From: Jason Wang <jasowang@redhat.com>
Date: Fri, 28 Feb 2014 03:30:29 +0000 (+0800)
Subject: x86, hyperv: Bypass the timer_irq_works() check
X-Git-Tag: v3.15-rc1~171^2
X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=ca3ba2a2f4a49a308e7d78c784d51b2332064f15;p=~emulex%2Finfiniband.git

x86, hyperv: Bypass the timer_irq_works() check

This patch bypass the timer_irq_works() check for hyperv guest since:

- It was guaranteed to work.
- timer_irq_works() may fail sometime due to the lpj calibration were inaccurate
  in a hyperv guest or a buggy host.

In the future, we should get the tsc frequency from hypervisor and use preset
lpj instead.

[ hpa: I would prefer to not defer things to "the future" in the future... ]

Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: <stable@vger.kernel.org>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: http://lkml.kernel.org/r/1393558229-14755-1-git-send-email-jasowang@redhat.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 9f7ca266864..832d05a914b 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -26,6 +26,7 @@
 #include <asm/irq_regs.h>
 #include <asm/i8259.h>
 #include <asm/apic.h>
+#include <asm/timer.h>
 
 struct ms_hyperv_info ms_hyperv;
 EXPORT_SYMBOL_GPL(ms_hyperv);
@@ -105,6 +106,11 @@ static void __init ms_hyperv_init_platform(void)
 
 	if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
 		clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
+
+#ifdef CONFIG_X86_IO_APIC
+	no_timer_check = 1;
+#endif
+
 }
 
 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {