1af585b92SGleb Natapov /* 2af585b92SGleb Natapov * kvm asynchronous fault support 3af585b92SGleb Natapov * 4af585b92SGleb Natapov * Copyright 2010 Red Hat, Inc. 5af585b92SGleb Natapov * 6af585b92SGleb Natapov * Author: 7af585b92SGleb Natapov * Gleb Natapov <gleb@redhat.com> 8af585b92SGleb Natapov * 9af585b92SGleb Natapov * This file is free software; you can redistribute it and/or modify 10af585b92SGleb Natapov * it under the terms of version 2 of the GNU General Public License 11af585b92SGleb Natapov * as published by the Free Software Foundation. 12af585b92SGleb Natapov * 13af585b92SGleb Natapov * This program is distributed in the hope that it will be useful, 14af585b92SGleb Natapov * but WITHOUT ANY WARRANTY; without even the implied warranty of 15af585b92SGleb Natapov * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16af585b92SGleb Natapov * GNU General Public License for more details. 17af585b92SGleb Natapov * 18af585b92SGleb Natapov * You should have received a copy of the GNU General Public License 19af585b92SGleb Natapov * along with this program; if not, write to the Free Software Foundation, 20af585b92SGleb Natapov * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. 21af585b92SGleb Natapov */ 22af585b92SGleb Natapov 23af585b92SGleb Natapov #include <linux/kvm_host.h> 24af585b92SGleb Natapov #include <linux/slab.h> 25af585b92SGleb Natapov #include <linux/module.h> 26af585b92SGleb Natapov #include <linux/mmu_context.h> 27af585b92SGleb Natapov 28af585b92SGleb Natapov #include "async_pf.h" 29af585b92SGleb Natapov #include <trace/events/kvm.h> 30af585b92SGleb Natapov 31e0ead41aSDominik Dingel static inline void kvm_async_page_present_sync(struct kvm_vcpu *vcpu, 32e0ead41aSDominik Dingel struct kvm_async_pf *work) 33e0ead41aSDominik Dingel { 34e0ead41aSDominik Dingel #ifdef CONFIG_KVM_ASYNC_PF_SYNC 35e0ead41aSDominik Dingel kvm_arch_async_page_present(vcpu, work); 36e0ead41aSDominik Dingel #endif 37e0ead41aSDominik Dingel } 38e0ead41aSDominik Dingel static inline void kvm_async_page_present_async(struct kvm_vcpu *vcpu, 39e0ead41aSDominik Dingel struct kvm_async_pf *work) 40e0ead41aSDominik Dingel { 41e0ead41aSDominik Dingel #ifndef CONFIG_KVM_ASYNC_PF_SYNC 42e0ead41aSDominik Dingel kvm_arch_async_page_present(vcpu, work); 43e0ead41aSDominik Dingel #endif 44e0ead41aSDominik Dingel } 45e0ead41aSDominik Dingel 46af585b92SGleb Natapov static struct kmem_cache *async_pf_cache; 47af585b92SGleb Natapov 48af585b92SGleb Natapov int kvm_async_pf_init(void) 49af585b92SGleb Natapov { 50af585b92SGleb Natapov async_pf_cache = KMEM_CACHE(kvm_async_pf, 0); 51af585b92SGleb Natapov 52af585b92SGleb Natapov if (!async_pf_cache) 53af585b92SGleb Natapov return -ENOMEM; 54af585b92SGleb Natapov 55af585b92SGleb Natapov return 0; 56af585b92SGleb Natapov } 57af585b92SGleb Natapov 58af585b92SGleb Natapov void kvm_async_pf_deinit(void) 59af585b92SGleb Natapov { 60af585b92SGleb Natapov if (async_pf_cache) 61af585b92SGleb Natapov kmem_cache_destroy(async_pf_cache); 62af585b92SGleb Natapov async_pf_cache = NULL; 63af585b92SGleb Natapov } 64af585b92SGleb Natapov 65af585b92SGleb Natapov void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu) 66af585b92SGleb Natapov { 67af585b92SGleb Natapov INIT_LIST_HEAD(&vcpu->async_pf.done); 68af585b92SGleb Natapov INIT_LIST_HEAD(&vcpu->async_pf.queue); 69af585b92SGleb Natapov spin_lock_init(&vcpu->async_pf.lock); 70af585b92SGleb Natapov } 71af585b92SGleb Natapov 72af585b92SGleb Natapov static void async_pf_execute(struct work_struct *work) 73af585b92SGleb Natapov { 74af585b92SGleb Natapov struct kvm_async_pf *apf = 75af585b92SGleb Natapov container_of(work, struct kvm_async_pf, work); 76af585b92SGleb Natapov struct mm_struct *mm = apf->mm; 77af585b92SGleb Natapov struct kvm_vcpu *vcpu = apf->vcpu; 78af585b92SGleb Natapov unsigned long addr = apf->addr; 79af585b92SGleb Natapov gva_t gva = apf->gva; 80af585b92SGleb Natapov 81af585b92SGleb Natapov might_sleep(); 82af585b92SGleb Natapov 83af585b92SGleb Natapov use_mm(mm); 84af585b92SGleb Natapov down_read(&mm->mmap_sem); 85f2e10669Schai wen get_user_pages(current, mm, addr, 1, 1, 0, NULL, NULL); 86af585b92SGleb Natapov up_read(&mm->mmap_sem); 87e0ead41aSDominik Dingel kvm_async_page_present_sync(vcpu, apf); 88af585b92SGleb Natapov unuse_mm(mm); 89af585b92SGleb Natapov 90af585b92SGleb Natapov spin_lock(&vcpu->async_pf.lock); 91af585b92SGleb Natapov list_add_tail(&apf->link, &vcpu->async_pf.done); 92af585b92SGleb Natapov spin_unlock(&vcpu->async_pf.lock); 93af585b92SGleb Natapov 94af585b92SGleb Natapov /* 95af585b92SGleb Natapov * apf may be freed by kvm_check_async_pf_completion() after 96af585b92SGleb Natapov * this point 97af585b92SGleb Natapov */ 98af585b92SGleb Natapov 99f2e10669Schai wen trace_kvm_async_pf_completed(addr, gva); 100af585b92SGleb Natapov 101af585b92SGleb Natapov if (waitqueue_active(&vcpu->wq)) 102af585b92SGleb Natapov wake_up_interruptible(&vcpu->wq); 103af585b92SGleb Natapov 104af585b92SGleb Natapov mmdrop(mm); 105af585b92SGleb Natapov kvm_put_kvm(vcpu->kvm); 106af585b92SGleb Natapov } 107af585b92SGleb Natapov 108af585b92SGleb Natapov void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu) 109af585b92SGleb Natapov { 110af585b92SGleb Natapov /* cancel outstanding work queue item */ 111af585b92SGleb Natapov while (!list_empty(&vcpu->async_pf.queue)) { 112af585b92SGleb Natapov struct kvm_async_pf *work = 113af585b92SGleb Natapov list_entry(vcpu->async_pf.queue.next, 114af585b92SGleb Natapov typeof(*work), queue); 115af585b92SGleb Natapov list_del(&work->queue); 11698fda169SRadim Krčmář if (cancel_work_sync(&work->work)) { 11728b441e2SRadim Krčmář mmdrop(work->mm); 11828b441e2SRadim Krčmář kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */ 119af585b92SGleb Natapov kmem_cache_free(async_pf_cache, work); 120af585b92SGleb Natapov } 12128b441e2SRadim Krčmář } 122af585b92SGleb Natapov 123af585b92SGleb Natapov spin_lock(&vcpu->async_pf.lock); 124af585b92SGleb Natapov while (!list_empty(&vcpu->async_pf.done)) { 125af585b92SGleb Natapov struct kvm_async_pf *work = 126af585b92SGleb Natapov list_entry(vcpu->async_pf.done.next, 127af585b92SGleb Natapov typeof(*work), link); 128af585b92SGleb Natapov list_del(&work->link); 129af585b92SGleb Natapov kmem_cache_free(async_pf_cache, work); 130af585b92SGleb Natapov } 131af585b92SGleb Natapov spin_unlock(&vcpu->async_pf.lock); 132af585b92SGleb Natapov 133af585b92SGleb Natapov vcpu->async_pf.queued = 0; 134af585b92SGleb Natapov } 135af585b92SGleb Natapov 136af585b92SGleb Natapov void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu) 137af585b92SGleb Natapov { 138af585b92SGleb Natapov struct kvm_async_pf *work; 139af585b92SGleb Natapov 14015096ffcSXiao Guangrong while (!list_empty_careful(&vcpu->async_pf.done) && 14115096ffcSXiao Guangrong kvm_arch_can_inject_async_page_present(vcpu)) { 142af585b92SGleb Natapov spin_lock(&vcpu->async_pf.lock); 14315096ffcSXiao Guangrong work = list_first_entry(&vcpu->async_pf.done, typeof(*work), 14415096ffcSXiao Guangrong link); 145af585b92SGleb Natapov list_del(&work->link); 146af585b92SGleb Natapov spin_unlock(&vcpu->async_pf.lock); 147af585b92SGleb Natapov 14856028d08SGleb Natapov kvm_arch_async_page_ready(vcpu, work); 149af585b92SGleb Natapov kvm_arch_async_page_present(vcpu, work); 150af585b92SGleb Natapov 151af585b92SGleb Natapov list_del(&work->queue); 152af585b92SGleb Natapov vcpu->async_pf.queued--; 153af585b92SGleb Natapov kmem_cache_free(async_pf_cache, work); 154af585b92SGleb Natapov } 15515096ffcSXiao Guangrong } 156af585b92SGleb Natapov 157e0ead41aSDominik Dingel int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva, 158af585b92SGleb Natapov struct kvm_arch_async_pf *arch) 159af585b92SGleb Natapov { 160af585b92SGleb Natapov struct kvm_async_pf *work; 161af585b92SGleb Natapov 162af585b92SGleb Natapov if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU) 163af585b92SGleb Natapov return 0; 164af585b92SGleb Natapov 165af585b92SGleb Natapov /* setup delayed work */ 166af585b92SGleb Natapov 167af585b92SGleb Natapov /* 168af585b92SGleb Natapov * do alloc nowait since if we are going to sleep anyway we 169af585b92SGleb Natapov * may as well sleep faulting in page 170af585b92SGleb Natapov */ 171af585b92SGleb Natapov work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT); 172af585b92SGleb Natapov if (!work) 173af585b92SGleb Natapov return 0; 174af585b92SGleb Natapov 175f2e10669Schai wen work->wakeup_all = false; 176af585b92SGleb Natapov work->vcpu = vcpu; 177af585b92SGleb Natapov work->gva = gva; 178e0ead41aSDominik Dingel work->addr = hva; 179af585b92SGleb Natapov work->arch = *arch; 180af585b92SGleb Natapov work->mm = current->mm; 181af585b92SGleb Natapov atomic_inc(&work->mm->mm_count); 182af585b92SGleb Natapov kvm_get_kvm(work->vcpu->kvm); 183af585b92SGleb Natapov 184af585b92SGleb Natapov /* this can't really happen otherwise gfn_to_pfn_async 185af585b92SGleb Natapov would succeed */ 186af585b92SGleb Natapov if (unlikely(kvm_is_error_hva(work->addr))) 187af585b92SGleb Natapov goto retry_sync; 188af585b92SGleb Natapov 189af585b92SGleb Natapov INIT_WORK(&work->work, async_pf_execute); 190af585b92SGleb Natapov if (!schedule_work(&work->work)) 191af585b92SGleb Natapov goto retry_sync; 192af585b92SGleb Natapov 193af585b92SGleb Natapov list_add_tail(&work->queue, &vcpu->async_pf.queue); 194af585b92SGleb Natapov vcpu->async_pf.queued++; 195af585b92SGleb Natapov kvm_arch_async_page_not_present(vcpu, work); 196af585b92SGleb Natapov return 1; 197af585b92SGleb Natapov retry_sync: 198af585b92SGleb Natapov kvm_put_kvm(work->vcpu->kvm); 199af585b92SGleb Natapov mmdrop(work->mm); 200af585b92SGleb Natapov kmem_cache_free(async_pf_cache, work); 201af585b92SGleb Natapov return 0; 202af585b92SGleb Natapov } 203344d9588SGleb Natapov 204344d9588SGleb Natapov int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu) 205344d9588SGleb Natapov { 206344d9588SGleb Natapov struct kvm_async_pf *work; 207344d9588SGleb Natapov 20864f638c7SXiao Guangrong if (!list_empty_careful(&vcpu->async_pf.done)) 209344d9588SGleb Natapov return 0; 210344d9588SGleb Natapov 211344d9588SGleb Natapov work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC); 212344d9588SGleb Natapov if (!work) 213344d9588SGleb Natapov return -ENOMEM; 214344d9588SGleb Natapov 215f2e10669Schai wen work->wakeup_all = true; 216344d9588SGleb Natapov INIT_LIST_HEAD(&work->queue); /* for list_del to work */ 217344d9588SGleb Natapov 21864f638c7SXiao Guangrong spin_lock(&vcpu->async_pf.lock); 219344d9588SGleb Natapov list_add_tail(&work->link, &vcpu->async_pf.done); 22064f638c7SXiao Guangrong spin_unlock(&vcpu->async_pf.lock); 22164f638c7SXiao Guangrong 222344d9588SGleb Natapov vcpu->async_pf.queued++; 223344d9588SGleb Natapov return 0; 224344d9588SGleb Natapov } 225