KVM: MIPS/VZ: Support guest CP0_BadInstr[P]

Add support for VZ guest CP0_BadInstr and CP0_BadInstrP registers, as
found on most VZ capable cores. These guest registers need context
switching, and exposing via the KVM ioctl API when they are present.

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: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-doc@vger.kernel.org

Documentation/virtual/kvm/api.txt

@@ -2079,6 +2079,8 @@ registers, find a list below:
   MIPS  | KVM_REG_MIPS_CP0_WIRED        | 32
   MIPS  | KVM_REG_MIPS_CP0_HWRENA       | 32
   MIPS  | KVM_REG_MIPS_CP0_BADVADDR     | 64
+  MIPS  | KVM_REG_MIPS_CP0_BADINSTR     | 32
+  MIPS  | KVM_REG_MIPS_CP0_BADINSTRP    | 32
   MIPS  | KVM_REG_MIPS_CP0_COUNT        | 32
   MIPS  | KVM_REG_MIPS_CP0_ENTRYHI      | 64
   MIPS  | KVM_REG_MIPS_CP0_COMPARE      | 32

arch/mips/include/asm/kvm_host.h

@@ -40,6 +40,8 @@
 #define KVM_REG_MIPS_CP0_WIRED		MIPS_CP0_32(6, 0)
 #define KVM_REG_MIPS_CP0_HWRENA		MIPS_CP0_32(7, 0)
 #define KVM_REG_MIPS_CP0_BADVADDR	MIPS_CP0_64(8, 0)
+#define KVM_REG_MIPS_CP0_BADINSTR	MIPS_CP0_32(8, 1)
+#define KVM_REG_MIPS_CP0_BADINSTRP	MIPS_CP0_32(8, 2)
 #define KVM_REG_MIPS_CP0_COUNT		MIPS_CP0_32(9, 0)
 #define KVM_REG_MIPS_CP0_ENTRYHI	MIPS_CP0_64(10, 0)
 #define KVM_REG_MIPS_CP0_COMPARE	MIPS_CP0_32(11, 0)
@@ -669,6 +671,8 @@ __BUILD_KVM_RW_HW(pagegrain,      32, MIPS_CP0_TLB_PG_MASK,  1)
 __BUILD_KVM_RW_HW(wired,          32, MIPS_CP0_TLB_WIRED,    0)
 __BUILD_KVM_RW_HW(hwrena,         32, MIPS_CP0_HWRENA,       0)
 __BUILD_KVM_RW_HW(badvaddr,       l,  MIPS_CP0_BAD_VADDR,    0)
+__BUILD_KVM_RW_HW(badinstr,       32, MIPS_CP0_BAD_VADDR,    1)
+__BUILD_KVM_RW_HW(badinstrp,      32, MIPS_CP0_BAD_VADDR,    2)
 __BUILD_KVM_RW_SW(count,          32, MIPS_CP0_COUNT,        0)
 __BUILD_KVM_RW_HW(entryhi,        l,  MIPS_CP0_TLB_HI,       0)
 __BUILD_KVM_RW_HW(compare,        32, MIPS_CP0_COMPARE,      0)

arch/mips/kvm/vz.c

@@ -1221,6 +1221,10 @@ static unsigned long kvm_vz_num_regs(struct kvm_vcpu *vcpu)
 	ret = ARRAY_SIZE(kvm_vz_get_one_regs);
 	if (cpu_guest_has_userlocal)
 		++ret;
+	if (cpu_guest_has_badinstr)
+		++ret;
+	if (cpu_guest_has_badinstrp)
+		++ret;
 	ret += __arch_hweight8(cpu_data[0].guest.kscratch_mask);
 
 	return ret;
@@ -1242,6 +1246,18 @@ static int kvm_vz_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices)
 			return -EFAULT;
 		++indices;
 	}
+	if (cpu_guest_has_badinstr) {
+		index = KVM_REG_MIPS_CP0_BADINSTR;
+		if (copy_to_user(indices, &index, sizeof(index)))
+			return -EFAULT;
+		++indices;
+	}
+	if (cpu_guest_has_badinstrp) {
+		index = KVM_REG_MIPS_CP0_BADINSTRP;
+		if (copy_to_user(indices, &index, sizeof(index)))
+			return -EFAULT;
+		++indices;
+	}
 	for (i = 0; i < 6; ++i) {
 		if (!cpu_guest_has_kscr(i + 2))
 			continue;
@@ -1327,6 +1343,16 @@ static int kvm_vz_get_one_reg(struct kvm_vcpu *vcpu,
 	case KVM_REG_MIPS_CP0_BADVADDR:
 		*v = (long)read_gc0_badvaddr();
 		break;
+	case KVM_REG_MIPS_CP0_BADINSTR:
+		if (!cpu_guest_has_badinstr)
+			return -EINVAL;
+		*v = read_gc0_badinstr();
+		break;
+	case KVM_REG_MIPS_CP0_BADINSTRP:
+		if (!cpu_guest_has_badinstrp)
+			return -EINVAL;
+		*v = read_gc0_badinstrp();
+		break;
 	case KVM_REG_MIPS_CP0_COUNT:
 		*v = kvm_mips_read_count(vcpu);
 		break;
@@ -1472,6 +1498,16 @@ static int kvm_vz_set_one_reg(struct kvm_vcpu *vcpu,
 	case KVM_REG_MIPS_CP0_BADVADDR:
 		write_gc0_badvaddr(v);
 		break;
+	case KVM_REG_MIPS_CP0_BADINSTR:
+		if (!cpu_guest_has_badinstr)
+			return -EINVAL;
+		write_gc0_badinstr(v);
+		break;
+	case KVM_REG_MIPS_CP0_BADINSTRP:
+		if (!cpu_guest_has_badinstrp)
+			return -EINVAL;
+		write_gc0_badinstrp(v);
+		break;
 	case KVM_REG_MIPS_CP0_COUNT:
 		kvm_mips_write_count(vcpu, v);
 		break;
@@ -1871,6 +1907,11 @@ static int kvm_vz_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 			kvm_restore_gc0_kscratch6(cop0);
 	}
 
+	if (cpu_guest_has_badinstr)
+		kvm_restore_gc0_badinstr(cop0);
+	if (cpu_guest_has_badinstrp)
+		kvm_restore_gc0_badinstrp(cop0);
+
 	/* restore Root.GuestCtl2 from unused Guest guestctl2 register */
 	if (cpu_has_guestctl2)
 		write_c0_guestctl2(
@@ -1945,6 +1986,11 @@ static int kvm_vz_vcpu_put(struct kvm_vcpu *vcpu, int cpu)
 			kvm_save_gc0_kscratch6(cop0);
 	}
 
+	if (cpu_guest_has_badinstr)
+		kvm_save_gc0_badinstr(cop0);
+	if (cpu_guest_has_badinstrp)
+		kvm_save_gc0_badinstrp(cop0);
+
 	kvm_vz_save_timer(vcpu);
 
 	/* save Root.GuestCtl2 in unused Guest guestctl2 register */