Xen x86 trap in

diff --git a/xen/arch/x86/hvm/vmx/entry.S b/xen/arch/x86/hvm/vmx/entry.S
index 664ed83..ea47a9b 100644
--- a/xen/arch/x86/hvm/vmx/entry.S
+++ b/xen/arch/x86/hvm/vmx/entry.S
@@ -30,6 +30,13 @@
 #define VMLAUNCH     .byte 0x0f,0x01,0xc2

 ENTRY(vmx_asm_vmexit_handler)
+       cmp $0x4b000000, %rax
+       jne .Lnormal
+       RDTSC
+       shl $0x20, %rdx
+       or %rax, %rdx
+       mov $0x4b000000, %rax
+.Lnormal:
         push %rdi
         push %rsi
         push %rdx
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index f2554d6..e5191fe 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2955,7 +2955,14 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
     {
         int rc;
         HVMTRACE_1D(VMMCALL, regs->eax);
+       if (regs->rax == 0x4b000000)
+       {
+               regs->rdx = hvm_get_guest_tsc_fixed(v, regs->rdx);
+               rc = HVM_HCALL_completed;
+               goto skip_vmcall;
+       }
         rc = hvm_do_hypercall(regs);
+skip_vmcall:
         if ( rc != HVM_HCALL_preempted )
         {
             update_guest_eip(); /* Safe: VMCALL */