[Xen-changelog] [xen master] x86/VPMU: disable when NMI watchdog is on

[patchbot@xxxxxxx]

commit e5e09b5c46444b0ab8450c6d6ee8316d4016ac18
Author:     Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
AuthorDate: Tue Feb 3 11:30:09 2015 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Feb 3 11:30:09 2015 +0100

    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 <boris.ostrovsky@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 docs/misc/xen-command-line.markdown |    2 ++
 xen/arch/x86/hvm/vpmu.c             |   13 +++++++++++++
 2 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/docs/misc/xen-command-line.markdown 
b/docs/misc/xen-command-line.markdown
index 2274e74..bc316be 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -1346,6 +1346,8 @@ 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 63b2158..b2e8e65 100644
--- a/xen/arch/x86/hvm/vpmu.c
+++ b/xen/arch/x86/hvm/vpmu.c
@@ -24,6 +24,7 @@
 #include <asm/regs.h>
 #include <asm/types.h>
 #include <asm/msr.h>
+#include <asm/nmi.h>
 #include <asm/hvm/support.h>
 #include <asm/hvm/vmx/vmx.h>
 #include <asm/hvm/vmx/vmcs.h>
@@ -288,3 +289,15 @@ 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);
--
generated by git-patchbot for /home/xen/git/xen.git#master

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