Commit 1e2ae9ec authored Apr 15, 2016 by Vitaly Kuznetsov Committed by Ingo Molnar Apr 16, 2016

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 <vkuznets@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Cathy Avery <cavery@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: devel@linuxdriverproject.org
Link: http://lkml.kernel.org/r/1460728232-31433-1-git-send-email-vkuznets@redhat.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 2e572599

arch/x86/kernel/cpu/mshyperv.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -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 = {