/*
* Copyright (C) 2012 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/preempt.h>
#include <linux/kvm_host.h>
#include <linux/wait.h>
#include <asm/cputype.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_psci.h>
#include <asm/kvm_host.h>
#include <uapi/linux/psci.h>
/*
* This is an implementation of the Power State Coordination Interface
* as described in ARM document number ARM DEN 0022A.
*/
#define AFFINITY_MASK(level) ~((0x1UL << ((level) * MPIDR_LEVEL_BITS)) - 1)
static unsigned long psci_affinity_mask(unsigned long affinity_level)
{
if (affinity_level <= 3)
return MPIDR_HWID_BITMASK & AFFINITY_MASK(affinity_level);
return 0;
}
static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
{
/*
* NOTE: For simplicity, we make VCPU suspend emulation to be
* same-as WFI (Wait-for-interrupt) emulation.
*
* This means for KVM the wakeup events are interrupts and
* this is consistent with intended use of StateID as described
* in section 5.4.1 of PSCI v0.2 specification (ARM DEN 0022A).
*
* Further, we also treat power-down request to be same as
* stand-by request as-per section 5.4.2 clause 3 of PSCI v0.2
* specification (ARM DEN 0022A). This means all suspend states
* for KVM will preserve the register state.
*/
kvm_vcpu_block(vcpu);
return PSCI_RET_SUCCESS;
}
static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
{
vcpu->arch.power_off = true;
}
static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
{
struct kvm *kvm = source_vcpu->kvm;
struct kvm_vcpu *vcpu = NULL;
struct swait_queue_head *wq;
unsigned long cpu_id;
unsigned long context_id;
phys_addr_t target_pc;
cpu_id = vcpu_get_reg(source_vcpu, 1) & MPIDR_HWID_BITMASK;
if (vcpu_mode_is_32bit(source_vcpu))
cpu_id &= ~((u32) 0);
vcpu = kvm_mpidr_to_vcpu(kvm, cpu_id);
/*
* Make sure the caller requested a valid CPU and that the CPU is
* turned off.
*/
if (!vcpu)
return PSCI_RET_INVALID_PARAMS;
if (!vcpu->arch.power_off) {
if (kvm_psci_version(source_vcpu) != KVM_ARM_PSCI_0_1)
return PSCI_RET_ALREADY_ON;
else
return PSCI_RET_INVALID_PARAMS;
}
target_pc = vcpu_get_reg(source_vcpu, 2);
context_id = vcpu_get_reg(source_vcpu, 3);
kvm_reset_vcpu(vcpu);
/* Gracefully handle Thumb2 entry point */
if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
target_pc &= ~((phys_addr_t) 1);
vcpu_set_thumb(vcpu);
}
/* Propagate caller endianness */
if (kvm_vcpu_is_be(source_vcpu))
kvm_vcpu_set_be(vcpu);
*vcpu_pc(vcpu) = target_pc;
/*
* NOTE: We always update r0 (or x0) because for PSCI v0.1
* the general puspose registers are undefined upon CPU_ON.
*/
vcpu_set_reg(vcpu, 0, context_id);
vcpu->arch.power_off = false;
smp_mb(); /* Make sure the above is visible */
wq = kvm_arch_vcpu_wq(vcpu);
swake_up(wq);
return PSCI_RET_SUCCESS;
}
static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
{
int i, matching_cpus = 0;
unsigned long mpidr;
unsigned long target_affinity;
unsigned long target_affinity_mask;
unsigned long lowest_affinity_level;
struct kvm *kvm = vcpu->kvm;
struct kvm_vcpu *tmp;
target_affinity = vcpu_get_reg(vcpu, 1);
lowest_affinity_level = vcpu_get_reg(vcpu, 2);
/* Determine target affinity mask */
target_affinity_mask = psci_affinity_mask(lowest_affinity_level);
if (!target_affinity_mask)
return PSCI_RET_INVALID_PARAMS;
/* Ignore other bits of target affinity */
target_affinity &= target_affinity_mask;
/*
* If one or more VCPU matching target affinity are running
* then ON else OFF
*/
kvm_for_each_vcpu(i, tmp, kvm) {
mpidr = kvm_vcpu_get_mpidr_aff(tmp);
if ((mpidr & target_affinity_mask) == target_affinity) {
matching_cpus++;
if (!tmp->arch.power_off)
return PSCI_0_2_AFFINITY_LEVEL_ON;
}
}
if (!matching_cpus)
return PSCI_RET_INVALID_PARAMS;
return PSCI_0_2_AFFINITY_LEVEL_OFF;
}
static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
{
int i;
struct kvm_vcpu *tmp;
/*
* The KVM ABI specifies that a system event exit may call KVM_RUN
* again and may perform shutdown/reboot at a later time that when the
* actual request is made. Since we are implementing PSCI and a
* caller of PSCI reboot and shutdown expects that the system shuts
* down or reboots immediately, let's make sure that VCPUs are not run
* after this call is handled and before the VCPUs have been
* re-initialized.
*/
kvm_for_each_vcpu(i, tmp, vcpu->kvm) {
tmp->arch.power_off = true;
kvm_vcpu_kick(tmp);
}
memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
vcpu->run->system_event.type = type;
vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
}
static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
{
kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
}
static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
{
kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);
}
int kvm_psci_version(struct kvm_vcpu *vcpu)
{
if (test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features))
return KVM_ARM_PSCI_0_2;
return KVM_ARM_PSCI_0_1;
}
static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
{
int ret = 1;
unsigned long psci_fn = vcpu_get_reg(vcpu, 0) & ~((u32) 0);
unsigned long val;
switch (psci_fn) {
case PSCI_0_2_FN_PSCI_VERSION:
/*
* Bits[31:16] = Major Version = 0
* Bits[15:0] = Minor Version = 2
*/
val = 2;
break;
case PSCI_0_2_FN_CPU_SUSPEND:
case PSCI_0_2_FN64_CPU_SUSPEND:
val = kvm_psci_vcpu_suspend(vcpu);
break;
case PSCI_0_2_FN_CPU_OFF:
kvm_psci_vcpu_off(vcpu);
val = PSCI_RET_SUCCESS;
break;
case PSCI_0_2_FN_CPU_ON:
case PSCI_0_2_FN64_CPU_ON:
val = kvm_psci_vcpu_on(vcpu);
break;
case PSCI_0_2_FN_AFFINITY_INFO:
case PSCI_0_2_FN64_AFFINITY_INFO:
val = kvm_psci_vcpu_affinity_info(vcpu);
break;
case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
/*
* Trusted OS is MP hence does not require migration
* or
* Trusted OS is not present
*/
val = PSCI_0_2_TOS_MP;
break;
case PSCI_0_2_FN_SYSTEM_OFF:
kvm_psci_system_off(vcpu);
/*
* We should'nt be going back to guest VCPU after
* receiving SYSTEM_OFF request.
*
* If user space accidently/deliberately resumes
* guest VCPU after SYSTEM_OFF request then guest
* VCPU should see internal failure from PSCI return
* value. To achieve this, we preload r0 (or x0) with
* PSCI return value INTERNAL_FAILURE.
*/
val = PSCI_RET_INTERNAL_FAILURE;
ret = 0;
break;
case PSCI_0_2_FN_SYSTEM_RESET:
kvm_psci_system_reset(vcpu);
/*
* Same reason as SYSTEM_OFF for preloading r0 (or x0)
* with PSCI return value INTERNAL_FAILURE.
*/
val = PSCI_RET_INTERNAL_FAILURE;
ret = 0;
break;
default:
val = PSCI_RET_NOT_SUPPORTED;
break;
}
vcpu_set_reg(vcpu, 0, val);
return ret;
}
static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
{
unsigned long psci_fn = vcpu_get_reg(vcpu, 0) & ~((u32) 0);
unsigned long val;
switch (psci_fn) {
case KVM_PSCI_FN_CPU_OFF:
kvm_psci_vcpu_off(vcpu);
val = PSCI_RET_SUCCESS;
break;
case KVM_PSCI_FN_CPU_ON:
val = kvm_psci_vcpu_on(vcpu);
break;
default:
val = PSCI_RET_NOT_SUPPORTED;
break;
}
vcpu_set_reg(vcpu, 0, val);
return 1;
}
/**
* kvm_psci_call - handle PSCI call if r0 value is in range
* @vcpu: Pointer to the VCPU struct
*
* Handle PSCI calls from guests through traps from HVC instructions.
* The calling convention is similar to SMC calls to the secure world
* where the function number is placed in r0.
*
* This function returns: > 0 (success), 0 (success but exit to user
* space), and < 0 (errors)
*
* Errors:
* -EINVAL: Unrecognized PSCI function
*/
int kvm_psci_call(struct kvm_vcpu *vcpu)
{
switch (kvm_psci_version(vcpu)) {
case KVM_ARM_PSCI_0_2:
return kvm_psci_0_2_call(vcpu);
case KVM_ARM_PSCI_0_1:
return kvm_psci_0_1_call(vcpu);
default:
return -EINVAL;
};
}
