From a11589563e96bf262767294b89b25a9d44e7303b Mon Sep 17 00:00:00 2001 From: Tianyu Lan Date: Mon, 6 Apr 2020 08:53:29 -0700 Subject: x86/Hyper-V: Report crash register data or kmsg before running crash kernel 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: 81b18bce48af ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic") Reviewed-by: Michael Kelley Signed-off-by: Tianyu Lan Link: https://lore.kernel.org/r/20200406155331.2105-5-Tianyu.Lan@microsoft.com Signed-off-by: Wei Liu --- arch/x86/kernel/cpu/mshyperv.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'arch/x86') diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 53706fb56433..ebf34c7bc8bc 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) { -- cgit v1.2.3-59-g8ed1b