[Xen-devel] [PATCH 2/3] x86/vpmu: Decrement vpmu_count early in vpmu_destroy()

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

vpmu_count should be decremented even if VPMU_CONTEXT_ALLOCATED
is not set because on Intel processors the context is allocated
lazily and, in fact, might never happen.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
---
 xen/arch/x86/cpu/vpmu.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/cpu/vpmu.c b/xen/arch/x86/cpu/vpmu.c
index 0252171..9fa8a18 100644
--- a/xen/arch/x86/cpu/vpmu.c
+++ b/xen/arch/x86/cpu/vpmu.c
@@ -536,6 +536,11 @@ void vpmu_destroy(struct vcpu *v)
 {
     struct vpmu_struct *vpmu = vcpu_vpmu(v);
 
+    spin_lock(&vpmu_lock);
+    if ( !is_hardware_domain(v->domain) )
+        vpmu_count--;
+    spin_unlock(&vpmu_lock);
+
     if ( !vpmu_is_set(vpmu, VPMU_CONTEXT_ALLOCATED) )
         return;
 
@@ -557,11 +562,6 @@ void vpmu_destroy(struct vcpu *v)
                          vpmu_save_force, v, 1);
          vpmu->arch_vpmu_ops->arch_vpmu_destroy(v);
     }
-
-    spin_lock(&vpmu_lock);
-    if ( !is_hardware_domain(v->domain) )
-        vpmu_count--;
-    spin_unlock(&vpmu_lock);
 }
 
 static int pvpmu_init(struct domain *d, xen_pmu_params_t *params)
-- 
1.8.3.1


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