diff options
Diffstat (limited to 'arch/arm64/kvm/hyp')
| -rw-r--r-- | arch/arm64/kvm/hyp/nvhe/hyp-init.S | 48 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/nvhe/psci-relay.c | 115 |
2 files changed, 163 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S index b0856b006bc0..d07e75f8242e 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S +++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S @@ -9,6 +9,7 @@ #include <asm/alternative.h> #include <asm/assembler.h> +#include <asm/el2_setup.h> #include <asm/kvm_arm.h> #include <asm/kvm_asm.h> #include <asm/kvm_mmu.h> @@ -139,6 +140,53 @@ alternative_else_nop_endif ret SYM_CODE_END(___kvm_hyp_init) +/* + * PSCI CPU_ON entry point + * + * x0: struct kvm_nvhe_init_params PA + */ +SYM_CODE_START(kvm_hyp_cpu_entry) + mov x1, #1 // is_cpu_on = true + b __kvm_hyp_init_cpu +SYM_CODE_END(kvm_hyp_cpu_entry) + +/* + * Common code for CPU entry points. Initializes EL2 state and + * installs the hypervisor before handing over to a C handler. + * + * x0: struct kvm_nvhe_init_params PA + * x1: bool is_cpu_on + */ +SYM_CODE_START_LOCAL(__kvm_hyp_init_cpu) + mov x28, x0 // Stash arguments + mov x29, x1 + + /* Check that the core was booted in EL2. */ + mrs x0, CurrentEL + cmp x0, #CurrentEL_EL2 + b.eq 2f + + /* The core booted in EL1. KVM cannot be initialized on it. */ +1: wfe + wfi + b 1b + +2: msr SPsel, #1 // We want to use SP_EL{1,2} + + /* Initialize EL2 CPU state to sane values. */ + init_el2_state nvhe // Clobbers x0..x2 + + /* Enable MMU, set vectors and stack. */ + mov x0, x28 + bl ___kvm_hyp_init // Clobbers x0..x3 + + /* Leave idmap. */ + mov x0, x29 + ldr x1, =kvm_host_psci_cpu_entry + kimg_hyp_va x1, x2 + br x1 +SYM_CODE_END(__kvm_hyp_init_cpu) + SYM_CODE_START(__kvm_handle_stub_hvc) cmp x0, #HVC_SOFT_RESTART b.ne 1f diff --git a/arch/arm64/kvm/hyp/nvhe/psci-relay.c b/arch/arm64/kvm/hyp/nvhe/psci-relay.c index 5ad56a875ffa..637e22ed71fc 100644 --- a/arch/arm64/kvm/hyp/nvhe/psci-relay.c +++ b/arch/arm64/kvm/hyp/nvhe/psci-relay.c @@ -9,12 +9,17 @@ #include <asm/kvm_mmu.h> #include <kvm/arm_hypercalls.h> #include <linux/arm-smccc.h> +#include <linux/kvm_host.h> #include <linux/psci.h> #include <kvm/arm_psci.h> #include <uapi/linux/psci.h> #include <nvhe/trap_handler.h> +void kvm_hyp_cpu_entry(unsigned long r0); + +void __noreturn __host_enter(struct kvm_cpu_context *host_ctxt); + /* Config options set by the host. */ __ro_after_init u32 kvm_host_psci_version; __ro_after_init struct psci_0_1_function_ids kvm_host_psci_0_1_function_ids; @@ -22,6 +27,24 @@ __ro_after_init s64 hyp_physvirt_offset; #define __hyp_pa(x) ((phys_addr_t)((x)) + hyp_physvirt_offset) +#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 u64 get_psci_func_id(struct kvm_cpu_context *host_ctxt) { DECLARE_REG(u64, func_id, host_ctxt, 0); @@ -75,11 +98,101 @@ static __noreturn unsigned long psci_forward_noreturn(struct kvm_cpu_context *ho hyp_panic(); /* unreachable */ } +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(hyp_symbol_addr(cpu_on_args), cpu_id); + init_params = per_cpu_ptr(hyp_symbol_addr(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(hyp_symbol_addr(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; +} + +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(hyp_symbol_addr(kvm_host_data))->host_ctxt; + boot_args = this_cpu_ptr(hyp_symbol_addr(cpu_on_args)); + + cpu_reg(host_ctxt, 0) = boot_args->r0; + write_sysreg_el2(boot_args->pc, SYS_ELR); + 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 ((func_id == kvm_host_psci_0_1_function_ids.cpu_off) || (func_id == kvm_host_psci_0_1_function_ids.migrate)) return psci_forward(host_ctxt); + else if (func_id == kvm_host_psci_0_1_function_ids.cpu_on) + return psci_cpu_on(func_id, host_ctxt); else return PSCI_RET_NOT_SUPPORTED; } @@ -98,6 +211,8 @@ static unsigned long psci_0_2_handler(u64 func_id, struct kvm_cpu_context *host_ case PSCI_0_2_FN_SYSTEM_RESET: psci_forward_noreturn(host_ctxt); unreachable(); + case PSCI_0_2_FN64_CPU_ON: + return psci_cpu_on(func_id, host_ctxt); default: return PSCI_RET_NOT_SUPPORTED; } |