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Commit 017917fe authored by Tianyu Lan's avatar Tianyu Lan Committed by Greg Kroah-Hartman
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x86/Hyper-V: Report crash register data or kmsg before running crash kernel 



commit a11589563e96bf262767294b89b25a9d44e7303b upstream.

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: 81b18bce ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Signed-off-by: default avatarTianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20200406155331.2105-5-Tianyu.Lan@microsoft.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d55d3d74

arch/x86/kernel/cpu/mshyperv.c

+10 −0
Original line number Diff line number Diff line
@@ -250,6 +250,16 @@ 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) {