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authorTianyu Lan <Tianyu.Lan@microsoft.com>2020-04-06 08:53:28 -0700
committerWei Liu <wei.liu@kernel.org>2020-04-11 17:18:22 +0100
commit73f26e526f19afb3a06b76b970a76bcac2cafd05 (patch)
tree3768bb3bf6debd7f89fcaf68eb15744f20f83c1c /drivers/hv
parent7f11a2cc10a4ae3a70e2c73361f4a9a33503539b (diff)
x86/Hyper-V: Trigger crash enlightenment only once during system crash.
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(). Fixes: 7ed4325a44ea ("Drivers: hv: vmbus: Make panic reporting to be more useful") Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Link: https://lore.kernel.org/r/20200406155331.2105-4-Tianyu.Lan@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'drivers/hv')
-rw-r--r--drivers/hv/vmbus_drv.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 00a511f15926..333dad39b1c1 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -55,7 +55,13 @@ static int hyperv_panic_event(struct notifier_block *nb, unsigned long val,
vmbus_initiate_unload(true);
- if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
+ /*
+ * Hyper-V should be notified only once about a panic. If we will be
+ * doing hyperv_report_panic_msg() later with kmsg data, don't do
+ * the notification here.
+ */
+ if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE
+ && !hv_panic_page) {
regs = current_pt_regs();
hyperv_report_panic(regs, val);
}
@@ -68,7 +74,13 @@ static int hyperv_die_event(struct notifier_block *nb, unsigned long val,
struct die_args *die = (struct die_args *)args;
struct pt_regs *regs = die->regs;
- hyperv_report_panic(regs, val);
+ /*
+ * Hyper-V should be notified only once about a panic. If we will be
+ * doing hyperv_report_panic_msg() later with kmsg data, don't do
+ * the notification here.
+ */
+ if (!hv_panic_page)
+ hyperv_report_panic(regs, val);
return NOTIFY_DONE;
}