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9ee83635d8
When sending a call-function IPI-many to vCPUs, yield to the IPI target vCPU which is marked as preempted. but when emulating HLT, an idling vCPU will be voluntarily scheduled out and mark as preempted from the guest kernel perspective. yielding to idle vCPU is pointless and increase unnecessary vmexit, maybe miss the true preempted vCPU so yield to IPI target vCPU only if vCPU is busy and preempted Signed-off-by: Li RongQing <lirongqing@baidu.com> Message-Id: <1644380201-29423-1-git-send-email-lirongqing@baidu.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1133 lines
27 KiB
C
1133 lines
27 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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#define pr_fmt(fmt) "kvm-guest: " fmt
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#include <linux/context_tracking.h>
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#include <linux/init.h>
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#include <linux/irq.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 <linux/syscore_ops.h>
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#include <linux/cc_platform.h>
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#include <linux/efi.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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#include <asm/ptrace.h>
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#include <asm/reboot.h>
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#include <asm/svm.h>
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#include <asm/e820/api.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 flags = kvm_read_and_reset_apf_flags();
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irqentry_state_t state;
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if (!flags)
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return false;
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state = irqentry_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 (flags & 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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WARN_ONCE(1, "Unexpected async PF flags: %x\n", flags);
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}
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instrumentation_end();
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irqentry_exit(regs, state);
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return true;
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}
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DEFINE_IDTENTRY_SYSVEC(sysvec_kvm_asyncpf_interrupt)
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{
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struct pt_regs *old_regs = set_irq_regs(regs);
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u32 token;
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ack_APIC_irq();
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inc_irq_stat(irq_hv_callback_count);
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if (__this_cpu_read(apf_reason.enabled)) {
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token = __this_cpu_read(apf_reason.token);
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kvm_async_pf_task_wake(token);
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__this_cpu_write(apf_reason.token, 0);
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wrmsrl(MSR_KVM_ASYNC_PF_ACK, 1);
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}
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set_irq_regs(old_regs);
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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_debug("stealtime: cpu %d, msr %llx\n", cpu,
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(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_INT) && kvmapf) {
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u64 pa = slow_virt_to_phys(this_cpu_ptr(&apf_reason));
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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 | KVM_ASYNC_PF_DELIVERY_AS_INT;
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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_INT, HYPERVISOR_CALLBACK_VECTOR);
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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_debug("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_debug("disable async PF for cpu %d\n", 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 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 (!cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
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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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if (kvm_para_has_feature(KVM_FEATURE_MIGRATION_CONTROL))
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wrmsrl(MSR_KVM_MIGRATION_CONTROL, 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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static DEFINE_PER_CPU(cpumask_var_t, __pv_cpu_mask);
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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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!boot_cpu_has(X86_FEATURE_MWAIT) &&
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(num_possible_cpus() != 1));
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}
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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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(num_possible_cpus() != 1));
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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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!boot_cpu_has(X86_FEATURE_MWAIT) &&
|
|
(num_possible_cpus() != 1));
|
|
}
|
|
|
|
#define KVM_IPI_CLUSTER_SIZE (2 * BITS_PER_LONG)
|
|
|
|
static void __send_ipi_mask(const struct cpumask *mask, int vector)
|
|
{
|
|
unsigned long flags;
|
|
int cpu, apic_id, icr;
|
|
int min = 0, max = 0;
|
|
#ifdef CONFIG_X86_64
|
|
__uint128_t ipi_bitmap = 0;
|
|
#else
|
|
u64 ipi_bitmap = 0;
|
|
#endif
|
|
long ret;
|
|
|
|
if (cpumask_empty(mask))
|
|
return;
|
|
|
|
local_irq_save(flags);
|
|
|
|
switch (vector) {
|
|
default:
|
|
icr = APIC_DM_FIXED | vector;
|
|
break;
|
|
case NMI_VECTOR:
|
|
icr = APIC_DM_NMI;
|
|
break;
|
|
}
|
|
|
|
for_each_cpu(cpu, mask) {
|
|
apic_id = per_cpu(x86_cpu_to_apicid, cpu);
|
|
if (!ipi_bitmap) {
|
|
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 + 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-guest: 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-guest: 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);
|
|
}
|
|
|
|
static int __init setup_efi_kvm_sev_migration(void)
|
|
{
|
|
efi_char16_t efi_sev_live_migration_enabled[] = L"SevLiveMigrationEnabled";
|
|
efi_guid_t efi_variable_guid = AMD_SEV_MEM_ENCRYPT_GUID;
|
|
efi_status_t status;
|
|
unsigned long size;
|
|
bool enabled;
|
|
|
|
if (!cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT) ||
|
|
!kvm_para_has_feature(KVM_FEATURE_MIGRATION_CONTROL))
|
|
return 0;
|
|
|
|
if (!efi_enabled(EFI_BOOT))
|
|
return 0;
|
|
|
|
if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
|
|
pr_info("%s : EFI runtime services are not enabled\n", __func__);
|
|
return 0;
|
|
}
|
|
|
|
size = sizeof(enabled);
|
|
|
|
/* Get variable contents into buffer */
|
|
status = efi.get_variable(efi_sev_live_migration_enabled,
|
|
&efi_variable_guid, NULL, &size, &enabled);
|
|
|
|
if (status == EFI_NOT_FOUND) {
|
|
pr_info("%s : EFI live migration variable not found\n", __func__);
|
|
return 0;
|
|
}
|
|
|
|
if (status != EFI_SUCCESS) {
|
|
pr_info("%s : EFI variable retrieval failed\n", __func__);
|
|
return 0;
|
|
}
|
|
|
|
if (enabled == 0) {
|
|
pr_info("%s: live migration disabled in EFI\n", __func__);
|
|
return 0;
|
|
}
|
|
|
|
pr_info("%s : live migration enabled in EFI\n", __func__);
|
|
wrmsrl(MSR_KVM_MIGRATION_CONTROL, KVM_MIGRATION_READY);
|
|
|
|
return 1;
|
|
}
|
|
|
|
late_initcall(setup_efi_kvm_sev_migration);
|
|
|
|
/*
|
|
* 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("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 (!idle_cpu(cpu) && vcpu_is_preempted(cpu)) {
|
|
kvm_hypercall1(KVM_HC_SCHED_YIELD, per_cpu(x86_cpu_to_apicid, cpu));
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void kvm_flush_tlb_multi(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) {
|
|
/*
|
|
* The local vCPU is never preempted, so we do not explicitly
|
|
* skip check for local vCPU - it will never be cleared from
|
|
* 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_multi(flushmask, info);
|
|
}
|
|
|
|
static __init int kvm_alloc_cpumask(void)
|
|
{
|
|
int cpu;
|
|
|
|
if (!kvm_para_available() || nopv)
|
|
return 0;
|
|
|
|
if (pv_tlb_flush_supported() || pv_ipi_supported())
|
|
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);
|
|
|
|
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)
|
|
{
|
|
kvm_guest_cpu_offline(false);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void kvm_resume(void)
|
|
{
|
|
kvm_cpu_online(raw_smp_processor_id());
|
|
}
|
|
|
|
static struct syscore_ops kvm_syscore_ops = {
|
|
.suspend = kvm_suspend,
|
|
.resume = kvm_resume,
|
|
};
|
|
|
|
static void kvm_pv_guest_cpu_reboot(void *unused)
|
|
{
|
|
kvm_guest_cpu_offline(true);
|
|
}
|
|
|
|
static int kvm_pv_reboot_notify(struct notifier_block *nb,
|
|
unsigned long code, void *unused)
|
|
{
|
|
if (code == SYS_RESTART)
|
|
on_each_cpu(kvm_pv_guest_cpu_reboot, NULL, 1);
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
static struct notifier_block kvm_pv_reboot_nb = {
|
|
.notifier_call = kvm_pv_reboot_notify,
|
|
};
|
|
|
|
/*
|
|
* 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_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;
|
|
static_call_update(pv_steal_clock, kvm_steal_clock);
|
|
}
|
|
|
|
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_INT) && kvmapf) {
|
|
static_branch_enable(&kvm_async_pf_enabled);
|
|
alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_kvm_asyncpf_interrupt);
|
|
}
|
|
|
|
#ifdef CONFIG_SMP
|
|
if (pv_tlb_flush_supported()) {
|
|
pv_ops.mmu.flush_tlb_multi = kvm_flush_tlb_multi;
|
|
pv_ops.mmu.tlb_remove_table = tlb_remove_table;
|
|
pr_info("KVM setup pv remote TLB flush\n");
|
|
}
|
|
|
|
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("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("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(KVM_SIGNATURE, 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)
|
|
{
|
|
#ifdef CONFIG_SMP
|
|
if (pv_ipi_supported())
|
|
kvm_setup_pv_ipi();
|
|
#endif
|
|
}
|
|
|
|
static bool __init kvm_msi_ext_dest_id(void)
|
|
{
|
|
return kvm_para_has_feature(KVM_FEATURE_MSI_EXT_DEST_ID);
|
|
}
|
|
|
|
static void kvm_sev_hc_page_enc_status(unsigned long pfn, int npages, bool enc)
|
|
{
|
|
kvm_sev_hypercall3(KVM_HC_MAP_GPA_RANGE, pfn << PAGE_SHIFT, npages,
|
|
KVM_MAP_GPA_RANGE_ENC_STAT(enc) | KVM_MAP_GPA_RANGE_PAGE_SZ_4K);
|
|
}
|
|
|
|
static void __init kvm_init_platform(void)
|
|
{
|
|
if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT) &&
|
|
kvm_para_has_feature(KVM_FEATURE_MIGRATION_CONTROL)) {
|
|
unsigned long nr_pages;
|
|
int i;
|
|
|
|
pv_ops.mmu.notify_page_enc_status_changed =
|
|
kvm_sev_hc_page_enc_status;
|
|
|
|
/*
|
|
* Reset the host's shared pages list related to kernel
|
|
* specific page encryption status settings before we load a
|
|
* new kernel by kexec. Reset the page encryption status
|
|
* during early boot intead of just before kexec to avoid SMP
|
|
* races during kvm_pv_guest_cpu_reboot().
|
|
* NOTE: We cannot reset the complete shared pages list
|
|
* here as we need to retain the UEFI/OVMF firmware
|
|
* specific settings.
|
|
*/
|
|
|
|
for (i = 0; i < e820_table->nr_entries; i++) {
|
|
struct e820_entry *entry = &e820_table->entries[i];
|
|
|
|
if (entry->type != E820_TYPE_RAM)
|
|
continue;
|
|
|
|
nr_pages = DIV_ROUND_UP(entry->size, PAGE_SIZE);
|
|
|
|
kvm_sev_hypercall3(KVM_HC_MAP_GPA_RANGE, entry->addr,
|
|
nr_pages,
|
|
KVM_MAP_GPA_RANGE_ENCRYPTED | KVM_MAP_GPA_RANGE_PAGE_SZ_4K);
|
|
}
|
|
|
|
/*
|
|
* Ensure that _bss_decrypted section is marked as decrypted in the
|
|
* shared pages list.
|
|
*/
|
|
nr_pages = DIV_ROUND_UP(__end_bss_decrypted - __start_bss_decrypted,
|
|
PAGE_SIZE);
|
|
early_set_mem_enc_dec_hypercall((unsigned long)__start_bss_decrypted,
|
|
nr_pages, 0);
|
|
|
|
/*
|
|
* If not booted using EFI, enable Live migration support.
|
|
*/
|
|
if (!efi_enabled(EFI_BOOT))
|
|
wrmsrl(MSR_KVM_MIGRATION_CONTROL,
|
|
KVM_MIGRATION_READY);
|
|
}
|
|
kvmclock_init();
|
|
x86_platform.apic_post_init = kvm_apic_init;
|
|
}
|
|
|
|
#if defined(CONFIG_AMD_MEM_ENCRYPT)
|
|
static void kvm_sev_es_hcall_prepare(struct ghcb *ghcb, struct pt_regs *regs)
|
|
{
|
|
/* RAX and CPL are already in the GHCB */
|
|
ghcb_set_rbx(ghcb, regs->bx);
|
|
ghcb_set_rcx(ghcb, regs->cx);
|
|
ghcb_set_rdx(ghcb, regs->dx);
|
|
ghcb_set_rsi(ghcb, regs->si);
|
|
}
|
|
|
|
static bool kvm_sev_es_hcall_finish(struct ghcb *ghcb, struct pt_regs *regs)
|
|
{
|
|
/* No checking of the return state needed */
|
|
return true;
|
|
}
|
|
#endif
|
|
|
|
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.msi_ext_dest_id = kvm_msi_ext_dest_id,
|
|
.init.init_platform = kvm_init_platform,
|
|
#if defined(CONFIG_AMD_MEM_ENCRYPT)
|
|
.runtime.sev_es_hcall_prepare = kvm_sev_es_hcall_prepare,
|
|
.runtime.sev_es_hcall_finish = kvm_sev_es_hcall_finish,
|
|
#endif
|
|
};
|
|
|
|
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);
|
|
|
|
#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)
|
|
{
|
|
if (in_nmi())
|
|
return;
|
|
|
|
/*
|
|
* 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 (irqs_disabled()) {
|
|
if (READ_ONCE(*ptr) == val)
|
|
halt();
|
|
} else {
|
|
local_irq_disable();
|
|
|
|
/* safe_halt() will enable IRQ */
|
|
if (READ_ONCE(*ptr) == val)
|
|
safe_halt();
|
|
else
|
|
local_irq_enable();
|
|
}
|
|
}
|
|
|
|
#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)
|
|
{
|
|
/*
|
|
* In case host doesn't support KVM_FEATURE_PV_UNHALT there is still an
|
|
* advantage of keeping virt_spin_lock_key enabled: virt_spin_lock() is
|
|
* preferred over native qspinlock when vCPU is preempted.
|
|
*/
|
|
if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT)) {
|
|
pr_info("PV spinlocks disabled, no host support\n");
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Disable PV spinlocks and use native qspinlock when dedicated pCPUs
|
|
* are available.
|
|
*/
|
|
if (kvm_para_has_hint(KVM_HINTS_REALTIME)) {
|
|
pr_info("PV spinlocks disabled with KVM_HINTS_REALTIME hints\n");
|
|
goto out;
|
|
}
|
|
|
|
if (num_possible_cpus() == 1) {
|
|
pr_info("PV spinlocks disabled, single CPU\n");
|
|
goto out;
|
|
}
|
|
|
|
if (nopvspin) {
|
|
pr_info("PV spinlocks disabled, forced by \"nopvspin\" parameter\n");
|
|
goto out;
|
|
}
|
|
|
|
pr_info("PV spinlocks enabled\n");
|
|
|
|
__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);
|
|
}
|
|
/*
|
|
* When PV spinlock is enabled which is preferred over
|
|
* virt_spin_lock(), virt_spin_lock_key's value is meaningless.
|
|
* Just disable it anyway.
|
|
*/
|
|
out:
|
|
static_branch_disable(&virt_spin_lock_key);
|
|
}
|
|
|
|
#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("host does not support poll control\n");
|
|
pr_err_once("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;
|
|
|
|
/* Disable guest halt poll enables host halt poll */
|
|
smp_call_function_single(cpu, kvm_enable_host_haltpoll, NULL, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(arch_haltpoll_disable);
|
|
#endif
|