KVM: PPC: Book3S HV: HFSCR[PREFIX] does not exist

This facility is controlled by FSCR only. Reserved bits should not be
set in the HFSCR register (although it's likely harmless as this
position would not be re-used, and the L0 is forgiving here too).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220122105639.3477407-1-npiggin@gmail.com

arch/powerpc/include/asm/reg.h

@@ -417,7 +417,6 @@
 #define   FSCR_DSCR	__MASK(FSCR_DSCR_LG)
 #define   FSCR_INTR_CAUSE (ASM_CONST(0xFF) << 56)	/* interrupt cause */
 #define SPRN_HFSCR	0xbe	/* HV=1 Facility Status & Control Register */
-#define   HFSCR_PREFIX	__MASK(FSCR_PREFIX_LG)
 #define   HFSCR_MSGP	__MASK(FSCR_MSGP_LG)
 #define   HFSCR_TAR	__MASK(FSCR_TAR_LG)
 #define   HFSCR_EBB	__MASK(FSCR_EBB_LG)

arch/powerpc/kvm/book3s_hv.c

@@ -2834,7 +2834,7 @@ static int kvmppc_core_vcpu_create_hv(struct kvm_vcpu *vcpu)
 	 * to trap and then we emulate them.
 	 */
 	vcpu->arch.hfscr = HFSCR_TAR | HFSCR_EBB | HFSCR_PM | HFSCR_BHRB |
-		HFSCR_DSCR | HFSCR_VECVSX | HFSCR_FP | HFSCR_PREFIX;
+		HFSCR_DSCR | HFSCR_VECVSX | HFSCR_FP;
 	if (cpu_has_feature(CPU_FTR_HVMODE)) {
 		vcpu->arch.hfscr &= mfspr(SPRN_HFSCR);
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM