powerpc/powernv: Define and set POWER9 HFSCR doorbell bit

Define and set the POWER9 HFSCR doorbell bit so that guests can use
msgsndp.

ISA 3.0 calls this MSGP, so name it accordingly in the code.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/reg.h

@@ -309,6 +309,7 @@
 
 /* HFSCR and FSCR bit numbers are the same */
 #define FSCR_LM_LG	11	/* Enable Load Monitor Registers */
+#define FSCR_MSGP_LG	10	/* Enable MSGP */
 #define FSCR_TAR_LG	8	/* Enable Target Address Register */
 #define FSCR_EBB_LG	7	/* Enable Event Based Branching */
 #define FSCR_TM_LG	5	/* Enable Transactional Memory */
@@ -324,6 +325,7 @@
 #define   FSCR_DSCR	__MASK(FSCR_DSCR_LG)
 #define SPRN_HFSCR	0xbe	/* HV=1 Facility Status & Control Register */
 #define   HFSCR_LM	__MASK(FSCR_LM_LG)
+#define   HFSCR_MSGP	__MASK(FSCR_MSGP_LG)
 #define   HFSCR_TAR	__MASK(FSCR_TAR_LG)
 #define   HFSCR_EBB	__MASK(FSCR_EBB_LG)
 #define   HFSCR_TM	__MASK(FSCR_TM_LG)

arch/powerpc/kernel/cpu_setup_power.S

@@ -174,7 +174,7 @@ __init_FSCR:
 __init_HFSCR:
 	mfspr	r3,SPRN_HFSCR
 	ori	r3,r3,HFSCR_TAR|HFSCR_TM|HFSCR_BHRB|HFSCR_PM|\
-		      HFSCR_DSCR|HFSCR_VECVSX|HFSCR_FP|HFSCR_EBB
+		      HFSCR_DSCR|HFSCR_VECVSX|HFSCR_FP|HFSCR_EBB|HFSCR_MSGP
 	mtspr	SPRN_HFSCR,r3
 	blr