/*
 * Copyright (c) 1980, 1986, 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)param.c     8.3 (Berkeley) 8/20/94
 * $FreeBSD: src/sys/kern/subr_param.c,v 1.42.2.10 2002/03/09 21:05:47 silby Exp $
 */

#include "opt_param.h"
#include "opt_maxusers.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/sysctl.h>
#include <vm/pmap.h>
#include <machine/vmparam.h>

/*
 * System parameter formulae.
 */

#ifndef HZ_DEFAULT
#define HZ_DEFAULT      100
#endif
#define NPROC           (20 + 16 * maxusers)
#ifndef NBUF
#define NBUF            0
#endif
#ifndef MAXFILES
#define MAXFILES        (maxproc * 16)
#endif
#ifndef MAXPOSIXLOCKSPERUID
#define MAXPOSIXLOCKSPERUID (maxproc * 4)
#endif

static int sysctl_kern_vmm_guest(SYSCTL_HANDLER_ARGS);

int     hz;
int     stathz;
int     profhz;
int     ustick;                         /* tick interval in microseconds */
int     nstick;                         /* tick interval in nanoseconds */
int     maxusers;                       /* base tunable */
int     maxproc;                        /* maximum # of processes */
int     maxprocperuid;                  /* max # of procs per user */
int     maxfiles;                       /* system wide open files limit */
int     maxfilesrootres;                /* descriptors reserved for root use */
int     minfilesperproc;                /* per-proc min open files (safety) */
int     maxfilesperproc;                /* per-proc open files limit */
int     maxfilesperuser;                /* per-user open files limit */
int     maxposixlocksperuid;            /* max # POSIX locks per uid */
int     ncallout;                       /* maximum # of timer events */
long    nbuf;
long    nswbuf_mem;
long    nswbuf_kva;
long    nswbuf_raw;
long    maxswzone;                      /* max swmeta KVA storage */
long    maxbcache;                      /* max buffer cache KVA storage */
enum vmm_guest_type vmm_guest = VMM_GUEST_NONE; /* Running as VM guest? */
u_quad_t        maxtsiz;                        /* max text size */
u_quad_t        dfldsiz;                        /* initial data size limit */
u_quad_t        maxdsiz;                        /* max data size */
u_quad_t        dflssiz;                        /* initial stack size limit */
u_quad_t        maxssiz;                        /* max stack size */
u_quad_t        sgrowsiz;                       /* amount to grow stack */
u_quad_t        maxthrssiz;                     /* thread stack area */

SYSCTL_PROC(_kern, OID_AUTO, vmm_guest, CTLFLAG_RD | CTLTYPE_STRING,
            NULL, 0, sysctl_kern_vmm_guest, "A",
            "Virtual machine guest type");
SYSCTL_QUAD(_kern, OID_AUTO, maxssiz, CTLFLAG_RD, &maxssiz, 0,
            "Maximum user stack size");
SYSCTL_QUAD(_kern, OID_AUTO, maxthrssiz, CTLFLAG_RD, &maxthrssiz, 0,
            "Nominal threading stack area");

/*
 * These have to be allocated somewhere; allocating
 * them here forces loader errors if this file is omitted
 * (if they've been externed everywhere else; hah!).
 */
struct  buf *swbuf_mem;
struct  buf *swbuf_kva;
struct  buf *swbuf_raw;

struct vmm_bname {
        const char *str;
        enum vmm_guest_type type;
};

static struct vmm_bname vmm_bnames[] = {
        { "QEMU",       VMM_GUEST_QEMU },       /* QEMU */
        { "Plex86",     VMM_GUEST_PLEX86 },     /* Plex86 */
        { "Bochs",      VMM_GUEST_BOCHS },      /* Bochs */
        { "Xen",        VMM_GUEST_XEN },        /* Xen */
        { "BHYVE",      VMM_GUEST_BHYVE },      /* bhyve */
        { "Seabios",    VMM_GUEST_KVM},         /* KVM */
        { NULL, 0 }
};

static struct vmm_bname vmm_pnames[] = {
        { "VMware Virtual Platform",    VMM_GUEST_VMWARE },     /* VMWare VM */
        { "Virtual Machine",            VMM_GUEST_HYPERV },     /* MS Hyper-V */
        { "VirtualBox",                 VMM_GUEST_VBOX },       /* Sun VirtualBox */
        { "Parallels Virtual Platform", VMM_GUEST_PARALLELS },  /* Parallels VM */
        { "KVM",                        VMM_GUEST_KVM },        /* KVM */
        { NULL, 0 }
};

static const char *const vmm_guest_sysctl_names[] = {
        "none",
        "qemu",
        "plex86",
        "bochs",
        "xen",
        "bhyve",
        "kvm",
        "vmware",
        "hyperv",
        "vbox",
        "parallels",
        "vkernel",
        "nvmm",
        "unknown",
        NULL
};
CTASSERT(NELEM(vmm_guest_sysctl_names) - 1 == VMM_GUEST_LAST);

char            vmm_vendor[16];
SYSCTL_STRING(_kern, OID_AUTO, vmm_vendor, CTLFLAG_RD, vmm_vendor, 0,
    "Virtual machine vendor");

/*
 * Detect known Virtual Machine hosts by inspecting the emulated BIOS.
 */
enum vmm_guest_type
detect_virtual(void)
{
        char *sysenv;
        int i;

        sysenv = kgetenv("smbios.bios.vendor");
        if (sysenv != NULL) {
                for (i = 0; vmm_bnames[i].str != NULL; i++)
                        if (strcmp(sysenv, vmm_bnames[i].str) == 0) {
                                kfreeenv(sysenv);
                                return (vmm_bnames[i].type);
                        }
                kfreeenv(sysenv);
        }
        sysenv = kgetenv("smbios.system.product");
        if (sysenv != NULL) {
                for (i = 0; vmm_pnames[i].str != NULL; i++)
                        if (strcmp(sysenv, vmm_pnames[i].str) == 0) {
                                kfreeenv(sysenv);
                                return (vmm_pnames[i].type);
                        }
                kfreeenv(sysenv);
        }
        return (VMM_GUEST_NONE);
}

/*
 * Boot time overrides that are not scaled against main memory
 */
void
init_param1(void)
{
        hz = HZ_DEFAULT;
        TUNABLE_INT_FETCH("kern.hz", &hz);
        stathz = hz + 1;
        TUNABLE_INT_FETCH("kern.stathz", &stathz);
        profhz = stathz;
        ustick = 1000000 / hz;
        nstick = 1000000000 / hz;
        /* can adjust 30ms in 60s */
        ntp_default_tick_delta = howmany(30000000, 60 * hz);

#ifdef VM_SWZONE_SIZE_MAX
        maxswzone = VM_SWZONE_SIZE_MAX;
#endif
        TUNABLE_LONG_FETCH("kern.maxswzone", &maxswzone);
#ifdef VM_BCACHE_SIZE_MAX
        maxbcache = VM_BCACHE_SIZE_MAX;
#endif
        TUNABLE_LONG_FETCH("kern.maxbcache", &maxbcache);
        maxtsiz = MAXTSIZ;
        TUNABLE_QUAD_FETCH("kern.maxtsiz", &maxtsiz);
        dfldsiz = DFLDSIZ;
        TUNABLE_QUAD_FETCH("kern.dfldsiz", &dfldsiz);
        maxdsiz = MAXDSIZ;
        TUNABLE_QUAD_FETCH("kern.maxdsiz", &maxdsiz);
        dflssiz = DFLSSIZ;
        TUNABLE_QUAD_FETCH("kern.dflssiz", &dflssiz);
        maxssiz = MAXSSIZ;
        TUNABLE_QUAD_FETCH("kern.maxssiz", &maxssiz);
        sgrowsiz = SGROWSIZ;
        TUNABLE_QUAD_FETCH("kern.sgrowsiz", &sgrowsiz);
        maxthrssiz = MAXTHRSSIZ;
        TUNABLE_QUAD_FETCH("kern.maxthrssiz", &maxthrssiz);
}

/*
 * Boot time overrides that are scaled against main memory
 */
void
init_param2(int physpages)
{
        size_t limsize;

        /*
         * Calculate manually becaus the VM page queues / system is not set
         * up yet.
         */
        limsize = (size_t)physpages * PAGE_SIZE;
        if (limsize > KvaSize)
                limsize = KvaSize;
        if (maxswzone > limsize / 2)    /* maxswzone size (1/2 of phys mem) */
                maxswzone = limsize / 2;

        limsize /= 1024 * 1024;         /* smaller of KVM or physmem in MB */

        /* Base parameters */
        maxusers = MAXUSERS;
        TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
        if (maxusers == 0) {
                maxusers = limsize / 8;         /* ~384 per 3G */
                if (maxusers < 32)
                        maxusers = 32;
                /* no upper limit */
        }

        /*
         * The following can be overridden after boot via sysctl.  Note:
         * unless overridden, these macros are ultimately based on maxusers.
         *
         * Limit maxproc so that kmap entries cannot be exhausted by
         * processes.  This limitation can be a bit problematic because
         * processes can have a wide range of complexity.
         */
        maxproc = NPROC;
        TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
        if (maxproc < 32)
                maxproc = 32;
        if (maxproc > limsize * 40)
                maxproc = limsize * 40;

        /*
         * Maximum number of open files
         */
        maxfiles = MAXFILES;
        TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
        if (maxfiles < 128)
                maxfiles = 128;

        /*
         * Limit file descriptors so no single user can exhaust the
         * system.
         *
         * WARNING: Do not set minfilesperproc too high or the user
         *          can exhaust the system with a combination of fork()
         *          and open().  Actual worst case is:
         *
         *          (minfilesperproc * maxprocperuid) + maxfilesperuser
         */
        maxprocperuid = maxproc / 4;
        if (maxprocperuid < 128)
                maxprocperuid = maxproc / 2;
        minfilesperproc = 8;
        maxfilesperproc = maxfiles / 4;
        maxfilesperuser = maxfilesperproc * 2;
        maxfilesrootres = maxfiles / 20;

        /*
         * Severe hack to try to prevent pipe() descriptors from
         * blowing away kernel memory.
         */
        if (KvaSize <= (vm_offset_t)(1536LL * 1024 * 1024) &&
            maxfilesperuser > 20000) {
                maxfilesperuser = 20000;
        }

        maxposixlocksperuid = MAXPOSIXLOCKSPERUID;
        TUNABLE_INT_FETCH("kern.maxposixlocksperuid", &maxposixlocksperuid);

        /*
         * Unless overridden, NBUF is typically 0 (auto-sized later).
         */
        nbuf = NBUF;
        TUNABLE_LONG_FETCH("kern.nbuf", &nbuf);

        /*
         * Calculate the size of the callout wheel.  Limit to approximately
         * 5 minutes worth of table (maxproc would have to be pretty huge),
         * as more is not likely to gain us anything.
         */
        ncallout = 16 + maxproc + maxfiles;
        if (ncallout > 5*60*hz)
                ncallout = 5*60*hz;
        TUNABLE_INT_FETCH("kern.ncallout", &ncallout);
}

/*
 * Sysctl stringifying handler for kern.vmm_guest.
 */
static int
sysctl_kern_vmm_guest(SYSCTL_HANDLER_ARGS)
{
        return (SYSCTL_OUT(req, vmm_guest_sysctl_names[vmm_guest],
            strlen(vmm_guest_sysctl_names[vmm_guest])));
}