11859 need swapgs mitigation
Reviewed by: Robert Mustacchi <rm@fingolfin.org>
Reviewed by: Dan McDonald <danmcd@joyent.com>
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Robert Mustacchi <rm@fingolfin.org>

@@ -172,12 +172,13 @@
         cmpq    %r11, 24(%rsp)
         je      1f
         leaq    tr_brand_sys_sysenter(%rip), %r11
         cmpq    %r11, 24(%rsp)
         jne     2f
-1:      SWAPGS
-2:      popq    %r11
+1:      swapgs
+2:      lfence /* swapgs mitigation */
+        popq    %r11
 #endif  /* !__xpv */
 
         INTR_PUSH
 #if defined(__xpv)
         movl    $6, %edi