hw/vfio/helpers.c

/*
 * low level and IOMMU backend agnostic helpers used by VFIO devices,
 * related to regions, interrupts, capabilities
 *
 * 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 "qemu/osdep.h"
#include <sys/ioctl.h>

#include "hw/vfio/vfio-common.h"
#include "hw/hw.h"
#include "trace.h"
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "qemu/units.h"
#include "monitor/monitor.h"

/*
 * 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);
}

static inline const char *action_to_str(int action)
{
    switch (action) {
    case VFIO_IRQ_SET_ACTION_MASK:
        return "MASK";
    case VFIO_IRQ_SET_ACTION_UNMASK:
        return "UNMASK";
    case VFIO_IRQ_SET_ACTION_TRIGGER:
        return "TRIGGER";
    default:
        return "UNKNOWN ACTION";
    }
}

static const char *index_to_str(VFIODevice *vbasedev, int index)
{
    if (vbasedev->type != VFIO_DEVICE_TYPE_PCI) {
        return NULL;
    }

    switch (index) {
    case VFIO_PCI_INTX_IRQ_INDEX:
        return "INTX";
    case VFIO_PCI_MSI_IRQ_INDEX:
        return "MSI";
    case VFIO_PCI_MSIX_IRQ_INDEX:
        return "MSIX";
    case VFIO_PCI_ERR_IRQ_INDEX:
        return "ERR";
    case VFIO_PCI_REQ_IRQ_INDEX:
        return "REQ";
    default:
        return NULL;
    }
}

bool vfio_set_irq_signaling(VFIODevice *vbasedev, int index, int subindex,
                            int action, int fd, Error **errp)
{
    ERRP_GUARD();
    g_autofree struct vfio_irq_set *irq_set = NULL;
    int argsz;
    const char *name;
    int32_t *pfd;

    argsz = sizeof(*irq_set) + sizeof(*pfd);

    irq_set = g_malloc0(argsz);
    irq_set->argsz = argsz;
    irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | action;
    irq_set->index = index;
    irq_set->start = subindex;
    irq_set->count = 1;
    pfd = (int32_t *)&irq_set->data;
    *pfd = fd;

    if (!ioctl(vbasedev->fd, VFIO_DEVICE_SET_IRQS, irq_set)) {
        return true;
    }

    error_setg_errno(errp, errno, "VFIO_DEVICE_SET_IRQS failure");

    name = index_to_str(vbasedev, index);
    if (name) {
        error_prepend(errp, "%s-%d: ", name, subindex);
    } else {
        error_prepend(errp, "index %d-%d: ", index, subindex);
    }
    error_prepend(errp,
                  "Failed to %s %s eventfd signaling for interrupt ",
                  fd < 0 ? "tear down" : "set up", action_to_str(action));
    return false;
}

/*
 * 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;
    case 8:
        buf.qword = cpu_to_le64(data);
        break;
    default:
        hw_error("vfio: unsupported write size, %u 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;
    case 8:
        data = le64_to_cpu(buf.qword);
        break;
    default:
        hw_error("vfio: unsupported read size, %u 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,
    .valid = {
        .min_access_size = 1,
        .max_access_size = 8,
    },
    .impl = {
        .min_access_size = 1,
        .max_access_size = 8,
    },
};

int vfio_bitmap_alloc(VFIOBitmap *vbmap, hwaddr size)
{
    vbmap->pages = REAL_HOST_PAGE_ALIGN(size) / qemu_real_host_page_size();
    vbmap->size = ROUND_UP(vbmap->pages, sizeof(__u64) * BITS_PER_BYTE) /
                                         BITS_PER_BYTE;
    vbmap->bitmap = g_try_malloc0(vbmap->size);
    if (!vbmap->bitmap) {
        return -ENOMEM;
    }

    return 0;
}

struct vfio_info_cap_header *
vfio_get_cap(void *ptr, uint32_t cap_offset, uint16_t id)
{
    struct vfio_info_cap_header *hdr;

    for (hdr = ptr + cap_offset; hdr != ptr; hdr = ptr + hdr->next) {
        if (hdr->id == id) {
            return hdr;
        }
    }

    return NULL;
}

struct vfio_info_cap_header *
vfio_get_region_info_cap(struct vfio_region_info *info, uint16_t id)
{
    if (!(info->flags & VFIO_REGION_INFO_FLAG_CAPS)) {
        return NULL;
    }

    return vfio_get_cap((void *)info, info->cap_offset, id);
}

struct vfio_info_cap_header *
vfio_get_device_info_cap(struct vfio_device_info *info, uint16_t id)
{
    if (!(info->flags & VFIO_DEVICE_FLAGS_CAPS)) {
        return NULL;
    }

    return vfio_get_cap((void *)info, info->cap_offset, id);
}

static int vfio_setup_region_sparse_mmaps(VFIORegion *region,
                                          struct vfio_region_info *info)
{
    struct vfio_info_cap_header *hdr;
    struct vfio_region_info_cap_sparse_mmap *sparse;
    int i, j;

    hdr = vfio_get_region_info_cap(info, VFIO_REGION_INFO_CAP_SPARSE_MMAP);
    if (!hdr) {
        return -ENODEV;
    }

    sparse = container_of(hdr, struct vfio_region_info_cap_sparse_mmap, header);

    trace_vfio_region_sparse_mmap_header(region->vbasedev->name,
                                         region->nr, sparse->nr_areas);

    region->mmaps = g_new0(VFIOMmap, sparse->nr_areas);

    for (i = 0, j = 0; i < sparse->nr_areas; i++) {
        if (sparse->areas[i].size) {
            trace_vfio_region_sparse_mmap_entry(i, sparse->areas[i].offset,
                                            sparse->areas[i].offset +
                                            sparse->areas[i].size - 1);
            region->mmaps[j].offset = sparse->areas[i].offset;
            region->mmaps[j].size = sparse->areas[i].size;
            j++;
        }
    }

    region->nr_mmaps = j;
    region->mmaps = g_realloc(region->mmaps, j * sizeof(VFIOMmap));

    return 0;
}

int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region,
                      int index, const char *name)
{
    g_autofree struct vfio_region_info *info = NULL;
    int ret;

    ret = vfio_get_region_info(vbasedev, index, &info);
    if (ret) {
        return ret;
    }

    region->vbasedev = vbasedev;
    region->flags = info->flags;
    region->size = info->size;
    region->fd_offset = info->offset;
    region->nr = index;

    if (region->size) {
        region->mem = g_new0(MemoryRegion, 1);
        memory_region_init_io(region->mem, obj, &vfio_region_ops,
                              region, name, region->size);

        if (!vbasedev->no_mmap &&
            region->flags & VFIO_REGION_INFO_FLAG_MMAP) {

            ret = vfio_setup_region_sparse_mmaps(region, info);

            if (ret) {
                region->nr_mmaps = 1;
                region->mmaps = g_new0(VFIOMmap, region->nr_mmaps);
                region->mmaps[0].offset = 0;
                region->mmaps[0].size = region->size;
            }
        }
    }

    trace_vfio_region_setup(vbasedev->name, index, name,
                            region->flags, region->fd_offset, region->size);
    return 0;
}

static void vfio_subregion_unmap(VFIORegion *region, int index)
{
    trace_vfio_region_unmap(memory_region_name(&region->mmaps[index].mem),
                            region->mmaps[index].offset,
                            region->mmaps[index].offset +
                            region->mmaps[index].size - 1);
    memory_region_del_subregion(region->mem, &region->mmaps[index].mem);
    munmap(region->mmaps[index].mmap, region->mmaps[index].size);
    object_unparent(OBJECT(&region->mmaps[index].mem));
    region->mmaps[index].mmap = NULL;
}

int vfio_region_mmap(VFIORegion *region)
{
    int i, ret, prot = 0;
    char *name;

    if (!region->mem) {
        return 0;
    }

    prot |= region->flags & VFIO_REGION_INFO_FLAG_READ ? PROT_READ : 0;
    prot |= region->flags & VFIO_REGION_INFO_FLAG_WRITE ? PROT_WRITE : 0;

    for (i = 0; i < region->nr_mmaps; i++) {
        size_t align = MIN(1ULL << ctz64(region->mmaps[i].size), 1 * GiB);
        void *map_base, *map_align;

        /*
         * Align the mmap for more efficient mapping in the kernel.  Ideally
         * we'd know the PMD and PUD mapping sizes to use as discrete alignment
         * intervals, but we don't.  As of Linux v6.12, the largest PUD size
         * supporting huge pfnmap is 1GiB (ARCH_SUPPORTS_PUD_PFNMAP is only set
         * on x86_64).  Align by power-of-two size, capped at 1GiB.
         *
         * NB. qemu_memalign() and friends actually allocate memory, whereas
         * the region size here can exceed host memory, therefore we manually
         * create an oversized anonymous mapping and clean it up for alignment.
         */
        map_base = mmap(0, region->mmaps[i].size + align, PROT_NONE,
                        MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
        if (map_base == MAP_FAILED) {
            ret = -errno;
            goto no_mmap;
        }

        map_align = (void *)ROUND_UP((uintptr_t)map_base, (uintptr_t)align);
        munmap(map_base, map_align - map_base);
        munmap(map_align + region->mmaps[i].size,
               align - (map_align - map_base));

        region->mmaps[i].mmap = mmap(map_align, region->mmaps[i].size, prot,
                                     MAP_SHARED | MAP_FIXED,
                                     region->vbasedev->fd,
                                     region->fd_offset +
                                     region->mmaps[i].offset);
        if (region->mmaps[i].mmap == MAP_FAILED) {
            ret = -errno;
            goto no_mmap;
        }

        name = g_strdup_printf("%s mmaps[%d]",
                               memory_region_name(region->mem), i);
        memory_region_init_ram_device_ptr(&region->mmaps[i].mem,
                                          memory_region_owner(region->mem),
                                          name, region->mmaps[i].size,
                                          region->mmaps[i].mmap);
        g_free(name);
        memory_region_add_subregion(region->mem, region->mmaps[i].offset,
                                    &region->mmaps[i].mem);

        trace_vfio_region_mmap(memory_region_name(&region->mmaps[i].mem),
                               region->mmaps[i].offset,
                               region->mmaps[i].offset +
                               region->mmaps[i].size - 1);
    }

    return 0;

no_mmap:
    trace_vfio_region_mmap_fault(memory_region_name(region->mem), i,
                                 region->fd_offset + region->mmaps[i].offset,
                                 region->fd_offset + region->mmaps[i].offset +
                                 region->mmaps[i].size - 1, ret);

    region->mmaps[i].mmap = NULL;

    for (i--; i >= 0; i--) {
        vfio_subregion_unmap(region, i);
    }

    return ret;
}

void vfio_region_unmap(VFIORegion *region)
{
    int i;

    if (!region->mem) {
        return;
    }

    for (i = 0; i < region->nr_mmaps; i++) {
        if (region->mmaps[i].mmap) {
            vfio_subregion_unmap(region, i);
        }
    }
}

void vfio_region_exit(VFIORegion *region)
{
    int i;

    if (!region->mem) {
        return;
    }

    for (i = 0; i < region->nr_mmaps; i++) {
        if (region->mmaps[i].mmap) {
            memory_region_del_subregion(region->mem, &region->mmaps[i].mem);
        }
    }

    trace_vfio_region_exit(region->vbasedev->name, region->nr);
}

void vfio_region_finalize(VFIORegion *region)
{
    int i;

    if (!region->mem) {
        return;
    }

    for (i = 0; i < region->nr_mmaps; i++) {
        if (region->mmaps[i].mmap) {
            munmap(region->mmaps[i].mmap, region->mmaps[i].size);
            object_unparent(OBJECT(&region->mmaps[i].mem));
        }
    }

    object_unparent(OBJECT(region->mem));

    g_free(region->mem);
    g_free(region->mmaps);

    trace_vfio_region_finalize(region->vbasedev->name, region->nr);

    region->mem = NULL;
    region->mmaps = NULL;
    region->nr_mmaps = 0;
    region->size = 0;
    region->flags = 0;
    region->nr = 0;
}

void vfio_region_mmaps_set_enabled(VFIORegion *region, bool enabled)
{
    int i;

    if (!region->mem) {
        return;
    }

    for (i = 0; i < region->nr_mmaps; i++) {
        if (region->mmaps[i].mmap) {
            memory_region_set_enabled(&region->mmaps[i].mem, enabled);
        }
    }

    trace_vfio_region_mmaps_set_enabled(memory_region_name(region->mem),
                                        enabled);
}

int vfio_get_region_info(VFIODevice *vbasedev, int index,
                         struct vfio_region_info **info)
{
    size_t argsz = sizeof(struct vfio_region_info);

    *info = g_malloc0(argsz);

    (*info)->index = index;
retry:
    (*info)->argsz = argsz;

    if (ioctl(vbasedev->fd, VFIO_DEVICE_GET_REGION_INFO, *info)) {
        g_free(*info);
        *info = NULL;
        return -errno;
    }

    if ((*info)->argsz > argsz) {
        argsz = (*info)->argsz;
        *info = g_realloc(*info, argsz);

        goto retry;
    }

    return 0;
}

int vfio_get_dev_region_info(VFIODevice *vbasedev, uint32_t type,
                             uint32_t subtype, struct vfio_region_info **info)
{
    int i;

    for (i = 0; i < vbasedev->num_regions; i++) {
        struct vfio_info_cap_header *hdr;
        struct vfio_region_info_cap_type *cap_type;

        if (vfio_get_region_info(vbasedev, i, info)) {
            continue;
        }

        hdr = vfio_get_region_info_cap(*info, VFIO_REGION_INFO_CAP_TYPE);
        if (!hdr) {
            g_free(*info);
            continue;
        }

        cap_type = container_of(hdr, struct vfio_region_info_cap_type, header);

        trace_vfio_get_dev_region(vbasedev->name, i,
                                  cap_type->type, cap_type->subtype);

        if (cap_type->type == type && cap_type->subtype == subtype) {
            return 0;
        }

        g_free(*info);
    }

    *info = NULL;
    return -ENODEV;
}

bool vfio_has_region_cap(VFIODevice *vbasedev, int region, uint16_t cap_type)
{
    g_autofree struct vfio_region_info *info = NULL;
    bool ret = false;

    if (!vfio_get_region_info(vbasedev, region, &info)) {
        if (vfio_get_region_info_cap(info, cap_type)) {
            ret = true;
        }
    }

    return ret;
}

bool vfio_device_get_name(VFIODevice *vbasedev, Error **errp)
{
    ERRP_GUARD();
    struct stat st;

    if (vbasedev->fd < 0) {
        if (stat(vbasedev->sysfsdev, &st) < 0) {
            error_setg_errno(errp, errno, "no such host device");
            error_prepend(errp, VFIO_MSG_PREFIX, vbasedev->sysfsdev);
            return false;
        }
        /* User may specify a name, e.g: VFIO platform device */
        if (!vbasedev->name) {
            vbasedev->name = g_path_get_basename(vbasedev->sysfsdev);
        }
    } else {
        if (!vbasedev->iommufd) {
            error_setg(errp, "Use FD passing only with iommufd backend");
            return false;
        }
        /*
         * Give a name with fd so any function printing out vbasedev->name
         * will not break.
         */
        if (!vbasedev->name) {
            vbasedev->name = g_strdup_printf("VFIO_FD%d", vbasedev->fd);
        }
    }

    return true;
}

void vfio_device_set_fd(VFIODevice *vbasedev, const char *str, Error **errp)
{
    ERRP_GUARD();
    int fd = monitor_fd_param(monitor_cur(), str, errp);

    if (fd < 0) {
        error_prepend(errp, "Could not parse remote object fd %s:", str);
        return;
    }
    vbasedev->fd = fd;
}

void vfio_device_init(VFIODevice *vbasedev, int type, VFIODeviceOps *ops,
                      DeviceState *dev, bool ram_discard)
{
    vbasedev->type = type;
    vbasedev->ops = ops;
    vbasedev->dev = dev;
    vbasedev->fd = -1;

    vbasedev->ram_block_discard_allowed = ram_discard;
}

int vfio_device_get_aw_bits(VFIODevice *vdev)
{
    /*
     * iova_ranges is a sorted list. For old kernels that support
     * VFIO but not support query of iova ranges, iova_ranges is NULL,
     * in this case HOST_IOMMU_DEVICE_CAP_AW_BITS_MAX(64) is returned.
     */
    GList *l = g_list_last(vdev->bcontainer->iova_ranges);

    if (l) {
        Range *range = l->data;
        return range_get_last_bit(range) + 1;
    }

    return HOST_IOMMU_DEVICE_CAP_AW_BITS_MAX;
}

bool vfio_device_is_mdev(VFIODevice *vbasedev)
{
    g_autofree char *subsys = NULL;
    g_autofree char *tmp = NULL;

    if (!vbasedev->sysfsdev) {
        return false;
    }

    tmp = g_strdup_printf("%s/subsystem", vbasedev->sysfsdev);
    subsys = realpath(tmp, NULL);
    return subsys && (strcmp(subsys, "/sys/bus/mdev") == 0);
}

bool vfio_device_hiod_realize(VFIODevice *vbasedev, Error **errp)
{
    HostIOMMUDevice *hiod = vbasedev->hiod;

    if (!hiod) {
        return true;
    }

    return HOST_IOMMU_DEVICE_GET_CLASS(hiod)->realize(hiod, vbasedev, errp);
}