hw/vfio/common.c

/*
 * generic functions used by VFIO devices
 *
 * Copyright Red Hat, Inc. 2012
 *
 * Authors:
 *  Alex Williamson <alex.williamson@redhat.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 * Based on qemu-kvm device-assignment:
 *  Adapted for KVM by Qumranet.
 *  Copyright (c) 2007, Neocleus, Alex Novik (alex@neocleus.com)
 *  Copyright (c) 2007, Neocleus, Guy Zana (guy@neocleus.com)
 *  Copyright (C) 2008, Qumranet, Amit Shah (amit.shah@qumranet.com)
 *  Copyright (C) 2008, Red Hat, Amit Shah (amit.shah@redhat.com)
 *  Copyright (C) 2008, IBM, Muli Ben-Yehuda (muli@il.ibm.com)
 */

#include <sys/ioctl.h>
#include <sys/mman.h>
#include <linux/vfio.h>

#include "hw/vfio/vfio-common.h"
#include "hw/vfio/vfio.h"
#include "exec/address-spaces.h"
#include "exec/memory.h"
#include "hw/hw.h"
#include "qemu/error-report.h"
#include "sysemu/kvm.h"
#include "trace.h"

struct vfio_group_head vfio_group_list =
    QLIST_HEAD_INITIALIZER(vfio_group_list);
struct vfio_as_head vfio_address_spaces =
    QLIST_HEAD_INITIALIZER(vfio_address_spaces);

#ifdef CONFIG_KVM
/*
 * We have a single VFIO pseudo device per KVM VM.  Once created it lives
 * for the life of the VM.  Closing the file descriptor only drops our
 * reference to it and the device's reference to kvm.  Therefore once
 * initialized, this file descriptor is only released on QEMU exit and
 * we'll re-use it should another vfio device be attached before then.
 */
static int vfio_kvm_device_fd = -1;
#endif

/*
 * Common VFIO interrupt disable
 */
void vfio_disable_irqindex(VFIODevice *vbasedev, int index)
{
    struct vfio_irq_set irq_set = {
        .argsz = sizeof(irq_set),
        .flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_TRIGGER,
        .index = index,
        .start = 0,
        .count = 0,
    };

    ioctl(vbasedev->fd, VFIO_DEVICE_SET_IRQS, &irq_set);
}

void vfio_unmask_single_irqindex(VFIODevice *vbasedev, int index)
{
    struct vfio_irq_set irq_set = {
        .argsz = sizeof(irq_set),
        .flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_UNMASK,
        .index = index,
        .start = 0,
        .count = 1,
    };

    ioctl(vbasedev->fd, VFIO_DEVICE_SET_IRQS, &irq_set);
}

void vfio_mask_single_irqindex(VFIODevice *vbasedev, int index)
{
    struct vfio_irq_set irq_set = {
        .argsz = sizeof(irq_set),
        .flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_MASK,
        .index = index,
        .start = 0,
        .count = 1,
    };

    ioctl(vbasedev->fd, VFIO_DEVICE_SET_IRQS, &irq_set);
}

/*
 * IO Port/MMIO - Beware of the endians, VFIO is always little endian
 */
void vfio_region_write(void *opaque, hwaddr addr,
                       uint64_t data, unsigned size)
{
    VFIORegion *region = opaque;
    VFIODevice *vbasedev = region->vbasedev;
    union {
        uint8_t byte;
        uint16_t word;
        uint32_t dword;
        uint64_t qword;
    } buf;

    switch (size) {
    case 1:
        buf.byte = data;
        break;
    case 2:
        buf.word = cpu_to_le16(data);
        break;
    case 4:
        buf.dword = cpu_to_le32(data);
        break;
    default:
        hw_error("vfio: unsupported write size, %d bytes", size);
        break;
    }

    if (pwrite(vbasedev->fd, &buf, size, region->fd_offset + addr) != size) {
        error_report("%s(%s:region%d+0x%"HWADDR_PRIx", 0x%"PRIx64
                     ",%d) failed: %m",
                     __func__, vbasedev->name, region->nr,
                     addr, data, size);
    }

    trace_vfio_region_write(vbasedev->name, region->nr, addr, data, size);

    /*
     * A read or write to a BAR always signals an INTx EOI.  This will
     * do nothing if not pending (including not in INTx mode).  We assume
     * that a BAR access is in response to an interrupt and that BAR
     * accesses will service the interrupt.  Unfortunately, we don't know
     * which access will service the interrupt, so we're potentially
     * getting quite a few host interrupts per guest interrupt.
     */
    vbasedev->ops->vfio_eoi(vbasedev);
}

uint64_t vfio_region_read(void *opaque,
                          hwaddr addr, unsigned size)
{
    VFIORegion *region = opaque;
    VFIODevice *vbasedev = region->vbasedev;
    union {
        uint8_t byte;
        uint16_t word;
        uint32_t dword;
        uint64_t qword;
    } buf;
    uint64_t data = 0;

    if (pread(vbasedev->fd, &buf, size, region->fd_offset + addr) != size) {
        error_report("%s(%s:region%d+0x%"HWADDR_PRIx", %d) failed: %m",
                     __func__, vbasedev->name, region->nr,
                     addr, size);
        return (uint64_t)-1;
    }
    switch (size) {
    case 1:
        data = buf.byte;
        break;
    case 2:
        data = le16_to_cpu(buf.word);
        break;
    case 4:
        data = le32_to_cpu(buf.dword);
        break;
    default:
        hw_error("vfio: unsupported read size, %d bytes", size);
        break;
    }

    trace_vfio_region_read(vbasedev->name, region->nr, addr, size, data);

    /* Same as write above */
    vbasedev->ops->vfio_eoi(vbasedev);

    return data;
}

const MemoryRegionOps vfio_region_ops = {
    .read = vfio_region_read,
    .write = vfio_region_write,
    .endianness = DEVICE_LITTLE_ENDIAN,
};

/*
 * DMA - Mapping and unmapping for the "type1" IOMMU interface used on x86
 */
static int vfio_dma_unmap(VFIOContainer *container,
                          hwaddr iova, ram_addr_t size)
{
    struct vfio_iommu_type1_dma_unmap unmap = {
        .argsz = sizeof(unmap),
        .flags = 0,
        .iova = iova,
        .size = size,
    };

    if (ioctl(container->fd, VFIO_IOMMU_UNMAP_DMA, &unmap)) {
        error_report("VFIO_UNMAP_DMA: %d", -errno);
        return -errno;
    }

    return 0;
}

static int vfio_dma_map(VFIOContainer *container, hwaddr iova,
                        ram_addr_t size, void *vaddr, bool readonly)
{
    struct vfio_iommu_type1_dma_map map = {
        .argsz = sizeof(map),
        .flags = VFIO_DMA_MAP_FLAG_READ,
        .vaddr = (__u64)(uintptr_t)vaddr,
        .iova = iova,
        .size = size,
    };

    if (!readonly) {
        map.flags |= VFIO_DMA_MAP_FLAG_WRITE;
    }

    /*
     * Try the mapping, if it fails with EBUSY, unmap the region and try
     * again.  This shouldn't be necessary, but we sometimes see it in
     * the the VGA ROM space.
     */
    if (ioctl(container->fd, VFIO_IOMMU_MAP_DMA, &map) == 0 ||
        (errno == EBUSY && vfio_dma_unmap(container, iova, size) == 0 &&
         ioctl(container->fd, VFIO_IOMMU_MAP_DMA, &map) == 0)) {
        return 0;
    }

    error_report("VFIO_MAP_DMA: %d", -errno);
    return -errno;
}

static bool vfio_listener_skipped_section(MemoryRegionSection *section)
{
    return (!memory_region_is_ram(section->mr) &&
            !memory_region_is_iommu(section->mr)) ||
           /*
            * Sizing an enabled 64-bit BAR can cause spurious mappings to
            * addresses in the upper part of the 64-bit address space.  These
            * are never accessed by the CPU and beyond the address width of
            * some IOMMU hardware.  TODO: VFIO should tell us the IOMMU width.
            */
           section->offset_within_address_space & (1ULL << 63);
}

static void vfio_iommu_map_notify(Notifier *n, void *data)
{
    VFIOGuestIOMMU *giommu = container_of(n, VFIOGuestIOMMU, n);
    VFIOContainer *container = giommu->container;
    IOMMUTLBEntry *iotlb = data;
    MemoryRegion *mr;
    hwaddr xlat;
    hwaddr len = iotlb->addr_mask + 1;
    void *vaddr;
    int ret;

    trace_vfio_iommu_map_notify(iotlb->iova,
                                iotlb->iova + iotlb->addr_mask);

    /*
     * The IOMMU TLB entry we have just covers translation through
     * this IOMMU to its immediate target.  We need to translate
     * it the rest of the way through to memory.
     */
    rcu_read_lock();
    mr = address_space_translate(&address_space_memory,
                                 iotlb->translated_addr,
                                 &xlat, &len, iotlb->perm & IOMMU_WO);
    if (!memory_region_is_ram(mr)) {
        error_report("iommu map to non memory area %"HWADDR_PRIx"",
                     xlat);
        goto out;
    }
    /*
     * Translation truncates length to the IOMMU page size,
     * check that it did not truncate too much.
     */
    if (len & iotlb->addr_mask) {
        error_report("iommu has granularity incompatible with target AS");
        goto out;
    }

    if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) {
        vaddr = memory_region_get_ram_ptr(mr) + xlat;
        ret = vfio_dma_map(container, iotlb->iova,
                           iotlb->addr_mask + 1, vaddr,
                           !(iotlb->perm & IOMMU_WO) || mr->readonly);
        if (ret) {
            error_report("vfio_dma_map(%p, 0x%"HWADDR_PRIx", "
                         "0x%"HWADDR_PRIx", %p) = %d (%m)",
                         container, iotlb->iova,
                         iotlb->addr_mask + 1, vaddr, ret);
        }
    } else {
        ret = vfio_dma_unmap(container, iotlb->iova, iotlb->addr_mask + 1);
        if (ret) {
            error_report("vfio_dma_unmap(%p, 0x%"HWADDR_PRIx", "
                         "0x%"HWADDR_PRIx") = %d (%m)",
                         container, iotlb->iova,
                         iotlb->addr_mask + 1, ret);
        }
    }
out:
    rcu_read_unlock();
}

static void vfio_listener_region_add(MemoryListener *listener,
                                     MemoryRegionSection *section)
{
    VFIOContainer *container = container_of(listener, VFIOContainer,
                                            iommu_data.type1.listener);
    hwaddr iova, end;
    Int128 llend;
    void *vaddr;
    int ret;

    if (vfio_listener_skipped_section(section)) {
        trace_vfio_listener_region_add_skip(
                section->offset_within_address_space,
                section->offset_within_address_space +
                int128_get64(int128_sub(section->size, int128_one())));
        return;
    }

    if (unlikely((section->offset_within_address_space & ~TARGET_PAGE_MASK) !=
                 (section->offset_within_region & ~TARGET_PAGE_MASK))) {
        error_report("%s received unaligned region", __func__);
        return;
    }

    iova = TARGET_PAGE_ALIGN(section->offset_within_address_space);
    llend = int128_make64(section->offset_within_address_space);
    llend = int128_add(llend, section->size);
    llend = int128_and(llend, int128_exts64(TARGET_PAGE_MASK));

    if (int128_ge(int128_make64(iova), llend)) {
        return;
    }

    memory_region_ref(section->mr);

    if (memory_region_is_iommu(section->mr)) {
        VFIOGuestIOMMU *giommu;

        trace_vfio_listener_region_add_iommu(iova,
                    int128_get64(int128_sub(llend, int128_one())));
        /*
         * FIXME: We should do some checking to see if the
         * capabilities of the host VFIO IOMMU are adequate to model
         * the guest IOMMU
         *
         * FIXME: For VFIO iommu types which have KVM acceleration to
         * avoid bouncing all map/unmaps through qemu this way, this
         * would be the right place to wire that up (tell the KVM
         * device emulation the VFIO iommu handles to use).
         */
        /*
         * This assumes that the guest IOMMU is empty of
         * mappings at this point.
         *
         * One way of doing this is:
         * 1. Avoid sharing IOMMUs between emulated devices or different
         * IOMMU groups.
         * 2. Implement VFIO_IOMMU_ENABLE in the host kernel to fail if
         * there are some mappings in IOMMU.
         *
         * VFIO on SPAPR does that. Other IOMMU models may do that different,
         * they must make sure there are no existing mappings or
         * loop through existing mappings to map them into VFIO.
         */
        giommu = g_malloc0(sizeof(*giommu));
        giommu->iommu = section->mr;
        giommu->container = container;
        giommu->n.notify = vfio_iommu_map_notify;
        QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next);
        memory_region_register_iommu_notifier(giommu->iommu, &giommu->n);

        return;
    }

    /* Here we assume that memory_region_is_ram(section->mr)==true */

    end = int128_get64(llend);
    vaddr = memory_region_get_ram_ptr(section->mr) +
            section->offset_within_region +
            (iova - section->offset_within_address_space);

    trace_vfio_listener_region_add_ram(iova, end - 1, vaddr);

    ret = vfio_dma_map(container, iova, end - iova, vaddr, section->readonly);
    if (ret) {
        error_report("vfio_dma_map(%p, 0x%"HWADDR_PRIx", "
                     "0x%"HWADDR_PRIx", %p) = %d (%m)",
                     container, iova, end - iova, vaddr, ret);

        /*
         * On the initfn path, store the first error in the container so we
         * can gracefully fail.  Runtime, there's not much we can do other
         * than throw a hardware error.
         */
        if (!container->iommu_data.type1.initialized) {
            if (!container->iommu_data.type1.error) {
                container->iommu_data.type1.error = ret;
            }
        } else {
            hw_error("vfio: DMA mapping failed, unable to continue");
        }
    }
}

static void vfio_listener_region_del(MemoryListener *listener,
                                     MemoryRegionSection *section)
{
    VFIOContainer *container = container_of(listener, VFIOContainer,
                                            iommu_data.type1.listener);
    hwaddr iova, end;
    int ret;

    if (vfio_listener_skipped_section(section)) {
        trace_vfio_listener_region_del_skip(
                section->offset_within_address_space,
                section->offset_within_address_space +
                int128_get64(int128_sub(section->size, int128_one())));
        return;
    }

    if (unlikely((section->offset_within_address_space & ~TARGET_PAGE_MASK) !=
                 (section->offset_within_region & ~TARGET_PAGE_MASK))) {
        error_report("%s received unaligned region", __func__);
        return;
    }

    if (memory_region_is_iommu(section->mr)) {
        VFIOGuestIOMMU *giommu;

        QLIST_FOREACH(giommu, &container->giommu_list, giommu_next) {
            if (giommu->iommu == section->mr) {
                memory_region_unregister_iommu_notifier(&giommu->n);
                QLIST_REMOVE(giommu, giommu_next);
                g_free(giommu);
                break;
            }
        }

        /*
         * FIXME: We assume the one big unmap below is adequate to
         * remove any individual page mappings in the IOMMU which
         * might have been copied into VFIO. This works for a page table
         * based IOMMU where a big unmap flattens a large range of IO-PTEs.
         * That may not be true for all IOMMU types.
         */
    }

    iova = TARGET_PAGE_ALIGN(section->offset_within_address_space);
    end = (section->offset_within_address_space + int128_get64(section->size)) &
          TARGET_PAGE_MASK;

    if (iova >= end) {
        return;
    }

    trace_vfio_listener_region_del(iova, end - 1);

    ret = vfio_dma_unmap(container, iova, end - iova);
    memory_region_unref(section->mr);
    if (ret) {
        error_report("vfio_dma_unmap(%p, 0x%"HWADDR_PRIx", "
                     "0x%"HWADDR_PRIx") = %d (%m)",
                     container, iova, end - iova, ret);
    }
}

static const MemoryListener vfio_memory_listener = {
    .region_add = vfio_listener_region_add,
    .region_del = vfio_listener_region_del,
};

static void vfio_listener_release(VFIOContainer *container)
{
    memory_listener_unregister(&container->iommu_data.type1.listener);
}

int vfio_mmap_region(Object *obj, VFIORegion *region,
                     MemoryRegion *mem, MemoryRegion *submem,
                     void **map, size_t size, off_t offset,
                     const char *name)
{
    int ret = 0;
    VFIODevice *vbasedev = region->vbasedev;

    if (vbasedev->allow_mmap && size && region->flags &
        VFIO_REGION_INFO_FLAG_MMAP) {
        int prot = 0;

        if (region->flags & VFIO_REGION_INFO_FLAG_READ) {
            prot |= PROT_READ;
        }

        if (region->flags & VFIO_REGION_INFO_FLAG_WRITE) {
            prot |= PROT_WRITE;
        }

        *map = mmap(NULL, size, prot, MAP_SHARED,
                    vbasedev->fd,
                    region->fd_offset + offset);
        if (*map == MAP_FAILED) {
            *map = NULL;
            ret = -errno;
            goto empty_region;
        }

        memory_region_init_ram_ptr(submem, obj, name, size, *map);
        memory_region_set_skip_dump(submem);
    } else {
empty_region:
        /* Create a zero sized sub-region to make cleanup easy. */
        memory_region_init(submem, obj, name, 0);
    }

    memory_region_add_subregion(mem, offset, submem);

    return ret;
}

void vfio_reset_handler(void *opaque)
{
    VFIOGroup *group;
    VFIODevice *vbasedev;

    QLIST_FOREACH(group, &vfio_group_list, next) {
        QLIST_FOREACH(vbasedev, &group->device_list, next) {
            vbasedev->ops->vfio_compute_needs_reset(vbasedev);
        }
    }

    QLIST_FOREACH(group, &vfio_group_list, next) {
        QLIST_FOREACH(vbasedev, &group->device_list, next) {
            if (vbasedev->needs_reset) {
                vbasedev->ops->vfio_hot_reset_multi(vbasedev);
            }
        }
    }
}

static void vfio_kvm_device_add_group(VFIOGroup *group)
{
#ifdef CONFIG_KVM
    struct kvm_device_attr attr = {
        .group = KVM_DEV_VFIO_GROUP,
        .attr = KVM_DEV_VFIO_GROUP_ADD,
        .addr = (uint64_t)(unsigned long)&group->fd,
    };

    if (!kvm_enabled()) {
        return;
    }

    if (vfio_kvm_device_fd < 0) {
        struct kvm_create_device cd = {
            .type = KVM_DEV_TYPE_VFIO,
        };

        if (kvm_vm_ioctl(kvm_state, KVM_CREATE_DEVICE, &cd)) {
            error_report("Failed to create KVM VFIO device: %m");
            return;
        }

        vfio_kvm_device_fd = cd.fd;
    }

    if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
        error_report("Failed to add group %d to KVM VFIO device: %m",
                     group->groupid);
    }
#endif
}

static void vfio_kvm_device_del_group(VFIOGroup *group)
{
#ifdef CONFIG_KVM
    struct kvm_device_attr attr = {
        .group = KVM_DEV_VFIO_GROUP,
        .attr = KVM_DEV_VFIO_GROUP_DEL,
        .addr = (uint64_t)(unsigned long)&group->fd,
    };

    if (vfio_kvm_device_fd < 0) {
        return;
    }

    if (ioctl(vfio_kvm_device_fd, KVM_SET_DEVICE_ATTR, &attr)) {
        error_report("Failed to remove group %d from KVM VFIO device: %m",
                     group->groupid);
    }
#endif
}

static VFIOAddressSpace *vfio_get_address_space(AddressSpace *as)
{
    VFIOAddressSpace *space;

    QLIST_FOREACH(space, &vfio_address_spaces, list) {
        if (space->as == as) {
            return space;
        }
    }

    /* No suitable VFIOAddressSpace, create a new one */
    space = g_malloc0(sizeof(*space));
    space->as = as;
    QLIST_INIT(&space->containers);

    QLIST_INSERT_HEAD(&vfio_address_spaces, space, list);

    return space;
}

static void vfio_put_address_space(VFIOAddressSpace *space)
{
    if (QLIST_EMPTY(&space->containers)) {
        QLIST_REMOVE(space, list);
        g_free(space);
    }
}

static int vfio_connect_container(VFIOGroup *group, AddressSpace *as)
{
    VFIOContainer *container;
    int ret, fd;
    VFIOAddressSpace *space;

    space = vfio_get_address_space(as);

    QLIST_FOREACH(container, &space->containers, next) {
        if (!ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &container->fd)) {
            group->container = container;
            QLIST_INSERT_HEAD(&container->group_list, group, container_next);
            return 0;
        }
    }

    fd = qemu_open("/dev/vfio/vfio", O_RDWR);
    if (fd < 0) {
        error_report("vfio: failed to open /dev/vfio/vfio: %m");
        ret = -errno;
        goto put_space_exit;
    }

    ret = ioctl(fd, VFIO_GET_API_VERSION);
    if (ret != VFIO_API_VERSION) {
        error_report("vfio: supported vfio version: %d, "
                     "reported version: %d", VFIO_API_VERSION, ret);
        ret = -EINVAL;
        goto close_fd_exit;
    }

    container = g_malloc0(sizeof(*container));
    container->space = space;
    container->fd = fd;
    if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU) ||
        ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1v2_IOMMU)) {
        bool v2 = !!ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1v2_IOMMU);

        ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd);
        if (ret) {
            error_report("vfio: failed to set group container: %m");
            ret = -errno;
            goto free_container_exit;
        }

        ret = ioctl(fd, VFIO_SET_IOMMU,
                    v2 ? VFIO_TYPE1v2_IOMMU : VFIO_TYPE1_IOMMU);
        if (ret) {
            error_report("vfio: failed to set iommu for container: %m");
            ret = -errno;
            goto free_container_exit;
        }

        container->iommu_data.type1.listener = vfio_memory_listener;
        container->iommu_data.release = vfio_listener_release;

        memory_listener_register(&container->iommu_data.type1.listener,
                                 container->space->as);

        if (container->iommu_data.type1.error) {
            ret = container->iommu_data.type1.error;
            error_report("vfio: memory listener initialization failed for container");
            goto listener_release_exit;
        }

        container->iommu_data.type1.initialized = true;

    } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU)) {
        ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd);
        if (ret) {
            error_report("vfio: failed to set group container: %m");
            ret = -errno;
            goto free_container_exit;
        }
        ret = ioctl(fd, VFIO_SET_IOMMU, VFIO_SPAPR_TCE_IOMMU);
        if (ret) {
            error_report("vfio: failed to set iommu for container: %m");
            ret = -errno;
            goto free_container_exit;
        }

        /*
         * The host kernel code implementing VFIO_IOMMU_DISABLE is called
         * when container fd is closed so we do not call it explicitly
         * in this file.
         */
        ret = ioctl(fd, VFIO_IOMMU_ENABLE);
        if (ret) {
            error_report("vfio: failed to enable container: %m");
            ret = -errno;
            goto free_container_exit;
        }

        container->iommu_data.type1.listener = vfio_memory_listener;
        container->iommu_data.release = vfio_listener_release;

        memory_listener_register(&container->iommu_data.type1.listener,
                                 container->space->as);

    } else {
        error_report("vfio: No available IOMMU models");
        ret = -EINVAL;
        goto free_container_exit;
    }

    QLIST_INIT(&container->group_list);
    QLIST_INSERT_HEAD(&space->containers, container, next);

    group->container = container;
    QLIST_INSERT_HEAD(&container->group_list, group, container_next);

    return 0;
listener_release_exit:
    vfio_listener_release(container);

free_container_exit:
    g_free(container);

close_fd_exit:
    close(fd);

put_space_exit:
    vfio_put_address_space(space);

    return ret;
}

static void vfio_disconnect_container(VFIOGroup *group)
{
    VFIOContainer *container = group->container;

    if (ioctl(group->fd, VFIO_GROUP_UNSET_CONTAINER, &container->fd)) {
        error_report("vfio: error disconnecting group %d from container",
                     group->groupid);
    }

    QLIST_REMOVE(group, container_next);
    group->container = NULL;

    if (QLIST_EMPTY(&container->group_list)) {
        VFIOAddressSpace *space = container->space;

        if (container->iommu_data.release) {
            container->iommu_data.release(container);
        }
        QLIST_REMOVE(container, next);
        trace_vfio_disconnect_container(container->fd);
        close(container->fd);
        g_free(container);

        vfio_put_address_space(space);
    }
}

VFIOGroup *vfio_get_group(int groupid, AddressSpace *as)
{
    VFIOGroup *group;
    char path[32];
    struct vfio_group_status status = { .argsz = sizeof(status) };

    QLIST_FOREACH(group, &vfio_group_list, next) {
        if (group->groupid == groupid) {
            /* Found it.  Now is it already in the right context? */
            if (group->container->space->as == as) {
                return group;
            } else {
                error_report("vfio: group %d used in multiple address spaces",
                             group->groupid);
                return NULL;
            }
        }
    }

    group = g_malloc0(sizeof(*group));

    snprintf(path, sizeof(path), "/dev/vfio/%d", groupid);
    group->fd = qemu_open(path, O_RDWR);
    if (group->fd < 0) {
        error_report("vfio: error opening %s: %m", path);
        goto free_group_exit;
    }

    if (ioctl(group->fd, VFIO_GROUP_GET_STATUS, &status)) {
        error_report("vfio: error getting group status: %m");
        goto close_fd_exit;
    }

    if (!(status.flags & VFIO_GROUP_FLAGS_VIABLE)) {
        error_report("vfio: error, group %d is not viable, please ensure "
                     "all devices within the iommu_group are bound to their "
                     "vfio bus driver.", groupid);
        goto close_fd_exit;
    }

    group->groupid = groupid;
    QLIST_INIT(&group->device_list);

    if (vfio_connect_container(group, as)) {
        error_report("vfio: failed to setup container for group %d", groupid);
        goto close_fd_exit;
    }

    if (QLIST_EMPTY(&vfio_group_list)) {
        qemu_register_reset(vfio_reset_handler, NULL);
    }

    QLIST_INSERT_HEAD(&vfio_group_list, group, next);

    vfio_kvm_device_add_group(group);

    return group;

close_fd_exit:
    close(group->fd);

free_group_exit:
    g_free(group);

    return NULL;
}

void vfio_put_group(VFIOGroup *group)
{
    if (!group || !QLIST_EMPTY(&group->device_list)) {
        return;
    }

    vfio_kvm_device_del_group(group);
    vfio_disconnect_container(group);
    QLIST_REMOVE(group, next);
    trace_vfio_put_group(group->fd);
    close(group->fd);
    g_free(group);

    if (QLIST_EMPTY(&vfio_group_list)) {
        qemu_unregister_reset(vfio_reset_handler, NULL);
    }
}

int vfio_get_device(VFIOGroup *group, const char *name,
                       VFIODevice *vbasedev)
{
    struct vfio_device_info dev_info = { .argsz = sizeof(dev_info) };
    int ret, fd;

    fd = ioctl(group->fd, VFIO_GROUP_GET_DEVICE_FD, name);
    if (fd < 0) {
        error_report("vfio: error getting device %s from group %d: %m",
                     name, group->groupid);
        error_printf("Verify all devices in group %d are bound to vfio-<bus> "
                     "or pci-stub and not already in use\n", group->groupid);
        return fd;
    }

    ret = ioctl(fd, VFIO_DEVICE_GET_INFO, &dev_info);
    if (ret) {
        error_report("vfio: error getting device info: %m");
        close(fd);
        return ret;
    }

    vbasedev->fd = fd;
    vbasedev->group = group;
    QLIST_INSERT_HEAD(&group->device_list, vbasedev, next);

    vbasedev->num_irqs = dev_info.num_irqs;
    vbasedev->num_regions = dev_info.num_regions;
    vbasedev->flags = dev_info.flags;

    trace_vfio_get_device(name, dev_info.flags, dev_info.num_regions,
                          dev_info.num_irqs);

    vbasedev->reset_works = !!(dev_info.flags & VFIO_DEVICE_FLAGS_RESET);
    return 0;
}

void vfio_put_base_device(VFIODevice *vbasedev)
{
    if (!vbasedev->group) {
        return;
    }
    QLIST_REMOVE(vbasedev, next);
    vbasedev->group = NULL;
    trace_vfio_put_base_device(vbasedev->fd);
    close(vbasedev->fd);
}

static int vfio_container_do_ioctl(AddressSpace *as, int32_t groupid,
                                   int req, void *param)
{
    VFIOGroup *group;
    VFIOContainer *container;
    int ret = -1;

    group = vfio_get_group(groupid, as);
    if (!group) {
        error_report("vfio: group %d not registered", groupid);
        return ret;
    }

    container = group->container;
    if (group->container) {
        ret = ioctl(container->fd, req, param);
        if (ret < 0) {
            error_report("vfio: failed to ioctl %d to container: ret=%d, %s",
                         _IOC_NR(req) - VFIO_BASE, ret, strerror(errno));
        }
    }

    vfio_put_group(group);

    return ret;
}

int vfio_container_ioctl(AddressSpace *as, int32_t groupid,
                         int req, void *param)
{
    /* We allow only certain ioctls to the container */
    switch (req) {
    case VFIO_CHECK_EXTENSION:
    case VFIO_IOMMU_SPAPR_TCE_GET_INFO:
    case VFIO_EEH_PE_OP:
        break;
    default:
        /* Return an error on unknown requests */
        error_report("vfio: unsupported ioctl %X", req);
        return -1;
    }

    return vfio_container_do_ioctl(as, groupid, req, param);
}