linux/arch/powerpc/kernel
Michael Ellerman 56376c5864 powerpc/kvm: Fix lockups when running KVM guests on Power8
When running KVM guests on Power8 we can see a lockup where one CPU
stops responding. This often leads to a message such as:

  watchdog: CPU 136 detected hard LOCKUP on other CPUs 72
  Task dump for CPU 72:
  qemu-system-ppc R  running task    10560 20917  20908 0x00040004

And then backtraces on other CPUs, such as:

  Task dump for CPU 48:
  ksmd            R  running task    10032  1519      2 0x00000804
  Call Trace:
    ...
    --- interrupt: 901 at smp_call_function_many+0x3c8/0x460
        LR = smp_call_function_many+0x37c/0x460
    pmdp_invalidate+0x100/0x1b0
    __split_huge_pmd+0x52c/0xdb0
    try_to_unmap_one+0x764/0x8b0
    rmap_walk_anon+0x15c/0x370
    try_to_unmap+0xb4/0x170
    split_huge_page_to_list+0x148/0xa30
    try_to_merge_one_page+0xc8/0x990
    try_to_merge_with_ksm_page+0x74/0xf0
    ksm_scan_thread+0x10ec/0x1ac0
    kthread+0x160/0x1a0
    ret_from_kernel_thread+0x5c/0x78

This is caused by commit 8c1c7fb0b5 ("powerpc/64s/idle: avoid sync
for KVM state when waking from idle"), which added a check in
pnv_powersave_wakeup() to see if the kvm_hstate.hwthread_state is
already set to KVM_HWTHREAD_IN_KERNEL, and if so to skip the store and
test of kvm_hstate.hwthread_req.

The problem is that the primary does not set KVM_HWTHREAD_IN_KVM when
entering the guest, so it can then come out to cede with
KVM_HWTHREAD_IN_KERNEL set. It can then go idle in kvm_do_nap after
setting hwthread_req to 1, but because hwthread_state is still
KVM_HWTHREAD_IN_KERNEL we will skip the test of hwthread_req when we
wake up from idle and won't go to kvm_start_guest. From there the
thread will return somewhere garbage and crash.

Fix it by skipping the store of hwthread_state, but not the test of
hwthread_req, when coming out of idle. It's OK to skip the sync in
that case because hwthread_req will have been set on the same thread,
so there is no synchronisation required.

Fixes: 8c1c7fb0b5 ("powerpc/64s/idle: avoid sync for KVM state when waking from idle")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-04-19 16:22:20 +10:00
..
trace powerpc updates for 4.15 2017-11-16 12:47:46 -08:00
vdso32 License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vdso64 powerpc/vdso64: Add support for CLOCK_{REALTIME/MONOTONIC}_COARSE 2017-12-04 15:01:09 +11:00
.gitignore
align.c powerpc: Fix check for copy/paste instructions in alignment handler 2017-10-25 12:42:35 +02:00
asm-offsets.c Merge branch 'topic/paca' into next 2018-03-31 09:09:36 +11:00
audit.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
btext.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cacheinfo.c powerpc: Convert to using %pOF instead of full_name 2017-08-23 22:27:04 +10:00
cacheinfo.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compat_audit.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cpu_setup_6xx.S powerpc: Free up CPU feature bits on 64-bit machines 2018-03-24 00:38:51 +11:00
cpu_setup_44x.S
cpu_setup_fsl_booke.S powerpc: Free up CPU feature bits on 64-bit machines 2018-03-24 00:38:51 +11:00
cpu_setup_pa6t.S
cpu_setup_power.S Merge branch 'fixes' into next 2018-01-21 23:21:14 +11:00
cpu_setup_ppc970.S
cputable.c powerpc/64s: Remove POWER4 support 2018-04-01 00:47:50 +11:00
crash_dump.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
crash.c powerpc/64: Use array of paca pointers and allocate pacas individually 2018-03-30 23:34:23 +11:00
dbell.c powerpc: Introduce msgsnd/doorbell barrier primitives 2017-04-13 23:34:33 +10:00
dma-iommu.c powerpc: rename dma_direct_ to dma_nommu_ 2018-01-10 16:41:14 +01:00
dma-swiotlb.c swiotlb: rename swiotlb_free to swiotlb_exit 2018-01-15 09:35:39 +01:00
dma.c powerpc: rename swiotlb_dma_ops 2018-01-15 09:35:26 +01:00
dt_cpu_ftrs.c powerpc/64s: Fix CPU_FTRS_ALWAYS vs DT CPU features 2018-04-13 23:51:44 +10:00
eeh_cache.c powerpc/eeh: Fix misleading comment in __eeh_addr_cache_get_device() 2018-03-27 23:44:58 +11:00
eeh_dev.c powerpc/eeh: Create PHB PEs after EEH is initialized 2017-09-21 14:56:00 +10:00
eeh_driver.c powerpc/eeh: Fix race with driver un/bind 2018-04-01 00:47:45 +11:00
eeh_event.c powerpc/eeh: Manage EEH_PE_RECOVERING inside eeh_handle_normal_event() 2018-03-27 23:44:58 +11:00
eeh_pe.c powerpc/eeh: Fix enabling bridge MMIO windows 2018-04-19 13:02:38 +10:00
eeh_sysfs.c powerpc/eeh: Add EEH notify resume sysfs 2018-01-27 20:02:52 +11:00
eeh.c powerpc/eeh: Add eeh_state_active() helper 2018-03-27 23:45:19 +11:00
entry_32.S powerpc/8xx: Only perform perf counting when perf is in use. 2018-01-16 23:47:12 +11:00
entry_64.S powerpc/64s: Set assembler machine type to POWER4 2018-04-01 00:47:49 +11:00
epapr_hcalls.S ppc: move exports to definitions 2016-08-07 23:50:09 -04:00
epapr_paravirt.c
exceptions-64e.S powerpc/64s: Fix may_hard_irq_enable() for PMI soft masking 2018-02-08 23:56:10 +11:00
exceptions-64s.S powerpc/64s: Set assembler machine type to POWER4 2018-04-01 00:47:49 +11:00
fadump.c Revert "powerpc: Do not call ppc_md.panic in fadump panic notifier" 2017-12-05 23:21:46 +11:00
firmware.c
fpu.S Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-10-14 14:26:58 -07:00
fsl_booke_entry_mapping.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
head_8xx.S powerpc/8xx: Use L1 entry APG to handle _PAGE_ACCESSED for CONFIG_SWAP 2018-01-16 23:47:15 +11:00
head_32.S powerpc: Fix DABR match on hash based systems 2017-11-13 22:12:48 +11:00
head_40x.S ppc: move exports to definitions 2016-08-07 23:50:09 -04:00
head_44x.S ppc: move exports to definitions 2016-08-07 23:50:09 -04:00
head_64.S powerpc/64: Use array of paca pointers and allocate pacas individually 2018-03-30 23:34:23 +11:00
head_booke.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
head_fsl_booke.S ppc: move exports to definitions 2016-08-07 23:50:09 -04:00
hw_breakpoint.c powerpc: Update ptrace to use ppc_breakpoint_available() 2018-03-27 23:52:44 +11:00
idle_6xx.S
idle_book3e.S powerpc/64: Rename soft_enabled to irq_soft_mask 2018-01-19 22:37:01 +11:00
idle_book3s.S powerpc/kvm: Fix lockups when running KVM guests on Power8 2018-04-19 16:22:20 +10:00
idle_e500.S
idle_power4.S powerpc/64: Rename soft_enabled to irq_soft_mask 2018-01-19 22:37:01 +11:00
idle.c
ima_kexec.c powerpc: ima: send the kexec buffer to the next kernel 2016-12-20 09:48:44 -08:00
io-workarounds.c powerpc: Convert to using %pOF instead of full_name 2017-08-23 22:27:04 +10:00
io.c
iomap.c powerpc: iomap.c: introduce io{read|write}64_{lo_hi|hi_lo} 2018-04-05 14:59:26 +10:00
iommu.c powerpc/iommu: Use permission-specific DEVICE_ATTR variants 2017-09-01 16:42:54 +10:00
irq.c powerpc/64s: Fix lost pending interrupt due to race causing lost update to irq_happened 2018-03-23 08:41:40 +11:00
isa-bridge.c powerpc: Convert to using %pOF instead of full_name 2017-08-23 22:27:04 +10:00
jump_label.c
kexec_elf_64.c kernel/kexec_file.c: allow archs to set purgatory load address 2018-04-13 17:10:28 -07:00
kgdb.c powerpc/8xx: Getting rid of remaining use of CONFIG_8xx 2017-08-10 23:32:12 +10:00
kprobes-ftrace.c powerpc/kprobes: Do not disable interrupts for optprobes and kprobes_on_ftrace 2017-11-12 23:51:41 +11:00
kprobes.c powerpc/kprobes: Fix call trace due to incorrect preempt count 2018-03-31 00:10:33 +11:00
kvm_emul.S
kvm.c powerpc/64: Fix watchdog configuration regressions 2017-08-31 14:26:00 +10:00
l2cr_6xx.S powerpc/l2cr_6xx: Fix invalid use of register expressions 2017-08-15 21:04:32 +10:00
legacy_serial.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
machine_kexec_32.c
machine_kexec_64.c powerpc/64s: Allocate LPPACAs individually 2018-03-30 23:34:24 +11:00
machine_kexec_file_64.c kexec_file,x86,powerpc: factor out kexec_file_ops functions 2018-04-13 17:10:27 -07:00
machine_kexec.c powerpc: Update of_remove_property() call sites to remove null checking 2016-05-11 21:54:04 +10:00
Makefile powerpc updates for 4.17 2018-04-07 12:08:19 -07:00
mce_power.c powerpc/64s: Improve local TLB flush for boot and MCE on POWER9 2018-01-18 00:40:31 +11:00
mce.c powerpc updates for 4.16 2018-02-02 10:01:04 -08:00
misc_32.S powerpc/40x: Clear MSR_DR in one insn instead of two 2017-06-02 19:20:43 +10:00
misc_64.S powerpc: Remove unused flush_dcache_phys_range() 2018-03-20 16:47:53 +11:00
misc.S ppc: move exports to definitions 2016-08-07 23:50:09 -04:00
module_32.c powerpc/module: Only try to generate the ftrace_caller() stub once 2016-03-07 14:53:53 +11:00
module_64.c powerpc updates for 4.16 2018-02-02 10:01:04 -08:00
module.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
module.lds powerpc/modules: Fix alignment of .toc section in kernel modules 2017-12-11 13:03:35 +11:00
msi.c
nvram_64.c powerpc: Use sizeof(*foo) rather than sizeof(struct foo) 2018-03-20 16:47:53 +11:00
of_platform.c powerpc: Convert to using %pOF instead of full_name 2017-08-23 22:27:04 +10:00
optprobes_head.S powerpc/64: Rename soft_enabled to irq_soft_mask 2018-01-19 22:37:01 +11:00
optprobes.c powerpc/kprobes: Do not disable interrupts for optprobes and kprobes_on_ftrace 2017-11-12 23:51:41 +11:00
paca.c Merge branch 'topic/paca' into next 2018-03-31 09:09:36 +11:00
pci_32.c powerpc/PCI: Deprecate pci_get_bus_and_slot() 2018-01-11 17:21:55 -06:00
pci_64.c powerpc/64s: Replace CONFIG_PPC_STD_MMU_64 with CONFIG_PPC_BOOK3S_64 2017-11-06 16:48:14 +11:00
pci_dn.c powerpc/pci: Separate SR-IOV Calls 2017-12-11 13:03:35 +11:00
pci_of_scan.c pci-v4.16-changes 2018-02-06 09:59:40 -08:00
pci-common.c powerpc/pci: Use generic pci_mmap_resource_range() 2018-02-28 16:18:53 -06:00
pci-hotplug.c powerpc/pci: Unroll two pass loop when scanning bridges 2017-12-18 23:05:52 -06:00
pmc.c
ppc32.h
ppc_save_regs.S
proc_powerpc.c powerpc: Use octal numbers for file permissions 2018-01-22 05:48:33 +11:00
process.c powerpc: Don't write to DABR on >= Power8 if DAWR is disabled 2018-04-03 21:50:08 +10:00
prom_init_check.sh powerpc/mm/radix: Update command line parsing for disable_radix 2018-04-04 16:59:50 +10:00
prom_init.c powerpc/mm/radix: Update command line parsing for disable_radix 2018-04-04 16:59:50 +10:00
prom_parse.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
prom.c Merge branch 'topic/paca' into next 2018-03-31 09:09:36 +11:00
ptrace32.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
ptrace.c powerpc: Update ptrace to use ppc_breakpoint_available() 2018-03-27 23:52:44 +11:00
reloc_32.S
reloc_64.S powerpc/asm: Convert .llong directives to .8byte 2017-08-31 14:26:47 +10:00
rtas_flash.c powerpc: Use octal numbers for file permissions 2018-01-22 05:48:33 +11:00
rtas_pci.c powerpc/kernel: Change retrieval of pci_dn 2017-08-31 14:26:40 +10:00
rtas-proc.c powerpc: Use octal numbers for file permissions 2018-01-22 05:48:33 +11:00
rtas-rtc.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rtas.c locking/arch, powerpc/rtas: Use arch_spin_lock() instead of arch_spin_lock_flags() 2017-10-18 15:15:07 +02:00
rtasd.c vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
security.c powerpc: Move default security feature flags 2018-04-03 21:50:08 +10:00
setup_32.c powerpc/32: Add missing prototypes for (early|machine)_init() 2018-03-13 15:50:42 +11:00
setup_64.c powerpc/64s: Default l1d_size to 64K in RFI fallback flush 2018-04-17 19:29:04 +10:00
setup-common.c powerpc/64e: Fix oops due to deferral of paca allocation 2018-04-01 00:47:38 +11:00
setup.h powerpc/64: move default SPR recording 2018-03-30 23:34:26 +11:00
signal_32.c powerpc/32: Mark both tmp variables as unused 2018-03-13 15:50:33 +11:00
signal_64.c powerpc/tm: Fix endianness flip on trap 2018-01-22 05:48:36 +11:00
signal.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching 2018-01-31 13:02:18 -08:00
signal.h powerpc: Add missing prototypes for sys_sigreturn() & sys_rt_sigreturn() 2018-03-13 15:50:39 +11:00
smp-tbsync.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
smp.c powerpc: hard disable irqs in smp_send_stop loop 2018-04-03 22:59:10 +10:00
stacktrace.c powerpc: Make /proc/self/stack always print the current stack 2017-03-28 14:43:59 +11:00
suspend.c
swsusp_32.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
swsusp_64.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/nmi.h> 2017-03-02 08:42:30 +01:00
swsusp_asm64.S powerpc: Fix invalid use of register expressions 2017-08-10 22:29:41 +10:00
swsusp_booke.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
swsusp.c powerpc/swsusp: Include suspend.h to silence sparse warnings 2017-03-20 19:02:49 +11:00
sys_ppc32.c mm: add ksys_readahead() helper; remove in-kernel calls to sys_readahead() 2018-04-02 20:16:12 +02:00
syscalls.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next 2018-04-03 14:08:58 -07:00
sysfs.c Merge branch 'topic/paca' into next 2018-03-31 09:09:36 +11:00
systbl_chk.c powerpc: Standardise on NR_syscalls rather than __NR_syscalls. 2015-11-26 22:11:17 +11:00
systbl_chk.sh powerpc: Standardise on NR_syscalls rather than __NR_syscalls. 2015-11-26 22:11:17 +11:00
systbl.S powerpc/asm: Convert .llong directives to .8byte 2017-08-31 14:26:47 +10:00
tau_6xx.c treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
time.c powerpc: Fix oops due to bad access of lppaca on bare metal 2018-04-03 21:50:07 +10:00
tm.S powerpc updates for 4.15 2017-11-16 12:47:46 -08:00
traps.c powerpc/fscr: Enable interrupts earlier before calling get_user() 2018-04-10 11:23:23 +10:00
udbg_16550.c
udbg.c
uprobes.c powerpc/uprobes: Implement arch_uretprobe_is_alive() 2017-08-24 16:19:21 +10:00
vdso.c powerpc: Use feature bit for RTC presence rather than timebase presence 2018-03-24 00:36:45 +11:00
vecemu.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vector.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vmlinux.lds.S powerpc updates for 4.16 2018-02-02 10:01:04 -08:00
watchdog.c powerpc/watchdog: Print the NIP in soft_nmi_interrupt() 2018-01-28 17:08:29 +11:00