// SPDX-License-Identifier: GPL-2.0-only
#include <dirent.h>
#include <fcntl.h>
#include <libgen.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <sys/eventfd.h>
#include <sys/ioctl.h>
#include <sys/mman.h>

#include <linux/limits.h>
#include <linux/mman.h>
#include <linux/types.h>
#include <linux/vfio.h>
#include <linux/iommufd.h>

#include "../../../kselftest.h"
#include <libvfio.h>

const char *default_iommu_mode = MODE_IOMMUFD;

/* Reminder: Keep in sync with FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(). */
static const struct iommu_mode iommu_modes[] = {
        {
                .name = MODE_VFIO_TYPE1_IOMMU,
                .container_path = "/dev/vfio/vfio",
                .iommu_type = VFIO_TYPE1_IOMMU,
        },
        {
                .name = MODE_VFIO_TYPE1V2_IOMMU,
                .container_path = "/dev/vfio/vfio",
                .iommu_type = VFIO_TYPE1v2_IOMMU,
        },
        {
                .name = MODE_IOMMUFD_COMPAT_TYPE1,
                .container_path = "/dev/iommu",
                .iommu_type = VFIO_TYPE1_IOMMU,
        },
        {
                .name = MODE_IOMMUFD_COMPAT_TYPE1V2,
                .container_path = "/dev/iommu",
                .iommu_type = VFIO_TYPE1v2_IOMMU,
        },
        {
                .name = MODE_IOMMUFD,
        },
};

static const struct iommu_mode *lookup_iommu_mode(const char *iommu_mode)
{
        int i;

        if (!iommu_mode)
                iommu_mode = default_iommu_mode;

        for (i = 0; i < ARRAY_SIZE(iommu_modes); i++) {
                if (strcmp(iommu_mode, iommu_modes[i].name))
                        continue;

                return &iommu_modes[i];
        }

        VFIO_FAIL("Unrecognized IOMMU mode: %s\n", iommu_mode);
}

int __iommu_hva2iova(struct iommu *iommu, void *vaddr, iova_t *iova)
{
        struct dma_region *region;

        list_for_each_entry(region, &iommu->dma_regions, link) {
                if (vaddr < region->vaddr)
                        continue;

                if (vaddr >= region->vaddr + region->size)
                        continue;

                if (iova)
                        *iova = region->iova + (vaddr - region->vaddr);

                return 0;
        }

        return -ENOENT;
}

iova_t iommu_hva2iova(struct iommu *iommu, void *vaddr)
{
        iova_t iova;
        int ret;

        ret = __iommu_hva2iova(iommu, vaddr, &iova);
        VFIO_ASSERT_EQ(ret, 0, "%p is not mapped into the iommu\n", vaddr);

        return iova;
}

static int vfio_iommu_map(struct iommu *iommu, struct dma_region *region)
{
        struct vfio_iommu_type1_dma_map args = {
                .argsz = sizeof(args),
                .flags = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE,
                .vaddr = (u64)region->vaddr,
                .iova = region->iova,
                .size = region->size,
        };

        if (ioctl(iommu->container_fd, VFIO_IOMMU_MAP_DMA, &args))
                return -errno;

        return 0;
}

static int iommufd_map(struct iommu *iommu, struct dma_region *region)
{
        struct iommu_ioas_map args = {
                .size = sizeof(args),
                .flags = IOMMU_IOAS_MAP_READABLE |
                         IOMMU_IOAS_MAP_WRITEABLE |
                         IOMMU_IOAS_MAP_FIXED_IOVA,
                .user_va = (u64)region->vaddr,
                .iova = region->iova,
                .length = region->size,
                .ioas_id = iommu->ioas_id,
        };

        if (ioctl(iommu->iommufd, IOMMU_IOAS_MAP, &args))
                return -errno;

        return 0;
}

int __iommu_map(struct iommu *iommu, struct dma_region *region)
{
        int ret;

        if (iommu->iommufd)
                ret = iommufd_map(iommu, region);
        else
                ret = vfio_iommu_map(iommu, region);

        if (ret)
                return ret;

        list_add(&region->link, &iommu->dma_regions);

        return 0;
}

static int __vfio_iommu_unmap(int fd, u64 iova, u64 size, u32 flags, u64 *unmapped)
{
        struct vfio_iommu_type1_dma_unmap args = {
                .argsz = sizeof(args),
                .iova = iova,
                .size = size,
                .flags = flags,
        };

        if (ioctl(fd, VFIO_IOMMU_UNMAP_DMA, &args))
                return -errno;

        if (unmapped)
                *unmapped = args.size;

        return 0;
}

static int vfio_iommu_unmap(struct iommu *iommu, struct dma_region *region,
                            u64 *unmapped)
{
        return __vfio_iommu_unmap(iommu->container_fd, region->iova,
                                  region->size, 0, unmapped);
}

static int __iommufd_unmap(int fd, u64 iova, u64 length, u32 ioas_id, u64 *unmapped)
{
        struct iommu_ioas_unmap args = {
                .size = sizeof(args),
                .iova = iova,
                .length = length,
                .ioas_id = ioas_id,
        };

        if (ioctl(fd, IOMMU_IOAS_UNMAP, &args))
                return -errno;

        if (unmapped)
                *unmapped = args.length;

        return 0;
}

static int iommufd_unmap(struct iommu *iommu, struct dma_region *region,
                         u64 *unmapped)
{
        return __iommufd_unmap(iommu->iommufd, region->iova, region->size,
                               iommu->ioas_id, unmapped);
}

int __iommu_unmap(struct iommu *iommu, struct dma_region *region, u64 *unmapped)
{
        int ret;

        if (iommu->iommufd)
                ret = iommufd_unmap(iommu, region, unmapped);
        else
                ret = vfio_iommu_unmap(iommu, region, unmapped);

        if (ret)
                return ret;

        list_del_init(&region->link);

        return 0;
}

int __iommu_unmap_all(struct iommu *iommu, u64 *unmapped)
{
        int ret;
        struct dma_region *curr, *next;

        if (iommu->iommufd)
                ret = __iommufd_unmap(iommu->iommufd, 0, UINT64_MAX,
                                      iommu->ioas_id, unmapped);
        else
                ret = __vfio_iommu_unmap(iommu->container_fd, 0, 0,
                                         VFIO_DMA_UNMAP_FLAG_ALL, unmapped);

        if (ret)
                return ret;

        list_for_each_entry_safe(curr, next, &iommu->dma_regions, link)
                list_del_init(&curr->link);

        return 0;
}

static struct vfio_info_cap_header *next_cap_hdr(void *buf, u32 bufsz,
                                                 u32 *cap_offset)
{
        struct vfio_info_cap_header *hdr;

        if (!*cap_offset)
                return NULL;

        VFIO_ASSERT_LT(*cap_offset, bufsz);
        VFIO_ASSERT_GE(bufsz - *cap_offset, sizeof(*hdr));

        hdr = (struct vfio_info_cap_header *)((u8 *)buf + *cap_offset);
        *cap_offset = hdr->next;

        return hdr;
}

static struct vfio_info_cap_header *vfio_iommu_info_cap_hdr(struct vfio_iommu_type1_info *info,
                                                            u16 cap_id)
{
        struct vfio_info_cap_header *hdr;
        u32 cap_offset = info->cap_offset;
        u32 max_depth;
        u32 depth = 0;

        if (!(info->flags & VFIO_IOMMU_INFO_CAPS))
                return NULL;

        if (cap_offset)
                VFIO_ASSERT_GE(cap_offset, sizeof(*info));

        max_depth = (info->argsz - sizeof(*info)) / sizeof(*hdr);

        while ((hdr = next_cap_hdr(info, info->argsz, &cap_offset))) {
                depth++;
                VFIO_ASSERT_LE(depth, max_depth, "Capability chain contains a cycle\n");

                if (hdr->id == cap_id)
                        return hdr;
        }

        return NULL;
}

/* Return buffer including capability chain, if present. Free with free() */
static struct vfio_iommu_type1_info *vfio_iommu_get_info(int container_fd)
{
        struct vfio_iommu_type1_info *info;

        info = malloc(sizeof(*info));
        VFIO_ASSERT_NOT_NULL(info);

        *info = (struct vfio_iommu_type1_info) {
                .argsz = sizeof(*info),
        };

        ioctl_assert(container_fd, VFIO_IOMMU_GET_INFO, info);
        VFIO_ASSERT_GE(info->argsz, sizeof(*info));

        info = realloc(info, info->argsz);
        VFIO_ASSERT_NOT_NULL(info);

        ioctl_assert(container_fd, VFIO_IOMMU_GET_INFO, info);
        VFIO_ASSERT_GE(info->argsz, sizeof(*info));

        return info;
}

/*
 * Return iova ranges for the device's container. Normalize vfio_iommu_type1 to
 * report iommufd's iommu_iova_range. Free with free().
 */
static struct iommu_iova_range *vfio_iommu_iova_ranges(struct iommu *iommu,
                                                       u32 *nranges)
{
        struct vfio_iommu_type1_info_cap_iova_range *cap_range;
        struct vfio_iommu_type1_info *info;
        struct vfio_info_cap_header *hdr;
        struct iommu_iova_range *ranges = NULL;

        info = vfio_iommu_get_info(iommu->container_fd);
        hdr = vfio_iommu_info_cap_hdr(info, VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE);
        VFIO_ASSERT_NOT_NULL(hdr);

        cap_range = container_of(hdr, struct vfio_iommu_type1_info_cap_iova_range, header);
        VFIO_ASSERT_GT(cap_range->nr_iovas, 0);

        ranges = calloc(cap_range->nr_iovas, sizeof(*ranges));
        VFIO_ASSERT_NOT_NULL(ranges);

        for (u32 i = 0; i < cap_range->nr_iovas; i++) {
                ranges[i] = (struct iommu_iova_range){
                        .start = cap_range->iova_ranges[i].start,
                        .last = cap_range->iova_ranges[i].end,
                };
        }

        *nranges = cap_range->nr_iovas;

        free(info);
        return ranges;
}

/* Return iova ranges of the device's IOAS. Free with free() */
static struct iommu_iova_range *iommufd_iova_ranges(struct iommu *iommu,
                                                    u32 *nranges)
{
        struct iommu_iova_range *ranges;
        int ret;

        struct iommu_ioas_iova_ranges query = {
                .size = sizeof(query),
                .ioas_id = iommu->ioas_id,
        };

        ret = ioctl(iommu->iommufd, IOMMU_IOAS_IOVA_RANGES, &query);
        VFIO_ASSERT_EQ(ret, -1);
        VFIO_ASSERT_EQ(errno, EMSGSIZE);
        VFIO_ASSERT_GT(query.num_iovas, 0);

        ranges = calloc(query.num_iovas, sizeof(*ranges));
        VFIO_ASSERT_NOT_NULL(ranges);

        query.allowed_iovas = (uintptr_t)ranges;

        ioctl_assert(iommu->iommufd, IOMMU_IOAS_IOVA_RANGES, &query);
        *nranges = query.num_iovas;

        return ranges;
}

static int iova_range_comp(const void *a, const void *b)
{
        const struct iommu_iova_range *ra = a, *rb = b;

        if (ra->start < rb->start)
                return -1;

        if (ra->start > rb->start)
                return 1;

        return 0;
}

/* Return sorted IOVA ranges of the device. Free with free(). */
struct iommu_iova_range *iommu_iova_ranges(struct iommu *iommu, u32 *nranges)
{
        struct iommu_iova_range *ranges;

        if (iommu->iommufd)
                ranges = iommufd_iova_ranges(iommu, nranges);
        else
                ranges = vfio_iommu_iova_ranges(iommu, nranges);

        if (!ranges)
                return NULL;

        VFIO_ASSERT_GT(*nranges, 0);

        /* Sort and check that ranges are sane and non-overlapping */
        qsort(ranges, *nranges, sizeof(*ranges), iova_range_comp);
        VFIO_ASSERT_LT(ranges[0].start, ranges[0].last);

        for (u32 i = 1; i < *nranges; i++) {
                VFIO_ASSERT_LT(ranges[i].start, ranges[i].last);
                VFIO_ASSERT_LT(ranges[i - 1].last, ranges[i].start);
        }

        return ranges;
}

static u32 iommufd_ioas_alloc(int iommufd)
{
        struct iommu_ioas_alloc args = {
                .size = sizeof(args),
        };

        ioctl_assert(iommufd, IOMMU_IOAS_ALLOC, &args);
        return args.out_ioas_id;
}

struct iommu *iommu_init(const char *iommu_mode)
{
        const char *container_path;
        struct iommu *iommu;
        int version;

        iommu = calloc(1, sizeof(*iommu));
        VFIO_ASSERT_NOT_NULL(iommu);

        INIT_LIST_HEAD(&iommu->dma_regions);

        iommu->mode = lookup_iommu_mode(iommu_mode);

        container_path = iommu->mode->container_path;
        if (container_path) {
                iommu->container_fd = open(container_path, O_RDWR);
                VFIO_ASSERT_GE(iommu->container_fd, 0, "open(%s) failed\n", container_path);

                version = ioctl(iommu->container_fd, VFIO_GET_API_VERSION);
                VFIO_ASSERT_EQ(version, VFIO_API_VERSION, "Unsupported version: %d\n", version);
        } else {
                /*
                 * Require device->iommufd to be >0 so that a simple non-0 check can be
                 * used to check if iommufd is enabled. In practice open() will never
                 * return 0 unless stdin is closed.
                 */
                iommu->iommufd = open("/dev/iommu", O_RDWR);
                VFIO_ASSERT_GT(iommu->iommufd, 0);

                iommu->ioas_id = iommufd_ioas_alloc(iommu->iommufd);
        }

        return iommu;
}

void iommu_cleanup(struct iommu *iommu)
{
        if (iommu->iommufd)
                VFIO_ASSERT_EQ(close(iommu->iommufd), 0);
        else
                VFIO_ASSERT_EQ(close(iommu->container_fd), 0);

        free(iommu);
}