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57b8daa70a
linux/arch/powerpc/kernel
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Paul Mackerras 57b8daa70a KVM: PPC: Book3S HV: Snapshot timebase offset on guest entry 
Currently, the HV KVM guest entry/exit code adds the timebase offset
from the vcore struct to the timebase on guest entry, and subtracts
it on guest exit.  Which is fine, except that it is possible for
userspace to change the offset using the SET_ONE_REG interface while
the vcore is running, as there is only one timebase offset per vcore
but potentially multiple VCPUs in the vcore.  If that were to happen,
KVM would subtract a different offset on guest exit from that which
it had added on guest entry, leading to the timebase being out of sync
between cores in the host, which then leads to bad things happening
such as hangs and spurious watchdog timeouts.

To fix this, we add a new field 'tb_offset_applied' to the vcore struct
which stores the offset that is currently applied to the timebase.
This value is set from the vcore tb_offset field on guest entry, and
is what is subtracted from the timebase on guest exit.  Since it is
zero when the timebase offset is not applied, we can simplify the
logic in kvmhv_start_timing and kvmhv_accumulate_time.

In addition, we had secondary threads reading the timebase while
running concurrently with code on the primary thread which would
eventually add or subtract the timebase offset from the timebase.
This occurred while saving or restoring the DEC register value on
the secondary threads.  Although no specific incorrect behaviour has
been observed, this is a race which should be fixed.  To fix it, we
move the DEC saving code to just before we call kvmhv_commence_exit,
and the DEC restoring code to after the point where we have waited
for the primary thread to switch the MMU context and add the timebase
offset.  That way we are sure that the timebase contains the guest
timebase value in both cases.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2018-05-17 15:16:45 +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 KVM: PPC: Book3S HV: Snapshot timebase offset on guest entry 2018-05-17 15:16:45 +10:00
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
crash.c powerpc/64: Use array of paca pointers and allocate pacas individually 2018-03-30 23:34:23 +11:00
dbell.c
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
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
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
head_44x.S
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
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
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
Makefile powerpc updates for 4.17 2018-04-07 12:08:19 -07:00
mce_power.c powerpc/mce: Fix a bug where mce loops on memory UE. 2018-04-24 13:54:51 +10:00
mce.c powerpc updates for 4.16 2018-02-02 10:01:04 -08:00
misc_32.S
misc_64.S powerpc: Remove unused flush_dcache_phys_range() 2018-03-20 16:47:53 +11:00
misc.S
module_32.c
module_64.c powerpc updates for 4.16 2018-02-02 10:01:04 -08:00
module.c
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
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: Fix deadlock with multiple calls to smp_send_stop 2018-04-27 16:35:57 +10:00
stacktrace.c
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
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
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
systbl_chk.sh
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