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/*
* Manages grant mappings from other domains.
*
* Diego Ongaro <diego.ongaro@citrix.com>, July 2008
*
* Files of type FTYPE_GNTMAP contain a gntmap, which is an array of
* (host address, grant handle) pairs. Grant handles come from a hypervisor map
* operation and are needed for the corresponding unmap.
*
* This is a rather naive implementation in terms of performance. If we start
* using it frequently, there's definitely some low-hanging fruit here.
*
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include <mini-os/os.h>
#include <mini-os/lib.h>
#include <mini-os/xmalloc.h>
#include <errno.h>
#include <xen/grant_table.h>
#include <inttypes.h>
#include <mini-os/gntmap.h>
#define DEFAULT_MAX_GRANTS 128
struct gntmap_entry {
unsigned long host_addr;
grant_handle_t handle;
};
static inline int
gntmap_entry_used(struct gntmap_entry *entry)
{
return entry->host_addr != 0;
}
static struct gntmap_entry*
gntmap_find_free_entry(struct gntmap *map)
{
int i;
for (i = 0; i < map->nentries; i++) {
if (!gntmap_entry_used(&map->entries[i]))
return &map->entries[i];
}
#ifdef GNTMAP_DEBUG
printk("gntmap_find_free_entry(map=%p): all %d entries full\n",
map, map->nentries);
#endif
return NULL;
}
static struct gntmap_entry*
gntmap_find_entry(struct gntmap *map, unsigned long addr)
{
int i;
for (i = 0; i < map->nentries; i++) {
if (map->entries[i].host_addr == addr)
return &map->entries[i];
}
return NULL;
}
int
gntmap_set_max_grants(struct gntmap *map, int count)
{
#ifdef GNTMAP_DEBUG
printk("gntmap_set_max_grants(map=%p, count=%d)\n", map, count);
#endif
if (map->nentries != 0)
return -EBUSY;
map->entries = xmalloc_array(struct gntmap_entry, count);
if (map->entries == NULL)
return -ENOMEM;
memset(map->entries, 0, sizeof(struct gntmap_entry) * count);
map->nentries = count;
return 0;
}
static int
_gntmap_map_grant_ref(struct gntmap_entry *entry,
unsigned long host_addr,
uint32_t domid,
uint32_t ref,
int writable)
{
struct gnttab_map_grant_ref op;
int rc;
op.ref = (grant_ref_t) ref;
op.dom = (domid_t) domid;
op.host_addr = (uint64_t) host_addr;
op.flags = GNTMAP_host_map;
if (!writable)
op.flags |= GNTMAP_readonly;
rc = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1);
if (rc != 0 || op.status != GNTST_okay) {
printk("GNTTABOP_map_grant_ref failed: "
"returned %d, status %" PRId16 "\n",
rc, op.status);
return rc != 0 ? rc : op.status;
}
entry->host_addr = host_addr;
entry->handle = op.handle;
return 0;
}
static int
_gntmap_unmap_grant_ref(struct gntmap_entry *entry)
{
struct gnttab_unmap_grant_ref op;
int rc;
op.host_addr = (uint64_t) entry->host_addr;
op.dev_bus_addr = 0;
op.handle = entry->handle;
rc = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1);
if (rc != 0 || op.status != GNTST_okay) {
printk("GNTTABOP_unmap_grant_ref failed: "
"returned %d, status %" PRId16 "\n",
rc, op.status);
return rc != 0 ? rc : op.status;
}
entry->host_addr = 0;
return 0;
}
int
gntmap_munmap(struct gntmap *map, unsigned long start_address, int count)
{
int i, rc;
struct gntmap_entry *ent;
#ifdef GNTMAP_DEBUG
printk("gntmap_munmap(map=%p, start_address=%lx, count=%d)\n",
map, start_address, count);
#endif
for (i = 0; i < count; i++) {
ent = gntmap_find_entry(map, start_address + PAGE_SIZE * i);
if (ent == NULL) {
printk("gntmap: tried to munmap unknown page\n");
return -EINVAL;
}
rc = _gntmap_unmap_grant_ref(ent);
if (rc != 0)
return rc;
}
return 0;
}
void*
gntmap_map_grant_refs(struct gntmap *map,
uint32_t count,
uint32_t *domids,
int domids_stride,
uint32_t *refs,
int writable)
{
unsigned long addr;
struct gntmap_entry *ent;
int i;
#ifdef GNTMAP_DEBUG
printk("gntmap_map_grant_refs(map=%p, count=%" PRIu32 ", "
"domids=%p [%" PRIu32 "...], domids_stride=%d, "
"refs=%p [%" PRIu32 "...], writable=%d)\n",
map, count,
domids, domids == NULL ? 0 : domids[0], domids_stride,
refs, refs == NULL ? 0 : refs[0], writable);
#endif
(void) gntmap_set_max_grants(map, DEFAULT_MAX_GRANTS);
addr = allocate_ondemand((unsigned long) count, 1);
if (addr == 0)
return NULL;
for (i = 0; i < count; i++) {
ent = gntmap_find_free_entry(map);
if (ent == NULL ||
_gntmap_map_grant_ref(ent,
addr + PAGE_SIZE * i,
domids[i * domids_stride],
refs[i],
writable) != 0) {
(void) gntmap_munmap(map, addr, i);
return NULL;
}
}
return (void*) addr;
}
void
gntmap_init(struct gntmap *map)
{
#ifdef GNTMAP_DEBUG
printk("gntmap_init(map=%p)\n", map);
#endif
map->nentries = 0;
map->entries = NULL;
}
void
gntmap_fini(struct gntmap *map)
{
struct gntmap_entry *ent;
int i;
#ifdef GNTMAP_DEBUG
printk("gntmap_fini(map=%p)\n", map);
#endif
for (i = 0; i < map->nentries; i++) {
ent = &map->entries[i];
if (gntmap_entry_used(ent))
(void) _gntmap_unmap_grant_ref(ent);
}
xfree(map->entries);
map->entries = NULL;
map->nentries = 0;
}