From e71c4e54d996d7ab70e778917cc1fff67a9f4dc0 Mon Sep 17 00:00:00 2001 From: Boris Ostrovsky Date: Wed, 18 Feb 2015 16:50:47 +0100 Subject: [PATCH] x86/VPMU: disable when NMI watchdog is on NMI watchdog sets APIC_LVTPC register to generate an NMI when PMU counter overflow occurs. This may be overwritten by VPMU code later, effectively turning off the watchdog. We should disable VPMU when NMI watchdog is running. Signed-off-by: Boris Ostrovsky Reviewed-by: Andrew Cooper master commit: e5e09b5c46444b0ab8450c6d6ee8316d4016ac18 master date: 2015-02-03 11:30:09 +0100 --- docs/misc/xen-command-line.markdown | 2 ++ xen/arch/x86/hvm/vpmu.c | 13 +++++++++++++ 2 files changed, 15 insertions(+) diff --git a/docs/misc/xen-command-line.markdown b/docs/misc/xen-command-line.markdown index aa121fbe5e..64c6fb7887 100644 --- a/docs/misc/xen-command-line.markdown +++ b/docs/misc/xen-command-line.markdown @@ -981,6 +981,8 @@ wrong behaviour (see handle\_pmc\_quirk()). If 'vpmu=bts' is specified the virtualisation of the Branch Trace Store (BTS) feature is switched on on Intel processors supporting this feature. +Note that if **watchdog** option is also specified vpmu will be turned off. + *Warning:* As the BTS virtualisation is not 100% safe and because of the nehalem quirk don't use the vpmu flag on production systems with Intel cpus! diff --git a/xen/arch/x86/hvm/vpmu.c b/xen/arch/x86/hvm/vpmu.c index 27441e27ab..e6795a514b 100644 --- a/xen/arch/x86/hvm/vpmu.c +++ b/xen/arch/x86/hvm/vpmu.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include @@ -284,3 +285,15 @@ void vpmu_dump(struct vcpu *v) vpmu->arch_vpmu_ops->arch_vpmu_dump(v); } +static int __init vpmu_init(void) +{ + /* NMI watchdog uses LVTPC and HW counter */ + if ( opt_watchdog && opt_vpmu_enabled ) + { + printk(XENLOG_WARNING "NMI watchdog is enabled. Turning VPMU off.\n"); + opt_vpmu_enabled = 0; + } + + return 0; +} +__initcall(vpmu_init);