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![Wanpeng Li](/assets/img/avatar_default.png)
[ Upstream commit 0361bdfddc
]
MSR_KVM_POLL_CONTROL is cleared on reset, thus reverting guests to
host-side polling after suspend/resume. Non-bootstrap CPUs are
restored correctly by the haltpoll driver because they are hot-unplugged
during suspend and hot-plugged during resume; however, the BSP
is not hotpluggable and remains in host-sde polling mode after
the guest resume. The makes the guest pay for the cost of vmexits
every time the guest enters idle.
Fix it by recording BSP's haltpoll state and resuming it during guest
resume.
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1650267752-46796-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
953 lines
22 KiB
C
953 lines
22 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/debugfs.h>
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#include <linux/nmi.h>
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#include <linux/swait.h>
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#include <linux/syscore_ops.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/reboot.h>
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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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static int has_guest_poll = 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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bool halted;
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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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/*
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* @interrupt_kernel: Is this called from a routine which interrupts the kernel
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* (other than user space)?
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*/
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void kvm_async_pf_task_wait(u32 token, int interrupt_kernel)
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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, *e;
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DECLARE_SWAITQUEUE(wait);
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rcu_irq_enter();
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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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kfree(e);
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raw_spin_unlock(&b->lock);
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rcu_irq_exit();
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return;
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}
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n.token = token;
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n.cpu = smp_processor_id();
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n.halted = is_idle_task(current) ||
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(IS_ENABLED(CONFIG_PREEMPT_COUNT)
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? preempt_count() > 1 || rcu_preempt_depth()
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: interrupt_kernel);
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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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for (;;) {
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if (!n.halted)
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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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rcu_irq_exit();
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if (!n.halted) {
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local_irq_enable();
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schedule();
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local_irq_disable();
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} else {
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/*
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* We cannot reschedule. So halt.
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*/
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native_safe_halt();
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local_irq_disable();
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}
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rcu_irq_enter();
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}
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if (!n.halted)
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finish_swait(&n.wq, &wait);
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rcu_irq_exit();
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return;
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}
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EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait);
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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 (n->halted)
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smp_send_reschedule(n->cpu);
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else 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 hlist_node *p, *next;
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struct kvm_task_sleep_head *b = &async_pf_sleepers[i];
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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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struct kvm_task_sleep_node *n =
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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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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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u32 kvm_read_and_reset_pf_reason(void)
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{
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u32 reason = 0;
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if (__this_cpu_read(apf_reason.enabled)) {
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reason = __this_cpu_read(apf_reason.reason);
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__this_cpu_write(apf_reason.reason, 0);
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}
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return reason;
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}
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EXPORT_SYMBOL_GPL(kvm_read_and_reset_pf_reason);
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NOKPROBE_SYMBOL(kvm_read_and_reset_pf_reason);
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dotraplinkage void
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do_async_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address)
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{
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enum ctx_state prev_state;
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switch (kvm_read_and_reset_pf_reason()) {
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default:
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do_page_fault(regs, error_code, address);
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break;
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case KVM_PV_REASON_PAGE_NOT_PRESENT:
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/* page is swapped out by the host. */
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prev_state = exception_enter();
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kvm_async_pf_task_wait((u32)address, !user_mode(regs));
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exception_exit(prev_state);
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break;
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case KVM_PV_REASON_PAGE_READY:
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rcu_irq_enter();
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kvm_async_pf_task_wake((u32)address);
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rcu_irq_exit();
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break;
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}
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}
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NOKPROBE_SYMBOL(do_async_page_fault);
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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 = slow_virt_to_phys(this_cpu_ptr(&apf_reason));
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#ifdef CONFIG_PREEMPTION
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pa |= KVM_ASYNC_PF_SEND_ALWAYS;
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#endif
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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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printk(KERN_INFO"KVM setup async PF for cpu %d\n",
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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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printk(KERN_INFO"Unregister pv shared memory for cpu %d\n",
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smp_processor_id());
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}
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static 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 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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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 void kvm_guest_cpu_offline(bool shutdown)
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{
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kvm_disable_steal_time();
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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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if (!shutdown)
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apf_task_wake_all();
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kvmclock_disable();
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}
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static int kvm_cpu_online(unsigned int cpu)
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{
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unsigned long flags;
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local_irq_save(flags);
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kvm_guest_cpu_init();
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local_irq_restore(flags);
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return 0;
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}
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#ifdef CONFIG_SMP
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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;
|
|
} 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 && 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;
|
|
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 int kvm_cpu_down_prepare(unsigned int cpu)
|
|
{
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
kvm_guest_cpu_offline(false);
|
|
local_irq_restore(flags);
|
|
return 0;
|
|
}
|
|
|
|
#endif
|
|
|
|
static int kvm_suspend(void)
|
|
{
|
|
u64 val = 0;
|
|
|
|
kvm_guest_cpu_offline(false);
|
|
|
|
#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
|
|
if (kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL))
|
|
rdmsrl(MSR_KVM_POLL_CONTROL, val);
|
|
has_guest_poll = !(val & 1);
|
|
#endif
|
|
return 0;
|
|
}
|
|
|
|
static void kvm_resume(void)
|
|
{
|
|
kvm_cpu_online(raw_smp_processor_id());
|
|
|
|
#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
|
|
if (kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL) && has_guest_poll)
|
|
wrmsrl(MSR_KVM_POLL_CONTROL, 0);
|
|
#endif
|
|
}
|
|
|
|
static struct syscore_ops kvm_syscore_ops = {
|
|
.suspend = kvm_suspend,
|
|
.resume = kvm_resume,
|
|
};
|
|
|
|
/*
|
|
* After a PV feature is registered, the host will keep writing to the
|
|
* registered memory location. If the guest happens to shutdown, this memory
|
|
* won't be valid. In cases like kexec, in which you install a new kernel, this
|
|
* means a random memory location will be kept being written.
|
|
*/
|
|
#ifdef CONFIG_KEXEC_CORE
|
|
static void kvm_crash_shutdown(struct pt_regs *regs)
|
|
{
|
|
kvm_guest_cpu_offline(true);
|
|
native_machine_crash_shutdown(regs);
|
|
}
|
|
#endif
|
|
|
|
static void __init kvm_apf_trap_init(void)
|
|
{
|
|
update_intr_gate(X86_TRAP_PF, async_page_fault);
|
|
}
|
|
|
|
static DEFINE_PER_CPU(cpumask_var_t, __pv_tlb_mask);
|
|
|
|
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_tlb_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_ASYNC_PF))
|
|
x86_init.irqs.trap_init = kvm_apf_trap_init;
|
|
|
|
if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
|
|
has_steal_clock = 1;
|
|
pv_ops.time.steal_clock = kvm_steal_clock;
|
|
}
|
|
|
|
if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
|
|
!kvm_para_has_hint(KVM_HINTS_REALTIME) &&
|
|
kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
|
|
pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others;
|
|
pv_ops.mmu.tlb_remove_table = tlb_remove_table;
|
|
}
|
|
|
|
if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
|
|
apic_set_eoi_write(kvm_guest_apic_eoi_write);
|
|
|
|
#ifdef CONFIG_SMP
|
|
smp_ops.smp_prepare_cpus = kvm_smp_prepare_cpus;
|
|
smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
|
|
if (kvm_para_has_feature(KVM_FEATURE_PV_SCHED_YIELD) &&
|
|
!kvm_para_has_hint(KVM_HINTS_REALTIME) &&
|
|
kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
|
|
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
|
|
|
|
#ifdef CONFIG_KEXEC_CORE
|
|
machine_ops.crash_shutdown = kvm_crash_shutdown;
|
|
#endif
|
|
|
|
register_syscore_ops(&kvm_syscore_ops);
|
|
|
|
/*
|
|
* 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 (kvm_para_has_feature(KVM_FEATURE_PV_SEND_IPI))
|
|
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_setup_pv_tlb_flush(void)
|
|
{
|
|
int cpu;
|
|
|
|
if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
|
|
!kvm_para_has_hint(KVM_HINTS_REALTIME) &&
|
|
kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
|
|
for_each_possible_cpu(cpu) {
|
|
zalloc_cpumask_var_node(per_cpu_ptr(&__pv_tlb_mask, cpu),
|
|
GFP_KERNEL, cpu_to_node(cpu));
|
|
}
|
|
pr_info("KVM setup pv remote TLB flush\n");
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
arch_initcall(kvm_setup_pv_tlb_flush);
|
|
|
|
#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
|