MIPS: Probe guest MVH

Probe for availablility of M{T,F}HC0 instructions used with e.g. XPA in
the VZ guest context, and make it available via cpu_guest_has_mvh. This
will be helpful in properly emulating the MAAR registers in KVM for MIPS
VZ.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

arch/mips/include/asm/cpu-features.h

@@ -532,6 +532,9 @@
 #ifndef cpu_guest_has_htw
 #define cpu_guest_has_htw	(cpu_data[0].guest.options & MIPS_CPU_HTW)
 #endif
+#ifndef cpu_guest_has_mvh
+#define cpu_guest_has_mvh	(cpu_data[0].guest.options & MIPS_CPU_MVH)
+#endif
 #ifndef cpu_guest_has_msa
 #define cpu_guest_has_msa	(cpu_data[0].guest.ases & MIPS_ASE_MSA)
 #endif

arch/mips/kernel/cpu-probe.c

@@ -1057,7 +1057,7 @@ static inline unsigned int decode_guest_config5(struct cpuinfo_mips *c)
 	unsigned int config5, config5_dyn;
 
 	probe_gc0_config_dyn(config5, config5, config5_dyn,
-			 MIPS_CONF_M | MIPS_CONF5_MRP);
+			 MIPS_CONF_M | MIPS_CONF5_MVH | MIPS_CONF5_MRP);
 
 	if (config5 & MIPS_CONF5_MRP)
 		c->guest.options |= MIPS_CPU_MAAR;
@@ -1067,6 +1067,9 @@ static inline unsigned int decode_guest_config5(struct cpuinfo_mips *c)
 	if (config5 & MIPS_CONF5_LLB)
 		c->guest.options |= MIPS_CPU_RW_LLB;
 
+	if (config5 & MIPS_CONF5_MVH)
+		c->guest.options |= MIPS_CPU_MVH;
+
 	if (config5 & MIPS_CONF_M)
 		c->guest.conf |= BIT(6);
 	return config5 & MIPS_CONF_M;