Index: kqemu-freebsd.c
@@ -33,6 +33,11 @@
 
 #include <machine/vmparam.h>
 #include <machine/stdarg.h>
+#ifdef __x86_64__
+#include <sys/pcpu.h>
+#include <machine/segments.h>
+#include <machine/tss.h>
+#endif
 
 #include "kqemu-kernel.h"
 
@@ -234,6 +239,19 @@
     va_end(ap);
 }
 
+#ifdef __x86_64__
+/* called with interrupts disabled */
+void CDECL kqemu_tss_workaround(void)
+{
+    int gsel_tss = GSEL(GPROC0_SEL, SEL_KPL);
+
+    gdt_segs[GPROC0_SEL].ssd_base = (long) &common_tss[PCPU_GET(cpuid)];
+    ssdtosyssd(&gdt_segs[GPROC0_SEL],
+       (struct system_segment_descriptor *)&gdt[GPROC0_SEL]);
+    ltr(gsel_tss);
+}
+#endif
+
 struct kqemu_instance { 
 #if __FreeBSD_version >= 500000
     TAILQ_ENTRY(kqemu_instance) kqemu_ent;
Index: common/kernel.c
@@ -1025,6 +1025,9 @@
 #ifdef __x86_64__
     uint16_t saved_ds, saved_es;
     unsigned long fs_base, gs_base;
+#ifdef __FreeBSD__
+    struct kqemu_global_state *g = s->global_state;
+#endif
 #endif
     
 #ifdef PROFILE
@@ -1188,6 +1191,13 @@
             apic_restore_nmi(s, apic_nmi_mask);
         }
         profile_record(s);
+#ifdef __FreeBSD__
+#ifdef __x86_64__
+        spin_lock(&g->lock);
+        kqemu_tss_workaround();
+        spin_unlock(&g->lock);
+#endif
+#endif
 
         if (s->mon_req == MON_REQ_IRQ) {
             struct kqemu_exception_regs *r;
Index: kqemu-kernel.h
@@ -44,4 +44,10 @@
 
 void CDECL kqemu_log(const char *fmt, ...);
 
+#ifdef __FreeBSD__
+#ifdef __x86_64__
+void CDECL kqemu_tss_workaround(void);
+#endif
+#endif
+
 #endif /* KQEMU_KERNEL_H */