X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;ds=sidebyside;f=arch%2Fx86%2Fkernel%2Fkvm.c;h=91b3d650898c70beef6f9d3ff365b924254ce501;hb=6adba527420651b6cacaf392541c09fb108711a2;hp=63b0ec8d3d4a4d8856ed21f7f9a174d7732c5ce0;hpb=e09d39968bd8befa087f10f970fa236e8694b643;p=mv-sheeva.git diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 63b0ec8d3d4..91b3d650898 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -27,16 +27,37 @@ #include #include #include +#include +#include +#include +#include +#include +#include #include +#include +#include +#include +#include #define MMU_QUEUE_SIZE 1024 +static int kvmapf = 1; + +static int parse_no_kvmapf(char *arg) +{ + kvmapf = 0; + return 0; +} + +early_param("no-kvmapf", parse_no_kvmapf); + struct kvm_para_state { u8 mmu_queue[MMU_QUEUE_SIZE]; int mmu_queue_len; }; static DEFINE_PER_CPU(struct kvm_para_state, para_state); +static DEFINE_PER_CPU(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64); static struct kvm_para_state *kvm_para_state(void) { @@ -50,6 +71,195 @@ static void kvm_io_delay(void) { } +#define KVM_TASK_SLEEP_HASHBITS 8 +#define KVM_TASK_SLEEP_HASHSIZE (1<list) { + struct kvm_task_sleep_node *n = + hlist_entry(p, typeof(*n), link); + if (n->token == token) + return n; + } + + return NULL; +} + +void kvm_async_pf_task_wait(u32 token) +{ + u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS); + struct kvm_task_sleep_head *b = &async_pf_sleepers[key]; + struct kvm_task_sleep_node n, *e; + DEFINE_WAIT(wait); + int cpu, idle; + + cpu = get_cpu(); + idle = idle_cpu(cpu); + put_cpu(); + + spin_lock(&b->lock); + e = _find_apf_task(b, token); + if (e) { + /* dummy entry exist -> wake up was delivered ahead of PF */ + hlist_del(&e->link); + kfree(e); + spin_unlock(&b->lock); + return; + } + + n.token = token; + n.cpu = smp_processor_id(); + n.mm = current->active_mm; + n.halted = idle || preempt_count() > 1; + atomic_inc(&n.mm->mm_count); + init_waitqueue_head(&n.wq); + hlist_add_head(&n.link, &b->list); + spin_unlock(&b->lock); + + for (;;) { + if (!n.halted) + prepare_to_wait(&n.wq, &wait, TASK_UNINTERRUPTIBLE); + if (hlist_unhashed(&n.link)) + break; + + if (!n.halted) { + local_irq_enable(); + schedule(); + local_irq_disable(); + } else { + /* + * We cannot reschedule. So halt. + */ + native_safe_halt(); + local_irq_disable(); + } + } + if (!n.halted) + finish_wait(&n.wq, &wait); + + return; +} +EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait); + +static void apf_task_wake_one(struct kvm_task_sleep_node *n) +{ + hlist_del_init(&n->link); + if (!n->mm) + return; + mmdrop(n->mm); + if (n->halted) + smp_send_reschedule(n->cpu); + else if (waitqueue_active(&n->wq)) + wake_up(&n->wq); +} + +static void apf_task_wake_all(void) +{ + int i; + + for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) { + struct hlist_node *p, *next; + struct kvm_task_sleep_head *b = &async_pf_sleepers[i]; + spin_lock(&b->lock); + hlist_for_each_safe(p, next, &b->list) { + struct kvm_task_sleep_node *n = + hlist_entry(p, typeof(*n), link); + if (n->cpu == smp_processor_id()) + apf_task_wake_one(n); + } + spin_unlock(&b->lock); + } +} + +void kvm_async_pf_task_wake(u32 token) +{ + u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS); + struct kvm_task_sleep_head *b = &async_pf_sleepers[key]; + struct kvm_task_sleep_node *n; + + if (token == ~0) { + apf_task_wake_all(); + return; + } + +again: + spin_lock(&b->lock); + n = _find_apf_task(b, token); + if (!n) { + /* + * async PF was not yet handled. + * Add dummy entry for the token. + */ + n = kmalloc(sizeof(*n), GFP_ATOMIC); + if (!n) { + /* + * Allocation failed! Busy wait while other cpu + * handles async PF. + */ + spin_unlock(&b->lock); + cpu_relax(); + goto again; + } + n->token = token; + n->cpu = smp_processor_id(); + n->mm = NULL; + init_waitqueue_head(&n->wq); + hlist_add_head(&n->link, &b->list); + } else + apf_task_wake_one(n); + spin_unlock(&b->lock); + return; +} +EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake); + +u32 kvm_read_and_reset_pf_reason(void) +{ + u32 reason = 0; + + if (__get_cpu_var(apf_reason).enabled) { + reason = __get_cpu_var(apf_reason).reason; + __get_cpu_var(apf_reason).reason = 0; + } + + return reason; +} +EXPORT_SYMBOL_GPL(kvm_read_and_reset_pf_reason); + +dotraplinkage void __kprobes +do_async_page_fault(struct pt_regs *regs, unsigned long error_code) +{ + switch (kvm_read_and_reset_pf_reason()) { + default: + do_page_fault(regs, error_code); + break; + case KVM_PV_REASON_PAGE_NOT_PRESENT: + /* page is swapped out by the host. */ + kvm_async_pf_task_wait((u32)read_cr2()); + break; + case KVM_PV_REASON_PAGE_READY: + kvm_async_pf_task_wake((u32)read_cr2()); + break; + } +} + static void kvm_mmu_op(void *buffer, unsigned len) { int r; @@ -231,10 +441,115 @@ static void __init paravirt_ops_setup(void) #endif } +void __cpuinit kvm_guest_cpu_init(void) +{ + if (!kvm_para_available()) + return; + + if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf) { + u64 pa = __pa(&__get_cpu_var(apf_reason)); + +#ifdef CONFIG_PREEMPT + pa |= KVM_ASYNC_PF_SEND_ALWAYS; +#endif + wrmsrl(MSR_KVM_ASYNC_PF_EN, pa | KVM_ASYNC_PF_ENABLED); + __get_cpu_var(apf_reason).enabled = 1; + printk(KERN_INFO"KVM setup async PF for cpu %d\n", + smp_processor_id()); + } +} + +static void kvm_pv_disable_apf(void *unused) +{ + if (!__get_cpu_var(apf_reason).enabled) + return; + + wrmsrl(MSR_KVM_ASYNC_PF_EN, 0); + __get_cpu_var(apf_reason).enabled = 0; + + printk(KERN_INFO"Unregister pv shared memory for cpu %d\n", + smp_processor_id()); +} + +static int kvm_pv_reboot_notify(struct notifier_block *nb, + unsigned long code, void *unused) +{ + if (code == SYS_RESTART) + on_each_cpu(kvm_pv_disable_apf, NULL, 1); + return NOTIFY_DONE; +} + +static struct notifier_block kvm_pv_reboot_nb = { + .notifier_call = kvm_pv_reboot_notify, +}; + +#ifdef CONFIG_SMP +static void __init kvm_smp_prepare_boot_cpu(void) +{ + WARN_ON(kvm_register_clock("primary cpu clock")); + kvm_guest_cpu_init(); + native_smp_prepare_boot_cpu(); +} + +static void kvm_guest_cpu_online(void *dummy) +{ + kvm_guest_cpu_init(); +} + +static void kvm_guest_cpu_offline(void *dummy) +{ + kvm_pv_disable_apf(NULL); + apf_task_wake_all(); +} + +static int __cpuinit kvm_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + int cpu = (unsigned long)hcpu; + switch (action) { + case CPU_ONLINE: + case CPU_DOWN_FAILED: + case CPU_ONLINE_FROZEN: + smp_call_function_single(cpu, kvm_guest_cpu_online, NULL, 0); + break; + case CPU_DOWN_PREPARE: + case CPU_DOWN_PREPARE_FROZEN: + smp_call_function_single(cpu, kvm_guest_cpu_offline, NULL, 1); + break; + default: + break; + } + return NOTIFY_OK; +} + +static struct notifier_block __cpuinitdata kvm_cpu_notifier = { + .notifier_call = kvm_cpu_notify, +}; +#endif + +static void __init kvm_apf_trap_init(void) +{ + set_intr_gate(14, &async_page_fault); +} + void __init kvm_guest_init(void) { + int i; + if (!kvm_para_available()) return; paravirt_ops_setup(); + register_reboot_notifier(&kvm_pv_reboot_nb); + for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) + spin_lock_init(&async_pf_sleepers[i].lock); + if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF)) + x86_init.irqs.trap_init = kvm_apf_trap_init; + +#ifdef CONFIG_SMP + smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu; + register_cpu_notifier(&kvm_cpu_notifier); +#else + kvm_guest_cpu_init(); +#endif }