MIPS: KVM: Add Config4/5 and writing of Config registers

Add Config4 and Config5 co-processor 0 registers, and add capability to
write the Config1, Config3, Config4, and Config5 registers using the KVM
API.

Only supported bits can be written, to minimise the chances of the guest
being given a configuration from e.g. QEMU that is inconsistent with
that being emulated, and as such the handling is in trap_emul.c as it
may need to be different for VZ. Currently the only modification
permitted is to make Config4 and Config5 exist via the M bits, but other
bits will be added for FPU and MSA support in future patches.

Care should be taken by userland not to change bits without fully
handling the possible extra state that may then exist and which the
guest may begin to use and depend on.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 6996447..3f58ee1 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -48,6 +48,8 @@
 #define KVM_REG_MIPS_CP0_CONFIG1	MIPS_CP0_32(16, 1)
 #define KVM_REG_MIPS_CP0_CONFIG2	MIPS_CP0_32(16, 2)
 #define KVM_REG_MIPS_CP0_CONFIG3	MIPS_CP0_32(16, 3)
+#define KVM_REG_MIPS_CP0_CONFIG4	MIPS_CP0_32(16, 4)
+#define KVM_REG_MIPS_CP0_CONFIG5	MIPS_CP0_32(16, 5)
 #define KVM_REG_MIPS_CP0_CONFIG7	MIPS_CP0_32(16, 7)
 #define KVM_REG_MIPS_CP0_XCONTEXT	MIPS_CP0_64(20, 0)
 #define KVM_REG_MIPS_CP0_ERROREPC	MIPS_CP0_64(30, 0)
@@ -209,6 +211,8 @@
 #define MIPS_CP0_CONFIG1_SEL	1
 #define MIPS_CP0_CONFIG2_SEL	2
 #define MIPS_CP0_CONFIG3_SEL	3
+#define MIPS_CP0_CONFIG4_SEL	4
+#define MIPS_CP0_CONFIG5_SEL	5
 
 /* Config0 register bits */
 #define CP0C0_M			31
@@ -461,11 +465,15 @@
 #define kvm_read_c0_guest_config1(cop0)		(cop0->reg[MIPS_CP0_CONFIG][1])
 #define kvm_read_c0_guest_config2(cop0)		(cop0->reg[MIPS_CP0_CONFIG][2])
 #define kvm_read_c0_guest_config3(cop0)		(cop0->reg[MIPS_CP0_CONFIG][3])
+#define kvm_read_c0_guest_config4(cop0)		(cop0->reg[MIPS_CP0_CONFIG][4])
+#define kvm_read_c0_guest_config5(cop0)		(cop0->reg[MIPS_CP0_CONFIG][5])
 #define kvm_read_c0_guest_config7(cop0)		(cop0->reg[MIPS_CP0_CONFIG][7])
 #define kvm_write_c0_guest_config(cop0, val)	(cop0->reg[MIPS_CP0_CONFIG][0] = (val))
 #define kvm_write_c0_guest_config1(cop0, val)	(cop0->reg[MIPS_CP0_CONFIG][1] = (val))
 #define kvm_write_c0_guest_config2(cop0, val)	(cop0->reg[MIPS_CP0_CONFIG][2] = (val))
 #define kvm_write_c0_guest_config3(cop0, val)	(cop0->reg[MIPS_CP0_CONFIG][3] = (val))
+#define kvm_write_c0_guest_config4(cop0, val)	(cop0->reg[MIPS_CP0_CONFIG][4] = (val))
+#define kvm_write_c0_guest_config5(cop0, val)	(cop0->reg[MIPS_CP0_CONFIG][5] = (val))
 #define kvm_write_c0_guest_config7(cop0, val)	(cop0->reg[MIPS_CP0_CONFIG][7] = (val))
 #define kvm_read_c0_guest_errorepc(cop0)	(cop0->reg[MIPS_CP0_ERROR_PC][0])
 #define kvm_write_c0_guest_errorepc(cop0, val)	(cop0->reg[MIPS_CP0_ERROR_PC][0] = (val))
@@ -735,6 +743,11 @@
 					    struct kvm_run *run,
 					    struct kvm_vcpu *vcpu);
 
+unsigned int kvm_mips_config1_wrmask(struct kvm_vcpu *vcpu);
+unsigned int kvm_mips_config3_wrmask(struct kvm_vcpu *vcpu);
+unsigned int kvm_mips_config4_wrmask(struct kvm_vcpu *vcpu);
+unsigned int kvm_mips_config5_wrmask(struct kvm_vcpu *vcpu);
+
 /* Dynamic binary translation */
 extern int kvm_mips_trans_cache_index(uint32_t inst, uint32_t *opc,
 				      struct kvm_vcpu *vcpu);