// SPDX-License-Identifier: GPL-2.0-only
/*
 *  copyright (c) 2006 IBM Corporation
 *  Authored by: Mike D. Day <ncmike@us.ibm.com>
 */

#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/kobject.h>
#include <linux/err.h>

#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>

#include <xen/xen.h>
#include <xen/xenbus.h>
#include <xen/interface/xen.h>
#include <xen/interface/version.h>
#ifdef CONFIG_XEN_HAVE_VPMU
#include <xen/interface/xenpmu.h>
#endif

#define HYPERVISOR_ATTR_RO(_name) \
static struct hyp_sysfs_attr _name##_attr = __ATTR_RO(_name)

#define HYPERVISOR_ATTR_RW(_name) \
static struct hyp_sysfs_attr _name##_attr = __ATTR_RW(_name)

struct hyp_sysfs_attr {
        struct attribute attr;
        ssize_t (*show)(struct hyp_sysfs_attr *, char *);
        ssize_t (*store)(struct hyp_sysfs_attr *, const char *, size_t);
        union {
                void *hyp_attr_data;
                unsigned long hyp_attr_value;
        };
};

static ssize_t type_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        return sprintf(buffer, "xen\n");
}

HYPERVISOR_ATTR_RO(type);

static int __init xen_sysfs_type_init(void)
{
        return sysfs_create_file(hypervisor_kobj, &type_attr.attr);
}

static ssize_t guest_type_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        const char *type;

        switch (xen_domain_type) {
        case XEN_NATIVE:
                /* ARM only. */
                type = "Xen";
                break;
        case XEN_PV_DOMAIN:
                type = "PV";
                break;
        case XEN_HVM_DOMAIN:
                type = xen_pvh_domain() ? "PVH" : "HVM";
                break;
        default:
                return -EINVAL;
        }

        return sprintf(buffer, "%s\n", type);
}

HYPERVISOR_ATTR_RO(guest_type);

static int __init xen_sysfs_guest_type_init(void)
{
        return sysfs_create_file(hypervisor_kobj, &guest_type_attr.attr);
}

/* xen version attributes */
static ssize_t major_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        int version = HYPERVISOR_xen_version(XENVER_version, NULL);
        if (version)
                return sprintf(buffer, "%d\n", version >> 16);
        return -ENODEV;
}

HYPERVISOR_ATTR_RO(major);

static ssize_t minor_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        int version = HYPERVISOR_xen_version(XENVER_version, NULL);
        if (version)
                return sprintf(buffer, "%d\n", version & 0xff);
        return -ENODEV;
}

HYPERVISOR_ATTR_RO(minor);

static ssize_t extra_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        int ret = -ENOMEM;
        char *extra;

        extra = kmalloc(XEN_EXTRAVERSION_LEN, GFP_KERNEL);
        if (extra) {
                ret = HYPERVISOR_xen_version(XENVER_extraversion, extra);
                if (!ret)
                        ret = sprintf(buffer, "%s\n", extra);
                kfree(extra);
        }

        return ret;
}

HYPERVISOR_ATTR_RO(extra);

static struct attribute *version_attrs[] = {
        &major_attr.attr,
        &minor_attr.attr,
        &extra_attr.attr,
        NULL
};

static const struct attribute_group version_group = {
        .name = "version",
        .attrs = version_attrs,
};

static int __init xen_sysfs_version_init(void)
{
        return sysfs_create_group(hypervisor_kobj, &version_group);
}

/* UUID */

static ssize_t uuid_show_fallback(struct hyp_sysfs_attr *attr, char *buffer)
{
        char *vm, *val;
        int ret;
        extern int xenstored_ready;

        if (!xenstored_ready)
                return -EBUSY;

        vm = xenbus_read(XBT_NIL, "vm", "", NULL);
        if (IS_ERR(vm))
                return PTR_ERR(vm);
        val = xenbus_read(XBT_NIL, vm, "uuid", NULL);
        kfree(vm);
        if (IS_ERR(val))
                return PTR_ERR(val);
        ret = sprintf(buffer, "%s\n", val);
        kfree(val);
        return ret;
}

static ssize_t uuid_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        xen_domain_handle_t uuid;
        int ret;
        ret = HYPERVISOR_xen_version(XENVER_guest_handle, uuid);
        if (ret)
                return uuid_show_fallback(attr, buffer);
        ret = sprintf(buffer, "%pU\n", uuid);
        return ret;
}

HYPERVISOR_ATTR_RO(uuid);

static int __init xen_sysfs_uuid_init(void)
{
        return sysfs_create_file(hypervisor_kobj, &uuid_attr.attr);
}

/* xen compilation attributes */

static ssize_t compiler_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        int ret = -ENOMEM;
        struct xen_compile_info *info;

        info = kmalloc_obj(struct xen_compile_info);
        if (info) {
                ret = HYPERVISOR_xen_version(XENVER_compile_info, info);
                if (!ret)
                        ret = sprintf(buffer, "%s\n", info->compiler);
                kfree(info);
        }

        return ret;
}

HYPERVISOR_ATTR_RO(compiler);

static ssize_t compiled_by_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        int ret = -ENOMEM;
        struct xen_compile_info *info;

        info = kmalloc_obj(struct xen_compile_info);
        if (info) {
                ret = HYPERVISOR_xen_version(XENVER_compile_info, info);
                if (!ret)
                        ret = sprintf(buffer, "%s\n", info->compile_by);
                kfree(info);
        }

        return ret;
}

HYPERVISOR_ATTR_RO(compiled_by);

static ssize_t compile_date_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        int ret = -ENOMEM;
        struct xen_compile_info *info;

        info = kmalloc_obj(struct xen_compile_info);
        if (info) {
                ret = HYPERVISOR_xen_version(XENVER_compile_info, info);
                if (!ret)
                        ret = sprintf(buffer, "%s\n", info->compile_date);
                kfree(info);
        }

        return ret;
}

HYPERVISOR_ATTR_RO(compile_date);

static struct attribute *xen_compile_attrs[] = {
        &compiler_attr.attr,
        &compiled_by_attr.attr,
        &compile_date_attr.attr,
        NULL
};

static const struct attribute_group xen_compilation_group = {
        .name = "compilation",
        .attrs = xen_compile_attrs,
};

static int __init xen_sysfs_compilation_init(void)
{
        return sysfs_create_group(hypervisor_kobj, &xen_compilation_group);
}

/* xen properties info */

static ssize_t capabilities_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        int ret = -ENOMEM;
        char *caps;

        caps = kmalloc(XEN_CAPABILITIES_INFO_LEN, GFP_KERNEL);
        if (caps) {
                ret = HYPERVISOR_xen_version(XENVER_capabilities, caps);
                if (!ret)
                        ret = sprintf(buffer, "%s\n", caps);
                kfree(caps);
        }

        return ret;
}

HYPERVISOR_ATTR_RO(capabilities);

static ssize_t changeset_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        int ret = -ENOMEM;
        char *cset;

        cset = kmalloc(XEN_CHANGESET_INFO_LEN, GFP_KERNEL);
        if (cset) {
                ret = HYPERVISOR_xen_version(XENVER_changeset, cset);
                if (!ret)
                        ret = sprintf(buffer, "%s\n", cset);
                kfree(cset);
        }

        return ret;
}

HYPERVISOR_ATTR_RO(changeset);

static ssize_t virtual_start_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        int ret = -ENOMEM;
        struct xen_platform_parameters *parms;

        parms = kmalloc_obj(struct xen_platform_parameters);
        if (parms) {
                ret = HYPERVISOR_xen_version(XENVER_platform_parameters,
                                             parms);
                if (!ret)
                        ret = sprintf(buffer, "%"PRI_xen_ulong"\n",
                                      parms->virt_start);
                kfree(parms);
        }

        return ret;
}

HYPERVISOR_ATTR_RO(virtual_start);

static ssize_t pagesize_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        int ret;

        ret = HYPERVISOR_xen_version(XENVER_pagesize, NULL);
        if (ret > 0)
                ret = sprintf(buffer, "%x\n", ret);

        return ret;
}

HYPERVISOR_ATTR_RO(pagesize);

static ssize_t xen_feature_show(int index, char *buffer)
{
        ssize_t ret;
        struct xen_feature_info info;

        info.submap_idx = index;
        ret = HYPERVISOR_xen_version(XENVER_get_features, &info);
        if (!ret)
                ret = sprintf(buffer, "%08x", info.submap);

        return ret;
}

static ssize_t features_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        ssize_t len;
        int i;

        len = 0;
        for (i = XENFEAT_NR_SUBMAPS-1; i >= 0; i--) {
                int ret = xen_feature_show(i, buffer + len);
                if (ret < 0) {
                        if (len == 0)
                                len = ret;
                        break;
                }
                len += ret;
        }
        if (len > 0)
                buffer[len++] = '\n';

        return len;
}

HYPERVISOR_ATTR_RO(features);

static ssize_t buildid_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        ssize_t ret;
        struct xen_build_id *buildid;

        ret = HYPERVISOR_xen_version(XENVER_build_id, NULL);
        if (ret < 0) {
                if (ret == -EPERM)
                        ret = sprintf(buffer, "<denied>");
                return ret;
        }

        buildid = kmalloc(sizeof(*buildid) + ret, GFP_KERNEL);
        if (!buildid)
                return -ENOMEM;

        buildid->len = ret;
        ret = HYPERVISOR_xen_version(XENVER_build_id, buildid);
        if (ret > 0)
                ret = sprintf(buffer, "%s", buildid->buf);
        kfree(buildid);

        return ret;
}

HYPERVISOR_ATTR_RO(buildid);

static struct attribute *xen_properties_attrs[] = {
        &capabilities_attr.attr,
        &changeset_attr.attr,
        &virtual_start_attr.attr,
        &pagesize_attr.attr,
        &features_attr.attr,
        &buildid_attr.attr,
        NULL
};

static const struct attribute_group xen_properties_group = {
        .name = "properties",
        .attrs = xen_properties_attrs,
};

static int __init xen_sysfs_properties_init(void)
{
        return sysfs_create_group(hypervisor_kobj, &xen_properties_group);
}

#define FLAG_UNAME "unknown"
#define FLAG_UNAME_FMT FLAG_UNAME "%02u"
#define FLAG_UNAME_MAX sizeof(FLAG_UNAME "XX")
#define FLAG_COUNT (sizeof(xen_start_flags) * BITS_PER_BYTE)
static_assert(sizeof(xen_start_flags) <=
              sizeof_field(struct hyp_sysfs_attr, hyp_attr_value));

static ssize_t flag_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        char *p = buffer;

        *p++ = '0' + ((xen_start_flags & attr->hyp_attr_value) != 0);
        *p++ = '\n';
        return p - buffer;
}

#define FLAG_NODE(flag, node)                           \
        [ilog2(flag)] = {                               \
                .attr = { .name = #node, .mode = 0444 },\
                .show = flag_show,                      \
                .hyp_attr_value = flag                  \
        }

/*
 * Add new, known flags here.  No other changes are required, but
 * note that each known flag wastes one entry in flag_unames[].
 * The code/complexity machinations to avoid this isn't worth it
 * for a few entries, but keep it in mind.
 */
static struct hyp_sysfs_attr flag_attrs[FLAG_COUNT] = {
        FLAG_NODE(SIF_PRIVILEGED, privileged),
        FLAG_NODE(SIF_INITDOMAIN, initdomain)
};
static struct attribute_group xen_flags_group = {
        .name = "start_flags",
        .attrs = (struct attribute *[FLAG_COUNT + 1]){}
};
static char flag_unames[FLAG_COUNT][FLAG_UNAME_MAX];

static int __init xen_sysfs_flags_init(void)
{
        for (unsigned fnum = 0; fnum != FLAG_COUNT; fnum++) {
                if (likely(flag_attrs[fnum].attr.name == NULL)) {
                        sprintf(flag_unames[fnum], FLAG_UNAME_FMT, fnum);
                        flag_attrs[fnum].attr.name = flag_unames[fnum];
                        flag_attrs[fnum].attr.mode = 0444;
                        flag_attrs[fnum].show = flag_show;
                        flag_attrs[fnum].hyp_attr_value = 1 << fnum;
                }
                xen_flags_group.attrs[fnum] = &flag_attrs[fnum].attr;
        }
        return sysfs_create_group(hypervisor_kobj, &xen_flags_group);
}

#ifdef CONFIG_XEN_HAVE_VPMU
struct pmu_mode {
        const char *name;
        uint32_t mode;
};

static struct pmu_mode pmu_modes[] = {
        {"off", XENPMU_MODE_OFF},
        {"self", XENPMU_MODE_SELF},
        {"hv", XENPMU_MODE_HV},
        {"all", XENPMU_MODE_ALL}
};

static ssize_t pmu_mode_store(struct hyp_sysfs_attr *attr,
                              const char *buffer, size_t len)
{
        int ret;
        struct xen_pmu_params xp;
        int i;

        for (i = 0; i < ARRAY_SIZE(pmu_modes); i++) {
                if (strncmp(buffer, pmu_modes[i].name, len - 1) == 0) {
                        xp.val = pmu_modes[i].mode;
                        break;
                }
        }

        if (i == ARRAY_SIZE(pmu_modes))
                return -EINVAL;

        xp.version.maj = XENPMU_VER_MAJ;
        xp.version.min = XENPMU_VER_MIN;
        ret = HYPERVISOR_xenpmu_op(XENPMU_mode_set, &xp);
        if (ret)
                return ret;

        return len;
}

static ssize_t pmu_mode_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        int ret;
        struct xen_pmu_params xp;
        int i;
        uint32_t mode;

        xp.version.maj = XENPMU_VER_MAJ;
        xp.version.min = XENPMU_VER_MIN;
        ret = HYPERVISOR_xenpmu_op(XENPMU_mode_get, &xp);
        if (ret)
                return ret;

        mode = (uint32_t)xp.val;
        for (i = 0; i < ARRAY_SIZE(pmu_modes); i++) {
                if (mode == pmu_modes[i].mode)
                        return sprintf(buffer, "%s\n", pmu_modes[i].name);
        }

        return -EINVAL;
}
HYPERVISOR_ATTR_RW(pmu_mode);

static ssize_t pmu_features_store(struct hyp_sysfs_attr *attr,
                                  const char *buffer, size_t len)
{
        int ret;
        uint32_t features;
        struct xen_pmu_params xp;

        ret = kstrtou32(buffer, 0, &features);
        if (ret)
                return ret;

        xp.val = features;
        xp.version.maj = XENPMU_VER_MAJ;
        xp.version.min = XENPMU_VER_MIN;
        ret = HYPERVISOR_xenpmu_op(XENPMU_feature_set, &xp);
        if (ret)
                return ret;

        return len;
}

static ssize_t pmu_features_show(struct hyp_sysfs_attr *attr, char *buffer)
{
        int ret;
        struct xen_pmu_params xp;

        xp.version.maj = XENPMU_VER_MAJ;
        xp.version.min = XENPMU_VER_MIN;
        ret = HYPERVISOR_xenpmu_op(XENPMU_feature_get, &xp);
        if (ret)
                return ret;

        return sprintf(buffer, "0x%x\n", (uint32_t)xp.val);
}
HYPERVISOR_ATTR_RW(pmu_features);

static struct attribute *xen_pmu_attrs[] = {
        &pmu_mode_attr.attr,
        &pmu_features_attr.attr,
        NULL
};

static const struct attribute_group xen_pmu_group = {
        .name = "pmu",
        .attrs = xen_pmu_attrs,
};

static int __init xen_sysfs_pmu_init(void)
{
        return sysfs_create_group(hypervisor_kobj, &xen_pmu_group);
}
#endif

static int __init hyper_sysfs_init(void)
{
        int ret;

        if (!xen_domain())
                return -ENODEV;

        ret = xen_sysfs_type_init();
        if (ret)
                goto out;
        ret = xen_sysfs_guest_type_init();
        if (ret)
                goto guest_type_out;
        ret = xen_sysfs_version_init();
        if (ret)
                goto version_out;
        ret = xen_sysfs_compilation_init();
        if (ret)
                goto comp_out;
        ret = xen_sysfs_uuid_init();
        if (ret)
                goto uuid_out;
        ret = xen_sysfs_properties_init();
        if (ret)
                goto prop_out;
        ret = xen_sysfs_flags_init();
        if (ret)
                goto flags_out;
#ifdef CONFIG_XEN_HAVE_VPMU
        if (xen_initial_domain()) {
                ret = xen_sysfs_pmu_init();
                if (ret) {
                        sysfs_remove_group(hypervisor_kobj, &xen_flags_group);
                        goto flags_out;
                }
        }
#endif
        goto out;

flags_out:
        sysfs_remove_group(hypervisor_kobj, &xen_properties_group);
prop_out:
        sysfs_remove_file(hypervisor_kobj, &uuid_attr.attr);
uuid_out:
        sysfs_remove_group(hypervisor_kobj, &xen_compilation_group);
comp_out:
        sysfs_remove_group(hypervisor_kobj, &version_group);
version_out:
        sysfs_remove_file(hypervisor_kobj, &guest_type_attr.attr);
guest_type_out:
        sysfs_remove_file(hypervisor_kobj, &type_attr.attr);
out:
        return ret;
}
device_initcall(hyper_sysfs_init);

static ssize_t hyp_sysfs_show(struct kobject *kobj,
                              struct attribute *attr,
                              char *buffer)
{
        struct hyp_sysfs_attr *hyp_attr;
        hyp_attr = container_of(attr, struct hyp_sysfs_attr, attr);
        if (hyp_attr->show)
                return hyp_attr->show(hyp_attr, buffer);
        return 0;
}

static ssize_t hyp_sysfs_store(struct kobject *kobj,
                               struct attribute *attr,
                               const char *buffer,
                               size_t len)
{
        struct hyp_sysfs_attr *hyp_attr;
        hyp_attr = container_of(attr, struct hyp_sysfs_attr, attr);
        if (hyp_attr->store)
                return hyp_attr->store(hyp_attr, buffer, len);
        return 0;
}

static const struct sysfs_ops hyp_sysfs_ops = {
        .show = hyp_sysfs_show,
        .store = hyp_sysfs_store,
};

static const struct kobj_type hyp_sysfs_kobj_type = {
        .sysfs_ops = &hyp_sysfs_ops,
};

static int __init hypervisor_subsys_init(void)
{
        if (!xen_domain())
                return -ENODEV;

        hypervisor_kobj->ktype = &hyp_sysfs_kobj_type;
        return 0;
}
device_initcall(hypervisor_subsys_init);