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-rw-r--r--arch/i386/xen/enlighten.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/i386/xen/enlighten.c b/arch/i386/xen/enlighten.c
index 031dc1dcf81..42756771b8e 100644
--- a/arch/i386/xen/enlighten.c
+++ b/arch/i386/xen/enlighten.c
@@ -291,6 +291,18 @@ static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
load_TLS_descriptor(t, cpu, 2);
xen_mc_issue(PARAVIRT_LAZY_CPU);
+
+ /*
+ * XXX sleazy hack: If we're being called in a lazy-cpu zone,
+ * it means we're in a context switch, and %gs has just been
+ * saved. This means we can zero it out to prevent faults on
+ * exit from the hypervisor if the next process has no %gs.
+ * Either way, it has been saved, and the new value will get
+ * loaded properly. This will go away as soon as Xen has been
+ * modified to not save/restore %gs for normal hypercalls.
+ */
+ if (xen_get_lazy_mode() == PARAVIRT_LAZY_CPU)
+ loadsegment(gs, 0);
}
static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,