From 7d0b678231c097279f86221eed0138df8badb3a4 Mon Sep 17 00:00:00 2001 From: Keir Fraser Date: Thu, 24 Jul 2008 14:14:27 +0100 Subject: minios: grant table map (gntdev) for minios I've implemented a grant map for mini-os to support the xc_gnttab_*() functions, the equivalent of gntdev in linux. This is useful for my work in putting xenstored in a stub domain. Signed-off-by: Diego Ongaro --- extras/mini-os/gntmap.c | 250 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 250 insertions(+) create mode 100644 extras/mini-os/gntmap.c (limited to 'extras/mini-os/gntmap.c') diff --git a/extras/mini-os/gntmap.c b/extras/mini-os/gntmap.c new file mode 100644 index 0000000000..babb96329e --- /dev/null +++ b/extras/mini-os/gntmap.c @@ -0,0 +1,250 @@ +/* + * Manages grant mappings from other domains. + * + * Diego Ongaro , 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 +#include +#include +#include +#include +#include "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 %d\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.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 %d\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[0], domids_stride, + refs, 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; +} -- cgit v1.2.3