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authorTianyu Lan <Tianyu.Lan@microsoft.com>2020-04-06 18:53:29 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-04-23 11:37:55 +0300
commitc3e090ce368986f427ca70b3e6f391ef1461bd20 (patch)
tree8032795c82217b925be6862f6b83ef967e6000f9
parenteec9231fae6af74bf1844ed9df553ffe3c425b33 (diff)
downloadlinux-c3e090ce368986f427ca70b3e6f391ef1461bd20.tar.xz
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: 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>
-rw-r--r--arch/x86/kernel/cpu/mshyperv.c10
1 files changed, 10 insertions, 0 deletions
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) {