diff options
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 18 | ||||
| -rw-r--r-- | arch/x86/kvm/Kconfig | 1 | ||||
| -rw-r--r-- | arch/x86/kvm/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu.c | 52 | ||||
| -rw-r--r-- | arch/x86/kvm/paging_tmpl.h | 4 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 112 | ||||
| -rw-r--r-- | include/linux/kvm_host.h | 31 | ||||
| -rw-r--r-- | include/trace/events/kvm.h | 90 | ||||
| -rw-r--r-- | virt/kvm/Kconfig | 3 | ||||
| -rw-r--r-- | virt/kvm/async_pf.c | 190 | ||||
| -rw-r--r-- | virt/kvm/async_pf.h | 36 | ||||
| -rw-r--r-- | virt/kvm/kvm_main.c | 48 |
12 files changed, 570 insertions, 16 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index f702f82aa1eb..b5f4c1a36d65 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -83,11 +83,14 @@ #define KVM_NR_FIXED_MTRR_REGION 88 #define KVM_NR_VAR_MTRR 8 +#define ASYNC_PF_PER_VCPU 64 + extern spinlock_t kvm_lock; extern struct list_head vm_list; struct kvm_vcpu; struct kvm; +struct kvm_async_pf; enum kvm_reg { VCPU_REGS_RAX = 0, @@ -412,6 +415,11 @@ struct kvm_vcpu_arch { u64 hv_vapic; cpumask_var_t wbinvd_dirty_mask; + + struct { + bool halted; + gfn_t gfns[roundup_pow_of_two(ASYNC_PF_PER_VCPU)]; + } apf; }; struct kvm_arch { @@ -585,6 +593,10 @@ struct kvm_x86_ops { const struct trace_print_flags *exit_reasons_str; }; +struct kvm_arch_async_pf { + gfn_t gfn; +}; + extern struct kvm_x86_ops *kvm_x86_ops; int kvm_mmu_module_init(void); @@ -799,4 +811,10 @@ void kvm_set_shared_msr(unsigned index, u64 val, u64 mask); bool kvm_is_linear_rip(struct kvm_vcpu *vcpu, unsigned long linear_rip); +void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu, + struct kvm_async_pf *work); +void kvm_arch_async_page_present(struct kvm_vcpu *vcpu, + struct kvm_async_pf *work); +extern bool kvm_find_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn); + #endif /* _ASM_X86_KVM_HOST_H */ diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index ddc131ff438f..50f63648ce1b 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -28,6 +28,7 @@ config KVM select HAVE_KVM_IRQCHIP select HAVE_KVM_EVENTFD select KVM_APIC_ARCHITECTURE + select KVM_ASYNC_PF select USER_RETURN_NOTIFIER select KVM_MMIO ---help--- diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile index 31a7035c4bd9..c53bf19b1da0 100644 --- a/arch/x86/kvm/Makefile +++ b/arch/x86/kvm/Makefile @@ -9,6 +9,7 @@ kvm-y += $(addprefix ../../../virt/kvm/, kvm_main.o ioapic.o \ coalesced_mmio.o irq_comm.o eventfd.o \ assigned-dev.o) kvm-$(CONFIG_IOMMU_API) += $(addprefix ../../../virt/kvm/, iommu.o) +kvm-$(CONFIG_KVM_ASYNC_PF) += $(addprefix ../../../virt/kvm/, async_pf.o) kvm-y += x86.o mmu.o emulate.o i8259.o irq.o lapic.o \ i8254.o timer.o diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index fbb04aee8301..4ab04de5a76a 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -18,9 +18,11 @@ * */ +#include "irq.h" #include "mmu.h" #include "x86.h" #include "kvm_cache_regs.h" +#include "x86.h" #include <linux/kvm_host.h> #include <linux/types.h> @@ -2587,6 +2589,50 @@ static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva, error_code & PFERR_WRITE_MASK, gfn); } +int kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn) +{ + struct kvm_arch_async_pf arch; + arch.gfn = gfn; + + return kvm_setup_async_pf(vcpu, gva, gfn, &arch); +} + +static bool can_do_async_pf(struct kvm_vcpu *vcpu) +{ + if (unlikely(!irqchip_in_kernel(vcpu->kvm) || + kvm_event_needs_reinjection(vcpu))) + return false; + + return kvm_x86_ops->interrupt_allowed(vcpu); +} + +static bool try_async_pf(struct kvm_vcpu *vcpu, gfn_t gfn, gva_t gva, + pfn_t *pfn) +{ + bool async; + + *pfn = gfn_to_pfn_async(vcpu->kvm, gfn, &async); + + if (!async) + return false; /* *pfn has correct page already */ + + put_page(pfn_to_page(*pfn)); + + if (can_do_async_pf(vcpu)) { + trace_kvm_try_async_get_page(async, *pfn); + if (kvm_find_async_pf_gfn(vcpu, gfn)) { + trace_kvm_async_pf_doublefault(gva, gfn); + kvm_make_request(KVM_REQ_APF_HALT, vcpu); + return true; + } else if (kvm_arch_setup_async_pf(vcpu, gva, gfn)) + return true; + } + + *pfn = gfn_to_pfn(vcpu->kvm, gfn); + + return false; +} + static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code) { @@ -2609,7 +2655,11 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, mmu_seq = vcpu->kvm->mmu_notifier_seq; smp_rmb(); - pfn = gfn_to_pfn(vcpu->kvm, gfn); + + if (try_async_pf(vcpu, gfn, gpa, &pfn)) + return 0; + + /* mmio */ if (is_error_pfn(pfn)) return kvm_handle_bad_page(vcpu->kvm, gfn, pfn); spin_lock(&vcpu->kvm->mmu_lock); diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index cd7a833a3b52..c45376dd041a 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -568,7 +568,9 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, mmu_seq = vcpu->kvm->mmu_notifier_seq; smp_rmb(); - pfn = gfn_to_pfn(vcpu->kvm, walker.gfn); + + if (try_async_pf(vcpu, walker.gfn, addr, &pfn)) + return 0; /* mmio */ if (is_error_pfn(pfn)) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c05d47701292..3cd4d091c2f3 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -43,6 +43,7 @@ #include <linux/slab.h> #include <linux/perf_event.h> #include <linux/uaccess.h> +#include <linux/hash.h> #include <trace/events/kvm.h> #define CREATE_TRACE_POINTS @@ -155,6 +156,13 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { u64 __read_mostly host_xcr0; +static inline void kvm_async_pf_hash_reset(struct kvm_vcpu *vcpu) +{ + int i; + for (i = 0; i < roundup_pow_of_two(ASYNC_PF_PER_VCPU); i++) + vcpu->arch.apf.gfns[i] = ~0; +} + static void kvm_on_user_return(struct user_return_notifier *urn) { unsigned slot; @@ -5115,6 +5123,12 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) vcpu->fpu_active = 0; kvm_x86_ops->fpu_deactivate(vcpu); } + if (kvm_check_request(KVM_REQ_APF_HALT, vcpu)) { + /* Page is swapped out. Do synthetic halt */ + vcpu->arch.apf.halted = true; + r = 1; + goto out; + } } r = kvm_mmu_reload(vcpu); @@ -5243,7 +5257,8 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) r = 1; while (r > 0) { - if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE) + if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE && + !vcpu->arch.apf.halted) r = vcpu_enter_guest(vcpu); else { srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx); @@ -5256,6 +5271,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE; case KVM_MP_STATE_RUNNABLE: + vcpu->arch.apf.halted = false; break; case KVM_MP_STATE_SIPI_RECEIVED: default: @@ -5277,6 +5293,9 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) vcpu->run->exit_reason = KVM_EXIT_INTR; ++vcpu->stat.request_irq_exits; } + + kvm_check_async_pf_completion(vcpu); + if (signal_pending(current)) { r = -EINTR; vcpu->run->exit_reason = KVM_EXIT_INTR; @@ -5792,6 +5811,10 @@ int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu) kvm_make_request(KVM_REQ_EVENT, vcpu); + kvm_clear_async_pf_completion_queue(vcpu); + kvm_async_pf_hash_reset(vcpu); + vcpu->arch.apf.halted = false; + return kvm_x86_ops->vcpu_reset(vcpu); } @@ -5880,6 +5903,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu) if (!zalloc_cpumask_var(&vcpu->arch.wbinvd_dirty_mask, GFP_KERNEL)) goto fail_free_mce_banks; + kvm_async_pf_hash_reset(vcpu); + return 0; fail_free_mce_banks: kfree(vcpu->arch.mce_banks); @@ -5938,8 +5963,10 @@ static void kvm_free_vcpus(struct kvm *kvm) /* * Unpin any mmu pages first. */ - kvm_for_each_vcpu(i, vcpu, kvm) + kvm_for_each_vcpu(i, vcpu, kvm) { + kvm_clear_async_pf_completion_queue(vcpu); kvm_unload_vcpu_mmu(vcpu); + } kvm_for_each_vcpu(i, vcpu, kvm) kvm_arch_vcpu_free(vcpu); @@ -6050,7 +6077,9 @@ void kvm_arch_flush_shadow(struct kvm *kvm) int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu) { - return vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE + return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE && + !vcpu->arch.apf.halted) + || !list_empty_careful(&vcpu->async_pf.done) || vcpu->arch.mp_state == KVM_MP_STATE_SIPI_RECEIVED || vcpu->arch.nmi_pending || (kvm_arch_interrupt_allowed(vcpu) && @@ -6109,6 +6138,83 @@ void kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags) } EXPORT_SYMBOL_GPL(kvm_set_rflags); +static inline u32 kvm_async_pf_hash_fn(gfn_t gfn) +{ + return hash_32(gfn & 0xffffffff, order_base_2(ASYNC_PF_PER_VCPU)); +} + +static inline u32 kvm_async_pf_next_probe(u32 key) +{ + return (key + 1) & (roundup_pow_of_two(ASYNC_PF_PER_VCPU) - 1); +} + +static void kvm_add_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + u32 key = kvm_async_pf_hash_fn(gfn); + + while (vcpu->arch.apf.gfns[key] != ~0) + key = kvm_async_pf_next_probe(key); + + vcpu->arch.apf.gfns[key] = gfn; +} + +static u32 kvm_async_pf_gfn_slot(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + int i; + u32 key = kvm_async_pf_hash_fn(gfn); + + for (i = 0; i < roundup_pow_of_two(ASYNC_PF_PER_VCPU) && + (vcpu->arch.apf.gfns[key] != gfn || + vcpu->arch.apf.gfns[key] == ~0); i++) + key = kvm_async_pf_next_probe(key); + + return key; +} + +bool kvm_find_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + return vcpu->arch.apf.gfns[kvm_async_pf_gfn_slot(vcpu, gfn)] == gfn; +} + +static void kvm_del_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn) +{ + u32 i, j, k; + + i = j = kvm_async_pf_gfn_slot(vcpu, gfn); + while (true) { + vcpu->arch.apf.gfns[i] = ~0; + do { + j = kvm_async_pf_next_probe(j); + if (vcpu->arch.apf.gfns[j] == ~0) + return; + k = kvm_async_pf_hash_fn(vcpu->arch.apf.gfns[j]); + /* + * k lies cyclically in ]i,j] + * | i.k.j | + * |....j i.k.| or |.k..j i...| + */ + } while ((i <= j) ? (i < k && k <= j) : (i < k || k <= j)); + vcpu->arch.apf.gfns[i] = vcpu->arch.apf.gfns[j]; + i = j; + } +} + +void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu, + struct kvm_async_pf *work) +{ + trace_kvm_async_pf_not_present(work->gva); + + kvm_make_request(KVM_REQ_APF_HALT, vcpu); + kvm_add_async_pf_gfn(vcpu, work->arch.gfn); +} + +void kvm_arch_async_page_present(struct kvm_vcpu *vcpu, + struct kvm_async_pf *work) +{ + trace_kvm_async_pf_ready(work->gva); + kvm_del_async_pf_gfn(vcpu, work->arch.gfn); +} + EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit); EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq); EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_page_fault); diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index a0557422715e..e56acc7857e2 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -40,6 +40,7 @@ #define KVM_REQ_KICK 9 #define KVM_REQ_DEACTIVATE_FPU 10 #define KVM_REQ_EVENT 11 +#define KVM_REQ_APF_HALT 12 #define KVM_USERSPACE_IRQ_SOURCE_ID 0 @@ -74,6 +75,26 @@ int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx, struct kvm_io_device *dev); +#ifdef CONFIG_KVM_ASYNC_PF +struct kvm_async_pf { + struct work_struct work; + struct list_head link; + struct list_head queue; + struct kvm_vcpu *vcpu; + struct mm_struct *mm; + gva_t gva; + unsigned long addr; + struct kvm_arch_async_pf arch; + struct page *page; + bool done; +}; + +void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu); +void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu); +int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn, + struct kvm_arch_async_pf *arch); +#endif + struct kvm_vcpu { struct kvm *kvm; #ifdef CONFIG_PREEMPT_NOTIFIERS @@ -104,6 +125,15 @@ struct kvm_vcpu { gpa_t mmio_phys_addr; #endif +#ifdef CONFIG_KVM_ASYNC_PF + struct { + u32 queued; + struct list_head queue; + struct list_head done; + spinlock_t lock; + } async_pf; +#endif + struct kvm_vcpu_arch arch; }; @@ -302,6 +332,7 @@ void kvm_set_page_accessed(struct page *page); pfn_t hva_to_pfn_atomic(struct kvm *kvm, unsigned long addr); pfn_t gfn_to_pfn_atomic(struct kvm *kvm, gfn_t gfn); +pfn_t gfn_to_pfn_async(struct kvm *kvm, gfn_t gfn, bool *async); pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn); pfn_t gfn_to_pfn_memslot(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn); diff --git a/include/trace/events/kvm.h b/include/trace/events/kvm.h index 6dd3a51ab1cb..a78a5e574632 100644 --- a/include/trace/events/kvm.h +++ b/include/trace/events/kvm.h @@ -185,6 +185,96 @@ TRACE_EVENT(kvm_age_page, __entry->referenced ? "YOUNG" : "OLD") ); +#ifdef CONFIG_KVM_ASYNC_PF +TRACE_EVENT( + kvm_try_async_get_page, + TP_PROTO(bool async, u64 pfn), + TP_ARGS(async, pfn), + + TP_STRUCT__entry( + __field(__u64, pfn) + ), + + TP_fast_assign( + __entry->pfn = (!async) ? pfn : (u64)-1; + ), + + TP_printk("pfn %#llx", __entry->pfn) +); + +TRACE_EVENT( + kvm_async_pf_not_present, + TP_PROTO(u64 gva), + TP_ARGS(gva), + + TP_STRUCT__entry( + __field(__u64, gva) + ), + + TP_fast_assign( + __entry->gva = gva; + ), + + TP_printk("gva %#llx not present", __entry->gva) +); + +TRACE_EVENT( + kvm_async_pf_ready, + TP_PROTO(u64 gva), + TP_ARGS(gva), + + TP_STRUCT__entry( + __field(__u64, gva) + ), + + TP_fast_assign( + __entry->gva = gva; + ), + + TP_printk("gva %#llx ready", __entry->gva) +); + +TRACE_EVENT( + kvm_async_pf_completed, + TP_PROTO(unsigned long address, struct page *page, u64 gva), + TP_ARGS(address, page, gva), + + TP_STRUCT__entry( + __field(unsigned long, address) + __field(pfn_t, pfn) + __field(u64, gva) + ), + + TP_fast_assign( + __entry->address = address; + __entry->pfn = page ? page_to_pfn(page) : 0; + __entry->gva = gva; + ), + + TP_printk("gva %#llx address %#lx pfn %#llx", __entry->gva, + __entry->address, __entry->pfn) +); + +TRACE_EVENT( + kvm_async_pf_doublefault, + TP_PROTO(u64 gva, u64 gfn), + TP_ARGS(gva, gfn), + + TP_STRUCT__entry( + __field(u64, gva) + __field(u64, gfn) + ), + + TP_fast_assign( + __entry->gva = gva; + __entry->gfn = gfn; + ), + + TP_printk("gva = %#llx, gfn = %#llx", __entry->gva, __entry->gfn) +); + +#endif + #endif /* _TRACE_KVM_MAIN_H */ /* This part must be outside protection */ diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 7f1178f6b839..f63ccb0a5982 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -15,3 +15,6 @@ config KVM_APIC_ARCHITECTURE config KVM_MMIO bool + +config KVM_ASYNC_PF + bool diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c new file mode 100644 index 000000000000..857d63431cb7 --- /dev/null +++ b/virt/kvm/async_pf.c @@ -0,0 +1,190 @@ +/* + * kvm asynchronous fault support + * + * Copyright 2010 Red Hat, Inc. + * + * Author: + * Gleb Natapov <gleb@redhat.com> + * + * This file is free software; you can redistribute it and/or modify + * it under the terms of version 2 of the GNU General Public License + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. + */ + +#include <linux/kvm_host.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/mmu_context.h> + +#include "async_pf.h" +#include <trace/events/kvm.h> + +static struct kmem_cache *async_pf_cache; + +int kvm_async_pf_init(void) +{ + async_pf_cache = KMEM_CACHE(kvm_async_pf, 0); + + if (!async_pf_cache) + return -ENOMEM; + + return 0; +} + +void kvm_async_pf_deinit(void) +{ + if (async_pf_cache) + kmem_cache_destroy(async_pf_cache); + async_pf_cache = NULL; +} + +void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu) +{ + INIT_LIST_HEAD(&vcpu->async_pf.done); + INIT_LIST_HEAD(&vcpu->async_pf.queue); + spin_lock_init(&vcpu->async_pf.lock); +} + +static void async_pf_execute(struct work_struct *work) +{ + struct page *page = NULL; + struct kvm_async_pf *apf = + container_of(work, struct kvm_async_pf, work); + struct mm_struct *mm = apf->mm; + struct kvm_vcpu *vcpu = apf->vcpu; + unsigned long addr = apf->addr; + gva_t gva = apf->gva; + + might_sleep(); + + use_mm(mm); + down_read(&mm->mmap_sem); + get_user_pages(current, mm, addr, 1, 1, 0, &page, NULL); + up_read(&mm->mmap_sem); + unuse_mm(mm); + + spin_lock(&vcpu->async_pf.lock); + list_add_tail(&apf->link, &vcpu->async_pf.done); + apf->page = page; + apf->done = true; + spin_unlock(&vcpu->async_pf.lock); + + /* + * apf may be freed by kvm_check_async_pf_completion() after + * this point + */ + + trace_kvm_async_pf_completed(addr, page, gva); + + if (waitqueue_active(&vcpu->wq)) + wake_up_interruptible(&vcpu->wq); + + mmdrop(mm); + kvm_put_kvm(vcpu->kvm); +} + +void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu) +{ + /* cancel outstanding work queue item */ + while (!list_empty(&vcpu->async_pf.queue)) { + struct kvm_async_pf *work = + list_entry(vcpu->async_pf.queue.next, + typeof(*work), queue); + cancel_work_sync(&work->work); + list_del(&work->queue); + if (!work->done) /* work was canceled */ + kmem_cache_free(async_pf_cache, work); + } + + spin_lock(&vcpu->async_pf.lock); + while (!list_empty(&vcpu->async_pf.done)) { + struct kvm_async_pf *work = + list_entry(vcpu->async_pf.done.next, + typeof(*work), link); + list_del(&work->link); + if (work->page) + put_page(work->page); + kmem_cache_free(async_pf_cache, work); + } + spin_unlock(&vcpu->async_pf.lock); + + vcpu->async_pf.queued = 0; +} + +void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu) +{ + struct kvm_async_pf *work; + + if (list_empty_careful(&vcpu->async_pf.done)) + return; + + spin_lock(&vcpu->async_pf.lock); + work = list_first_entry(&vcpu->async_pf.done, typeof(*work), link); + list_del(&work->link); + spin_unlock(&vcpu->async_pf.lock); + + kvm_arch_async_page_present(vcpu, work); + + list_del(&work->queue); + vcpu->async_pf.queued--; + if (work->page) + put_page(work->page); + kmem_cache_free(async_pf_cache, work); +} + +int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn, + struct kvm_arch_async_pf *arch) +{ + struct kvm_async_pf *work; + + if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU) + return 0; + + /* setup delayed work */ + + /* + * do alloc nowait since if we are going to sleep anyway we + * may as well sleep faulting in page + */ + work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT); + if (!work) + return 0; + + work->page = NULL; + work->done = false; + work->vcpu = vcpu; + work->gva = gva; + work->addr = gfn_to_hva(vcpu->kvm, gfn); + work->arch = *arch; + work->mm = current->mm; + atomic_inc(&work->mm->mm_count); + kvm_get_kvm(work->vcpu->kvm); + + /* this can't really happen otherwise gfn_to_pfn_async + would succeed */ + if (unlikely(kvm_is_error_hva(work->addr))) + goto retry_sync; + + INIT_WORK(&work->work, async_pf_execute); + if (!schedule_work(&work->work)) + goto retry_sync; + + list_add_tail(&work->queue, &vcpu->async_pf.queue); + vcpu->async_pf.queued++; + kvm_arch_async_page_not_present(vcpu, work); + return 1; +retry_sync: + kvm_put_kvm(work->vcpu->kvm); + mmdrop(work->mm); + kmem_cache_free(async_pf_cache, work); + return 0; +} diff --git a/virt/kvm/async_pf.h b/virt/kvm/async_pf.h new file mode 100644 index 000000000000..e7ef6447cb82 --- /dev/null +++ b/virt/kvm/async_pf.h @@ -0,0 +1,36 @@ +/* + * kvm asynchronous fault support + * + * Copyright 2010 Red Hat, Inc. + * + * Author: + * Gleb Natapov <gleb@redhat.com> + * + * This file is free software; you can redistribute it and/or modify + * it under the terms of version 2 of the GNU General Public License + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. + */ + +#ifndef __KVM_ASYNC_PF_H__ +#define __KVM_ASYNC_PF_H__ + +#ifdef CONFIG_KVM_ASYNC_PF +int kvm_async_pf_init(void); +void kvm_async_pf_deinit(void); +void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu); +#else +#define kvm_async_pf_init() (0) +#define kvm_async_pf_deinit() do{}while(0) +#define kvm_async_pf_vcpu_init(C) do{}while(0) +#endif + +#endif diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 5225052aebc1..75fd590c0214 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -55,6 +55,7 @@ #include <asm-generic/bitops/le.h> #include "coalesced_mmio.h" +#include "async_pf.h" #define CREATE_TRACE_POINTS #include <trace/events/kvm.h> @@ -186,6 +187,7 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id) vcpu->kvm = kvm; vcpu->vcpu_id = id; init_waitqueue_head(&vcpu->wq); + kvm_async_pf_vcpu_init(vcpu); page = alloc_page(GFP_KERNEL | __GFP_ZERO); if (!page) { @@ -946,15 +948,20 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn) } EXPORT_SYMBOL_GPL(gfn_to_hva); -static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic) +static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic, + bool *async) { struct page *page[1]; - int npages; + int npages = 0; pfn_t pfn; - if (atomic) + /* we can do it either atomically or asynchronously, not both */ + BUG_ON(atomic && async); + + if (atomic || async) npages = __get_user_pages_fast(addr, 1, 1, page); - else { + + if (unlikely(npages != 1) && !atomic) { might_sleep(); npages = get_user_pages_fast(addr, 1, 1, page); } @@ -976,6 +983,9 @@ static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic) if (vma == NULL || addr < vma->vm_start || !(vma->vm_flags & VM_PFNMAP)) { + if (async && !(vma->vm_flags & VM_PFNMAP) && + (vma->vm_flags & VM_WRITE)) + *async = true; up_read(¤t->mm->mmap_sem); return_fault_page: get_page(fault_page); @@ -993,32 +1003,41 @@ return_fault_page: pfn_t hva_to_pfn_atomic(struct kvm *kvm, unsigned long addr) { - return hva_to_pfn(kvm, addr, true); + return hva_to_pfn(kvm, addr, true, NULL); } EXPORT_SYMBOL_GPL(hva_to_pfn_atomic); -static pfn_t __gfn_to_pfn(struct kvm *kvm, gfn_t gfn, bool atomic) +static pfn_t __gfn_to_pfn(struct kvm *kvm, gfn_t gfn, bool atomic, bool *async) { unsigned long addr; + if (async) + *async = false; + addr = gfn_to_hva(kvm, gfn); if (kvm_is_error_hva(addr)) { get_page(bad_page); return page_to_pfn(bad_page); } - return hva_to_pfn(kvm, addr, atomic); + return hva_to_pfn(kvm, addr, atomic, async); } pfn_t gfn_to_pfn_atomic(struct kvm *kvm, gfn_t gfn) { - return __gfn_to_pfn(kvm, gfn, true); + return __gfn_to_pfn(kvm, gfn, true, NULL); } EXPORT_SYMBOL_GPL(gfn_to_pfn_atomic); +pfn_t gfn_to_pfn_async(struct kvm *kvm, gfn_t gfn, bool *async) +{ + return __gfn_to_pfn(kvm, gfn, false, async); +} +EXPORT_SYMBOL_GPL(gfn_to_pfn_async); + pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn) { - return __gfn_to_pfn(kvm, gfn, false); + return __gfn_to_pfn(kvm, gfn, false, NULL); } EXPORT_SYMBOL_GPL(gfn_to_pfn); @@ -1026,7 +1045,7 @@ pfn_t gfn_to_pfn_memslot(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn) { unsigned long addr = gfn_to_hva_memslot(slot, gfn); - return hva_to_pfn(kvm, addr, false); + return hva_to_pfn(kvm, addr, false, NULL); } int gfn_to_page_many_atomic(struct kvm *kvm, gfn_t gfn, struct page **pages, @@ -2336,6 +2355,10 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, goto out_free_5; } + r = kvm_async_pf_init(); + if (r) + goto out_free; + kvm_chardev_ops.owner = module; kvm_vm_fops.owner = module; kvm_vcpu_fops.owner = module; @@ -2343,7 +2366,7 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, r = misc_register(&kvm_dev); if (r) { printk(KERN_ERR "kvm: misc device register failed\n"); - goto out_free; + goto out_unreg; } kvm_preempt_ops.sched_in = kvm_sched_in; @@ -2353,6 +2376,8 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, return 0; +out_unreg: + kvm_async_pf_deinit(); out_free: kmem_cache_destroy(kvm_vcpu_cache); out_free_5: @@ -2385,6 +2410,7 @@ void kvm_exit(void) kvm_exit_debug(); misc_deregister(&kvm_dev); kmem_cache_destroy(kvm_vcpu_cache); + kvm_async_pf_deinit(); sysdev_unregister(&kvm_sysdev); sysdev_class_unregister(&kvm_sysdev_class); unregister_reboot_notifier(&kvm_reboot_notifier); |
