// 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/align.h>
#include <linux/iommufd.h>
#include <linux/kernel.h>
#include <linux/limits.h>
#include <linux/log2.h>
#include <linux/mman.h>
#include <linux/overflow.h>
#include <linux/sizes.h>
#include <linux/types.h>
#include <linux/vfio.h>

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

#define PCI_SYSFS_PATH  "/sys/bus/pci/devices"

static void vfio_pci_irq_set(struct vfio_pci_device *device,
                             u32 index, u32 vector, u32 count, int *fds)
{
        u8 buf[sizeof(struct vfio_irq_set) + sizeof(int) * count] = {};
        struct vfio_irq_set *irq = (void *)&buf;
        int *irq_fds = (void *)&irq->data;

        irq->argsz = sizeof(buf);
        irq->flags = VFIO_IRQ_SET_ACTION_TRIGGER;
        irq->index = index;
        irq->start = vector;
        irq->count = count;

        if (count) {
                irq->flags |= VFIO_IRQ_SET_DATA_EVENTFD;
                memcpy(irq_fds, fds, sizeof(int) * count);
        } else {
                irq->flags |= VFIO_IRQ_SET_DATA_NONE;
        }

        ioctl_assert(device->fd, VFIO_DEVICE_SET_IRQS, irq);
}

void vfio_pci_irq_trigger(struct vfio_pci_device *device, u32 index, u32 vector)
{
        struct vfio_irq_set irq = {
                .argsz = sizeof(irq),
                .flags = VFIO_IRQ_SET_ACTION_TRIGGER | VFIO_IRQ_SET_DATA_NONE,
                .index = index,
                .start = vector,
                .count = 1,
        };

        ioctl_assert(device->fd, VFIO_DEVICE_SET_IRQS, &irq);
}

static void check_supported_irq_index(u32 index)
{
        /* VFIO selftests only supports MSI and MSI-x for now. */
        VFIO_ASSERT_TRUE(index == VFIO_PCI_MSI_IRQ_INDEX ||
                         index == VFIO_PCI_MSIX_IRQ_INDEX,
                         "Unsupported IRQ index: %u\n", index);
}

void vfio_pci_irq_enable(struct vfio_pci_device *device, u32 index, u32 vector,
                         int count)
{
        int i;

        check_supported_irq_index(index);

        for (i = vector; i < vector + count; i++) {
                VFIO_ASSERT_LT(device->msi_eventfds[i], 0);
                device->msi_eventfds[i] = eventfd(0, 0);
                VFIO_ASSERT_GE(device->msi_eventfds[i], 0);
        }

        vfio_pci_irq_set(device, index, vector, count, device->msi_eventfds + vector);
}

void vfio_pci_irq_disable(struct vfio_pci_device *device, u32 index)
{
        int i;

        check_supported_irq_index(index);

        for (i = 0; i < ARRAY_SIZE(device->msi_eventfds); i++) {
                if (device->msi_eventfds[i] < 0)
                        continue;

                VFIO_ASSERT_EQ(close(device->msi_eventfds[i]), 0);
                device->msi_eventfds[i] = -1;
        }

        vfio_pci_irq_set(device, index, 0, 0, NULL);
}

static void vfio_pci_irq_get(struct vfio_pci_device *device, u32 index,
                             struct vfio_irq_info *irq_info)
{
        irq_info->argsz = sizeof(*irq_info);
        irq_info->index = index;

        ioctl_assert(device->fd, VFIO_DEVICE_GET_IRQ_INFO, irq_info);
}

static void vfio_pci_region_get(struct vfio_pci_device *device, int index,
                                struct vfio_region_info *info)
{
        memset(info, 0, sizeof(*info));

        info->argsz = sizeof(*info);
        info->index = index;

        ioctl_assert(device->fd, VFIO_DEVICE_GET_REGION_INFO, info);
}

static void vfio_pci_bar_map(struct vfio_pci_device *device, int index)
{
        struct vfio_pci_bar *bar = &device->bars[index];
        size_t align, size;
        int prot = 0;
        void *vaddr;

        VFIO_ASSERT_LT(index, PCI_STD_NUM_BARS);
        VFIO_ASSERT_NULL(bar->vaddr);
        VFIO_ASSERT_TRUE(bar->info.flags & VFIO_REGION_INFO_FLAG_MMAP);
        VFIO_ASSERT_TRUE(is_power_of_2(bar->info.size));

        if (bar->info.flags & VFIO_REGION_INFO_FLAG_READ)
                prot |= PROT_READ;
        if (bar->info.flags & VFIO_REGION_INFO_FLAG_WRITE)
                prot |= PROT_WRITE;

        size = bar->info.size;

        /*
         * Align BAR mmaps to improve page fault granularity during potential
         * subsequent IOMMU mapping of these BAR vaddr. 1G for x86 is the
         * largest hugepage size across any architecture, so no benefit from
         * larger alignment. BARs smaller than 1G will be aligned by their
         * power-of-two size, guaranteeing sufficient alignment for smaller
         * hugepages, if present.
         */
        align = min_t(size_t, size, SZ_1G);

        vaddr = mmap_reserve(size, align, 0);
        bar->vaddr = mmap(vaddr, size, prot, MAP_SHARED | MAP_FIXED,
                          device->fd, bar->info.offset);
        VFIO_ASSERT_NE(bar->vaddr, MAP_FAILED);

        madvise(bar->vaddr, size, MADV_HUGEPAGE);
}

static void vfio_pci_bar_unmap(struct vfio_pci_device *device, int index)
{
        struct vfio_pci_bar *bar = &device->bars[index];

        VFIO_ASSERT_LT(index, PCI_STD_NUM_BARS);
        VFIO_ASSERT_NOT_NULL(bar->vaddr);

        VFIO_ASSERT_EQ(munmap(bar->vaddr, bar->info.size), 0);
        bar->vaddr = NULL;
}

static void vfio_pci_bar_unmap_all(struct vfio_pci_device *device)
{
        int i;

        for (i = 0; i < PCI_STD_NUM_BARS; i++) {
                if (device->bars[i].vaddr)
                        vfio_pci_bar_unmap(device, i);
        }
}

void vfio_pci_config_access(struct vfio_pci_device *device, bool write,
                            size_t config, size_t size, void *data)
{
        struct vfio_region_info *config_space = &device->config_space;
        int ret;

        if (write)
                ret = pwrite(device->fd, data, size, config_space->offset + config);
        else
                ret = pread(device->fd, data, size, config_space->offset + config);

        VFIO_ASSERT_EQ(ret, size, "Failed to %s PCI config space: 0x%lx\n",
                       write ? "write to" : "read from", config);
}

void vfio_pci_device_reset(struct vfio_pci_device *device)
{
        ioctl_assert(device->fd, VFIO_DEVICE_RESET, NULL);
}

static unsigned int vfio_pci_get_group_from_dev(const char *bdf)
{
        char dev_iommu_group_path[PATH_MAX] = {0};
        char sysfs_path[PATH_MAX] = {0};
        unsigned int group;
        int ret;

        snprintf(sysfs_path, PATH_MAX, "%s/%s/iommu_group", PCI_SYSFS_PATH, bdf);

        ret = readlink(sysfs_path, dev_iommu_group_path, sizeof(dev_iommu_group_path));
        VFIO_ASSERT_NE(ret, -1, "Failed to get the IOMMU group for device: %s\n", bdf);

        ret = sscanf(basename(dev_iommu_group_path), "%u", &group);
        VFIO_ASSERT_EQ(ret, 1, "Failed to get the IOMMU group for device: %s\n", bdf);

        return group;
}

static void vfio_pci_group_setup(struct vfio_pci_device *device, const char *bdf)
{
        struct vfio_group_status group_status = {
                .argsz = sizeof(group_status),
        };
        char group_path[32];
        int group;

        group = vfio_pci_get_group_from_dev(bdf);
        snprintf(group_path, sizeof(group_path), "/dev/vfio/%d", group);

        device->group_fd = open(group_path, O_RDWR);
        VFIO_ASSERT_GE(device->group_fd, 0, "open(%s) failed\n", group_path);

        ioctl_assert(device->group_fd, VFIO_GROUP_GET_STATUS, &group_status);
        VFIO_ASSERT_TRUE(group_status.flags & VFIO_GROUP_FLAGS_VIABLE);

        ioctl_assert(device->group_fd, VFIO_GROUP_SET_CONTAINER, &device->iommu->container_fd);
}

static void vfio_pci_container_setup(struct vfio_pci_device *device, const char *bdf)
{
        struct iommu *iommu = device->iommu;
        unsigned long iommu_type = iommu->mode->iommu_type;
        int ret;

        vfio_pci_group_setup(device, bdf);

        ret = ioctl(iommu->container_fd, VFIO_CHECK_EXTENSION, iommu_type);
        VFIO_ASSERT_GT(ret, 0, "VFIO IOMMU type %lu not supported\n", iommu_type);

        /*
         * Allow multiple threads to race to set the IOMMU type on the
         * container. The first will succeed and the rest should fail
         * because the IOMMU type is already set.
         */
        (void)ioctl(iommu->container_fd, VFIO_SET_IOMMU, (void *)iommu_type);

        device->fd = ioctl(device->group_fd, VFIO_GROUP_GET_DEVICE_FD, bdf);
        VFIO_ASSERT_GE(device->fd, 0);
}

static void vfio_pci_device_setup(struct vfio_pci_device *device)
{
        int i;

        device->info.argsz = sizeof(device->info);
        ioctl_assert(device->fd, VFIO_DEVICE_GET_INFO, &device->info);

        vfio_pci_region_get(device, VFIO_PCI_CONFIG_REGION_INDEX, &device->config_space);

        /* Sanity check VFIO does not advertise mmap for config space */
        VFIO_ASSERT_TRUE(!(device->config_space.flags & VFIO_REGION_INFO_FLAG_MMAP),
                         "PCI config space should not support mmap()\n");

        for (i = 0; i < PCI_STD_NUM_BARS; i++) {
                struct vfio_pci_bar *bar = device->bars + i;

                vfio_pci_region_get(device, i, &bar->info);
                if (bar->info.flags & VFIO_REGION_INFO_FLAG_MMAP)
                        vfio_pci_bar_map(device, i);
        }

        vfio_pci_irq_get(device, VFIO_PCI_MSI_IRQ_INDEX, &device->msi_info);
        vfio_pci_irq_get(device, VFIO_PCI_MSIX_IRQ_INDEX, &device->msix_info);

        for (i = 0; i < ARRAY_SIZE(device->msi_eventfds); i++)
                device->msi_eventfds[i] = -1;
}

const char *vfio_pci_get_cdev_path(const char *bdf)
{
        char dir_path[PATH_MAX];
        struct dirent *entry;
        char *cdev_path;
        DIR *dir;

        cdev_path = calloc(PATH_MAX, 1);
        VFIO_ASSERT_NOT_NULL(cdev_path);

        snprintf(dir_path, sizeof(dir_path), "/sys/bus/pci/devices/%s/vfio-dev/", bdf);

        dir = opendir(dir_path);
        VFIO_ASSERT_NOT_NULL(dir, "Failed to open directory %s\n", dir_path);

        while ((entry = readdir(dir)) != NULL) {
                /* Find the file that starts with "vfio" */
                if (strncmp("vfio", entry->d_name, 4))
                        continue;

                snprintf(cdev_path, PATH_MAX, "/dev/vfio/devices/%s", entry->d_name);
                break;
        }

        VFIO_ASSERT_NE(cdev_path[0], 0, "Failed to find vfio cdev file.\n");
        VFIO_ASSERT_EQ(closedir(dir), 0);

        return cdev_path;
}

static void vfio_device_bind_iommufd(int device_fd, int iommufd)
{
        struct vfio_device_bind_iommufd args = {
                .argsz = sizeof(args),
                .iommufd = iommufd,
        };

        ioctl_assert(device_fd, VFIO_DEVICE_BIND_IOMMUFD, &args);
}

static void vfio_device_attach_iommufd_pt(int device_fd, u32 pt_id)
{
        struct vfio_device_attach_iommufd_pt args = {
                .argsz = sizeof(args),
                .pt_id = pt_id,
        };

        ioctl_assert(device_fd, VFIO_DEVICE_ATTACH_IOMMUFD_PT, &args);
}

static void vfio_pci_iommufd_setup(struct vfio_pci_device *device, const char *bdf)
{
        const char *cdev_path = vfio_pci_get_cdev_path(bdf);

        device->fd = open(cdev_path, O_RDWR);
        VFIO_ASSERT_GE(device->fd, 0);
        free((void *)cdev_path);

        vfio_device_bind_iommufd(device->fd, device->iommu->iommufd);
        vfio_device_attach_iommufd_pt(device->fd, device->iommu->ioas_id);
}

struct vfio_pci_device *vfio_pci_device_init(const char *bdf, struct iommu *iommu)
{
        struct vfio_pci_device *device;

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

        VFIO_ASSERT_NOT_NULL(iommu);
        device->iommu = iommu;
        device->bdf = bdf;

        if (iommu->mode->container_path)
                vfio_pci_container_setup(device, bdf);
        else
                vfio_pci_iommufd_setup(device, bdf);

        vfio_pci_device_setup(device);
        vfio_pci_driver_probe(device);

        return device;
}

void vfio_pci_device_cleanup(struct vfio_pci_device *device)
{
        int i;

        if (device->driver.initialized)
                vfio_pci_driver_remove(device);

        vfio_pci_bar_unmap_all(device);

        VFIO_ASSERT_EQ(close(device->fd), 0);

        for (i = 0; i < ARRAY_SIZE(device->msi_eventfds); i++) {
                if (device->msi_eventfds[i] < 0)
                        continue;

                VFIO_ASSERT_EQ(close(device->msi_eventfds[i]), 0);
        }

        if (device->group_fd)
                VFIO_ASSERT_EQ(close(device->group_fd), 0);

        free(device);
}