blob: 24543d2a34905c66cfe39b68831b5e242359a5eb [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2020 - Google LLC
* Author: David Brazdil <dbrazdil@google.com>
*/
#include <asm/kvm_asm.h>
#include <asm/kvm_hyp.h>
#include <asm/kvm_mmu.h>
#include <linux/arm-smccc.h>
#include <linux/kvm_host.h>
#include <uapi/linux/psci.h>
#include <nvhe/memory.h>
#include <nvhe/trap_handler.h>
void kvm_hyp_cpu_entry(unsigned long r0);
void kvm_hyp_cpu_resume(unsigned long r0);
void __noreturn __host_enter(struct kvm_cpu_context *host_ctxt);
/* Config options set by the host. */
struct kvm_host_psci_config __ro_after_init kvm_host_psci_config;
#define INVALID_CPU_ID UINT_MAX
struct psci_boot_args {
atomic_t lock;
unsigned long pc;
unsigned long r0;
};
#define PSCI_BOOT_ARGS_UNLOCKED 0
#define PSCI_BOOT_ARGS_LOCKED 1
#define PSCI_BOOT_ARGS_INIT \
((struct psci_boot_args){ \
.lock = ATOMIC_INIT(PSCI_BOOT_ARGS_UNLOCKED), \
})
static DEFINE_PER_CPU(struct psci_boot_args, cpu_on_args) = PSCI_BOOT_ARGS_INIT;
static DEFINE_PER_CPU(struct psci_boot_args, suspend_args) = PSCI_BOOT_ARGS_INIT;
#define is_psci_0_1(what, func_id) \
(kvm_host_psci_config.psci_0_1_ ## what ## _implemented && \
(func_id) == kvm_host_psci_config.function_ids_0_1.what)
static bool is_psci_0_1_call(u64 func_id)
{
return (is_psci_0_1(cpu_suspend, func_id) ||
is_psci_0_1(cpu_on, func_id) ||
is_psci_0_1(cpu_off, func_id) ||
is_psci_0_1(migrate, func_id));
}
static bool is_psci_0_2_call(u64 func_id)
{
/* SMCCC reserves IDs 0x00-1F with the given 32/64-bit base for PSCI. */
return (PSCI_0_2_FN(0) <= func_id && func_id <= PSCI_0_2_FN(31)) ||
(PSCI_0_2_FN64(0) <= func_id && func_id <= PSCI_0_2_FN64(31));
}
static unsigned long psci_call(unsigned long fn, unsigned long arg0,
unsigned long arg1, unsigned long arg2)
{
struct arm_smccc_res res;
arm_smccc_1_1_smc(fn, arg0, arg1, arg2, &res);
return res.a0;
}
static unsigned long psci_forward(struct kvm_cpu_context *host_ctxt)
{
return psci_call(cpu_reg(host_ctxt, 0), cpu_reg(host_ctxt, 1),
cpu_reg(host_ctxt, 2), cpu_reg(host_ctxt, 3));
}
static unsigned int find_cpu_id(u64 mpidr)
{
unsigned int i;
/* Reject invalid MPIDRs */
if (mpidr & ~MPIDR_HWID_BITMASK)
return INVALID_CPU_ID;
for (i = 0; i < NR_CPUS; i++) {
if (cpu_logical_map(i) == mpidr)
return i;
}
return INVALID_CPU_ID;
}
static __always_inline bool try_acquire_boot_args(struct psci_boot_args *args)
{
return atomic_cmpxchg_acquire(&args->lock,
PSCI_BOOT_ARGS_UNLOCKED,
PSCI_BOOT_ARGS_LOCKED) ==
PSCI_BOOT_ARGS_UNLOCKED;
}
static __always_inline void release_boot_args(struct psci_boot_args *args)
{
atomic_set_release(&args->lock, PSCI_BOOT_ARGS_UNLOCKED);
}
static int psci_cpu_on(u64 func_id, struct kvm_cpu_context *host_ctxt)
{
DECLARE_REG(u64, mpidr, host_ctxt, 1);
DECLARE_REG(unsigned long, pc, host_ctxt, 2);
DECLARE_REG(unsigned long, r0, host_ctxt, 3);
unsigned int cpu_id;
struct psci_boot_args *boot_args;
struct kvm_nvhe_init_params *init_params;
int ret;
/*
* Find the logical CPU ID for the given MPIDR. The search set is
* the set of CPUs that were online at the point of KVM initialization.
* Booting other CPUs is rejected because their cpufeatures were not
* checked against the finalized capabilities. This could be relaxed
* by doing the feature checks in hyp.
*/
cpu_id = find_cpu_id(mpidr);
if (cpu_id == INVALID_CPU_ID)
return PSCI_RET_INVALID_PARAMS;
boot_args = per_cpu_ptr(&cpu_on_args, cpu_id);
init_params = per_cpu_ptr(&kvm_init_params, cpu_id);
/* Check if the target CPU is already being booted. */
if (!try_acquire_boot_args(boot_args))
return PSCI_RET_ALREADY_ON;
boot_args->pc = pc;
boot_args->r0 = r0;
wmb();
ret = psci_call(func_id, mpidr,
__hyp_pa(&kvm_hyp_cpu_entry),
__hyp_pa(init_params));
/* If successful, the lock will be released by the target CPU. */
if (ret != PSCI_RET_SUCCESS)
release_boot_args(boot_args);
return ret;
}
static int psci_cpu_suspend(u64 func_id, struct kvm_cpu_context *host_ctxt)
{
DECLARE_REG(u64, power_state, host_ctxt, 1);
DECLARE_REG(unsigned long, pc, host_ctxt, 2);
DECLARE_REG(unsigned long, r0, host_ctxt, 3);
struct psci_boot_args *boot_args;
struct kvm_nvhe_init_params *init_params;
boot_args = this_cpu_ptr(&suspend_args);
init_params = this_cpu_ptr(&kvm_init_params);
/*
* No need to acquire a lock before writing to boot_args because a core
* can only suspend itself. Racy CPU_ON calls use a separate struct.
*/
boot_args->pc = pc;
boot_args->r0 = r0;
/*
* Will either return if shallow sleep state, or wake up into the entry
* point if it is a deep sleep state.
*/
return psci_call(func_id, power_state,
__hyp_pa(&kvm_hyp_cpu_resume),
__hyp_pa(init_params));
}
static int psci_system_suspend(u64 func_id, struct kvm_cpu_context *host_ctxt)
{
DECLARE_REG(unsigned long, pc, host_ctxt, 1);
DECLARE_REG(unsigned long, r0, host_ctxt, 2);
struct psci_boot_args *boot_args;
struct kvm_nvhe_init_params *init_params;
boot_args = this_cpu_ptr(&suspend_args);
init_params = this_cpu_ptr(&kvm_init_params);
/*
* No need to acquire a lock before writing to boot_args because a core
* can only suspend itself. Racy CPU_ON calls use a separate struct.
*/
boot_args->pc = pc;
boot_args->r0 = r0;
/* Will only return on error. */
return psci_call(func_id,
__hyp_pa(&kvm_hyp_cpu_resume),
__hyp_pa(init_params), 0);
}
asmlinkage void __noreturn __kvm_host_psci_cpu_entry(bool is_cpu_on)
{
struct psci_boot_args *boot_args;
struct kvm_cpu_context *host_ctxt;
host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
if (is_cpu_on)
boot_args = this_cpu_ptr(&cpu_on_args);
else
boot_args = this_cpu_ptr(&suspend_args);
cpu_reg(host_ctxt, 0) = boot_args->r0;
write_sysreg_el2(boot_args->pc, SYS_ELR);
if (is_cpu_on)
release_boot_args(boot_args);
__host_enter(host_ctxt);
}
static unsigned long psci_0_1_handler(u64 func_id, struct kvm_cpu_context *host_ctxt)
{
if (is_psci_0_1(cpu_off, func_id) || is_psci_0_1(migrate, func_id))
return psci_forward(host_ctxt);
if (is_psci_0_1(cpu_on, func_id))
return psci_cpu_on(func_id, host_ctxt);
if (is_psci_0_1(cpu_suspend, func_id))
return psci_cpu_suspend(func_id, host_ctxt);
return PSCI_RET_NOT_SUPPORTED;
}
static unsigned long psci_0_2_handler(u64 func_id, struct kvm_cpu_context *host_ctxt)
{
switch (func_id) {
case PSCI_0_2_FN_PSCI_VERSION:
case PSCI_0_2_FN_CPU_OFF:
case PSCI_0_2_FN64_AFFINITY_INFO:
case PSCI_0_2_FN64_MIGRATE:
case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
case PSCI_0_2_FN64_MIGRATE_INFO_UP_CPU:
return psci_forward(host_ctxt);
/*
* SYSTEM_OFF/RESET should not return according to the spec.
* Allow it so as to stay robust to broken firmware.
*/
case PSCI_0_2_FN_SYSTEM_OFF:
case PSCI_0_2_FN_SYSTEM_RESET:
return psci_forward(host_ctxt);
case PSCI_0_2_FN64_CPU_SUSPEND:
return psci_cpu_suspend(func_id, host_ctxt);
case PSCI_0_2_FN64_CPU_ON:
return psci_cpu_on(func_id, host_ctxt);
default:
return PSCI_RET_NOT_SUPPORTED;
}
}
static unsigned long psci_1_0_handler(u64 func_id, struct kvm_cpu_context *host_ctxt)
{
switch (func_id) {
case PSCI_1_0_FN_PSCI_FEATURES:
case PSCI_1_0_FN_SET_SUSPEND_MODE:
case PSCI_1_1_FN64_SYSTEM_RESET2:
return psci_forward(host_ctxt);
case PSCI_1_0_FN64_SYSTEM_SUSPEND:
return psci_system_suspend(func_id, host_ctxt);
default:
return psci_0_2_handler(func_id, host_ctxt);
}
}
bool kvm_host_psci_handler(struct kvm_cpu_context *host_ctxt)
{
DECLARE_REG(u64, func_id, host_ctxt, 0);
unsigned long ret;
switch (kvm_host_psci_config.version) {
case PSCI_VERSION(0, 1):
if (!is_psci_0_1_call(func_id))
return false;
ret = psci_0_1_handler(func_id, host_ctxt);
break;
case PSCI_VERSION(0, 2):
if (!is_psci_0_2_call(func_id))
return false;
ret = psci_0_2_handler(func_id, host_ctxt);
break;
default:
if (!is_psci_0_2_call(func_id))
return false;
ret = psci_1_0_handler(func_id, host_ctxt);
break;
}
cpu_reg(host_ctxt, 0) = ret;
cpu_reg(host_ctxt, 1) = 0;
cpu_reg(host_ctxt, 2) = 0;
cpu_reg(host_ctxt, 3) = 0;
return true;
}