RE: [PATCH V2 4/6] x86/Hyper-V: Report crash register data or ksmg before running crash kernel
From: Michael Kelley <hidden>
Date: 2020-03-23 17:16:45
Also in:
lkml
From: Tianyu Lan <redacted> Sent: Monday, March 23, 2020 6:09 AM
When a guest VM panics, Hyper-V should be notified only once via the crash synthetic MSRs. Current Linux code might write these crash MSRs twice during a system panic: 1) hyperv_panic/die_event() calling hyperv_report_panic() 2) hv_kmsg_dump() calling hyperv_report_panic_msg() Fix this by not calling hyperv_report_panic() if a kmsg dump has been successfully registered. The notification will happen later via hyperv_report_panic_msg().
I think this patch got the wrong commit message. This message is the same as in patch 3 of the series.
quoted hunk ↗ jump to hunk
Signed-off-by: Tianyu Lan <redacted> --- Change since v1: Update commit log --- arch/x86/kernel/cpu/mshyperv.c | 10 ++++++++++ 1 file changed, 10 insertions(+)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) { --2.14.5