2 * Copyright (C) 2012 - ARM Ltd
3 * Author: Marc Zyngier <marc.zyngier@arm.com>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 #include <linux/preempt.h>
19 #include <linux/kvm_host.h>
20 #include <linux/wait.h>
22 #include <asm/cputype.h>
23 #include <asm/kvm_emulate.h>
24 #include <asm/kvm_psci.h>
25 #include <asm/kvm_host.h>
27 #include <uapi/linux/psci.h>
30 * This is an implementation of the Power State Coordination Interface
31 * as described in ARM document number ARM DEN 0022A.
34 #define AFFINITY_MASK(level) ~((0x1UL << ((level) * MPIDR_LEVEL_BITS)) - 1)
36 static unsigned long psci_affinity_mask(unsigned long affinity_level
)
38 if (affinity_level
<= 3)
39 return MPIDR_HWID_BITMASK
& AFFINITY_MASK(affinity_level
);
44 static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu
*vcpu
)
47 * NOTE: For simplicity, we make VCPU suspend emulation to be
48 * same-as WFI (Wait-for-interrupt) emulation.
50 * This means for KVM the wakeup events are interrupts and
51 * this is consistent with intended use of StateID as described
52 * in section 5.4.1 of PSCI v0.2 specification (ARM DEN 0022A).
54 * Further, we also treat power-down request to be same as
55 * stand-by request as-per section 5.4.2 clause 3 of PSCI v0.2
56 * specification (ARM DEN 0022A). This means all suspend states
57 * for KVM will preserve the register state.
60 kvm_clear_request(KVM_REQ_UNHALT
, vcpu
);
62 return PSCI_RET_SUCCESS
;
65 static void kvm_psci_vcpu_off(struct kvm_vcpu
*vcpu
)
67 vcpu
->arch
.power_off
= true;
68 kvm_make_request(KVM_REQ_SLEEP
, vcpu
);
72 static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu
*source_vcpu
)
74 struct kvm
*kvm
= source_vcpu
->kvm
;
75 struct kvm_vcpu
*vcpu
= NULL
;
76 struct swait_queue_head
*wq
;
78 unsigned long context_id
;
79 phys_addr_t target_pc
;
81 cpu_id
= vcpu_get_reg(source_vcpu
, 1) & MPIDR_HWID_BITMASK
;
82 if (vcpu_mode_is_32bit(source_vcpu
))
85 vcpu
= kvm_mpidr_to_vcpu(kvm
, cpu_id
);
88 * Make sure the caller requested a valid CPU and that the CPU is
92 return PSCI_RET_INVALID_PARAMS
;
93 if (!vcpu
->arch
.power_off
) {
94 if (kvm_psci_version(source_vcpu
) != KVM_ARM_PSCI_0_1
)
95 return PSCI_RET_ALREADY_ON
;
97 return PSCI_RET_INVALID_PARAMS
;
100 target_pc
= vcpu_get_reg(source_vcpu
, 2);
101 context_id
= vcpu_get_reg(source_vcpu
, 3);
103 kvm_reset_vcpu(vcpu
);
105 /* Gracefully handle Thumb2 entry point */
106 if (vcpu_mode_is_32bit(vcpu
) && (target_pc
& 1)) {
107 target_pc
&= ~((phys_addr_t
) 1);
108 vcpu_set_thumb(vcpu
);
111 /* Propagate caller endianness */
112 if (kvm_vcpu_is_be(source_vcpu
))
113 kvm_vcpu_set_be(vcpu
);
115 *vcpu_pc(vcpu
) = target_pc
;
117 * NOTE: We always update r0 (or x0) because for PSCI v0.1
118 * the general puspose registers are undefined upon CPU_ON.
120 vcpu_set_reg(vcpu
, 0, context_id
);
121 vcpu
->arch
.power_off
= false;
122 smp_mb(); /* Make sure the above is visible */
124 wq
= kvm_arch_vcpu_wq(vcpu
);
127 return PSCI_RET_SUCCESS
;
130 static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu
*vcpu
)
132 int i
, matching_cpus
= 0;
134 unsigned long target_affinity
;
135 unsigned long target_affinity_mask
;
136 unsigned long lowest_affinity_level
;
137 struct kvm
*kvm
= vcpu
->kvm
;
138 struct kvm_vcpu
*tmp
;
140 target_affinity
= vcpu_get_reg(vcpu
, 1);
141 lowest_affinity_level
= vcpu_get_reg(vcpu
, 2);
143 /* Determine target affinity mask */
144 target_affinity_mask
= psci_affinity_mask(lowest_affinity_level
);
145 if (!target_affinity_mask
)
146 return PSCI_RET_INVALID_PARAMS
;
148 /* Ignore other bits of target affinity */
149 target_affinity
&= target_affinity_mask
;
152 * If one or more VCPU matching target affinity are running
155 kvm_for_each_vcpu(i
, tmp
, kvm
) {
156 mpidr
= kvm_vcpu_get_mpidr_aff(tmp
);
157 if ((mpidr
& target_affinity_mask
) == target_affinity
) {
159 if (!tmp
->arch
.power_off
)
160 return PSCI_0_2_AFFINITY_LEVEL_ON
;
165 return PSCI_RET_INVALID_PARAMS
;
167 return PSCI_0_2_AFFINITY_LEVEL_OFF
;
170 static void kvm_prepare_system_event(struct kvm_vcpu
*vcpu
, u32 type
)
173 struct kvm_vcpu
*tmp
;
176 * The KVM ABI specifies that a system event exit may call KVM_RUN
177 * again and may perform shutdown/reboot at a later time that when the
178 * actual request is made. Since we are implementing PSCI and a
179 * caller of PSCI reboot and shutdown expects that the system shuts
180 * down or reboots immediately, let's make sure that VCPUs are not run
181 * after this call is handled and before the VCPUs have been
184 kvm_for_each_vcpu(i
, tmp
, vcpu
->kvm
)
185 tmp
->arch
.power_off
= true;
186 kvm_make_all_cpus_request(vcpu
->kvm
, KVM_REQ_SLEEP
);
188 memset(&vcpu
->run
->system_event
, 0, sizeof(vcpu
->run
->system_event
));
189 vcpu
->run
->system_event
.type
= type
;
190 vcpu
->run
->exit_reason
= KVM_EXIT_SYSTEM_EVENT
;
193 static void kvm_psci_system_off(struct kvm_vcpu
*vcpu
)
195 kvm_prepare_system_event(vcpu
, KVM_SYSTEM_EVENT_SHUTDOWN
);
198 static void kvm_psci_system_reset(struct kvm_vcpu
*vcpu
)
200 kvm_prepare_system_event(vcpu
, KVM_SYSTEM_EVENT_RESET
);
203 int kvm_psci_version(struct kvm_vcpu
*vcpu
)
205 if (test_bit(KVM_ARM_VCPU_PSCI_0_2
, vcpu
->arch
.features
))
206 return KVM_ARM_PSCI_0_2
;
208 return KVM_ARM_PSCI_0_1
;
211 static int kvm_psci_0_2_call(struct kvm_vcpu
*vcpu
)
213 struct kvm
*kvm
= vcpu
->kvm
;
214 unsigned long psci_fn
= vcpu_get_reg(vcpu
, 0) & ~((u32
) 0);
219 case PSCI_0_2_FN_PSCI_VERSION
:
221 * Bits[31:16] = Major Version = 0
222 * Bits[15:0] = Minor Version = 2
226 case PSCI_0_2_FN_CPU_SUSPEND
:
227 case PSCI_0_2_FN64_CPU_SUSPEND
:
228 val
= kvm_psci_vcpu_suspend(vcpu
);
230 case PSCI_0_2_FN_CPU_OFF
:
231 kvm_psci_vcpu_off(vcpu
);
232 val
= PSCI_RET_SUCCESS
;
234 case PSCI_0_2_FN_CPU_ON
:
235 case PSCI_0_2_FN64_CPU_ON
:
236 mutex_lock(&kvm
->lock
);
237 val
= kvm_psci_vcpu_on(vcpu
);
238 mutex_unlock(&kvm
->lock
);
240 case PSCI_0_2_FN_AFFINITY_INFO
:
241 case PSCI_0_2_FN64_AFFINITY_INFO
:
242 val
= kvm_psci_vcpu_affinity_info(vcpu
);
244 case PSCI_0_2_FN_MIGRATE_INFO_TYPE
:
246 * Trusted OS is MP hence does not require migration
248 * Trusted OS is not present
250 val
= PSCI_0_2_TOS_MP
;
252 case PSCI_0_2_FN_SYSTEM_OFF
:
253 kvm_psci_system_off(vcpu
);
255 * We should'nt be going back to guest VCPU after
256 * receiving SYSTEM_OFF request.
258 * If user space accidently/deliberately resumes
259 * guest VCPU after SYSTEM_OFF request then guest
260 * VCPU should see internal failure from PSCI return
261 * value. To achieve this, we preload r0 (or x0) with
262 * PSCI return value INTERNAL_FAILURE.
264 val
= PSCI_RET_INTERNAL_FAILURE
;
267 case PSCI_0_2_FN_SYSTEM_RESET
:
268 kvm_psci_system_reset(vcpu
);
270 * Same reason as SYSTEM_OFF for preloading r0 (or x0)
271 * with PSCI return value INTERNAL_FAILURE.
273 val
= PSCI_RET_INTERNAL_FAILURE
;
277 val
= PSCI_RET_NOT_SUPPORTED
;
281 vcpu_set_reg(vcpu
, 0, val
);
285 static int kvm_psci_0_1_call(struct kvm_vcpu
*vcpu
)
287 struct kvm
*kvm
= vcpu
->kvm
;
288 unsigned long psci_fn
= vcpu_get_reg(vcpu
, 0) & ~((u32
) 0);
292 case KVM_PSCI_FN_CPU_OFF
:
293 kvm_psci_vcpu_off(vcpu
);
294 val
= PSCI_RET_SUCCESS
;
296 case KVM_PSCI_FN_CPU_ON
:
297 mutex_lock(&kvm
->lock
);
298 val
= kvm_psci_vcpu_on(vcpu
);
299 mutex_unlock(&kvm
->lock
);
302 val
= PSCI_RET_NOT_SUPPORTED
;
306 vcpu_set_reg(vcpu
, 0, val
);
311 * kvm_psci_call - handle PSCI call if r0 value is in range
312 * @vcpu: Pointer to the VCPU struct
314 * Handle PSCI calls from guests through traps from HVC instructions.
315 * The calling convention is similar to SMC calls to the secure world
316 * where the function number is placed in r0.
318 * This function returns: > 0 (success), 0 (success but exit to user
319 * space), and < 0 (errors)
322 * -EINVAL: Unrecognized PSCI function
324 int kvm_psci_call(struct kvm_vcpu
*vcpu
)
326 switch (kvm_psci_version(vcpu
)) {
327 case KVM_ARM_PSCI_0_2
:
328 return kvm_psci_0_2_call(vcpu
);
329 case KVM_ARM_PSCI_0_1
:
330 return kvm_psci_0_1_call(vcpu
);