diff options
Diffstat (limited to 'virt/kvm/coalesced_mmio.c')
| -rw-r--r-- | virt/kvm/coalesced_mmio.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c new file mode 100644 index 00000000..fc848756 --- /dev/null +++ b/virt/kvm/coalesced_mmio.c @@ -0,0 +1,191 @@ +/* + * 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; +} |