drivers/xen/tpmback/interface.c

   1  /*****************************************************************************
   2  * drivers/xen/tpmback/interface.c
   3  *
   4  * Vritual TPM interface management.
   5  *
   6  * Copyright (c) 2005, IBM Corporation
   7  *
   8  * Author: Stefan Berger, stefanb@us.ibm.com
   9  *
  10  * This code has been derived from drivers/xen/netback/interface.c
  11  * Copyright (c) 2004, Keir Fraser
  12  */
  13
  14 #include "common.h"
  15 #include <xen/balloon.h>
  16 #include <xen/gnttab.h>
  17
  18 static kmem_cache_t *tpmif_cachep;
  19 int num_frontends = 0;
  20
  21 LIST_HEAD(tpmif_list);
  22
  23 static tpmif_t *alloc_tpmif(domid_t domid, struct backend_info *bi)
  24 {
  25         tpmif_t *tpmif;
  26
  27         tpmif = kmem_cache_alloc(tpmif_cachep, GFP_KERNEL);
  28         if (!tpmif)
  29                 return ERR_PTR(-ENOMEM);
  30
  31         memset(tpmif, 0, sizeof (*tpmif));
  32         tpmif->domid = domid;
  33         tpmif->status = DISCONNECTED;
  34         tpmif->bi = bi;
  35         snprintf(tpmif->devname, sizeof(tpmif->devname), "tpmif%d", domid);
  36         atomic_set(&tpmif->refcnt, 1);
  37
  38         tpmif->pagerange = balloon_alloc_empty_page_range(TPMIF_TX_RING_SIZE);
  39         BUG_ON(tpmif->pagerange == NULL);
  40         tpmif->mmap_vstart = (unsigned long)pfn_to_kaddr(
  41                                             page_to_pfn(tpmif->pagerange));
  42
  43         list_add(&tpmif->tpmif_list, &tpmif_list);
  44         num_frontends++;
  45
  46         return tpmif;
  47 }
  48
  49 static void free_tpmif(tpmif_t * tpmif)
  50 {
  51         num_frontends--;
  52         list_del(&tpmif->tpmif_list);
  53         balloon_dealloc_empty_page_range(tpmif->pagerange, TPMIF_TX_RING_SIZE);
  54         kmem_cache_free(tpmif_cachep, tpmif);
  55 }
  56
  57 tpmif_t *tpmif_find(domid_t domid, struct backend_info *bi)
  58 {
  59         tpmif_t *tpmif;
  60
  61         list_for_each_entry(tpmif, &tpmif_list, tpmif_list) {
  62                 if (tpmif->bi == bi) {
  63                         if (tpmif->domid == domid) {
  64                                 tpmif_get(tpmif);
  65                                 return tpmif;
  66                         } else {
  67                                 return ERR_PTR(-EEXIST);
  68                         }
  69                 }
  70         }
  71
  72         return alloc_tpmif(domid, bi);
  73 }
  74
  75 static int map_frontend_page(tpmif_t *tpmif, unsigned long shared_page)
  76 {
  77         int ret;
  78         struct gnttab_map_grant_ref op;
  79
  80         gnttab_set_map_op(&op, (unsigned long)tpmif->tx_area->addr,
  81                           GNTMAP_host_map, shared_page, tpmif->domid);
  82
  83         lock_vm_area(tpmif->tx_area);
  84         ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1);
  85         unlock_vm_area(tpmif->tx_area);
  86         BUG_ON(ret);
  87
  88         if (op.status) {
  89                 DPRINTK(" Grant table operation failure !\n");
  90                 return op.status;
  91         }
  92
  93         tpmif->shmem_ref = shared_page;
  94         tpmif->shmem_handle = op.handle;
  95
  96         return 0;
  97 }
  98
  99 static void unmap_frontend_page(tpmif_t *tpmif)
 100 {
 101         struct gnttab_unmap_grant_ref op;
 102         int ret;
 103
 104         gnttab_set_unmap_op(&op, (unsigned long)tpmif->tx_area->addr,
 105                             GNTMAP_host_map, tpmif->shmem_handle);
 106
 107         lock_vm_area(tpmif->tx_area);
 108         ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1);
 109         unlock_vm_area(tpmif->tx_area);
 110         BUG_ON(ret);
 111 }
 112
 113 int tpmif_map(tpmif_t *tpmif, unsigned long shared_page, unsigned int evtchn)
 114 {
 115         int err;
 116         struct evtchn_bind_interdomain bind_interdomain;
 117
 118         if (tpmif->irq) {
 119                 return 0;
 120         }
 121
 122         if ((tpmif->tx_area = alloc_vm_area(PAGE_SIZE)) == NULL)
 123                 return -ENOMEM;
 124
 125         err = map_frontend_page(tpmif, shared_page);
 126         if (err) {
 127                 free_vm_area(tpmif->tx_area);
 128                 return err;
 129         }
 130
 131
 132         bind_interdomain.remote_dom  = tpmif->domid;
 133         bind_interdomain.remote_port = evtchn;
 134
 135         err = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
 136                                           &bind_interdomain);
 137         if (err) {
 138                 unmap_frontend_page(tpmif);
 139                 free_vm_area(tpmif->tx_area);
 140                 return err;
 141         }
 142
 143         tpmif->evtchn = bind_interdomain.local_port;
 144
 145         tpmif->tx = (tpmif_tx_interface_t *)tpmif->tx_area->addr;
 146
 147         tpmif->irq = bind_evtchn_to_irqhandler(
 148                 tpmif->evtchn, tpmif_be_int, 0, tpmif->devname, tpmif);
 149         tpmif->shmem_ref = shared_page;
 150         tpmif->active = 1;
 151
 152         return 0;
 153 }
 154
 155 void tpmif_disconnect_complete(tpmif_t *tpmif)
 156 {
 157         if (tpmif->irq)
 158                 unbind_from_irqhandler(tpmif->irq, tpmif);
 159
 160         if (tpmif->tx) {
 161                 unmap_frontend_page(tpmif);
 162                 free_vm_area(tpmif->tx_area);
 163         }
 164
 165         free_tpmif(tpmif);
 166 }
 167
 168 void __init tpmif_interface_init(void)
 169 {
 170         tpmif_cachep = kmem_cache_create("tpmif_cache", sizeof (tpmif_t),
 171                                          0, 0, NULL, NULL);
 172 }
 173
 174 void __exit tpmif_interface_exit(void)
 175 {
 176         kmem_cache_destroy(tpmif_cachep);
 177 }