#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/hardirq.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/hash.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/kprobes.h>
#include <asm/timer.h>
+#include <asm/cpu.h>
+#include <asm/traps.h>
+#include <asm/desc.h>
+#include <asm/tlbflush.h>
#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)
{
{
}
+#define KVM_TASK_SLEEP_HASHBITS 8
+#define KVM_TASK_SLEEP_HASHSIZE (1<<KVM_TASK_SLEEP_HASHBITS)
+
+struct kvm_task_sleep_node {
+ struct hlist_node link;
+ wait_queue_head_t wq;
+ u32 token;
+ int cpu;
+ bool halted;
+ struct mm_struct *mm;
+};
+
+static struct kvm_task_sleep_head {
+ spinlock_t lock;
+ struct hlist_head list;
+} async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE];
+
+static struct kvm_task_sleep_node *_find_apf_task(struct kvm_task_sleep_head *b,
+ u32 token)
+{
+ struct hlist_node *p;
+
+ hlist_for_each(p, &b->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;
#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)
+{
+#ifdef CONFIG_KVM_CLOCK
+ WARN_ON(kvm_register_clock("primary cpu clock"));
+#endif
+ 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
}
projects / mv-sheeva.git / blobdiff