[PATCH v3 2/3] vcpu: track hvm vcpu number on the system

[Chao Gao <chao.gao@intel.com>]

This number is used to calculate how many hvm vcpu on a pcpu on average.
This counting is x86 specific.

Signed-off-by: Chao Gao <chao.gao@intel.com>
---
 xen/arch/x86/domain.c        | 10 ++++++++++
 xen/include/asm-x86/domain.h |  2 ++
 2 files changed, 12 insertions(+)

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 13cdc50..050fe0e 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -66,6 +66,9 @@
 
 DEFINE_PER_CPU(struct vcpu *, curr_vcpu);
 
+/* how many hvm vcpu on this system? */
+atomic_t num_hvm_vcpus;
+
 static void default_idle(void);
 void (*pm_idle) (void) __read_mostly = default_idle;
 void (*dead_idle) (void) __read_mostly = default_dead_idle;
@@ -467,7 +470,11 @@ int vcpu_initialise(struct vcpu *v)
             xfree(v->arch.pv_vcpu.trap_ctxt);
     }
     else if ( !is_idle_domain(v->domain) )
+    {
         vpmu_initialise(v);
+        if ( is_hvm_domain(v->domain) )
+            atomic_inc(&num_hvm_vcpus);
+    }
 
     return rc;
 }
@@ -489,7 +496,10 @@ void vcpu_destroy(struct vcpu *v)
         vpmu_destroy(v);
 
     if ( is_hvm_vcpu(v) )
+    {
         hvm_vcpu_destroy(v);
+        atomic_dec(&num_hvm_vcpus);
+    }
     else
         xfree(v->arch.pv_vcpu.trap_ctxt);
 }
diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
index 924caac..769cde2 100644
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -31,6 +31,8 @@
 #define nmi_pending            nmi_state.pending
 #define mce_pending            mce_state.pending
 
+extern atomic_t num_hvm_vcpus;
+
 struct trap_bounce {
     uint32_t      error_code;
     uint8_t       flags; /* TBF_ */
-- 
1.8.3.1


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