vmx: Disable vPMU feature by default

Signed-off-by: Shan Haitao <haitao.shan@intel.com>

xen/arch/x86/hvm/vmx/vpmu.c

@@ -31,6 +31,9 @@
 #include <public/hvm/save.h>
 #include <asm/hvm/vmx/vpmu.h>
 
+static int __read_mostly opt_vpmu_enabled;
+boolean_param("vpmu", opt_vpmu_enabled);
+
 int vpmu_do_wrmsr(struct cpu_user_regs *regs)
 {
     struct vpmu_struct *vpmu = vcpu_vpmu(current);
@@ -79,6 +82,9 @@ void vpmu_initialise(struct vcpu *v)
 {
     struct vpmu_struct *vpmu = vcpu_vpmu(v);
 
+    if ( !opt_vpmu_enabled )
+        return;
+
     if ( vpmu->flags & VPMU_CONTEXT_ALLOCATED )
         vpmu_destroy(v);