diff options
| -rw-r--r-- | drivers/xen/Kconfig | 8 | ||||
| -rw-r--r-- | drivers/xen/privcmd.c | 405 | ||||
| -rw-r--r-- | include/uapi/xen/privcmd.h | 18 | ||||
| -rw-r--r-- | include/xen/interface/hvm/ioreq.h | 51 |
4 files changed, 476 insertions, 6 deletions
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig index d43153fec18e..d5989871dd5d 100644 --- a/drivers/xen/Kconfig +++ b/drivers/xen/Kconfig @@ -269,12 +269,12 @@ config XEN_PRIVCMD disaggregated Xen setups this driver might be needed for other domains, too. -config XEN_PRIVCMD_IRQFD - bool "Xen irqfd support" +config XEN_PRIVCMD_EVENTFD + bool "Xen Ioeventfd and irqfd support" depends on XEN_PRIVCMD && XEN_VIRTIO && EVENTFD help - Using the irqfd mechanism a virtio backend running in a daemon can - speed up interrupt injection into a guest. + Using the ioeventfd / irqfd mechanism a virtio backend running in a + daemon can speed up interrupt delivery from / to a guest. config XEN_ACPI_PROCESSOR tristate "Xen ACPI processor" diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c index da88173bac43..1ce7f3c7a950 100644 --- a/drivers/xen/privcmd.c +++ b/drivers/xen/privcmd.c @@ -29,15 +29,18 @@ #include <linux/seq_file.h> #include <linux/miscdevice.h> #include <linux/moduleparam.h> +#include <linux/virtio_mmio.h> #include <asm/xen/hypervisor.h> #include <asm/xen/hypercall.h> #include <xen/xen.h> +#include <xen/events.h> #include <xen/privcmd.h> #include <xen/interface/xen.h> #include <xen/interface/memory.h> #include <xen/interface/hvm/dm_op.h> +#include <xen/interface/hvm/ioreq.h> #include <xen/features.h> #include <xen/page.h> #include <xen/xen-ops.h> @@ -782,6 +785,7 @@ static long privcmd_ioctl_mmap_resource(struct file *file, goto out; pages = vma->vm_private_data; + for (i = 0; i < kdata.num; i++) { xen_pfn_t pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]); @@ -838,7 +842,7 @@ out: return rc; } -#ifdef CONFIG_XEN_PRIVCMD_IRQFD +#ifdef CONFIG_XEN_PRIVCMD_EVENTFD /* Irqfd support */ static struct workqueue_struct *irqfd_cleanup_wq; static DEFINE_MUTEX(irqfds_lock); @@ -1079,6 +1083,389 @@ static void privcmd_irqfd_exit(void) destroy_workqueue(irqfd_cleanup_wq); } + +/* Ioeventfd Support */ +#define QUEUE_NOTIFY_VQ_MASK 0xFFFF + +static DEFINE_MUTEX(ioreq_lock); +static LIST_HEAD(ioreq_list); + +/* per-eventfd structure */ +struct privcmd_kernel_ioeventfd { + struct eventfd_ctx *eventfd; + struct list_head list; + u64 addr; + unsigned int addr_len; + unsigned int vq; +}; + +/* per-guest CPU / port structure */ +struct ioreq_port { + int vcpu; + unsigned int port; + struct privcmd_kernel_ioreq *kioreq; +}; + +/* per-guest structure */ +struct privcmd_kernel_ioreq { + domid_t dom; + unsigned int vcpus; + u64 uioreq; + struct ioreq *ioreq; + spinlock_t lock; /* Protects ioeventfds list */ + struct list_head ioeventfds; + struct list_head list; + struct ioreq_port ports[0]; +}; + +static irqreturn_t ioeventfd_interrupt(int irq, void *dev_id) +{ + struct ioreq_port *port = dev_id; + struct privcmd_kernel_ioreq *kioreq = port->kioreq; + struct ioreq *ioreq = &kioreq->ioreq[port->vcpu]; + struct privcmd_kernel_ioeventfd *kioeventfd; + unsigned int state = STATE_IOREQ_READY; + + if (ioreq->state != STATE_IOREQ_READY || + ioreq->type != IOREQ_TYPE_COPY || ioreq->dir != IOREQ_WRITE) + return IRQ_NONE; + + /* + * We need a barrier, smp_mb(), here to ensure reads are finished before + * `state` is updated. Since the lock implementation ensures that + * appropriate barrier will be added anyway, we can avoid adding + * explicit barrier here. + * + * Ideally we don't need to update `state` within the locks, but we do + * that here to avoid adding explicit barrier. + */ + + spin_lock(&kioreq->lock); + ioreq->state = STATE_IOREQ_INPROCESS; + + list_for_each_entry(kioeventfd, &kioreq->ioeventfds, list) { + if (ioreq->addr == kioeventfd->addr + VIRTIO_MMIO_QUEUE_NOTIFY && + ioreq->size == kioeventfd->addr_len && + (ioreq->data & QUEUE_NOTIFY_VQ_MASK) == kioeventfd->vq) { + eventfd_signal(kioeventfd->eventfd, 1); + state = STATE_IORESP_READY; + break; + } + } + spin_unlock(&kioreq->lock); + + /* + * We need a barrier, smp_mb(), here to ensure writes are finished + * before `state` is updated. Since the lock implementation ensures that + * appropriate barrier will be added anyway, we can avoid adding + * explicit barrier here. + */ + + ioreq->state = state; + + if (state == STATE_IORESP_READY) { + notify_remote_via_evtchn(port->port); + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static void ioreq_free(struct privcmd_kernel_ioreq *kioreq) +{ + struct ioreq_port *ports = kioreq->ports; + int i; + + lockdep_assert_held(&ioreq_lock); + + list_del(&kioreq->list); + + for (i = kioreq->vcpus - 1; i >= 0; i--) + unbind_from_irqhandler(irq_from_evtchn(ports[i].port), &ports[i]); + + kfree(kioreq); +} + +static +struct privcmd_kernel_ioreq *alloc_ioreq(struct privcmd_ioeventfd *ioeventfd) +{ + struct privcmd_kernel_ioreq *kioreq; + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + struct page **pages; + unsigned int *ports; + int ret, size, i; + + lockdep_assert_held(&ioreq_lock); + + size = struct_size(kioreq, ports, ioeventfd->vcpus); + kioreq = kzalloc(size, GFP_KERNEL); + if (!kioreq) + return ERR_PTR(-ENOMEM); + + kioreq->dom = ioeventfd->dom; + kioreq->vcpus = ioeventfd->vcpus; + kioreq->uioreq = ioeventfd->ioreq; + spin_lock_init(&kioreq->lock); + INIT_LIST_HEAD(&kioreq->ioeventfds); + + /* The memory for ioreq server must have been mapped earlier */ + mmap_write_lock(mm); + vma = find_vma(mm, (unsigned long)ioeventfd->ioreq); + if (!vma) { + pr_err("Failed to find vma for ioreq page!\n"); + mmap_write_unlock(mm); + ret = -EFAULT; + goto error_kfree; + } + + pages = vma->vm_private_data; + kioreq->ioreq = (struct ioreq *)(page_to_virt(pages[0])); + mmap_write_unlock(mm); + + size = sizeof(*ports) * kioreq->vcpus; + ports = kzalloc(size, GFP_KERNEL); + if (!ports) { + ret = -ENOMEM; + goto error_kfree; + } + + if (copy_from_user(ports, u64_to_user_ptr(ioeventfd->ports), size)) { + ret = -EFAULT; + goto error_kfree_ports; + } + + for (i = 0; i < kioreq->vcpus; i++) { + kioreq->ports[i].vcpu = i; + kioreq->ports[i].port = ports[i]; + kioreq->ports[i].kioreq = kioreq; + + ret = bind_evtchn_to_irqhandler_lateeoi(ports[i], + ioeventfd_interrupt, IRQF_SHARED, "ioeventfd", + &kioreq->ports[i]); + if (ret < 0) + goto error_unbind; + } + + kfree(ports); + + list_add_tail(&kioreq->list, &ioreq_list); + + return kioreq; + +error_unbind: + while (--i >= 0) + unbind_from_irqhandler(irq_from_evtchn(ports[i]), &kioreq->ports[i]); +error_kfree_ports: + kfree(ports); +error_kfree: + kfree(kioreq); + return ERR_PTR(ret); +} + +static struct privcmd_kernel_ioreq * +get_ioreq(struct privcmd_ioeventfd *ioeventfd, struct eventfd_ctx *eventfd) +{ + struct privcmd_kernel_ioreq *kioreq; + unsigned long flags; + + list_for_each_entry(kioreq, &ioreq_list, list) { + struct privcmd_kernel_ioeventfd *kioeventfd; + + /* + * kioreq fields can be accessed here without a lock as they are + * never updated after being added to the ioreq_list. + */ + if (kioreq->uioreq != ioeventfd->ioreq) { + continue; + } else if (kioreq->dom != ioeventfd->dom || + kioreq->vcpus != ioeventfd->vcpus) { + pr_err("Invalid ioeventfd configuration mismatch, dom (%u vs %u), vcpus (%u vs %u)\n", + kioreq->dom, ioeventfd->dom, kioreq->vcpus, + ioeventfd->vcpus); + return ERR_PTR(-EINVAL); + } + + /* Look for a duplicate eventfd for the same guest */ + spin_lock_irqsave(&kioreq->lock, flags); + list_for_each_entry(kioeventfd, &kioreq->ioeventfds, list) { + if (eventfd == kioeventfd->eventfd) { + spin_unlock_irqrestore(&kioreq->lock, flags); + return ERR_PTR(-EBUSY); + } + } + spin_unlock_irqrestore(&kioreq->lock, flags); + + return kioreq; + } + + /* Matching kioreq isn't found, allocate a new one */ + return alloc_ioreq(ioeventfd); +} + +static void ioeventfd_free(struct privcmd_kernel_ioeventfd *kioeventfd) +{ + list_del(&kioeventfd->list); + eventfd_ctx_put(kioeventfd->eventfd); + kfree(kioeventfd); +} + +static int privcmd_ioeventfd_assign(struct privcmd_ioeventfd *ioeventfd) +{ + struct privcmd_kernel_ioeventfd *kioeventfd; + struct privcmd_kernel_ioreq *kioreq; + unsigned long flags; + struct fd f; + int ret; + + /* Check for range overflow */ + if (ioeventfd->addr + ioeventfd->addr_len < ioeventfd->addr) + return -EINVAL; + + /* Vhost requires us to support length 1, 2, 4, and 8 */ + if (!(ioeventfd->addr_len == 1 || ioeventfd->addr_len == 2 || + ioeventfd->addr_len == 4 || ioeventfd->addr_len == 8)) + return -EINVAL; + + /* 4096 vcpus limit enough ? */ + if (!ioeventfd->vcpus || ioeventfd->vcpus > 4096) + return -EINVAL; + + kioeventfd = kzalloc(sizeof(*kioeventfd), GFP_KERNEL); + if (!kioeventfd) + return -ENOMEM; + + f = fdget(ioeventfd->event_fd); + if (!f.file) { + ret = -EBADF; + goto error_kfree; + } + + kioeventfd->eventfd = eventfd_ctx_fileget(f.file); + fdput(f); + + if (IS_ERR(kioeventfd->eventfd)) { + ret = PTR_ERR(kioeventfd->eventfd); + goto error_kfree; + } + + kioeventfd->addr = ioeventfd->addr; + kioeventfd->addr_len = ioeventfd->addr_len; + kioeventfd->vq = ioeventfd->vq; + + mutex_lock(&ioreq_lock); + kioreq = get_ioreq(ioeventfd, kioeventfd->eventfd); + if (IS_ERR(kioreq)) { + mutex_unlock(&ioreq_lock); + ret = PTR_ERR(kioreq); + goto error_eventfd; + } + + spin_lock_irqsave(&kioreq->lock, flags); + list_add_tail(&kioeventfd->list, &kioreq->ioeventfds); + spin_unlock_irqrestore(&kioreq->lock, flags); + + mutex_unlock(&ioreq_lock); + + return 0; + +error_eventfd: + eventfd_ctx_put(kioeventfd->eventfd); + +error_kfree: + kfree(kioeventfd); + return ret; +} + +static int privcmd_ioeventfd_deassign(struct privcmd_ioeventfd *ioeventfd) +{ + struct privcmd_kernel_ioreq *kioreq, *tkioreq; + struct eventfd_ctx *eventfd; + unsigned long flags; + int ret = 0; + + eventfd = eventfd_ctx_fdget(ioeventfd->event_fd); + if (IS_ERR(eventfd)) + return PTR_ERR(eventfd); + + mutex_lock(&ioreq_lock); + list_for_each_entry_safe(kioreq, tkioreq, &ioreq_list, list) { + struct privcmd_kernel_ioeventfd *kioeventfd, *tmp; + /* + * kioreq fields can be accessed here without a lock as they are + * never updated after being added to the ioreq_list. + */ + if (kioreq->dom != ioeventfd->dom || + kioreq->uioreq != ioeventfd->ioreq || + kioreq->vcpus != ioeventfd->vcpus) + continue; + + spin_lock_irqsave(&kioreq->lock, flags); + list_for_each_entry_safe(kioeventfd, tmp, &kioreq->ioeventfds, list) { + if (eventfd == kioeventfd->eventfd) { + ioeventfd_free(kioeventfd); + spin_unlock_irqrestore(&kioreq->lock, flags); + + if (list_empty(&kioreq->ioeventfds)) + ioreq_free(kioreq); + goto unlock; + } + } + spin_unlock_irqrestore(&kioreq->lock, flags); + break; + } + + pr_err("Ioeventfd isn't already assigned, dom: %u, addr: %llu\n", + ioeventfd->dom, ioeventfd->addr); + ret = -ENODEV; + +unlock: + mutex_unlock(&ioreq_lock); + eventfd_ctx_put(eventfd); + + return ret; +} + +static long privcmd_ioctl_ioeventfd(struct file *file, void __user *udata) +{ + struct privcmd_data *data = file->private_data; + struct privcmd_ioeventfd ioeventfd; + + if (copy_from_user(&ioeventfd, udata, sizeof(ioeventfd))) + return -EFAULT; + + /* No other flags should be set */ + if (ioeventfd.flags & ~PRIVCMD_IOEVENTFD_FLAG_DEASSIGN) + return -EINVAL; + + /* If restriction is in place, check the domid matches */ + if (data->domid != DOMID_INVALID && data->domid != ioeventfd.dom) + return -EPERM; + + if (ioeventfd.flags & PRIVCMD_IOEVENTFD_FLAG_DEASSIGN) + return privcmd_ioeventfd_deassign(&ioeventfd); + + return privcmd_ioeventfd_assign(&ioeventfd); +} + +static void privcmd_ioeventfd_exit(void) +{ + struct privcmd_kernel_ioreq *kioreq, *tmp; + unsigned long flags; + + mutex_lock(&ioreq_lock); + list_for_each_entry_safe(kioreq, tmp, &ioreq_list, list) { + struct privcmd_kernel_ioeventfd *kioeventfd, *tmp; + + spin_lock_irqsave(&kioreq->lock, flags); + list_for_each_entry_safe(kioeventfd, tmp, &kioreq->ioeventfds, list) + ioeventfd_free(kioeventfd); + spin_unlock_irqrestore(&kioreq->lock, flags); + + ioreq_free(kioreq); + } + mutex_unlock(&ioreq_lock); +} #else static inline long privcmd_ioctl_irqfd(struct file *file, void __user *udata) { @@ -1093,7 +1480,16 @@ static inline int privcmd_irqfd_init(void) static inline void privcmd_irqfd_exit(void) { } -#endif /* CONFIG_XEN_PRIVCMD_IRQFD */ + +static inline long privcmd_ioctl_ioeventfd(struct file *file, void __user *udata) +{ + return -EOPNOTSUPP; +} + +static inline void privcmd_ioeventfd_exit(void) +{ +} +#endif /* CONFIG_XEN_PRIVCMD_EVENTFD */ static long privcmd_ioctl(struct file *file, unsigned int cmd, unsigned long data) @@ -1134,6 +1530,10 @@ static long privcmd_ioctl(struct file *file, ret = privcmd_ioctl_irqfd(file, udata); break; + case IOCTL_PRIVCMD_IOEVENTFD: + ret = privcmd_ioctl_ioeventfd(file, udata); + break; + default: break; } @@ -1278,6 +1678,7 @@ err_privcmdbuf: static void __exit privcmd_exit(void) { + privcmd_ioeventfd_exit(); privcmd_irqfd_exit(); misc_deregister(&privcmd_dev); misc_deregister(&xen_privcmdbuf_dev); diff --git a/include/uapi/xen/privcmd.h b/include/uapi/xen/privcmd.h index e145bca5105c..8b8c5d1420fe 100644 --- a/include/uapi/xen/privcmd.h +++ b/include/uapi/xen/privcmd.h @@ -110,6 +110,22 @@ struct privcmd_irqfd { __u8 pad[2]; }; +/* For privcmd_ioeventfd::flags */ +#define PRIVCMD_IOEVENTFD_FLAG_DEASSIGN (1 << 0) + +struct privcmd_ioeventfd { + __u64 ioreq; + __u64 ports; + __u64 addr; + __u32 addr_len; + __u32 event_fd; + __u32 vcpus; + __u32 vq; + __u32 flags; + domid_t dom; + __u8 pad[2]; +}; + /* * @cmd: IOCTL_PRIVCMD_HYPERCALL * @arg: &privcmd_hypercall_t @@ -139,5 +155,7 @@ struct privcmd_irqfd { _IOC(_IOC_NONE, 'P', 7, sizeof(struct privcmd_mmap_resource)) #define IOCTL_PRIVCMD_IRQFD \ _IOW('P', 8, struct privcmd_irqfd) +#define IOCTL_PRIVCMD_IOEVENTFD \ + _IOW('P', 9, struct privcmd_ioeventfd) #endif /* __LINUX_PUBLIC_PRIVCMD_H__ */ diff --git a/include/xen/interface/hvm/ioreq.h b/include/xen/interface/hvm/ioreq.h new file mode 100644 index 000000000000..b02cfeae7eb5 --- /dev/null +++ b/include/xen/interface/hvm/ioreq.h @@ -0,0 +1,51 @@ +/* SPDX-License-Identifier: MIT */ +/* + * ioreq.h: I/O request definitions for device models + * Copyright (c) 2004, Intel Corporation. + */ + +#ifndef __XEN_PUBLIC_HVM_IOREQ_H__ +#define __XEN_PUBLIC_HVM_IOREQ_H__ + +#define IOREQ_READ 1 +#define IOREQ_WRITE 0 + +#define STATE_IOREQ_NONE 0 +#define STATE_IOREQ_READY 1 +#define STATE_IOREQ_INPROCESS 2 +#define STATE_IORESP_READY 3 + +#define IOREQ_TYPE_PIO 0 /* pio */ +#define IOREQ_TYPE_COPY 1 /* mmio ops */ +#define IOREQ_TYPE_PCI_CONFIG 2 +#define IOREQ_TYPE_TIMEOFFSET 7 +#define IOREQ_TYPE_INVALIDATE 8 /* mapcache */ + +/* + * VMExit dispatcher should cooperate with instruction decoder to + * prepare this structure and notify service OS and DM by sending + * virq. + * + * For I/O type IOREQ_TYPE_PCI_CONFIG, the physical address is formatted + * as follows: + * + * 63....48|47..40|39..35|34..32|31........0 + * SEGMENT |BUS |DEV |FN |OFFSET + */ +struct ioreq { + uint64_t addr; /* physical address */ + uint64_t data; /* data (or paddr of data) */ + uint32_t count; /* for rep prefixes */ + uint32_t size; /* size in bytes */ + uint32_t vp_eport; /* evtchn for notifications to/from device model */ + uint16_t _pad0; + uint8_t state:4; + uint8_t data_is_ptr:1; /* if 1, data above is the guest paddr + * of the real data to use. */ + uint8_t dir:1; /* 1=read, 0=write */ + uint8_t df:1; + uint8_t _pad1:1; + uint8_t type; /* I/O type */ +}; + +#endif /* __XEN_PUBLIC_HVM_IOREQ_H__ */ |