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