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_host.h>
26 #include <kvm/arm_psci.h>
29 * This is an implementation of the Power State Coordination Interface
30 * as described in ARM document number ARM DEN 0022A.
33 #define AFFINITY_MASK(level) ~((0x1UL << ((level) * MPIDR_LEVEL_BITS)) - 1)
35 static unsigned long psci_affinity_mask(unsigned long affinity_level)
37 if (affinity_level <= 3)
38 return MPIDR_HWID_BITMASK & AFFINITY_MASK(affinity_level);
43 static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
46 * NOTE: For simplicity, we make VCPU suspend emulation to be
47 * same-as WFI (Wait-for-interrupt) emulation.
49 * This means for KVM the wakeup events are interrupts and
50 * this is consistent with intended use of StateID as described
51 * in section 5.4.1 of PSCI v0.2 specification (ARM DEN 0022A).
53 * Further, we also treat power-down request to be same as
54 * stand-by request as-per section 5.4.2 clause 3 of PSCI v0.2
55 * specification (ARM DEN 0022A). This means all suspend states
56 * for KVM will preserve the register state.
59 kvm_clear_request(KVM_REQ_UNHALT, vcpu);
61 return PSCI_RET_SUCCESS;
64 static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
66 vcpu->arch.power_off = true;
67 kvm_make_request(KVM_REQ_SLEEP, vcpu);
71 static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
73 struct kvm *kvm = source_vcpu->kvm;
74 struct kvm_vcpu *vcpu = NULL;
75 struct swait_queue_head *wq;
77 unsigned long context_id;
78 phys_addr_t target_pc;
80 cpu_id = vcpu_get_reg(source_vcpu, 1) & MPIDR_HWID_BITMASK;
81 if (vcpu_mode_is_32bit(source_vcpu))
84 vcpu = kvm_mpidr_to_vcpu(kvm, cpu_id);
87 * Make sure the caller requested a valid CPU and that the CPU is
91 return PSCI_RET_INVALID_PARAMS;
92 if (!vcpu->arch.power_off) {
93 if (kvm_psci_version(source_vcpu) != KVM_ARM_PSCI_0_1)
94 return PSCI_RET_ALREADY_ON;
96 return PSCI_RET_INVALID_PARAMS;
99 target_pc = vcpu_get_reg(source_vcpu, 2);
100 context_id = vcpu_get_reg(source_vcpu, 3);
102 kvm_reset_vcpu(vcpu);
104 /* Gracefully handle Thumb2 entry point */
105 if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
106 target_pc &= ~((phys_addr_t) 1);
107 vcpu_set_thumb(vcpu);
110 /* Propagate caller endianness */
111 if (kvm_vcpu_is_be(source_vcpu))
112 kvm_vcpu_set_be(vcpu);
114 *vcpu_pc(vcpu) = target_pc;
116 * NOTE: We always update r0 (or x0) because for PSCI v0.1
117 * the general puspose registers are undefined upon CPU_ON.
119 vcpu_set_reg(vcpu, 0, context_id);
120 vcpu->arch.power_off = false;
121 smp_mb(); /* Make sure the above is visible */
123 wq = kvm_arch_vcpu_wq(vcpu);
126 return PSCI_RET_SUCCESS;
129 static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
131 int i, matching_cpus = 0;
133 unsigned long target_affinity;
134 unsigned long target_affinity_mask;
135 unsigned long lowest_affinity_level;
136 struct kvm *kvm = vcpu->kvm;
137 struct kvm_vcpu *tmp;
139 target_affinity = vcpu_get_reg(vcpu, 1);
140 lowest_affinity_level = vcpu_get_reg(vcpu, 2);
142 /* Determine target affinity mask */
143 target_affinity_mask = psci_affinity_mask(lowest_affinity_level);
144 if (!target_affinity_mask)
145 return PSCI_RET_INVALID_PARAMS;
147 /* Ignore other bits of target affinity */
148 target_affinity &= target_affinity_mask;
151 * If one or more VCPU matching target affinity are running
154 kvm_for_each_vcpu(i, tmp, kvm) {
155 mpidr = kvm_vcpu_get_mpidr_aff(tmp);
156 if ((mpidr & target_affinity_mask) == target_affinity) {
158 if (!tmp->arch.power_off)
159 return PSCI_0_2_AFFINITY_LEVEL_ON;
164 return PSCI_RET_INVALID_PARAMS;
166 return PSCI_0_2_AFFINITY_LEVEL_OFF;
169 static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
172 struct kvm_vcpu *tmp;
175 * The KVM ABI specifies that a system event exit may call KVM_RUN
176 * again and may perform shutdown/reboot at a later time that when the
177 * actual request is made. Since we are implementing PSCI and a
178 * caller of PSCI reboot and shutdown expects that the system shuts
179 * down or reboots immediately, let's make sure that VCPUs are not run
180 * after this call is handled and before the VCPUs have been
183 kvm_for_each_vcpu(i, tmp, vcpu->kvm)
184 tmp->arch.power_off = true;
185 kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
187 memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
188 vcpu->run->system_event.type = type;
189 vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
192 static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
194 kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
197 static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
199 kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);
202 int kvm_psci_version(struct kvm_vcpu *vcpu)
204 if (test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features))
205 return KVM_ARM_PSCI_0_2;
207 return KVM_ARM_PSCI_0_1;
210 static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
212 struct kvm *kvm = vcpu->kvm;
213 unsigned long psci_fn = vcpu_get_reg(vcpu, 0) & ~((u32) 0);
218 case PSCI_0_2_FN_PSCI_VERSION:
220 * Bits[31:16] = Major Version = 0
221 * Bits[15:0] = Minor Version = 2
223 val = KVM_ARM_PSCI_0_2;
225 case PSCI_0_2_FN_CPU_SUSPEND:
226 case PSCI_0_2_FN64_CPU_SUSPEND:
227 val = kvm_psci_vcpu_suspend(vcpu);
229 case PSCI_0_2_FN_CPU_OFF:
230 kvm_psci_vcpu_off(vcpu);
231 val = PSCI_RET_SUCCESS;
233 case PSCI_0_2_FN_CPU_ON:
234 case PSCI_0_2_FN64_CPU_ON:
235 mutex_lock(&kvm->lock);
236 val = kvm_psci_vcpu_on(vcpu);
237 mutex_unlock(&kvm->lock);
239 case PSCI_0_2_FN_AFFINITY_INFO:
240 case PSCI_0_2_FN64_AFFINITY_INFO:
241 val = kvm_psci_vcpu_affinity_info(vcpu);
243 case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
245 * Trusted OS is MP hence does not require migration
247 * Trusted OS is not present
249 val = PSCI_0_2_TOS_MP;
251 case PSCI_0_2_FN_SYSTEM_OFF:
252 kvm_psci_system_off(vcpu);
254 * We should'nt be going back to guest VCPU after
255 * receiving SYSTEM_OFF request.
257 * If user space accidently/deliberately resumes
258 * guest VCPU after SYSTEM_OFF request then guest
259 * VCPU should see internal failure from PSCI return
260 * value. To achieve this, we preload r0 (or x0) with
261 * PSCI return value INTERNAL_FAILURE.
263 val = PSCI_RET_INTERNAL_FAILURE;
266 case PSCI_0_2_FN_SYSTEM_RESET:
267 kvm_psci_system_reset(vcpu);
269 * Same reason as SYSTEM_OFF for preloading r0 (or x0)
270 * with PSCI return value INTERNAL_FAILURE.
272 val = PSCI_RET_INTERNAL_FAILURE;
276 val = PSCI_RET_NOT_SUPPORTED;
280 vcpu_set_reg(vcpu, 0, val);
284 static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
286 struct kvm *kvm = vcpu->kvm;
287 unsigned long psci_fn = vcpu_get_reg(vcpu, 0) & ~((u32) 0);
291 case KVM_PSCI_FN_CPU_OFF:
292 kvm_psci_vcpu_off(vcpu);
293 val = PSCI_RET_SUCCESS;
295 case KVM_PSCI_FN_CPU_ON:
296 mutex_lock(&kvm->lock);
297 val = kvm_psci_vcpu_on(vcpu);
298 mutex_unlock(&kvm->lock);
301 val = PSCI_RET_NOT_SUPPORTED;
305 vcpu_set_reg(vcpu, 0, val);
310 * kvm_psci_call - handle PSCI call if r0 value is in range
311 * @vcpu: Pointer to the VCPU struct
313 * Handle PSCI calls from guests through traps from HVC instructions.
314 * The calling convention is similar to SMC calls to the secure world
315 * where the function number is placed in r0.
317 * This function returns: > 0 (success), 0 (success but exit to user
318 * space), and < 0 (errors)
321 * -EINVAL: Unrecognized PSCI function
323 int kvm_psci_call(struct kvm_vcpu *vcpu)
325 switch (kvm_psci_version(vcpu)) {
326 case KVM_ARM_PSCI_0_2:
327 return kvm_psci_0_2_call(vcpu);
328 case KVM_ARM_PSCI_0_1:
329 return kvm_psci_0_1_call(vcpu);