| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * KVM paravirt_ops implementation |
| * |
| * Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
| * Copyright IBM Corporation, 2007 |
| * Authors: Anthony Liguori <aliguori@us.ibm.com> |
| */ |
| |
| #include <linux/context_tracking.h> |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/kvm_para.h> |
| #include <linux/cpu.h> |
| #include <linux/mm.h> |
| #include <linux/highmem.h> |
| #include <linux/hardirq.h> |
| #include <linux/notifier.h> |
| #include <linux/reboot.h> |
| #include <linux/hash.h> |
| #include <linux/sched.h> |
| #include <linux/slab.h> |
| #include <linux/kprobes.h> |
| #include <linux/debugfs.h> |
| #include <linux/nmi.h> |
| #include <linux/swait.h> |
| #include <linux/syscore_ops.h> |
| #include <asm/timer.h> |
| #include <asm/cpu.h> |
| #include <asm/traps.h> |
| #include <asm/desc.h> |
| #include <asm/tlbflush.h> |
| #include <asm/apic.h> |
| #include <asm/apicdef.h> |
| #include <asm/hypervisor.h> |
| #include <asm/tlb.h> |
| #include <asm/reboot.h> |
| |
| static int kvmapf = 1; |
| |
| static int __init parse_no_kvmapf(char *arg) |
| { |
| kvmapf = 0; |
| return 0; |
| } |
| |
| early_param("no-kvmapf", parse_no_kvmapf); |
| |
| static int steal_acc = 1; |
| static int __init parse_no_stealacc(char *arg) |
| { |
| steal_acc = 0; |
| return 0; |
| } |
| |
| early_param("no-steal-acc", parse_no_stealacc); |
| |
| static DEFINE_PER_CPU_DECRYPTED(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64); |
| DEFINE_PER_CPU_DECRYPTED(struct kvm_steal_time, steal_time) __aligned(64) __visible; |
| static int has_steal_clock = 0; |
| |
| static int has_guest_poll = 0; |
| /* |
| * No need for any "IO delay" on KVM |
| */ |
| static void kvm_io_delay(void) |
| { |
| } |
| |
| #define KVM_TASK_SLEEP_HASHBITS 8 |
| #define KVM_TASK_SLEEP_HASHSIZE (1<<KVM_TASK_SLEEP_HASHBITS) |
| |
| struct kvm_task_sleep_node { |
| struct hlist_node link; |
| struct swait_queue_head wq; |
| u32 token; |
| int cpu; |
| bool halted; |
| }; |
| |
| static struct kvm_task_sleep_head { |
| raw_spinlock_t lock; |
| struct hlist_head list; |
| } async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE]; |
| |
| static struct kvm_task_sleep_node *_find_apf_task(struct kvm_task_sleep_head *b, |
| u32 token) |
| { |
| struct hlist_node *p; |
| |
| hlist_for_each(p, &b->list) { |
| struct kvm_task_sleep_node *n = |
| hlist_entry(p, typeof(*n), link); |
| if (n->token == token) |
| return n; |
| } |
| |
| return NULL; |
| } |
| |
| /* |
| * @interrupt_kernel: Is this called from a routine which interrupts the kernel |
| * (other than user space)? |
| */ |
| void kvm_async_pf_task_wait(u32 token, int interrupt_kernel) |
| { |
| u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS); |
| struct kvm_task_sleep_head *b = &async_pf_sleepers[key]; |
| struct kvm_task_sleep_node n, *e; |
| DECLARE_SWAITQUEUE(wait); |
| |
| rcu_irq_enter(); |
| |
| raw_spin_lock(&b->lock); |
| e = _find_apf_task(b, token); |
| if (e) { |
| /* dummy entry exist -> wake up was delivered ahead of PF */ |
| hlist_del(&e->link); |
| kfree(e); |
| raw_spin_unlock(&b->lock); |
| |
| rcu_irq_exit(); |
| return; |
| } |
| |
| n.token = token; |
| n.cpu = smp_processor_id(); |
| n.halted = is_idle_task(current) || |
| (IS_ENABLED(CONFIG_PREEMPT_COUNT) |
| ? preempt_count() > 1 || rcu_preempt_depth() |
| : interrupt_kernel); |
| init_swait_queue_head(&n.wq); |
| hlist_add_head(&n.link, &b->list); |
| raw_spin_unlock(&b->lock); |
| |
| for (;;) { |
| if (!n.halted) |
| prepare_to_swait_exclusive(&n.wq, &wait, TASK_UNINTERRUPTIBLE); |
| if (hlist_unhashed(&n.link)) |
| break; |
| |
| rcu_irq_exit(); |
| |
| if (!n.halted) { |
| local_irq_enable(); |
| schedule(); |
| local_irq_disable(); |
| } else { |
| /* |
| * We cannot reschedule. So halt. |
| */ |
| native_safe_halt(); |
| local_irq_disable(); |
| } |
| |
| rcu_irq_enter(); |
| } |
| if (!n.halted) |
| finish_swait(&n.wq, &wait); |
| |
| rcu_irq_exit(); |
| return; |
| } |
| EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait); |
| |
| static void apf_task_wake_one(struct kvm_task_sleep_node *n) |
| { |
| hlist_del_init(&n->link); |
| if (n->halted) |
| smp_send_reschedule(n->cpu); |
| else if (swq_has_sleeper(&n->wq)) |
| swake_up_one(&n->wq); |
| } |
| |
| static void apf_task_wake_all(void) |
| { |
| int i; |
| |
| for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) { |
| struct hlist_node *p, *next; |
| struct kvm_task_sleep_head *b = &async_pf_sleepers[i]; |
| raw_spin_lock(&b->lock); |
| hlist_for_each_safe(p, next, &b->list) { |
| struct kvm_task_sleep_node *n = |
| hlist_entry(p, typeof(*n), link); |
| if (n->cpu == smp_processor_id()) |
| apf_task_wake_one(n); |
| } |
| raw_spin_unlock(&b->lock); |
| } |
| } |
| |
| void kvm_async_pf_task_wake(u32 token) |
| { |
| u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS); |
| struct kvm_task_sleep_head *b = &async_pf_sleepers[key]; |
| struct kvm_task_sleep_node *n; |
| |
| if (token == ~0) { |
| apf_task_wake_all(); |
| return; |
| } |
| |
| again: |
| raw_spin_lock(&b->lock); |
| n = _find_apf_task(b, token); |
| if (!n) { |
| /* |
| * async PF was not yet handled. |
| * Add dummy entry for the token. |
| */ |
| n = kzalloc(sizeof(*n), GFP_ATOMIC); |
| if (!n) { |
| /* |
| * Allocation failed! Busy wait while other cpu |
| * handles async PF. |
| */ |
| raw_spin_unlock(&b->lock); |
| cpu_relax(); |
| goto again; |
| } |
| n->token = token; |
| n->cpu = smp_processor_id(); |
| init_swait_queue_head(&n->wq); |
| hlist_add_head(&n->link, &b->list); |
| } else |
| apf_task_wake_one(n); |
| raw_spin_unlock(&b->lock); |
| return; |
| } |
| EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake); |
| |
| u32 kvm_read_and_reset_pf_reason(void) |
| { |
| u32 reason = 0; |
| |
| if (__this_cpu_read(apf_reason.enabled)) { |
| reason = __this_cpu_read(apf_reason.reason); |
| __this_cpu_write(apf_reason.reason, 0); |
| } |
| |
| return reason; |
| } |
| EXPORT_SYMBOL_GPL(kvm_read_and_reset_pf_reason); |
| NOKPROBE_SYMBOL(kvm_read_and_reset_pf_reason); |
| |
| dotraplinkage void |
| do_async_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address) |
| { |
| enum ctx_state prev_state; |
| |
| switch (kvm_read_and_reset_pf_reason()) { |
| default: |
| do_page_fault(regs, error_code, address); |
| break; |
| case KVM_PV_REASON_PAGE_NOT_PRESENT: |
| /* page is swapped out by the host. */ |
| prev_state = exception_enter(); |
| kvm_async_pf_task_wait((u32)address, !user_mode(regs)); |
| exception_exit(prev_state); |
| break; |
| case KVM_PV_REASON_PAGE_READY: |
| rcu_irq_enter(); |
| kvm_async_pf_task_wake((u32)address); |
| rcu_irq_exit(); |
| break; |
| } |
| } |
| NOKPROBE_SYMBOL(do_async_page_fault); |
| |
| static void __init paravirt_ops_setup(void) |
| { |
| pv_info.name = "KVM"; |
| |
| if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY)) |
| pv_ops.cpu.io_delay = kvm_io_delay; |
| |
| #ifdef CONFIG_X86_IO_APIC |
| no_timer_check = 1; |
| #endif |
| } |
| |
| static void kvm_register_steal_time(void) |
| { |
| int cpu = smp_processor_id(); |
| struct kvm_steal_time *st = &per_cpu(steal_time, cpu); |
| |
| if (!has_steal_clock) |
| return; |
| |
| wrmsrl(MSR_KVM_STEAL_TIME, (slow_virt_to_phys(st) | KVM_MSR_ENABLED)); |
| pr_info("kvm-stealtime: cpu %d, msr %llx\n", |
| cpu, (unsigned long long) slow_virt_to_phys(st)); |
| } |
| |
| static DEFINE_PER_CPU_DECRYPTED(unsigned long, kvm_apic_eoi) = KVM_PV_EOI_DISABLED; |
| |
| static notrace void kvm_guest_apic_eoi_write(u32 reg, u32 val) |
| { |
| /** |
| * This relies on __test_and_clear_bit to modify the memory |
| * in a way that is atomic with respect to the local CPU. |
| * The hypervisor only accesses this memory from the local CPU so |
| * there's no need for lock or memory barriers. |
| * An optimization barrier is implied in apic write. |
| */ |
| if (__test_and_clear_bit(KVM_PV_EOI_BIT, this_cpu_ptr(&kvm_apic_eoi))) |
| return; |
| apic->native_eoi_write(APIC_EOI, APIC_EOI_ACK); |
| } |
| |
| static void kvm_guest_cpu_init(void) |
| { |
| if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf) { |
| u64 pa = slow_virt_to_phys(this_cpu_ptr(&apf_reason)); |
| |
| #ifdef CONFIG_PREEMPTION |
| pa |= KVM_ASYNC_PF_SEND_ALWAYS; |
| #endif |
| pa |= KVM_ASYNC_PF_ENABLED; |
| |
| if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_VMEXIT)) |
| pa |= KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT; |
| |
| wrmsrl(MSR_KVM_ASYNC_PF_EN, pa); |
| __this_cpu_write(apf_reason.enabled, 1); |
| printk(KERN_INFO"KVM setup async PF for cpu %d\n", |
| smp_processor_id()); |
| } |
| |
| if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) { |
| unsigned long pa; |
| /* Size alignment is implied but just to make it explicit. */ |
| BUILD_BUG_ON(__alignof__(kvm_apic_eoi) < 4); |
| __this_cpu_write(kvm_apic_eoi, 0); |
| pa = slow_virt_to_phys(this_cpu_ptr(&kvm_apic_eoi)) |
| | KVM_MSR_ENABLED; |
| wrmsrl(MSR_KVM_PV_EOI_EN, pa); |
| } |
| |
| if (has_steal_clock) |
| kvm_register_steal_time(); |
| } |
| |
| static void kvm_pv_disable_apf(void) |
| { |
| if (!__this_cpu_read(apf_reason.enabled)) |
| return; |
| |
| wrmsrl(MSR_KVM_ASYNC_PF_EN, 0); |
| __this_cpu_write(apf_reason.enabled, 0); |
| |
| printk(KERN_INFO"Unregister pv shared memory for cpu %d\n", |
| smp_processor_id()); |
| } |
| |
| static void kvm_disable_steal_time(void) |
| { |
| if (!has_steal_clock) |
| return; |
| |
| wrmsr(MSR_KVM_STEAL_TIME, 0, 0); |
| } |
| |
| static void kvm_pv_guest_cpu_reboot(void *unused) |
| { |
| /* |
| * We disable PV EOI before we load a new kernel by kexec, |
| * since MSR_KVM_PV_EOI_EN stores a pointer into old kernel's memory. |
| * New kernel can re-enable when it boots. |
| */ |
| if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) |
| wrmsrl(MSR_KVM_PV_EOI_EN, 0); |
| kvm_pv_disable_apf(); |
| kvm_disable_steal_time(); |
| } |
| |
| 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, |
| }; |
| |
| static u64 kvm_steal_clock(int cpu) |
| { |
| u64 steal; |
| struct kvm_steal_time *src; |
| int version; |
| |
| src = &per_cpu(steal_time, cpu); |
| do { |
| version = src->version; |
| virt_rmb(); |
| steal = src->steal; |
| virt_rmb(); |
| } while ((version & 1) || (version != src->version)); |
| |
| return steal; |
| } |
| |
| static inline void __set_percpu_decrypted(void *ptr, unsigned long size) |
| { |
| early_set_memory_decrypted((unsigned long) ptr, size); |
| } |
| |
| /* |
| * Iterate through all possible CPUs and map the memory region pointed |
| * by apf_reason, steal_time and kvm_apic_eoi as decrypted at once. |
| * |
| * Note: we iterate through all possible CPUs to ensure that CPUs |
| * hotplugged will have their per-cpu variable already mapped as |
| * decrypted. |
| */ |
| static void __init sev_map_percpu_data(void) |
| { |
| int cpu; |
| |
| if (!sev_active()) |
| return; |
| |
| for_each_possible_cpu(cpu) { |
| __set_percpu_decrypted(&per_cpu(apf_reason, cpu), sizeof(apf_reason)); |
| __set_percpu_decrypted(&per_cpu(steal_time, cpu), sizeof(steal_time)); |
| __set_percpu_decrypted(&per_cpu(kvm_apic_eoi, cpu), sizeof(kvm_apic_eoi)); |
| } |
| } |
| |
| static void kvm_guest_cpu_offline(bool shutdown) |
| { |
| kvm_disable_steal_time(); |
| if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) |
| wrmsrl(MSR_KVM_PV_EOI_EN, 0); |
| kvm_pv_disable_apf(); |
| if (!shutdown) |
| apf_task_wake_all(); |
| kvmclock_disable(); |
| } |
| |
| static int kvm_cpu_online(unsigned int cpu) |
| { |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| kvm_guest_cpu_init(); |
| local_irq_restore(flags); |
| return 0; |
| } |
| |
| #ifdef CONFIG_SMP |
| #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 && 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 |