diff options
Diffstat (limited to 'arch/x86/kernel/cpu/mshyperv.c')
| -rw-r--r-- | arch/x86/kernel/cpu/mshyperv.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 6c044543545e..f37e02e41a77 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -30,6 +30,7 @@ #include <asm/apic.h> #include <asm/timer.h> #include <asm/reboot.h> +#include <asm/nmi.h> struct ms_hyperv_info ms_hyperv; EXPORT_SYMBOL_GPL(ms_hyperv); @@ -157,6 +158,26 @@ static unsigned char hv_get_nmi_reason(void) return 0; } +#ifdef CONFIG_X86_LOCAL_APIC +/* + * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes + * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle + * unknown NMI on the first CPU which gets it. + */ +static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs) +{ + static atomic_t nmi_cpu = ATOMIC_INIT(-1); + + if (!unknown_nmi_panic) + return NMI_DONE; + + if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1) + return NMI_HANDLED; + + return NMI_DONE; +} +#endif + static void __init ms_hyperv_init_platform(void) { /* @@ -182,6 +203,9 @@ static void __init ms_hyperv_init_platform(void) pr_info("HyperV: LAPIC Timer Frequency: %#x\n", lapic_timer_frequency); } + + register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST, + "hv_nmi_unknown"); #endif if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE) |