KVM: PPC: Book3S HV: Add H_SET_MODE hcall handling

This adds support for the H_SET_MODE hcall.  This hcall is a
multiplexer that has several functions, some of which are called
rarely, and some which are potentially called very frequently.
Here we add support for the functions that set the debug registers
CIABR (Completed Instruction Address Breakpoint Register) and
DAWR/DAWRX (Data Address Watchpoint Register and eXtension),
since they could be updated by the guest as often as every context
switch.

This also adds a kvmppc_power8_compatible() function to test to see
if a guest is compatible with POWER8 or not.  The CIABR and DAWR/X
only exist on POWER8.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index 5dbbb29..85bc8c0 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -279,6 +279,12 @@
 #define H_GET_24X7_DATA		0xF07C
 #define H_GET_PERF_COUNTER_INFO	0xF080
 
+/* Values for 2nd argument to H_SET_MODE */
+#define H_SET_MODE_RESOURCE_SET_CIABR		1
+#define H_SET_MODE_RESOURCE_SET_DAWR		2
+#define H_SET_MODE_RESOURCE_ADDR_TRANS_MODE	3
+#define H_SET_MODE_RESOURCE_LE			4
+
 #ifndef __ASSEMBLY__
 
 /**