[Xen-changelog] [xen master] x86/VPMU: Initialize VPMU's lvtpc vector

[patchbot@xxxxxxx]

commit 0c3f24645b07b875bc1294fb4627f01e030690fe
Author:     Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
AuthorDate: Tue Nov 24 18:33:08 2015 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Nov 24 18:33:08 2015 +0100

    x86/VPMU: Initialize VPMU's lvtpc vector
    
    If a guest sets up performance counters so that they can generate
    a PMC interrupt but does not initilaize APIC LVTPC register the
    resulting interrupt will cause an APIC error.
    
    Note that a guest deciding to clear LVTPC in order to unduce the error
    will not be successful in achieving its goal: emulation code only
    looks at the mask bit and always sets the vector to PMU_APIC_VECTOR.
    Only the initial value of LVTPC (which is zero) that gets loaded into
    APIC as result of PMC initialization is the problem.
    
    Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
---
 xen/arch/x86/cpu/vpmu.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/xen/arch/x86/cpu/vpmu.c b/xen/arch/x86/cpu/vpmu.c
index 2f5156a..d870dcc 100644
--- a/xen/arch/x86/cpu/vpmu.c
+++ b/xen/arch/x86/cpu/vpmu.c
@@ -480,6 +480,8 @@ void vpmu_initialise(struct vcpu *v)
         return; /* Don't bother restoring vpmu_count, VPMU is off forever */
     }
 
+    vpmu->hw_lapic_lvtpc = PMU_APIC_VECTOR | APIC_LVT_MASKED;
+
     if ( ret )
         printk(XENLOG_G_WARNING "VPMU: Initialization failed for %pv\n", v);
 
--
generated by git-patchbot for /home/xen/git/xen.git#master

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