[Xen-changelog] [xen stable-4.4] x86/VPMU: disable when NMI watchdog is on

[patchbot@xxxxxxx]

commit c9750068f80817261957ec8ce096c819d495af21
Author:     Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
AuthorDate: Wed Feb 18 16:45:14 2015 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Feb 18 16:45:14 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>
    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(+), 0 deletions(-)

diff --git a/docs/misc/xen-command-line.markdown 
b/docs/misc/xen-command-line.markdown
index b50a753..7cfa303 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -1015,6 +1015,8 @@ 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 27441e2..e6795a5 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>
@@ -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);
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.4

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