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x86/Hyper-V: Report crash register data or kmsg before running crash kernel

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We want to notify Hyper-V when a Linux guest VM crash occurs, so
there is a record of the crash even when kdump is enabled.   But
crash_kexec_post_notifiers defaults to "false", so the kdump kernel
runs before the notifiers and Hyper-V never gets notified.  Fix this by
always setting crash_kexec_post_notifiers to be true for Hyper-V VMs.

Fixes: 81b18bce48 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20200406155331.2105-5-Tianyu.Lan@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
This commit is contained in:
Tianyu Lan 2020-04-06 08:53:29 -07:00 committed by Wei Liu
parent 73f26e526f
commit a11589563e
1 changed files with 10 additions and 0 deletions
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10
arch/x86/kernel/cpu/mshyperv.c
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@ -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) {