KVM: Provide callback to get/set control registers in emulator ops.

Use this callback instead of directly call kvm function. Also rename
realmode_(set|get)_cr to emulator_(set|get)_cr since function has nothing
to do with real mode.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/x86/include/asm/kvm_emulate.h

@@ -108,7 +108,8 @@ struct x86_emulate_ops {
 				const void *new,
 				unsigned int bytes,
 				struct kvm_vcpu *vcpu);
-
+	ulong (*get_cr)(int cr, struct kvm_vcpu *vcpu);
+	void (*set_cr)(int cr, ulong val, struct kvm_vcpu *vcpu);
 };
 
 /* Type, address-of, and value of an instruction's operand. */

arch/x86/include/asm/kvm_host.h

@@ -586,8 +586,6 @@ void realmode_lidt(struct kvm_vcpu *vcpu, u16 size, unsigned long address);
 void realmode_lmsw(struct kvm_vcpu *vcpu, unsigned long msw,
 		   unsigned long *rflags);
 
-unsigned long realmode_get_cr(struct kvm_vcpu *vcpu, int cr);
-void realmode_set_cr(struct kvm_vcpu *vcpu, int cr, unsigned long value);
 void kvm_enable_efer_bits(u64);
 int kvm_get_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *data);
 int kvm_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data);

arch/x86/kvm/emulate.c

@@ -2483,7 +2483,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 			break;
 		case 4: /* smsw */
 			c->dst.bytes = 2;
-			c->dst.val = realmode_get_cr(ctxt->vcpu, 0);
+			c->dst.val = ops->get_cr(0, ctxt->vcpu);
 			break;
 		case 6: /* lmsw */
 			realmode_lmsw(ctxt->vcpu, (u16)c->src.val,
@@ -2519,8 +2519,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 	case 0x20: /* mov cr, reg */
 		if (c->modrm_mod != 3)
 			goto cannot_emulate;
-		c->regs[c->modrm_rm] =
-				realmode_get_cr(ctxt->vcpu, c->modrm_reg);
+		c->regs[c->modrm_rm] = ops->get_cr(c->modrm_reg, ctxt->vcpu);
 		c->dst.type = OP_NONE;	/* no writeback */
 		break;
 	case 0x21: /* mov from dr to reg */
@@ -2534,7 +2533,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 	case 0x22: /* mov reg, cr */
 		if (c->modrm_mod != 3)
 			goto cannot_emulate;
-		realmode_set_cr(ctxt->vcpu, c->modrm_reg, c->modrm_val);
+		ops->set_cr(c->modrm_reg, c->modrm_val, ctxt->vcpu);
 		c->dst.type = OP_NONE;
 		break;
 	case 0x23: /* mov from reg to dr */

arch/x86/kvm/x86.c

@@ -3423,12 +3423,70 @@ void kvm_report_emulation_failure(struct kvm_vcpu *vcpu, const char *context)
 }
 EXPORT_SYMBOL_GPL(kvm_report_emulation_failure);
 
+static u64 mk_cr_64(u64 curr_cr, u32 new_val)
+{
+	return (curr_cr & ~((1ULL << 32) - 1)) | new_val;
+}
+
+static unsigned long emulator_get_cr(int cr, struct kvm_vcpu *vcpu)
+{
+	unsigned long value;
+
+	switch (cr) {
+	case 0:
+		value = kvm_read_cr0(vcpu);
+		break;
+	case 2:
+		value = vcpu->arch.cr2;
+		break;
+	case 3:
+		value = vcpu->arch.cr3;
+		break;
+	case 4:
+		value = kvm_read_cr4(vcpu);
+		break;
+	case 8:
+		value = kvm_get_cr8(vcpu);
+		break;
+	default:
+		vcpu_printf(vcpu, "%s: unexpected cr %u\n", __func__, cr);
+		return 0;
+	}
+
+	return value;
+}
+
+static void emulator_set_cr(int cr, unsigned long val, struct kvm_vcpu *vcpu)
+{
+	switch (cr) {
+	case 0:
+		kvm_set_cr0(vcpu, mk_cr_64(kvm_read_cr0(vcpu), val));
+		break;
+	case 2:
+		vcpu->arch.cr2 = val;
+		break;
+	case 3:
+		kvm_set_cr3(vcpu, val);
+		break;
+	case 4:
+		kvm_set_cr4(vcpu, mk_cr_64(kvm_read_cr4(vcpu), val));
+		break;
+	case 8:
+		kvm_set_cr8(vcpu, val & 0xfUL);
+		break;
+	default:
+		vcpu_printf(vcpu, "%s: unexpected cr %u\n", __func__, cr);
+	}
+}
+
 static struct x86_emulate_ops emulate_ops = {
 	.read_std            = kvm_read_guest_virt_system,
 	.fetch               = kvm_fetch_guest_virt,
 	.read_emulated       = emulator_read_emulated,
 	.write_emulated      = emulator_write_emulated,
 	.cmpxchg_emulated    = emulator_cmpxchg_emulated,
+	.get_cr              = emulator_get_cr,
+	.set_cr              = emulator_set_cr,
 };
 
 static void cache_all_regs(struct kvm_vcpu *vcpu)
@@ -4026,11 +4084,6 @@ int kvm_fix_hypercall(struct kvm_vcpu *vcpu)
 	return __emulator_write_emulated(rip, instruction, 3, vcpu, false);
 }
 
-static u64 mk_cr_64(u64 curr_cr, u32 new_val)
-{
-	return (curr_cr & ~((1ULL << 32) - 1)) | new_val;
-}
-
 void realmode_lgdt(struct kvm_vcpu *vcpu, u16 limit, unsigned long base)
 {
 	struct desc_ptr dt = { limit, base };
@@ -4052,57 +4105,6 @@ void realmode_lmsw(struct kvm_vcpu *vcpu, unsigned long msw,
 	*rflags = kvm_get_rflags(vcpu);
 }
 
-unsigned long realmode_get_cr(struct kvm_vcpu *vcpu, int cr)
-{
-	unsigned long value;
-
-	switch (cr) {
-	case 0:
-		value = kvm_read_cr0(vcpu);
-		break;
-	case 2:
-		value = vcpu->arch.cr2;
-		break;
-	case 3:
-		value = vcpu->arch.cr3;
-		break;
-	case 4:
-		value = kvm_read_cr4(vcpu);
-		break;
-	case 8:
-		value = kvm_get_cr8(vcpu);
-		break;
-	default:
-		vcpu_printf(vcpu, "%s: unexpected cr %u\n", __func__, cr);
-		return 0;
-	}
-
-	return value;
-}
-
-void realmode_set_cr(struct kvm_vcpu *vcpu, int cr, unsigned long val)
-{
-	switch (cr) {
-	case 0:
-		kvm_set_cr0(vcpu, mk_cr_64(kvm_read_cr0(vcpu), val));
-		break;
-	case 2:
-		vcpu->arch.cr2 = val;
-		break;
-	case 3:
-		kvm_set_cr3(vcpu, val);
-		break;
-	case 4:
-		kvm_set_cr4(vcpu, mk_cr_64(kvm_read_cr4(vcpu), val));
-		break;
-	case 8:
-		kvm_set_cr8(vcpu, val & 0xfUL);
-		break;
-	default:
-		vcpu_printf(vcpu, "%s: unexpected cr %u\n", __func__, cr);
-	}
-}
-
 static int move_to_next_stateful_cpuid_entry(struct kvm_vcpu *vcpu, int i)
 {
 	struct kvm_cpuid_entry2 *e = &vcpu->arch.cpuid_entries[i];