KVM: s390: Fix possible host kernel bug on lctl(g) handling
[linux-2.6.git] / arch / s390 / kvm / intercept.c
1 /*
2  * intercept.c - in-kernel handling for sie intercepts
3  *
4  * Copyright IBM Corp. 2008
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License (version 2 only)
8  * as published by the Free Software Foundation.
9  *
10  *    Author(s): Carsten Otte <cotte@de.ibm.com>
11  *               Christian Borntraeger <borntraeger@de.ibm.com>
12  */
13
14 #include <linux/kvm_host.h>
15 #include <linux/errno.h>
16 #include <linux/pagemap.h>
17
18 #include <asm/kvm_host.h>
19
20 #include "kvm-s390.h"
21 #include "gaccess.h"
22
23 static int handle_lctlg(struct kvm_vcpu *vcpu)
24 {
25         int reg1 = (vcpu->arch.sie_block->ipa & 0x00f0) >> 4;
26         int reg3 = vcpu->arch.sie_block->ipa & 0x000f;
27         int base2 = vcpu->arch.sie_block->ipb >> 28;
28         int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16) +
29                         ((vcpu->arch.sie_block->ipb & 0xff00) << 4);
30         u64 useraddr;
31         int reg, rc;
32
33         vcpu->stat.instruction_lctlg++;
34         if ((vcpu->arch.sie_block->ipb & 0xff) != 0x2f)
35                 return -ENOTSUPP;
36
37         useraddr = disp2;
38         if (base2)
39                 useraddr += vcpu->arch.guest_gprs[base2];
40
41         if (useraddr & 7)
42                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
43
44         reg = reg1;
45
46         VCPU_EVENT(vcpu, 5, "lctlg r1:%x, r3:%x,b2:%x,d2:%x", reg1, reg3, base2,
47                    disp2);
48
49         do {
50                 rc = get_guest_u64(vcpu, useraddr,
51                                    &vcpu->arch.sie_block->gcr[reg]);
52                 if (rc == -EFAULT) {
53                         kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
54                         break;
55                 }
56                 useraddr += 8;
57                 if (reg == reg3)
58                         break;
59                 reg = (reg + 1) % 16;
60         } while (1);
61         return 0;
62 }
63
64 static int handle_lctl(struct kvm_vcpu *vcpu)
65 {
66         int reg1 = (vcpu->arch.sie_block->ipa & 0x00f0) >> 4;
67         int reg3 = vcpu->arch.sie_block->ipa & 0x000f;
68         int base2 = vcpu->arch.sie_block->ipb >> 28;
69         int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
70         u64 useraddr;
71         u32 val = 0;
72         int reg, rc;
73
74         vcpu->stat.instruction_lctl++;
75
76         useraddr = disp2;
77         if (base2)
78                 useraddr += vcpu->arch.guest_gprs[base2];
79
80         if (useraddr & 3)
81                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
82
83         VCPU_EVENT(vcpu, 5, "lctl r1:%x, r3:%x,b2:%x,d2:%x", reg1, reg3, base2,
84                    disp2);
85
86         reg = reg1;
87         do {
88                 rc = get_guest_u32(vcpu, useraddr, &val);
89                 if (rc == -EFAULT) {
90                         kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
91                         break;
92                 }
93                 vcpu->arch.sie_block->gcr[reg] &= 0xffffffff00000000ul;
94                 vcpu->arch.sie_block->gcr[reg] |= val;
95                 useraddr += 4;
96                 if (reg == reg3)
97                         break;
98                 reg = (reg + 1) % 16;
99         } while (1);
100         return 0;
101 }
102
103 static intercept_handler_t instruction_handlers[256] = {
104         [0x83] = kvm_s390_handle_diag,
105         [0xae] = kvm_s390_handle_sigp,
106         [0xb2] = kvm_s390_handle_priv,
107         [0xb7] = handle_lctl,
108         [0xeb] = handle_lctlg,
109 };
110
111 static int handle_noop(struct kvm_vcpu *vcpu)
112 {
113         switch (vcpu->arch.sie_block->icptcode) {
114         case 0x0:
115                 vcpu->stat.exit_null++;
116                 break;
117         case 0x10:
118                 vcpu->stat.exit_external_request++;
119                 break;
120         case 0x14:
121                 vcpu->stat.exit_external_interrupt++;
122                 break;
123         default:
124                 break; /* nothing */
125         }
126         return 0;
127 }
128
129 static int handle_stop(struct kvm_vcpu *vcpu)
130 {
131         int rc;
132
133         vcpu->stat.exit_stop_request++;
134         atomic_clear_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
135         spin_lock_bh(&vcpu->arch.local_int.lock);
136         if (vcpu->arch.local_int.action_bits & ACTION_STORE_ON_STOP) {
137                 vcpu->arch.local_int.action_bits &= ~ACTION_STORE_ON_STOP;
138                 rc = __kvm_s390_vcpu_store_status(vcpu,
139                                                   KVM_S390_STORE_STATUS_NOADDR);
140                 if (rc >= 0)
141                         rc = -ENOTSUPP;
142         }
143
144         if (vcpu->arch.local_int.action_bits & ACTION_STOP_ON_STOP) {
145                 vcpu->arch.local_int.action_bits &= ~ACTION_STOP_ON_STOP;
146                 VCPU_EVENT(vcpu, 3, "%s", "cpu stopped");
147                 rc = -ENOTSUPP;
148         } else
149                 rc = 0;
150         spin_unlock_bh(&vcpu->arch.local_int.lock);
151         return rc;
152 }
153
154 static int handle_validity(struct kvm_vcpu *vcpu)
155 {
156         int viwhy = vcpu->arch.sie_block->ipb >> 16;
157         vcpu->stat.exit_validity++;
158         if (viwhy == 0x37) {
159                 fault_in_pages_writeable((char __user *)
160                                          vcpu->kvm->arch.guest_origin +
161                                          vcpu->arch.sie_block->prefix,
162                                          PAGE_SIZE);
163                 return 0;
164         }
165         VCPU_EVENT(vcpu, 2, "unhandled validity intercept code %d",
166                    viwhy);
167         return -ENOTSUPP;
168 }
169
170 static int handle_instruction(struct kvm_vcpu *vcpu)
171 {
172         intercept_handler_t handler;
173
174         vcpu->stat.exit_instruction++;
175         handler = instruction_handlers[vcpu->arch.sie_block->ipa >> 8];
176         if (handler)
177                 return handler(vcpu);
178         return -ENOTSUPP;
179 }
180
181 static int handle_prog(struct kvm_vcpu *vcpu)
182 {
183         vcpu->stat.exit_program_interruption++;
184         return kvm_s390_inject_program_int(vcpu, vcpu->arch.sie_block->iprcc);
185 }
186
187 static int handle_instruction_and_prog(struct kvm_vcpu *vcpu)
188 {
189         int rc, rc2;
190
191         vcpu->stat.exit_instr_and_program++;
192         rc = handle_instruction(vcpu);
193         rc2 = handle_prog(vcpu);
194
195         if (rc == -ENOTSUPP)
196                 vcpu->arch.sie_block->icptcode = 0x04;
197         if (rc)
198                 return rc;
199         return rc2;
200 }
201
202 static const intercept_handler_t intercept_funcs[0x48 >> 2] = {
203         [0x00 >> 2] = handle_noop,
204         [0x04 >> 2] = handle_instruction,
205         [0x08 >> 2] = handle_prog,
206         [0x0C >> 2] = handle_instruction_and_prog,
207         [0x10 >> 2] = handle_noop,
208         [0x14 >> 2] = handle_noop,
209         [0x1C >> 2] = kvm_s390_handle_wait,
210         [0x20 >> 2] = handle_validity,
211         [0x28 >> 2] = handle_stop,
212 };
213
214 int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu)
215 {
216         intercept_handler_t func;
217         u8 code = vcpu->arch.sie_block->icptcode;
218
219         if (code & 3 || code > 0x48)
220                 return -ENOTSUPP;
221         func = intercept_funcs[code >> 2];
222         if (func)
223                 return func(vcpu);
224         return -ENOTSUPP;
225 }