diff options
Diffstat (limited to '')
| -rw-r--r-- | arch/arm64/kernel/paravirt.c | 66 |
1 files changed, 44 insertions, 22 deletions
diff --git a/arch/arm64/kernel/paravirt.c b/arch/arm64/kernel/paravirt.c index 1ef702b0be2d..57c7c211f8c7 100644 --- a/arch/arm64/kernel/paravirt.c +++ b/arch/arm64/kernel/paravirt.c @@ -18,6 +18,7 @@ #include <linux/reboot.h> #include <linux/slab.h> #include <linux/types.h> +#include <linux/static_call.h> #include <asm/paravirt.h> #include <asm/pvclock-abi.h> @@ -26,11 +27,15 @@ struct static_key paravirt_steal_enabled; struct static_key paravirt_steal_rq_enabled; -struct paravirt_patch_template pv_ops; -EXPORT_SYMBOL_GPL(pv_ops); +static u64 native_steal_clock(int cpu) +{ + return 0; +} + +DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock); struct pv_time_stolen_time_region { - struct pvclock_vcpu_stolen_time *kaddr; + struct pvclock_vcpu_stolen_time __rcu *kaddr; }; static DEFINE_PER_CPU(struct pv_time_stolen_time_region, stolen_time_region); @@ -45,36 +50,50 @@ static int __init parse_no_stealacc(char *arg) early_param("no-steal-acc", parse_no_stealacc); /* return stolen time in ns by asking the hypervisor */ -static u64 pv_steal_clock(int cpu) +static u64 para_steal_clock(int cpu) { + struct pvclock_vcpu_stolen_time *kaddr = NULL; struct pv_time_stolen_time_region *reg; + u64 ret = 0; reg = per_cpu_ptr(&stolen_time_region, cpu); - if (!reg->kaddr) { - pr_warn_once("stolen time enabled but not configured for cpu %d\n", - cpu); + + /* + * paravirt_steal_clock() may be called before the CPU + * online notification callback runs. Until the callback + * has run we just return zero. + */ + rcu_read_lock(); + kaddr = rcu_dereference(reg->kaddr); + if (!kaddr) { + rcu_read_unlock(); return 0; } - return le64_to_cpu(READ_ONCE(reg->kaddr->stolen_time)); + ret = le64_to_cpu(READ_ONCE(kaddr->stolen_time)); + rcu_read_unlock(); + return ret; } -static int stolen_time_dying_cpu(unsigned int cpu) +static int stolen_time_cpu_down_prepare(unsigned int cpu) { + struct pvclock_vcpu_stolen_time *kaddr = NULL; struct pv_time_stolen_time_region *reg; reg = this_cpu_ptr(&stolen_time_region); if (!reg->kaddr) return 0; - memunmap(reg->kaddr); - memset(reg, 0, sizeof(*reg)); + kaddr = rcu_replace_pointer(reg->kaddr, NULL, true); + synchronize_rcu(); + memunmap(kaddr); return 0; } -static int init_stolen_time_cpu(unsigned int cpu) +static int stolen_time_cpu_online(unsigned int cpu) { + struct pvclock_vcpu_stolen_time *kaddr = NULL; struct pv_time_stolen_time_region *reg; struct arm_smccc_res res; @@ -85,17 +104,19 @@ static int init_stolen_time_cpu(unsigned int cpu) if (res.a0 == SMCCC_RET_NOT_SUPPORTED) return -EINVAL; - reg->kaddr = memremap(res.a0, + kaddr = memremap(res.a0, sizeof(struct pvclock_vcpu_stolen_time), MEMREMAP_WB); + rcu_assign_pointer(reg->kaddr, kaddr); + if (!reg->kaddr) { pr_warn("Failed to map stolen time data structure\n"); return -ENOMEM; } - if (le32_to_cpu(reg->kaddr->revision) != 0 || - le32_to_cpu(reg->kaddr->attributes) != 0) { + if (le32_to_cpu(kaddr->revision) != 0 || + le32_to_cpu(kaddr->attributes) != 0) { pr_warn_once("Unexpected revision or attributes in stolen time data\n"); return -ENXIO; } @@ -103,24 +124,25 @@ static int init_stolen_time_cpu(unsigned int cpu) return 0; } -static int pv_time_init_stolen_time(void) +static int __init pv_time_init_stolen_time(void) { int ret; - ret = cpuhp_setup_state(CPUHP_AP_ARM_KVMPV_STARTING, - "hypervisor/arm/pvtime:starting", - init_stolen_time_cpu, stolen_time_dying_cpu); + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, + "hypervisor/arm/pvtime:online", + stolen_time_cpu_online, + stolen_time_cpu_down_prepare); if (ret < 0) return ret; return 0; } -static bool has_pv_steal_clock(void) +static bool __init has_pv_steal_clock(void) { struct arm_smccc_res res; /* To detect the presence of PV time support we require SMCCC 1.1+ */ - if (psci_ops.smccc_version < SMCCC_VERSION_1_1) + if (arm_smccc_1_1_get_conduit() == SMCCC_CONDUIT_NONE) return false; arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, @@ -146,7 +168,7 @@ int __init pv_time_init(void) if (ret) return ret; - pv_ops.time.steal_clock = pv_steal_clock; + static_call_update(pv_steal_clock, para_steal_clock); static_key_slow_inc(¶virt_steal_enabled); if (steal_acc) |