/* * KVM coalesced MMIO * * Copyright (c) 2008 Bull S.A.S. * Copyright 2009 Red Hat, Inc. and/or its affiliates. * * Author: Laurent Vivier <Laurent.Vivier@bull.net> * */ #include "iodev.h" #include <linux/kvm_host.h> #include <linux/slab.h> #include <linux/kvm.h> #include "coalesced_mmio.h" static inline struct kvm_coalesced_mmio_dev *to_mmio(struct kvm_io_device *dev) { return container_of(dev, struct kvm_coalesced_mmio_dev, dev); } static int coalesced_mmio_in_range(struct kvm_coalesced_mmio_dev *dev, gpa_t addr, int len) { struct kvm_coalesced_mmio_zone *zone; struct kvm_coalesced_mmio_ring *ring; unsigned avail; int i; /* Are we able to batch it ? */ /* last is the first free entry * check if we don't meet the first used entry * there is always one unused entry in the buffer */ ring = dev->kvm->coalesced_mmio_ring; avail = (ring->first - ring->last - 1) % KVM_COALESCED_MMIO_MAX; if (avail < KVM_MAX_VCPUS) { /* full */ return 0; } /* is it in a batchable area ? */ for (i = 0; i < dev->nb_zones; i++) { zone = &dev->zone[i]; /* (addr,len) is fully included in * (zone->addr, zone->size) */ if (zone->addr <= addr && addr + len <= zone->addr + zone->size) return 1; } return 0; } static int coalesced_mmio_write(struct kvm_io_device *this, gpa_t addr, int len, const void *val) { struct kvm_coalesced_mmio_dev *dev = to_mmio(this); struct kvm_coalesced_mmio_ring *ring = dev->kvm->coalesced_mmio_ring; if (!coalesced_mmio_in_range(dev, addr, len)) return -EOPNOTSUPP; spin_lock(&dev->lock); /* copy data in first free entry of the ring */ ring->coalesced_mmio[ring->last].phys_addr = addr; ring->coalesced_mmio[ring->last].len = len; memcpy(ring->coalesced_mmio[ring->last].data, val, len); smp_wmb(); ring->last = (ring->last + 1) % KVM_COALESCED_MMIO_MAX; spin_unlock(&dev->lock); return 0; } static void coalesced_mmio_destructor(struct kvm_io_device *this) { struct kvm_coalesced_mmio_dev *dev = to_mmio(this); kfree(dev); } static const struct kvm_io_device_ops coalesced_mmio_ops = { .write = coalesced_mmio_write, .destructor = coalesced_mmio_destructor, }; int kvm_coalesced_mmio_init(struct kvm *kvm) { struct kvm_coalesced_mmio_dev *dev; struct page *page; int ret; ret = -ENOMEM; page = alloc_page(GFP_KERNEL | __GFP_ZERO); if (!page) goto out_err; kvm->coalesced_mmio_ring = page_address(page); ret = -ENOMEM; dev = kzalloc(sizeof(struct kvm_coalesced_mmio_dev), GFP_KERNEL); if (!dev) goto out_free_page; spin_lock_init(&dev->lock); kvm_iodevice_init(&dev->dev, &coalesced_mmio_ops); dev->kvm = kvm; kvm->coalesced_mmio_dev = dev; mutex_lock(&kvm->slots_lock); ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, &dev->dev); mutex_unlock(&kvm->slots_lock); if (ret < 0) goto out_free_dev; return ret; out_free_dev: kvm->coalesced_mmio_dev = NULL; kfree(dev); out_free_page: kvm->coalesced_mmio_ring = NULL; __free_page(page); out_err: return ret; } void kvm_coalesced_mmio_free(struct kvm *kvm) { if (kvm->coalesced_mmio_ring) free_page((unsigned long)kvm->coalesced_mmio_ring); } int kvm_vm_ioctl_register_coalesced_mmio(struct kvm *kvm, struct kvm_coalesced_mmio_zone *zone) { struct kvm_coalesced_mmio_dev *dev = kvm->coalesced_mmio_dev; if (dev == NULL) return -ENXIO; mutex_lock(&kvm->slots_lock); if (dev->nb_zones >= KVM_COALESCED_MMIO_ZONE_MAX) { mutex_unlock(&kvm->slots_lock); return -ENOBUFS; } dev->zone[dev->nb_zones] = *zone; dev->nb_zones++; mutex_unlock(&kvm->slots_lock); return 0; } int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm, struct kvm_coalesced_mmio_zone *zone) { int i; struct kvm_coalesced_mmio_dev *dev = kvm->coalesced_mmio_dev; struct kvm_coalesced_mmio_zone *z; if (dev == NULL) return -ENXIO; mutex_lock(&kvm->slots_lock); i = dev->nb_zones; while (i) { z = &dev->zone[i - 1]; /* unregister all zones * included in (zone->addr, zone->size) */ if (zone->addr <= z->addr && z->addr + z->size <= zone->addr + zone->size) { dev->nb_zones--; *z = dev->zone[dev->nb_zones]; } i--; } mutex_unlock(&kvm->slots_lock); return 0; }