MIPS: Probe guest CP0_UserLocal

Probe for presence of guest CP0_UserLocal register and expose via
cpu_guest_has_userlocal. This register is optional pre-r6, so this will
allow KVM to only save/restore/expose the guest CP0_UserLocal register
if it exists.
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

@@ -547,6 +547,9 @@
 #ifndef cpu_guest_has_maar
 #define cpu_guest_has_maar	(cpu_data[0].guest.options & MIPS_CPU_MAAR)
 #endif
+#ifndef cpu_guest_has_userlocal
+#define cpu_guest_has_userlocal	(cpu_data[0].guest.options & MIPS_CPU_ULRI)
+#endif
 
 /*
  * Guest dynamic capabilities

arch/mips/kernel/cpu-probe.c

@@ -1005,7 +1005,8 @@ static inline unsigned int decode_guest_config3(struct cpuinfo_mips *c)
 	unsigned int config3, config3_dyn;
 
 	probe_gc0_config_dyn(config3, config3, config3_dyn,
-			     MIPS_CONF_M | MIPS_CONF3_MSA | MIPS_CONF3_CTXTC);
+			     MIPS_CONF_M | MIPS_CONF3_MSA | MIPS_CONF3_ULRI |
+			     MIPS_CONF3_CTXTC);
 
 	if (config3 & MIPS_CONF3_CTXTC)
 		c->guest.options |= MIPS_CPU_CTXTC;
@@ -1015,6 +1016,9 @@ static inline unsigned int decode_guest_config3(struct cpuinfo_mips *c)
 	if (config3 & MIPS_CONF3_PW)
 		c->guest.options |= MIPS_CPU_HTW;
 
+	if (config3 & MIPS_CONF3_ULRI)
+		c->guest.options |= MIPS_CPU_ULRI;
+
 	if (config3 & MIPS_CONF3_SC)
 		c->guest.options |= MIPS_CPU_SEGMENTS;