[v7,2/3] kvm: add support for irqfd via eventfd-notification interface

Message ID	20090512182655.26131.53824.stgit@dev.haskins.net (mailing list archive)
State	New, archived
Headers	show Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n4CIRPra011583 for <patchwork-kvm@patchwork.kernel.org>; Tue, 12 May 2009 18:27:26 GMT From: Gregory Haskins <ghaskins@novell.com> Subject: [KVM PATCH v7 2/3] kvm: add support for irqfd via eventfd-notification interface To: kvm@vger.kernel.org Cc: viro@ZenIV.linux.org.uk, linux-kernel@vger.kernel.org, avi@redhat.com, davidel@xmailserver.org Date: Tue, 12 May 2009 14:26:56 -0400 Message-ID: <20090512182655.26131.53824.stgit@dev.haskins.net> In-Reply-To: <20090512181134.26131.10023.stgit@dev.haskins.net> References: <20090512181134.26131.10023.stgit@dev.haskins.net> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: kvm-owner@vger.kernel.org Precedence: bulk

diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile index b43c4ef..4d50904 100644 --- a/arch/x86/kvm/Makefile +++ b/arch/x86/kvm/Makefile @@ -3,7 +3,7 @@ # common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o ioapic.o \ - coalesced_mmio.o irq_comm.o) + coalesced_mmio.o irq_comm.o eventfd.o) ifeq ($(CONFIG_KVM_TRACE),y) common-objs += $(addprefix ../../../virt/kvm/, kvm_trace.o) endif diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index fd0a571..ba541f6 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1026,6 +1026,7 @@ int kvm_dev_ioctl_check_extension(long ext) case KVM_CAP_REINJECT_CONTROL: case KVM_CAP_IRQ_INJECT_STATUS: case KVM_CAP_ASSIGN_DEV_IRQ: + case KVM_CAP_EVENTFD: r = 1; break; case KVM_CAP_COALESCED_MMIO: diff --git a/include/linux/kvm.h b/include/linux/kvm.h index 3db5d8d..dfc4bcc 100644 --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -415,6 +415,7 @@ struct kvm_trace_rec { #define KVM_CAP_ASSIGN_DEV_IRQ 29 /* Another bug in KVM_SET_USER_MEMORY_REGION fixed: */ #define KVM_CAP_JOIN_MEMORY_REGIONS_WORKS 30 +#define KVM_CAP_EVENTFD 31 #ifdef KVM_CAP_IRQ_ROUTING @@ -454,6 +455,13 @@ struct kvm_irq_routing { #endif +struct kvm_irqfd { + __u32 fd; + __u32 gsi; + __u32 flags; + __u8 pad[20]; +}; + /* * ioctls for VM fds */ @@ -498,6 +506,8 @@ struct kvm_irq_routing { #define KVM_ASSIGN_SET_MSIX_ENTRY \ _IOW(KVMIO, 0x74, struct kvm_assigned_msix_entry) #define KVM_DEASSIGN_DEV_IRQ _IOW(KVMIO, 0x75, struct kvm_assigned_irq) +#define KVM_ASSIGN_IRQFD _IOW(KVMIO, 0x76, struct kvm_irqfd) +#define KVM_DEASSIGN_IRQFD _IOW(KVMIO, 0x77, __u32) /* * ioctls for vcpu fds diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 2b8df0c..1acc528 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -134,6 +134,7 @@ struct kvm { struct list_head vm_list; struct kvm_io_bus mmio_bus; struct kvm_io_bus pio_bus; + struct list_head irqfds; struct kvm_vm_stat stat; struct kvm_arch arch; atomic_t users_count; @@ -525,4 +526,8 @@ static inline void kvm_free_irq_routing(struct kvm *kvm) {} #endif +int kvm_assign_irqfd(struct kvm *kvm, int fd, int gsi, int flags); +int kvm_deassign_irqfd(struct kvm *kvm, int fd); +void kvm_irqfd_release(struct kvm *kvm); + #endif diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c new file mode 100644 index 0000000..71afd62 --- /dev/null +++ b/virt/kvm/eventfd.c @@ -0,0 +1,187 @@ +/* + * kvm eventfd support - use eventfd objects to signal various KVM events + * + * Copyright 2009 Novell. All Rights Reserved. + * + * Author: + * Gregory Haskins <ghaskins@novell.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/workqueue.h> +#include <linux/syscalls.h> +#include <linux/wait.h> +#include <linux/poll.h> +#include <linux/file.h> +#include <linux/list.h> + +/* + * -------------------------------------------------------------------- + * irqfd: Allows an fd to be used to inject an interrupt to the guest + * + * Credit goes to Avi Kivity for the original idea. + * -------------------------------------------------------------------- + */ +struct _irqfd { + struct kvm *kvm; + int gsi; + int fd; + struct file *file; + struct list_head list; + poll_table pt; + wait_queue_head_t *wqh; + wait_queue_t wait; + struct work_struct work; +}; + +static void +irqfd_inject(struct work_struct *work) +{ + struct _irqfd *irqfd = container_of(work, struct _irqfd, work); + struct kvm *kvm = irqfd->kvm; + + mutex_lock(&kvm->lock); + kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1); + kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0); + mutex_unlock(&kvm->lock); +} + +static int +irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key) +{ + struct _irqfd *irqfd = container_of(wait, struct _irqfd, wait); + + /* + * The wake_up with interrupts disabled. Therefore we need to defer + * the IRQ injection until later since we need to acquire the + * kvm->lock to do so. + */ + schedule_work(&irqfd->work); + + return 0; +} + +static void +irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh, + poll_table *pt) +{ + struct _irqfd *irqfd = container_of(pt, struct _irqfd, pt); + + irqfd->wqh = wqh; + add_wait_queue(wqh, &irqfd->wait); +} + +int +kvm_assign_irqfd(struct kvm *kvm, int fd, int gsi, int flags) +{ + struct _irqfd *irqfd; + struct file *file = NULL; + int ret; + + irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL); + if (!irqfd) + return -ENOMEM; + + irqfd->kvm = kvm; + irqfd->gsi = gsi; + irqfd->fd = fd; + INIT_LIST_HEAD(&irqfd->list); + INIT_WORK(&irqfd->work, irqfd_inject); + + /* + * Embed the file* lifetime in the irqfd. + */ + file = fget(fd); + if (IS_ERR(file)) { + ret = PTR_ERR(file); + goto fail; + } + + /* + * Install our own custom wake-up handling so we are notified via + * a callback whenever someone signals the underlying eventfd + */ + init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup); + init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc); + + ret = file->f_op->poll(file, &irqfd->pt); + if (ret < 0) + goto fail; + + irqfd->file = file; + + mutex_lock(&kvm->lock); + list_add_tail(&irqfd->list, &kvm->irqfds); + mutex_unlock(&kvm->lock); + + return 0; + +fail: + if (irqfd->wqh) + remove_wait_queue(irqfd->wqh, &irqfd->wait); + + if (file && !IS_ERR(file)) + fput(file); + + kfree(irqfd); + return ret; +} + +static void +irqfd_release(struct _irqfd *irqfd) +{ + remove_wait_queue(irqfd->wqh, &irqfd->wait); + + flush_work(&irqfd->work); + fput(irqfd->file); + + list_del(&irqfd->list); + kfree(irqfd); +} + +int +kvm_deassign_irqfd(struct kvm *kvm, int fd) +{ + struct _irqfd *irqfd, *tmp; + + mutex_lock(&kvm->lock); + + /* + * linear search isn't brilliant, but this should be a infrequent + * operation and the list should not grow very large + */ + list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds, list) { + if (irqfd->fd != fd) + continue; + + irqfd_release(irqfd); + mutex_unlock(&kvm->lock); + return 0; + } + mutex_unlock(&kvm->lock); + + return -ENOENT; +} + +void +kvm_irqfd_release(struct kvm *kvm) +{ + struct _irqfd *irqfd, *tmp; + + /* don't bother with the lock..we are shutting down */ + list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds, list) + irqfd_release(irqfd); +} diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 4d00942..7aa9f0a 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -983,6 +983,7 @@ static struct kvm *kvm_create_vm(void) atomic_inc(&kvm->mm->mm_count); spin_lock_init(&kvm->mmu_lock); kvm_io_bus_init(&kvm->pio_bus); + INIT_LIST_HEAD(&kvm->irqfds); mutex_init(&kvm->lock); kvm_io_bus_init(&kvm->mmio_bus); init_rwsem(&kvm->slots_lock); @@ -1034,6 +1035,7 @@ static void kvm_destroy_vm(struct kvm *kvm) spin_lock(&kvm_lock); list_del(&kvm->vm_list); spin_unlock(&kvm_lock); + kvm_irqfd_release(kvm); kvm_free_irq_routing(kvm); kvm_io_bus_destroy(&kvm->pio_bus); kvm_io_bus_destroy(&kvm->mmio_bus); @@ -2208,6 +2210,24 @@ static long kvm_vm_ioctl(struct file *filp, } #endif #endif /* KVM_CAP_IRQ_ROUTING */ + case KVM_ASSIGN_IRQFD: { + struct kvm_irqfd data; + + r = -EFAULT; + if (copy_from_user(&data, argp, sizeof data)) + goto out; + r = kvm_assign_irqfd(kvm, data.fd, data.gsi, data.flags); + break; + } + case KVM_DEASSIGN_IRQFD: { + u32 data; + + r = -EFAULT; + if (copy_from_user(&data, argp, sizeof data)) + goto out; + r = kvm_deassign_irqfd(kvm, data); + break; + } default: r = kvm_arch_vm_ioctl(filp, ioctl, arg); }

[v7,2/3] kvm: add support for irqfd via eventfd-notification interface

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