KVM: PPC: Book3S HV: Enable use of the new XIVE "single escalation" feature

That feature, provided by Power9 DD2.0 and later, when supported
by newer OPAL versions, allows us to sacrifice a queue (priority 7)
in favor of merging all the escalation interrupts of the queues
of a single VP into a single interrupt.

This reduces the number of host interrupts used up by KVM guests
especially when those guests use multiple priorities.

It will also enable a future change to control the masking of the
escalation interrupts more precisely to avoid spurious ones.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
diff --git a/arch/powerpc/include/asm/xive.h b/arch/powerpc/include/asm/xive.h
index b619a55..e602903 100644
--- a/arch/powerpc/include/asm/xive.h
+++ b/arch/powerpc/include/asm/xive.h
@@ -111,9 +111,10 @@
 
 extern void xive_native_sync_source(u32 hw_irq);
 extern bool is_xive_irq(struct irq_chip *chip);
-extern int xive_native_enable_vp(u32 vp_id);
+extern int xive_native_enable_vp(u32 vp_id, bool single_escalation);
 extern int xive_native_disable_vp(u32 vp_id);
 extern int xive_native_get_vp_info(u32 vp_id, u32 *out_cam_id, u32 *out_chip_id);
+extern bool xive_native_has_single_escalation(void);
 
 #else