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