081145] IOMMU table initialized, virtual merging enabled [ 0.081231] iommu: Adding device 0000:00:00.0 to group 0 [ 0.083493] HugeTLB registered 16.0 MiB page size, pre-allocated 0 pages [ 0.085216] SCSI subsystem initialized [ 0.085722] vgaarb: loaded [ 0.085885] usbcore: registered new interface driver usbfs [ 0.085961] usbcore: registered new interface driver hub [ 0.086096] usbcore: registered new device driver usb [ 0.086175] pps_core: LinuxPPS API ver. 1 registered [ 0.086217] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti