Skip to contentSkip to conversation

x86/hyperv: avoid reporting wrong NMI statuses for Gen2 instances

PATCH New Vitaly Kuznetsov 2 participants 2 messages Apr 15, 2016 – Apr 16, 2016

Subsystems (2)
x86 Hyper-V/Azure core and drivers
lore
Share & tools
lore

Vitaly Kuznetsov

author
#0 lore raw

PATCH 1/1 x86/hyperv: avoid reporting wrong NMI statuses for Gen2 instances

Generation2 instances don't support reporting NMI status on port 0x61, read from there returns 'ff' and we end up reporting nonsensical PCI error (as there is no PCI bus in these instances) on all NMIs:

NMI: PCI system error (SERR) for reason ff on CPU 0. Dazed and confused, but trying to continue

Fix the issue by overriding x86_platform.get_nmi_reason. Use 'booted on EFI' flag to detect Gen2 instances.

Signed-off-by Vitaly Kuznetsov <[email protected]>
---
 arch/x86/kernel/cpu/mshyperv.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)
arch/x86/kernel/cpu/mshyperv.c +12 -0
index 4e7c693..80fc084 100644
@@ -152,6 +152,11 @@ static struct clocksource hyperv_cs = {
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
+static unsigned char hv_get_nmi_reason(void)
+{
+	return 0;
+}
+
 static void __init ms_hyperv_init_platform(void)
 {
 	/*

@@ -191,6 +196,13 @@ static void __init ms_hyperv_init_platform(void)
 	machine_ops.crash_shutdown = hv_machine_crash_shutdown;
 #endif
 	mark_tsc_unstable("running on Hyper-V");
+
+	/*
+	 * Generation 2 instances don't support reading NMI statuses from
+	 * 0x61 port.
+	 */
+	if (efi_enabled(EFI_BOOT))
+		x86_platform.get_nmi_reason = hv_get_nmi_reason;
 }
 
 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
Signature · 1 line
2.5.5
merge bot
#1 lore raw

[tip:x86/urgent] x86/hyperv: Avoid reporting bogus NMI status for Gen2 instances

x86/hyperv: Avoid reporting bogus NMI status for Gen2 instances
Commit-ID:  1e2ae9ec072f3b7887f456426bc2cf23b80f661a
Gitweb:     http://git.kernel.org/tip/1e2ae9ec072f3b7887f456426bc2cf23b80f661a
Author:     Vitaly Kuznetsov <[email protected]>
AuthorDate: Fri, 15 Apr 2016 15:50:32 +0200
Committer:  Ingo Molnar <[email protected]>
CommitDate: Sat, 16 Apr 2016 11:18:21 +0200

x86/hyperv: Avoid reporting bogus NMI status for Gen2 instances

Generation2 instances don't support reporting the NMI status on port 0x61, read from there returns 'ff' and we end up reporting nonsensical PCI error (as there is no PCI bus in these instances) on all NMIs:

NMI: PCI system error (SERR) for reason ff on CPU 0. Dazed and confused, but trying to continue

Fix the issue by overriding x86_platform.get_nmi_reason. Use 'booted on EFI' flag to detect Gen2 instances.

Signed-off-by Vitaly Kuznetsov <[email protected]>
Cc Alexander Shishkin <[email protected]>
Cc Arnaldo Carvalho de Melo <[email protected]>
Cc Cathy Avery <[email protected]>
Cc Haiyang Zhang <[email protected]>
Cc Jiri Olsa <[email protected]>
Cc K. Y. Srinivasan <[email protected]>
Cc Linus Torvalds <[email protected]>
Cc Peter Zijlstra <[email protected]>
Cc Thomas Gleixner <[email protected]>
Cc [email protected]
Link http://lkml.kernel.org/r/[email protected] open here
Signed-off-by Ingo Molnar <[email protected]>
---
 arch/x86/kernel/cpu/mshyperv.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)
arch/x86/kernel/cpu/mshyperv.c +12 -0
index 4e7c693..10c11b4 100644
@@ -152,6 +152,11 @@ static struct clocksource hyperv_cs = {
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
+static unsigned char hv_get_nmi_reason(void)
+{
+	return 0;
+}
+
 static void __init ms_hyperv_init_platform(void)
 {
 	/*

@@ -191,6 +196,13 @@ static void __init ms_hyperv_init_platform(void)
 	machine_ops.crash_shutdown = hv_machine_crash_shutdown;
 #endif
 	mark_tsc_unstable("running on Hyper-V");
+
+	/*
+	 * Generation 2 instances don't support reading the NMI status from
+	 * 0x61 port.
+	 */
+	if (efi_enabled(EFI_BOOT))
+		x86_platform.get_nmi_reason = hv_get_nmi_reason;
 }
 
 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {