FreeBSD/Linux Kernel Cross Reference
sys/x86/xen/pv.c

     /*
      * Copyright (c) 2004 Christian Limpach.
      * Copyright (c) 2004-2006,2008 Kip Macy
      * Copyright (c) 2008 The NetBSD Foundation, Inc.
      * Copyright (c) 2013 Roger Pau Monné <roger.pau@citrix.com>
      * All rights reserved.
      *
      * 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.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/11.2/sys/x86/xen/pv.c 329462 2018-02-17 18:00:01Z kib $");
    
    #include "opt_ddb.h"
    #include "opt_kstack_pages.h"
    
    #include <sys/param.h>
    #include <sys/bus.h>
    #include <sys/kernel.h>
    #include <sys/reboot.h>
    #include <sys/systm.h>
    #include <sys/malloc.h>
    #include <sys/linker.h>
    #include <sys/lock.h>
    #include <sys/rwlock.h>
    #include <sys/boot.h>
    #include <sys/ctype.h>
    #include <sys/mutex.h>
    #include <sys/smp.h>
    
    #include <vm/vm.h>
    #include <vm/vm_extern.h>
    #include <vm/vm_kern.h>
    #include <vm/vm_page.h>
    #include <vm/vm_map.h>
    #include <vm/vm_object.h>
    #include <vm/vm_pager.h>
    #include <vm/vm_param.h>
    
    #include <machine/intr_machdep.h>
    #include <x86/apicvar.h>
    #include <x86/init.h>
    #include <machine/pc/bios.h>
    #include <machine/smp.h>
    #include <machine/intr_machdep.h>
    #include <machine/metadata.h>
    
    #include <xen/xen-os.h>
    #include <xen/hypervisor.h>
    #include <xen/xenstore/xenstorevar.h>
    #include <xen/xen_pv.h>
    #include <xen/xen_msi.h>
    
    #include <xen/interface/vcpu.h>
    
    #include <dev/xen/timer/timer.h>
    
    #ifdef DDB
    #include <ddb/ddb.h>
    #endif
    
    /* Native initial function */
    extern u_int64_t hammer_time(u_int64_t, u_int64_t);
    /* Xen initial function */
    uint64_t hammer_time_xen(start_info_t *, uint64_t);
    
    #define MAX_E820_ENTRIES        128
    
    /*--------------------------- Forward Declarations ---------------------------*/
    static caddr_t xen_pv_parse_preload_data(u_int64_t);
    static void xen_pv_parse_memmap(caddr_t, vm_paddr_t *, int *);
    
    #ifdef SMP
    static int xen_pv_start_all_aps(void);
    #endif
    
    /*---------------------------- Extern Declarations ---------------------------*/
    #ifdef SMP
    /* Variables used by amd64 mp_machdep to start APs */
    extern char *doublefault_stack;
   extern char *mce_stack;
   extern char *nmi_stack;
   #endif
   
   /*
    * Placed by the linker at the end of the bss section, which is the last
    * section loaded by Xen before loading the symtab and strtab.
    */
   extern uint32_t end;
   
   /*-------------------------------- Global Data -------------------------------*/
   /* Xen init_ops implementation. */
   struct init_ops xen_init_ops = {
           .parse_preload_data             = xen_pv_parse_preload_data,
           .early_clock_source_init        = xen_clock_init,
           .early_delay                    = xen_delay,
           .parse_memmap                   = xen_pv_parse_memmap,
   #ifdef SMP
           .start_all_aps                  = xen_pv_start_all_aps,
   #endif
           .msi_init =                     xen_msi_init,
   };
   
   static struct bios_smap xen_smap[MAX_E820_ENTRIES];
   
   /*-------------------------------- Xen PV init -------------------------------*/
   /*
    * First function called by the Xen PVH boot sequence.
    *
    * Set some Xen global variables and prepare the environment so it is
    * as similar as possible to what native FreeBSD init function expects.
    */
   uint64_t
   hammer_time_xen(start_info_t *si, uint64_t xenstack)
   {
           uint64_t physfree;
           uint64_t *PT4 = (u_int64_t *)xenstack;
           uint64_t *PT3 = (u_int64_t *)(xenstack + PAGE_SIZE);
           uint64_t *PT2 = (u_int64_t *)(xenstack + 2 * PAGE_SIZE);
           int i;
   
           xen_domain_type = XEN_PV_DOMAIN;
           vm_guest = VM_GUEST_XEN;
   
           if ((si == NULL) || (xenstack == 0)) {
                   xc_printf("ERROR: invalid start_info or xen stack, halting\n");
                   HYPERVISOR_shutdown(SHUTDOWN_crash);
           }
   
           xc_printf("FreeBSD PVH running on %s\n", si->magic);
   
           /* We use 3 pages of xen stack for the boot pagetables */
           physfree = xenstack + 3 * PAGE_SIZE - KERNBASE;
   
           /* Setup Xen global variables */
           HYPERVISOR_start_info = si;
           HYPERVISOR_shared_info =
               (shared_info_t *)(si->shared_info + KERNBASE);
   
           /*
            * Setup some misc global variables for Xen devices
            *
            * XXX: Devices that need these specific variables should
            *      be rewritten to fetch this info by themselves from the
            *      start_info page.
            */
           xen_store = (struct xenstore_domain_interface *)
               (ptoa(si->store_mfn) + KERNBASE);
           console_page = (char *)(ptoa(si->console.domU.mfn) + KERNBASE);
   
           /*
            * Use the stack Xen gives us to build the page tables
            * as native FreeBSD expects to find them (created
            * by the boot trampoline).
            */
           for (i = 0; i < (PAGE_SIZE / sizeof(uint64_t)); i++) {
                   /*
                    * Each slot of the level 4 pages points
                    * to the same level 3 page
                    */
                   PT4[i] = ((uint64_t)&PT3[0]) - KERNBASE;
                   PT4[i] |= PG_V | PG_RW | PG_U;
   
                   /*
                    * Each slot of the level 3 pages points
                    * to the same level 2 page
                    */
                   PT3[i] = ((uint64_t)&PT2[0]) - KERNBASE;
                   PT3[i] |= PG_V | PG_RW | PG_U;
   
                   /*
                    * The level 2 page slots are mapped with
                    * 2MB pages for 1GB.
                    */
                   PT2[i] = i * (2 * 1024 * 1024);
                   PT2[i] |= PG_V | PG_RW | PG_PS | PG_U;
           }
           load_cr3(((uint64_t)&PT4[0]) - KERNBASE);
   
           /* Set the hooks for early functions that diverge from bare metal */
           init_ops = xen_init_ops;
           apic_ops = xen_apic_ops;
   
           /* Now we can jump into the native init function */
           return (hammer_time(0, physfree));
   }
   
   /*-------------------------------- PV specific -------------------------------*/
   #ifdef SMP
   static bool
   start_xen_ap(int cpu)
   {
           struct vcpu_guest_context *ctxt;
           int ms, cpus = mp_naps;
           const size_t stacksize = kstack_pages * PAGE_SIZE;
   
           /* allocate and set up an idle stack data page */
           bootstacks[cpu] =
               (void *)kmem_malloc(kernel_arena, stacksize, M_WAITOK | M_ZERO);
           doublefault_stack =
               (char *)kmem_malloc(kernel_arena, PAGE_SIZE, M_WAITOK | M_ZERO);
           mce_stack =
               (char *)kmem_malloc(kernel_arena, PAGE_SIZE, M_WAITOK | M_ZERO);
           nmi_stack =
               (char *)kmem_malloc(kernel_arena, PAGE_SIZE, M_WAITOK | M_ZERO);
           dpcpu =
               (void *)kmem_malloc(kernel_arena, DPCPU_SIZE, M_WAITOK | M_ZERO);
   
           bootSTK = (char *)bootstacks[cpu] + kstack_pages * PAGE_SIZE - 8;
           bootAP = cpu;
   
           ctxt = malloc(sizeof(*ctxt), M_TEMP, M_WAITOK | M_ZERO);
   
           ctxt->flags = VGCF_IN_KERNEL;
           ctxt->user_regs.rip = (unsigned long) init_secondary;
           ctxt->user_regs.rsp = (unsigned long) bootSTK;
   
           /* Set the AP to use the same page tables */
           ctxt->ctrlreg[3] = KPML4phys;
   
           if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
                   panic("unable to initialize AP#%d", cpu);
   
           free(ctxt, M_TEMP);
   
           /* Launch the vCPU */
           if (HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL))
                   panic("unable to start AP#%d", cpu);
   
           /* Wait up to 5 seconds for it to start. */
           for (ms = 0; ms < 5000; ms++) {
                   if (mp_naps > cpus)
                           return (true);
                   DELAY(1000);
           }
   
           return (false);
   }
   
   static int
   xen_pv_start_all_aps(void)
   {
           int cpu;
   
           mtx_init(&ap_boot_mtx, "ap boot", NULL, MTX_SPIN);
   
           for (cpu = 1; cpu < mp_ncpus; cpu++) {
   
                   /* attempt to start the Application Processor */
                   if (!start_xen_ap(cpu))
                           panic("AP #%d failed to start!", cpu);
   
                   CPU_SET(cpu, &all_cpus);        /* record AP in CPU map */
           }
   
           return (mp_naps);
   }
   #endif /* SMP */
   
   /*
    * Functions to convert the "extra" parameters passed by Xen
    * into FreeBSD boot options.
    */
   static void
   xen_pv_set_env(void)
   {
           char *cmd_line_next, *cmd_line;
           size_t env_size;
   
           cmd_line = HYPERVISOR_start_info->cmd_line;
           env_size = sizeof(HYPERVISOR_start_info->cmd_line);
   
           /* Skip leading spaces */
           for (; isspace(*cmd_line) && (env_size != 0); cmd_line++)
                   env_size--;
   
           /* Replace ',' with '\0' */
           for (cmd_line_next = cmd_line; strsep(&cmd_line_next, ",") != NULL;)
                   ;
   
           init_static_kenv(cmd_line, 0);
   }
   
   static void
   xen_pv_set_boothowto(void)
   {
           int i;
           char *env;
   
           /* get equivalents from the environment */
           for (i = 0; howto_names[i].ev != NULL; i++) {
                   if ((env = kern_getenv(howto_names[i].ev)) != NULL) {
                           boothowto |= howto_names[i].mask;
                           freeenv(env);
                   }
           }
   }
   
   #ifdef DDB
   /*
    * The way Xen loads the symtab is different from the native boot loader,
    * because it's tailored for NetBSD. So we have to adapt and use the same
    * method as NetBSD. Portions of the code below have been picked from NetBSD:
    * sys/kern/kern_ksyms.c CVS Revision 1.71.
    */
   static void
   xen_pv_parse_symtab(void)
   {
           Elf_Ehdr *ehdr;
           Elf_Shdr *shdr;
           vm_offset_t sym_end;
           uint32_t size;
           int i, j;
   
           size = end;
           sym_end = HYPERVISOR_start_info->mod_start != 0 ?
               HYPERVISOR_start_info->mod_start :
               HYPERVISOR_start_info->mfn_list;
   
           /*
            * Make sure the size is right headed, sym_end is just a
            * high boundary, but at least allows us to fail earlier.
            */
           if ((vm_offset_t)&end + size > sym_end) {
                   xc_printf("Unable to load ELF symtab: size mismatch\n");
                   return;
           }
   
           ehdr = (Elf_Ehdr *)(&end + 1);
           if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) ||
               ehdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
               ehdr->e_version > 1) {
                   xc_printf("Unable to load ELF symtab: invalid symbol table\n");
                   return;
           }
   
           shdr = (Elf_Shdr *)((uint8_t *)ehdr + ehdr->e_shoff);
           /* Find the symbol table and the corresponding string table. */
           for (i = 1; i < ehdr->e_shnum; i++) {
                   if (shdr[i].sh_type != SHT_SYMTAB)
                           continue;
                   if (shdr[i].sh_offset == 0)
                           continue;
                   ksymtab = (uintptr_t)((uint8_t *)ehdr + shdr[i].sh_offset);
                   ksymtab_size = shdr[i].sh_size;
                   j = shdr[i].sh_link;
                   if (shdr[j].sh_offset == 0)
                           continue; /* Can this happen? */
                   kstrtab = (uintptr_t)((uint8_t *)ehdr + shdr[j].sh_offset);
                   break;
           }
   
           if (ksymtab == 0 || kstrtab == 0) {
                   xc_printf(
       "Unable to load ELF symtab: could not find symtab or strtab\n");
                   return;
           }
   }
   #endif
   
   static caddr_t
   xen_pv_parse_preload_data(u_int64_t modulep)
   {
           caddr_t          kmdp;
           vm_ooffset_t     off;
           vm_paddr_t       metadata;
           char             *envp;
   
           if (HYPERVISOR_start_info->mod_start != 0) {
                   preload_metadata = (caddr_t)(HYPERVISOR_start_info->mod_start);
   
                   kmdp = preload_search_by_type("elf kernel");
                   if (kmdp == NULL)
                           kmdp = preload_search_by_type("elf64 kernel");
                   KASSERT(kmdp != NULL, ("unable to find kernel"));
   
                   /*
                    * Xen has relocated the metadata and the modules,
                    * so we need to recalculate it's position. This is
                    * done by saving the original modulep address and
                    * then calculating the offset with mod_start,
                    * which contains the relocated modulep address.
                    */
                   metadata = MD_FETCH(kmdp, MODINFOMD_MODULEP, vm_paddr_t);
                   off = HYPERVISOR_start_info->mod_start - metadata;
   
                   preload_bootstrap_relocate(off);
   
                   boothowto = MD_FETCH(kmdp, MODINFOMD_HOWTO, int);
                   envp = MD_FETCH(kmdp, MODINFOMD_ENVP, char *);
                   if (envp != NULL)
                           envp += off;
                   init_static_kenv(envp, 0);
           } else {
                   /* Parse the extra boot information given by Xen */
                   xen_pv_set_env();
                   xen_pv_set_boothowto();
                   kmdp = NULL;
           }
   
   #ifdef DDB
           xen_pv_parse_symtab();
   #endif
           return (kmdp);
   }
   
   static void
   xen_pv_parse_memmap(caddr_t kmdp, vm_paddr_t *physmap, int *physmap_idx)
   {
           struct xen_memory_map memmap;
           u_int32_t size;
           int rc;
   
           /* Fetch the E820 map from Xen */
           memmap.nr_entries = MAX_E820_ENTRIES;
           set_xen_guest_handle(memmap.buffer, xen_smap);
           rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
           if (rc)
                   panic("unable to fetch Xen E820 memory map");
           size = memmap.nr_entries * sizeof(xen_smap[0]);
   
           bios_add_smap_entries(xen_smap, size, physmap, physmap_idx);
   }

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