From: Tianyu Lan Tianyu.Lan@microsoft.com
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: 81b18bce48af ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kernel/cpu/mshyperv.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
--- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -250,6 +250,16 @@ static void __init ms_hyperv_init_platfo 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) {