KVM: MIPS/VZ: Emulate hit CACHE ops for Octeon III

Octeon III doesn't implement the optional GuestCtl0.CG bit to allow
guest mode to execute virtual address based CACHE instructions, so
implement emulation of a few important ones specifically for Octeon III
in response to a GPSI exception.

Currently the main reason to perform these operations is for icache
synchronisation, so they are implemented as a simple icache flush with
local_flush_icache_range().

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <david.daney@cavium.com>
Cc: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

arch/mips/kvm/vz.c

@@ -1105,6 +1105,17 @@ static enum emulation_result kvm_vz_gpsi_cache(union mips_instruction inst,
 	case Index_Writeback_Inv_D:
 		flush_dcache_line_indexed(va);
 		return EMULATE_DONE;
+	case Hit_Invalidate_I:
+	case Hit_Invalidate_D:
+	case Hit_Writeback_Inv_D:
+		if (boot_cpu_type() == CPU_CAVIUM_OCTEON3) {
+			/* We can just flush entire icache */
+			local_flush_icache_range(0, 0);
+			return EMULATE_DONE;
+		}
+
+		/* So far, other platforms support guest hit cache ops */
+		break;
 	default:
 		break;
 	};