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b037b09b90
They were originally called _cond_rcu because they were special versions with conditional RCU handling. Now they're the standard entry and exit path, so the _cond_rcu part is just confusing. Drop it. Also change the signature to make them more extensible and more foolproof. No functional change -- it's pure refactoring. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/247fc67685263e0b673e1d7f808182d28ff80359.1593795633.git.luto@kernel.org
918 lines
21 KiB
C
918 lines
21 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* KVM paravirt_ops implementation
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*
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* Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
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* Copyright IBM Corporation, 2007
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* Authors: Anthony Liguori <aliguori@us.ibm.com>
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*/
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#include <linux/context_tracking.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/kvm_para.h>
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#include <linux/cpu.h>
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#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <linux/hardirq.h>
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#include <linux/notifier.h>
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#include <linux/reboot.h>
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#include <linux/hash.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/kprobes.h>
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#include <linux/nmi.h>
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#include <linux/swait.h>
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#include <asm/timer.h>
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#include <asm/cpu.h>
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#include <asm/traps.h>
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#include <asm/desc.h>
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#include <asm/tlbflush.h>
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#include <asm/apic.h>
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#include <asm/apicdef.h>
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#include <asm/hypervisor.h>
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#include <asm/tlb.h>
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#include <asm/cpuidle_haltpoll.h>
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DEFINE_STATIC_KEY_FALSE(kvm_async_pf_enabled);
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static int kvmapf = 1;
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static int __init parse_no_kvmapf(char *arg)
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{
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kvmapf = 0;
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return 0;
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}
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early_param("no-kvmapf", parse_no_kvmapf);
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static int steal_acc = 1;
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static int __init parse_no_stealacc(char *arg)
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{
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steal_acc = 0;
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return 0;
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}
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early_param("no-steal-acc", parse_no_stealacc);
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static DEFINE_PER_CPU_DECRYPTED(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);
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DEFINE_PER_CPU_DECRYPTED(struct kvm_steal_time, steal_time) __aligned(64) __visible;
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static int has_steal_clock = 0;
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/*
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* No need for any "IO delay" on KVM
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*/
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static void kvm_io_delay(void)
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{
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}
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#define KVM_TASK_SLEEP_HASHBITS 8
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#define KVM_TASK_SLEEP_HASHSIZE (1<<KVM_TASK_SLEEP_HASHBITS)
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struct kvm_task_sleep_node {
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struct hlist_node link;
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struct swait_queue_head wq;
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u32 token;
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int cpu;
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};
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static struct kvm_task_sleep_head {
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raw_spinlock_t lock;
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struct hlist_head list;
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} async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE];
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static struct kvm_task_sleep_node *_find_apf_task(struct kvm_task_sleep_head *b,
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u32 token)
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{
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struct hlist_node *p;
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hlist_for_each(p, &b->list) {
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struct kvm_task_sleep_node *n =
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hlist_entry(p, typeof(*n), link);
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if (n->token == token)
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return n;
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}
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return NULL;
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}
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static bool kvm_async_pf_queue_task(u32 token, struct kvm_task_sleep_node *n)
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{
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u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
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struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
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struct kvm_task_sleep_node *e;
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raw_spin_lock(&b->lock);
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e = _find_apf_task(b, token);
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if (e) {
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/* dummy entry exist -> wake up was delivered ahead of PF */
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hlist_del(&e->link);
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raw_spin_unlock(&b->lock);
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kfree(e);
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return false;
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}
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n->token = token;
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n->cpu = smp_processor_id();
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init_swait_queue_head(&n->wq);
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hlist_add_head(&n->link, &b->list);
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raw_spin_unlock(&b->lock);
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return true;
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}
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/*
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* kvm_async_pf_task_wait_schedule - Wait for pagefault to be handled
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* @token: Token to identify the sleep node entry
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*
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* Invoked from the async pagefault handling code or from the VM exit page
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* fault handler. In both cases RCU is watching.
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*/
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void kvm_async_pf_task_wait_schedule(u32 token)
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{
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struct kvm_task_sleep_node n;
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DECLARE_SWAITQUEUE(wait);
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lockdep_assert_irqs_disabled();
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if (!kvm_async_pf_queue_task(token, &n))
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return;
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for (;;) {
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prepare_to_swait_exclusive(&n.wq, &wait, TASK_UNINTERRUPTIBLE);
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if (hlist_unhashed(&n.link))
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break;
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local_irq_enable();
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schedule();
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local_irq_disable();
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}
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finish_swait(&n.wq, &wait);
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}
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EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait_schedule);
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static void apf_task_wake_one(struct kvm_task_sleep_node *n)
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{
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hlist_del_init(&n->link);
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if (swq_has_sleeper(&n->wq))
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swake_up_one(&n->wq);
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}
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static void apf_task_wake_all(void)
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{
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int i;
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for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) {
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struct kvm_task_sleep_head *b = &async_pf_sleepers[i];
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struct kvm_task_sleep_node *n;
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struct hlist_node *p, *next;
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raw_spin_lock(&b->lock);
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hlist_for_each_safe(p, next, &b->list) {
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n = hlist_entry(p, typeof(*n), link);
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if (n->cpu == smp_processor_id())
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apf_task_wake_one(n);
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}
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raw_spin_unlock(&b->lock);
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}
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}
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void kvm_async_pf_task_wake(u32 token)
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{
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u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
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struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
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struct kvm_task_sleep_node *n;
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if (token == ~0) {
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apf_task_wake_all();
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return;
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}
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again:
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raw_spin_lock(&b->lock);
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n = _find_apf_task(b, token);
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if (!n) {
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/*
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* async PF was not yet handled.
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* Add dummy entry for the token.
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*/
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n = kzalloc(sizeof(*n), GFP_ATOMIC);
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if (!n) {
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/*
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* Allocation failed! Busy wait while other cpu
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* handles async PF.
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*/
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raw_spin_unlock(&b->lock);
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cpu_relax();
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goto again;
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}
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n->token = token;
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n->cpu = smp_processor_id();
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init_swait_queue_head(&n->wq);
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hlist_add_head(&n->link, &b->list);
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} else {
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apf_task_wake_one(n);
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}
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raw_spin_unlock(&b->lock);
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return;
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}
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EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);
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noinstr u32 kvm_read_and_reset_apf_flags(void)
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{
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u32 flags = 0;
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if (__this_cpu_read(apf_reason.enabled)) {
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flags = __this_cpu_read(apf_reason.flags);
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__this_cpu_write(apf_reason.flags, 0);
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}
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return flags;
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}
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EXPORT_SYMBOL_GPL(kvm_read_and_reset_apf_flags);
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noinstr bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token)
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{
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u32 reason = kvm_read_and_reset_apf_flags();
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idtentry_state_t state;
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switch (reason) {
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case KVM_PV_REASON_PAGE_NOT_PRESENT:
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case KVM_PV_REASON_PAGE_READY:
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break;
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default:
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return false;
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}
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state = idtentry_enter(regs);
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instrumentation_begin();
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/*
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* If the host managed to inject an async #PF into an interrupt
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* disabled region, then die hard as this is not going to end well
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* and the host side is seriously broken.
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*/
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if (unlikely(!(regs->flags & X86_EFLAGS_IF)))
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panic("Host injected async #PF in interrupt disabled region\n");
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if (reason == KVM_PV_REASON_PAGE_NOT_PRESENT) {
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if (unlikely(!(user_mode(regs))))
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panic("Host injected async #PF in kernel mode\n");
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/* Page is swapped out by the host. */
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kvm_async_pf_task_wait_schedule(token);
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} else {
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kvm_async_pf_task_wake(token);
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}
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instrumentation_end();
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idtentry_exit(regs, state);
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return true;
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}
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static void __init paravirt_ops_setup(void)
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{
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pv_info.name = "KVM";
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if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
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pv_ops.cpu.io_delay = kvm_io_delay;
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#ifdef CONFIG_X86_IO_APIC
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no_timer_check = 1;
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#endif
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}
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static void kvm_register_steal_time(void)
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{
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int cpu = smp_processor_id();
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struct kvm_steal_time *st = &per_cpu(steal_time, cpu);
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if (!has_steal_clock)
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return;
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wrmsrl(MSR_KVM_STEAL_TIME, (slow_virt_to_phys(st) | KVM_MSR_ENABLED));
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pr_info("kvm-stealtime: cpu %d, msr %llx\n",
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cpu, (unsigned long long) slow_virt_to_phys(st));
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}
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static DEFINE_PER_CPU_DECRYPTED(unsigned long, kvm_apic_eoi) = KVM_PV_EOI_DISABLED;
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static notrace void kvm_guest_apic_eoi_write(u32 reg, u32 val)
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{
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/**
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* This relies on __test_and_clear_bit to modify the memory
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* in a way that is atomic with respect to the local CPU.
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* The hypervisor only accesses this memory from the local CPU so
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* there's no need for lock or memory barriers.
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* An optimization barrier is implied in apic write.
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*/
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if (__test_and_clear_bit(KVM_PV_EOI_BIT, this_cpu_ptr(&kvm_apic_eoi)))
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return;
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apic->native_eoi_write(APIC_EOI, APIC_EOI_ACK);
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}
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static void kvm_guest_cpu_init(void)
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{
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if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf) {
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u64 pa;
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WARN_ON_ONCE(!static_branch_likely(&kvm_async_pf_enabled));
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pa = slow_virt_to_phys(this_cpu_ptr(&apf_reason));
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pa |= KVM_ASYNC_PF_ENABLED;
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if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_VMEXIT))
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pa |= KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT;
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wrmsrl(MSR_KVM_ASYNC_PF_EN, pa);
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__this_cpu_write(apf_reason.enabled, 1);
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pr_info("KVM setup async PF for cpu %d\n", smp_processor_id());
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}
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if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) {
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unsigned long pa;
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/* Size alignment is implied but just to make it explicit. */
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BUILD_BUG_ON(__alignof__(kvm_apic_eoi) < 4);
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__this_cpu_write(kvm_apic_eoi, 0);
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pa = slow_virt_to_phys(this_cpu_ptr(&kvm_apic_eoi))
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| KVM_MSR_ENABLED;
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wrmsrl(MSR_KVM_PV_EOI_EN, pa);
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}
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if (has_steal_clock)
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kvm_register_steal_time();
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}
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static void kvm_pv_disable_apf(void)
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{
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if (!__this_cpu_read(apf_reason.enabled))
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return;
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wrmsrl(MSR_KVM_ASYNC_PF_EN, 0);
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__this_cpu_write(apf_reason.enabled, 0);
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pr_info("Unregister pv shared memory for cpu %d\n", smp_processor_id());
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}
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static void kvm_pv_guest_cpu_reboot(void *unused)
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{
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/*
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* We disable PV EOI before we load a new kernel by kexec,
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* since MSR_KVM_PV_EOI_EN stores a pointer into old kernel's memory.
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* New kernel can re-enable when it boots.
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*/
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if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
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wrmsrl(MSR_KVM_PV_EOI_EN, 0);
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kvm_pv_disable_apf();
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kvm_disable_steal_time();
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}
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static int kvm_pv_reboot_notify(struct notifier_block *nb,
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unsigned long code, void *unused)
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{
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if (code == SYS_RESTART)
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on_each_cpu(kvm_pv_guest_cpu_reboot, NULL, 1);
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return NOTIFY_DONE;
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}
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static struct notifier_block kvm_pv_reboot_nb = {
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.notifier_call = kvm_pv_reboot_notify,
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};
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static u64 kvm_steal_clock(int cpu)
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{
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u64 steal;
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struct kvm_steal_time *src;
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int version;
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src = &per_cpu(steal_time, cpu);
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do {
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version = src->version;
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virt_rmb();
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steal = src->steal;
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virt_rmb();
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} while ((version & 1) || (version != src->version));
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return steal;
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}
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void kvm_disable_steal_time(void)
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{
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if (!has_steal_clock)
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return;
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wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
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}
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static inline void __set_percpu_decrypted(void *ptr, unsigned long size)
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{
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early_set_memory_decrypted((unsigned long) ptr, size);
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}
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/*
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* Iterate through all possible CPUs and map the memory region pointed
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* by apf_reason, steal_time and kvm_apic_eoi as decrypted at once.
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*
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* Note: we iterate through all possible CPUs to ensure that CPUs
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* hotplugged will have their per-cpu variable already mapped as
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* decrypted.
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*/
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static void __init sev_map_percpu_data(void)
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{
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int cpu;
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if (!sev_active())
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return;
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for_each_possible_cpu(cpu) {
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__set_percpu_decrypted(&per_cpu(apf_reason, cpu), sizeof(apf_reason));
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__set_percpu_decrypted(&per_cpu(steal_time, cpu), sizeof(steal_time));
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__set_percpu_decrypted(&per_cpu(kvm_apic_eoi, cpu), sizeof(kvm_apic_eoi));
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}
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}
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static bool pv_tlb_flush_supported(void)
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{
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return (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
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!kvm_para_has_hint(KVM_HINTS_REALTIME) &&
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kvm_para_has_feature(KVM_FEATURE_STEAL_TIME));
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}
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static DEFINE_PER_CPU(cpumask_var_t, __pv_cpu_mask);
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#ifdef CONFIG_SMP
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static bool pv_ipi_supported(void)
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{
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return kvm_para_has_feature(KVM_FEATURE_PV_SEND_IPI);
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}
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static bool pv_sched_yield_supported(void)
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{
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return (kvm_para_has_feature(KVM_FEATURE_PV_SCHED_YIELD) &&
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!kvm_para_has_hint(KVM_HINTS_REALTIME) &&
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kvm_para_has_feature(KVM_FEATURE_STEAL_TIME));
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}
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#define KVM_IPI_CLUSTER_SIZE (2 * BITS_PER_LONG)
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static void __send_ipi_mask(const struct cpumask *mask, int vector)
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{
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unsigned long flags;
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int cpu, apic_id, icr;
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int min = 0, max = 0;
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#ifdef CONFIG_X86_64
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__uint128_t ipi_bitmap = 0;
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#else
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u64 ipi_bitmap = 0;
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#endif
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long ret;
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if (cpumask_empty(mask))
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return;
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local_irq_save(flags);
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switch (vector) {
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default:
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icr = APIC_DM_FIXED | vector;
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break;
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case NMI_VECTOR:
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icr = APIC_DM_NMI;
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break;
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}
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for_each_cpu(cpu, mask) {
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apic_id = per_cpu(x86_cpu_to_apicid, cpu);
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if (!ipi_bitmap) {
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min = max = apic_id;
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} else if (apic_id < min && max - apic_id < KVM_IPI_CLUSTER_SIZE) {
|
|
ipi_bitmap <<= min - apic_id;
|
|
min = apic_id;
|
|
} else if (apic_id < min + KVM_IPI_CLUSTER_SIZE) {
|
|
max = apic_id < max ? max : apic_id;
|
|
} else {
|
|
ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
|
|
(unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, icr);
|
|
WARN_ONCE(ret < 0, "KVM: failed to send PV IPI: %ld", ret);
|
|
min = max = apic_id;
|
|
ipi_bitmap = 0;
|
|
}
|
|
__set_bit(apic_id - min, (unsigned long *)&ipi_bitmap);
|
|
}
|
|
|
|
if (ipi_bitmap) {
|
|
ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
|
|
(unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, icr);
|
|
WARN_ONCE(ret < 0, "KVM: failed to send PV IPI: %ld", ret);
|
|
}
|
|
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
static void kvm_send_ipi_mask(const struct cpumask *mask, int vector)
|
|
{
|
|
__send_ipi_mask(mask, vector);
|
|
}
|
|
|
|
static void kvm_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
|
|
{
|
|
unsigned int this_cpu = smp_processor_id();
|
|
struct cpumask *new_mask = this_cpu_cpumask_var_ptr(__pv_cpu_mask);
|
|
const struct cpumask *local_mask;
|
|
|
|
cpumask_copy(new_mask, mask);
|
|
cpumask_clear_cpu(this_cpu, new_mask);
|
|
local_mask = new_mask;
|
|
__send_ipi_mask(local_mask, vector);
|
|
}
|
|
|
|
/*
|
|
* Set the IPI entry points
|
|
*/
|
|
static void kvm_setup_pv_ipi(void)
|
|
{
|
|
apic->send_IPI_mask = kvm_send_ipi_mask;
|
|
apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
|
|
pr_info("KVM setup pv IPIs\n");
|
|
}
|
|
|
|
static void kvm_smp_send_call_func_ipi(const struct cpumask *mask)
|
|
{
|
|
int cpu;
|
|
|
|
native_send_call_func_ipi(mask);
|
|
|
|
/* Make sure other vCPUs get a chance to run if they need to. */
|
|
for_each_cpu(cpu, mask) {
|
|
if (vcpu_is_preempted(cpu)) {
|
|
kvm_hypercall1(KVM_HC_SCHED_YIELD, per_cpu(x86_cpu_to_apicid, cpu));
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void __init kvm_smp_prepare_cpus(unsigned int max_cpus)
|
|
{
|
|
native_smp_prepare_cpus(max_cpus);
|
|
if (kvm_para_has_hint(KVM_HINTS_REALTIME))
|
|
static_branch_disable(&virt_spin_lock_key);
|
|
}
|
|
|
|
static void __init kvm_smp_prepare_boot_cpu(void)
|
|
{
|
|
/*
|
|
* Map the per-cpu variables as decrypted before kvm_guest_cpu_init()
|
|
* shares the guest physical address with the hypervisor.
|
|
*/
|
|
sev_map_percpu_data();
|
|
|
|
kvm_guest_cpu_init();
|
|
native_smp_prepare_boot_cpu();
|
|
kvm_spinlock_init();
|
|
}
|
|
|
|
static void kvm_guest_cpu_offline(void)
|
|
{
|
|
kvm_disable_steal_time();
|
|
if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
|
|
wrmsrl(MSR_KVM_PV_EOI_EN, 0);
|
|
kvm_pv_disable_apf();
|
|
apf_task_wake_all();
|
|
}
|
|
|
|
static int kvm_cpu_online(unsigned int cpu)
|
|
{
|
|
local_irq_disable();
|
|
kvm_guest_cpu_init();
|
|
local_irq_enable();
|
|
return 0;
|
|
}
|
|
|
|
static int kvm_cpu_down_prepare(unsigned int cpu)
|
|
{
|
|
local_irq_disable();
|
|
kvm_guest_cpu_offline();
|
|
local_irq_enable();
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
static void kvm_flush_tlb_others(const struct cpumask *cpumask,
|
|
const struct flush_tlb_info *info)
|
|
{
|
|
u8 state;
|
|
int cpu;
|
|
struct kvm_steal_time *src;
|
|
struct cpumask *flushmask = this_cpu_cpumask_var_ptr(__pv_cpu_mask);
|
|
|
|
cpumask_copy(flushmask, cpumask);
|
|
/*
|
|
* We have to call flush only on online vCPUs. And
|
|
* queue flush_on_enter for pre-empted vCPUs
|
|
*/
|
|
for_each_cpu(cpu, flushmask) {
|
|
src = &per_cpu(steal_time, cpu);
|
|
state = READ_ONCE(src->preempted);
|
|
if ((state & KVM_VCPU_PREEMPTED)) {
|
|
if (try_cmpxchg(&src->preempted, &state,
|
|
state | KVM_VCPU_FLUSH_TLB))
|
|
__cpumask_clear_cpu(cpu, flushmask);
|
|
}
|
|
}
|
|
|
|
native_flush_tlb_others(flushmask, info);
|
|
}
|
|
|
|
static void __init kvm_guest_init(void)
|
|
{
|
|
int i;
|
|
|
|
paravirt_ops_setup();
|
|
register_reboot_notifier(&kvm_pv_reboot_nb);
|
|
for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++)
|
|
raw_spin_lock_init(&async_pf_sleepers[i].lock);
|
|
|
|
if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
|
|
has_steal_clock = 1;
|
|
pv_ops.time.steal_clock = kvm_steal_clock;
|
|
}
|
|
|
|
if (pv_tlb_flush_supported()) {
|
|
pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others;
|
|
pv_ops.mmu.tlb_remove_table = tlb_remove_table;
|
|
pr_info("KVM setup pv remote TLB flush\n");
|
|
}
|
|
|
|
if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
|
|
apic_set_eoi_write(kvm_guest_apic_eoi_write);
|
|
|
|
if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf)
|
|
static_branch_enable(&kvm_async_pf_enabled);
|
|
|
|
#ifdef CONFIG_SMP
|
|
smp_ops.smp_prepare_cpus = kvm_smp_prepare_cpus;
|
|
smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
|
|
if (pv_sched_yield_supported()) {
|
|
smp_ops.send_call_func_ipi = kvm_smp_send_call_func_ipi;
|
|
pr_info("KVM setup pv sched yield\n");
|
|
}
|
|
if (cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/kvm:online",
|
|
kvm_cpu_online, kvm_cpu_down_prepare) < 0)
|
|
pr_err("kvm_guest: Failed to install cpu hotplug callbacks\n");
|
|
#else
|
|
sev_map_percpu_data();
|
|
kvm_guest_cpu_init();
|
|
#endif
|
|
|
|
/*
|
|
* Hard lockup detection is enabled by default. Disable it, as guests
|
|
* can get false positives too easily, for example if the host is
|
|
* overcommitted.
|
|
*/
|
|
hardlockup_detector_disable();
|
|
}
|
|
|
|
static noinline uint32_t __kvm_cpuid_base(void)
|
|
{
|
|
if (boot_cpu_data.cpuid_level < 0)
|
|
return 0; /* So we don't blow up on old processors */
|
|
|
|
if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
|
|
return hypervisor_cpuid_base("KVMKVMKVM\0\0\0", 0);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static inline uint32_t kvm_cpuid_base(void)
|
|
{
|
|
static int kvm_cpuid_base = -1;
|
|
|
|
if (kvm_cpuid_base == -1)
|
|
kvm_cpuid_base = __kvm_cpuid_base();
|
|
|
|
return kvm_cpuid_base;
|
|
}
|
|
|
|
bool kvm_para_available(void)
|
|
{
|
|
return kvm_cpuid_base() != 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kvm_para_available);
|
|
|
|
unsigned int kvm_arch_para_features(void)
|
|
{
|
|
return cpuid_eax(kvm_cpuid_base() | KVM_CPUID_FEATURES);
|
|
}
|
|
|
|
unsigned int kvm_arch_para_hints(void)
|
|
{
|
|
return cpuid_edx(kvm_cpuid_base() | KVM_CPUID_FEATURES);
|
|
}
|
|
EXPORT_SYMBOL_GPL(kvm_arch_para_hints);
|
|
|
|
static uint32_t __init kvm_detect(void)
|
|
{
|
|
return kvm_cpuid_base();
|
|
}
|
|
|
|
static void __init kvm_apic_init(void)
|
|
{
|
|
#if defined(CONFIG_SMP)
|
|
if (pv_ipi_supported())
|
|
kvm_setup_pv_ipi();
|
|
#endif
|
|
}
|
|
|
|
static void __init kvm_init_platform(void)
|
|
{
|
|
kvmclock_init();
|
|
x86_platform.apic_post_init = kvm_apic_init;
|
|
}
|
|
|
|
const __initconst struct hypervisor_x86 x86_hyper_kvm = {
|
|
.name = "KVM",
|
|
.detect = kvm_detect,
|
|
.type = X86_HYPER_KVM,
|
|
.init.guest_late_init = kvm_guest_init,
|
|
.init.x2apic_available = kvm_para_available,
|
|
.init.init_platform = kvm_init_platform,
|
|
};
|
|
|
|
static __init int activate_jump_labels(void)
|
|
{
|
|
if (has_steal_clock) {
|
|
static_key_slow_inc(¶virt_steal_enabled);
|
|
if (steal_acc)
|
|
static_key_slow_inc(¶virt_steal_rq_enabled);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
arch_initcall(activate_jump_labels);
|
|
|
|
static __init int kvm_alloc_cpumask(void)
|
|
{
|
|
int cpu;
|
|
bool alloc = false;
|
|
|
|
if (!kvm_para_available() || nopv)
|
|
return 0;
|
|
|
|
if (pv_tlb_flush_supported())
|
|
alloc = true;
|
|
|
|
#if defined(CONFIG_SMP)
|
|
if (pv_ipi_supported())
|
|
alloc = true;
|
|
#endif
|
|
|
|
if (alloc)
|
|
for_each_possible_cpu(cpu) {
|
|
zalloc_cpumask_var_node(per_cpu_ptr(&__pv_cpu_mask, cpu),
|
|
GFP_KERNEL, cpu_to_node(cpu));
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
arch_initcall(kvm_alloc_cpumask);
|
|
|
|
#ifdef CONFIG_PARAVIRT_SPINLOCKS
|
|
|
|
/* Kick a cpu by its apicid. Used to wake up a halted vcpu */
|
|
static void kvm_kick_cpu(int cpu)
|
|
{
|
|
int apicid;
|
|
unsigned long flags = 0;
|
|
|
|
apicid = per_cpu(x86_cpu_to_apicid, cpu);
|
|
kvm_hypercall2(KVM_HC_KICK_CPU, flags, apicid);
|
|
}
|
|
|
|
#include <asm/qspinlock.h>
|
|
|
|
static void kvm_wait(u8 *ptr, u8 val)
|
|
{
|
|
unsigned long flags;
|
|
|
|
if (in_nmi())
|
|
return;
|
|
|
|
local_irq_save(flags);
|
|
|
|
if (READ_ONCE(*ptr) != val)
|
|
goto out;
|
|
|
|
/*
|
|
* halt until it's our turn and kicked. Note that we do safe halt
|
|
* for irq enabled case to avoid hang when lock info is overwritten
|
|
* in irq spinlock slowpath and no spurious interrupt occur to save us.
|
|
*/
|
|
if (arch_irqs_disabled_flags(flags))
|
|
halt();
|
|
else
|
|
safe_halt();
|
|
|
|
out:
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
#ifdef CONFIG_X86_32
|
|
__visible bool __kvm_vcpu_is_preempted(long cpu)
|
|
{
|
|
struct kvm_steal_time *src = &per_cpu(steal_time, cpu);
|
|
|
|
return !!(src->preempted & KVM_VCPU_PREEMPTED);
|
|
}
|
|
PV_CALLEE_SAVE_REGS_THUNK(__kvm_vcpu_is_preempted);
|
|
|
|
#else
|
|
|
|
#include <asm/asm-offsets.h>
|
|
|
|
extern bool __raw_callee_save___kvm_vcpu_is_preempted(long);
|
|
|
|
/*
|
|
* Hand-optimize version for x86-64 to avoid 8 64-bit register saving and
|
|
* restoring to/from the stack.
|
|
*/
|
|
asm(
|
|
".pushsection .text;"
|
|
".global __raw_callee_save___kvm_vcpu_is_preempted;"
|
|
".type __raw_callee_save___kvm_vcpu_is_preempted, @function;"
|
|
"__raw_callee_save___kvm_vcpu_is_preempted:"
|
|
"movq __per_cpu_offset(,%rdi,8), %rax;"
|
|
"cmpb $0, " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax);"
|
|
"setne %al;"
|
|
"ret;"
|
|
".size __raw_callee_save___kvm_vcpu_is_preempted, .-__raw_callee_save___kvm_vcpu_is_preempted;"
|
|
".popsection");
|
|
|
|
#endif
|
|
|
|
/*
|
|
* Setup pv_lock_ops to exploit KVM_FEATURE_PV_UNHALT if present.
|
|
*/
|
|
void __init kvm_spinlock_init(void)
|
|
{
|
|
/* Does host kernel support KVM_FEATURE_PV_UNHALT? */
|
|
if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT))
|
|
return;
|
|
|
|
if (kvm_para_has_hint(KVM_HINTS_REALTIME))
|
|
return;
|
|
|
|
/* Don't use the pvqspinlock code if there is only 1 vCPU. */
|
|
if (num_possible_cpus() == 1)
|
|
return;
|
|
|
|
__pv_init_lock_hash();
|
|
pv_ops.lock.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath;
|
|
pv_ops.lock.queued_spin_unlock =
|
|
PV_CALLEE_SAVE(__pv_queued_spin_unlock);
|
|
pv_ops.lock.wait = kvm_wait;
|
|
pv_ops.lock.kick = kvm_kick_cpu;
|
|
|
|
if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
|
|
pv_ops.lock.vcpu_is_preempted =
|
|
PV_CALLEE_SAVE(__kvm_vcpu_is_preempted);
|
|
}
|
|
}
|
|
|
|
#endif /* CONFIG_PARAVIRT_SPINLOCKS */
|
|
|
|
#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
|
|
|
|
static void kvm_disable_host_haltpoll(void *i)
|
|
{
|
|
wrmsrl(MSR_KVM_POLL_CONTROL, 0);
|
|
}
|
|
|
|
static void kvm_enable_host_haltpoll(void *i)
|
|
{
|
|
wrmsrl(MSR_KVM_POLL_CONTROL, 1);
|
|
}
|
|
|
|
void arch_haltpoll_enable(unsigned int cpu)
|
|
{
|
|
if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL)) {
|
|
pr_err_once("kvm: host does not support poll control\n");
|
|
pr_err_once("kvm: host upgrade recommended\n");
|
|
return;
|
|
}
|
|
|
|
/* Enable guest halt poll disables host halt poll */
|
|
smp_call_function_single(cpu, kvm_disable_host_haltpoll, NULL, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(arch_haltpoll_enable);
|
|
|
|
void arch_haltpoll_disable(unsigned int cpu)
|
|
{
|
|
if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL))
|
|
return;
|
|
|
|
/* Enable guest halt poll disables host halt poll */
|
|
smp_call_function_single(cpu, kvm_enable_host_haltpoll, NULL, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(arch_haltpoll_disable);
|
|
#endif
|