From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx> Sent: Monday, March 23, 2020 6:09 AM
>
> When a guest VM panics, Hyper-V should be notified only once via the
> crash synthetic MSRs. Current Linux code might write these crash MSRs
> twice during a system panic:
> 1) hyperv_panic/die_event() calling hyperv_report_panic()
> 2) hv_kmsg_dump() calling hyperv_report_panic_msg()
>
> Fix this by not calling hyperv_report_panic() if a kmsg dump has been
> successfully registered. The notification will happen later via
> hyperv_report_panic_msg().
I think this patch got the wrong commit message. This message is the same
as in patch 3 of the series.
>
> Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
> ---
> Change since v1:
> Update commit log
> ---
> arch/x86/kernel/cpu/mshyperv.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index caa032ce3fe3..5e296a7e6036 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -263,6 +263,16 @@ static void __init ms_hyperv_init_platform(void)
> cpuid_eax(HYPERV_CPUID_NESTED_FEATURES);
> }
>
> + /*
> + * Hyper-V expects to get crash register data or kmsg when
> + * crash enlightment is available and system crashes. Set
> + * crash_kexec_post_notifiers to be true to make sure that
> + * calling crash enlightment interface before running kdump
> + * kernel.
> + */
> + if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE)
> + crash_kexec_post_notifiers = true;
> +
> #ifdef CONFIG_X86_LOCAL_APIC
> if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
> ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
> --
> 2.14.5
