/* * kvm asynchronous fault support * * Copyright 2010 Red Hat, Inc. * * Author: * Gleb Natapov * * 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 #include #include #include #include "async_pf.h" #include static inline void kvm_async_page_present_sync(struct kvm_vcpu *vcpu, struct kvm_async_pf *work) { #ifdef CONFIG_KVM_ASYNC_PF_SYNC kvm_arch_async_page_present(vcpu, work); #endif } static inline void kvm_async_page_present_async(struct kvm_vcpu *vcpu, struct kvm_async_pf *work) { #ifndef CONFIG_KVM_ASYNC_PF_SYNC kvm_arch_async_page_present(vcpu, work); #endif } 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) { 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 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; int locked = 1; might_sleep(); /* * This work is run asynchromously to the task which owns * mm and might be done in another context, so we must * access remotely. */ down_read(&mm->mmap_sem); get_user_pages_remote(NULL, mm, addr, 1, FOLL_WRITE, NULL, NULL, &locked); if (locked) up_read(&mm->mmap_sem); kvm_async_page_present_sync(vcpu, apf); spin_lock(&vcpu->async_pf.lock); list_add_tail(&apf->link, &vcpu->async_pf.done); apf->vcpu = NULL; 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, gva); /* * This memory barrier pairs with prepare_to_wait's set_current_state() */ smp_mb(); if (swait_active(&vcpu->wq)) swake_up(&vcpu->wq); mmput(mm); kvm_put_kvm(vcpu->kvm); } void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu) { spin_lock(&vcpu->async_pf.lock); /* cancel outstanding work queue item */ while (!list_empty(&vcpu->async_pf.queue)) { struct kvm_async_pf *work = list_first_entry(&vcpu->async_pf.queue, typeof(*work), queue); list_del(&work->queue); /* * We know it's present in vcpu->async_pf.done, do * nothing here. */ if (!work->vcpu) continue; spin_unlock(&vcpu->async_pf.lock); #ifdef CONFIG_KVM_ASYNC_PF_SYNC flush_work(&work->work); #else if (cancel_work_sync(&work->work)) { mmput(work->mm); kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */ kmem_cache_free(async_pf_cache, work); } #endif spin_lock(&vcpu->async_pf.lock); } while (!list_empty(&vcpu->async_pf.done)) { struct kvm_async_pf *work = list_first_entry(&vcpu->async_pf.done, typeof(*work), link); list_del(&work->link); 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; while (!list_empty_careful(&vcpu->async_pf.done) && kvm_arch_can_inject_async_page_present(vcpu)) { 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_ready(vcpu, work); kvm_async_page_present_async(vcpu, work); list_del(&work->queue); vcpu->async_pf.queued--; kmem_cache_free(async_pf_cache, work); } } int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva, 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 | __GFP_NOWARN); if (!work) return 0; work->wakeup_all = false; work->vcpu = vcpu; work->gva = gva; work->addr = hva; work->arch = *arch; work->mm = current->mm; atomic_inc(&work->mm->mm_users); 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); mmput(work->mm); kmem_cache_free(async_pf_cache, work); return 0; } int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu) { struct kvm_async_pf *work; if (!list_empty_careful(&vcpu->async_pf.done)) return 0; work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC); if (!work) return -ENOMEM; work->wakeup_all = true; INIT_LIST_HEAD(&work->queue); /* for list_del to work */ spin_lock(&vcpu->async_pf.lock); list_add_tail(&work->link, &vcpu->async_pf.done); spin_unlock(&vcpu->async_pf.lock); vcpu->async_pf.queued++; return 0; } 59374fded8c477f21453681f5995c'>047487241ff59374fded8c477f21453681f5995c (diff)
Merge branch 'sparc64-non-resumable-user-error-recovery'
Liam R. Howlett says: ==================== sparc64: Recover from userspace non-resumable PIO & MEM errors A non-resumable error from userspace is able to cause a kernel panic or trap loop due to the setup and handling of the queued traps once in the kernel. This patch series addresses both of these issues. The queues are fixed by simply zeroing the memory before use. PIO errors from userspace will result in a SIGBUS being sent to the user process. The MEM errors form userspace will result in a SIGKILL and also cause the offending pages to be claimed so they are no longer used in future tasks. SIGKILL is used to ensure that the process does not try to coredump and result in an attempt to read the memory again from within kernel space. Although there is a HV call to scrub the memory (mem_scrub), there is no easy way to guarantee that the real memory address(es) are not used by other tasks. Clearing the error with mem_scrub would zero the memory and cause the other processes to proceed with bad data. The handling of other non-resumable errors remain unchanged and will cause a panic. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/soc/fsl/qe')