x86/paravirt: make arch_flush_lazy_mmu/cpu disable preemption
Impact: avoid access to percpu vars in preempible context
They are intended to be used whenever there's the possibility
that there's some stale state which is going to be overwritten
with a queued update, or to force a state change when we may be
in lazy mode. Either way, we could end up calling it with
preemption enabled, so wrap the functions in their own little
preempt-disable section so they can be safely called in any
context (though preemption should never be enabled if we're actually
in a lazy state).
(Move out of line to avoid #include dependencies.)
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index e4c8fb6..dcba6c5 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -268,6 +268,30 @@
return __get_cpu_var(paravirt_lazy_mode);
}
+void arch_flush_lazy_mmu_mode(void)
+{
+ preempt_disable();
+
+ if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
+ arch_leave_lazy_mmu_mode();
+ arch_enter_lazy_mmu_mode();
+ }
+
+ preempt_enable();
+}
+
+void arch_flush_lazy_cpu_mode(void)
+{
+ preempt_disable();
+
+ if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
+ arch_leave_lazy_cpu_mode();
+ arch_enter_lazy_cpu_mode();
+ }
+
+ preempt_enable();
+}
+
struct pv_info pv_info = {
.name = "bare hardware",
.paravirt_enabled = 0,