Dan Magenheimer | 5bc20fc | 2011-05-26 10:02:21 -0600 | [diff] [blame] | 1 | /* |
| 2 | * Xen implementation for transcendent memory (tmem) |
| 3 | * |
| 4 | * Copyright (C) 2009-2010 Oracle Corp. All rights reserved. |
| 5 | * Author: Dan Magenheimer |
| 6 | */ |
| 7 | |
| 8 | #include <linux/kernel.h> |
| 9 | #include <linux/types.h> |
| 10 | #include <linux/init.h> |
| 11 | #include <linux/pagemap.h> |
| 12 | #include <linux/cleancache.h> |
| 13 | |
| 14 | #include <xen/xen.h> |
| 15 | #include <xen/interface/xen.h> |
| 16 | #include <asm/xen/hypercall.h> |
| 17 | #include <asm/xen/page.h> |
| 18 | #include <asm/xen/hypervisor.h> |
| 19 | |
| 20 | #define TMEM_CONTROL 0 |
| 21 | #define TMEM_NEW_POOL 1 |
| 22 | #define TMEM_DESTROY_POOL 2 |
| 23 | #define TMEM_NEW_PAGE 3 |
| 24 | #define TMEM_PUT_PAGE 4 |
| 25 | #define TMEM_GET_PAGE 5 |
| 26 | #define TMEM_FLUSH_PAGE 6 |
| 27 | #define TMEM_FLUSH_OBJECT 7 |
| 28 | #define TMEM_READ 8 |
| 29 | #define TMEM_WRITE 9 |
| 30 | #define TMEM_XCHG 10 |
| 31 | |
| 32 | /* Bits for HYPERVISOR_tmem_op(TMEM_NEW_POOL) */ |
| 33 | #define TMEM_POOL_PERSIST 1 |
| 34 | #define TMEM_POOL_SHARED 2 |
| 35 | #define TMEM_POOL_PAGESIZE_SHIFT 4 |
| 36 | #define TMEM_VERSION_SHIFT 24 |
| 37 | |
| 38 | |
| 39 | struct tmem_pool_uuid { |
| 40 | u64 uuid_lo; |
| 41 | u64 uuid_hi; |
| 42 | }; |
| 43 | |
| 44 | struct tmem_oid { |
| 45 | u64 oid[3]; |
| 46 | }; |
| 47 | |
| 48 | #define TMEM_POOL_PRIVATE_UUID { 0, 0 } |
| 49 | |
| 50 | /* flags for tmem_ops.new_pool */ |
| 51 | #define TMEM_POOL_PERSIST 1 |
| 52 | #define TMEM_POOL_SHARED 2 |
| 53 | |
| 54 | /* xen tmem foundation ops/hypercalls */ |
| 55 | |
| 56 | static inline int xen_tmem_op(u32 tmem_cmd, u32 tmem_pool, struct tmem_oid oid, |
| 57 | u32 index, unsigned long gmfn, u32 tmem_offset, u32 pfn_offset, u32 len) |
| 58 | { |
| 59 | struct tmem_op op; |
| 60 | int rc = 0; |
| 61 | |
| 62 | op.cmd = tmem_cmd; |
| 63 | op.pool_id = tmem_pool; |
| 64 | op.u.gen.oid[0] = oid.oid[0]; |
| 65 | op.u.gen.oid[1] = oid.oid[1]; |
| 66 | op.u.gen.oid[2] = oid.oid[2]; |
| 67 | op.u.gen.index = index; |
| 68 | op.u.gen.tmem_offset = tmem_offset; |
| 69 | op.u.gen.pfn_offset = pfn_offset; |
| 70 | op.u.gen.len = len; |
| 71 | set_xen_guest_handle(op.u.gen.gmfn, (void *)gmfn); |
| 72 | rc = HYPERVISOR_tmem_op(&op); |
| 73 | return rc; |
| 74 | } |
| 75 | |
| 76 | static int xen_tmem_new_pool(struct tmem_pool_uuid uuid, |
| 77 | u32 flags, unsigned long pagesize) |
| 78 | { |
| 79 | struct tmem_op op; |
| 80 | int rc = 0, pageshift; |
| 81 | |
| 82 | for (pageshift = 0; pagesize != 1; pageshift++) |
| 83 | pagesize >>= 1; |
| 84 | flags |= (pageshift - 12) << TMEM_POOL_PAGESIZE_SHIFT; |
| 85 | flags |= TMEM_SPEC_VERSION << TMEM_VERSION_SHIFT; |
| 86 | op.cmd = TMEM_NEW_POOL; |
| 87 | op.u.new.uuid[0] = uuid.uuid_lo; |
| 88 | op.u.new.uuid[1] = uuid.uuid_hi; |
| 89 | op.u.new.flags = flags; |
| 90 | rc = HYPERVISOR_tmem_op(&op); |
| 91 | return rc; |
| 92 | } |
| 93 | |
| 94 | /* xen generic tmem ops */ |
| 95 | |
| 96 | static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid, |
| 97 | u32 index, unsigned long pfn) |
| 98 | { |
| 99 | unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn; |
| 100 | |
| 101 | return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index, |
| 102 | gmfn, 0, 0, 0); |
| 103 | } |
| 104 | |
| 105 | static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid, |
| 106 | u32 index, unsigned long pfn) |
| 107 | { |
| 108 | unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn; |
| 109 | |
| 110 | return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index, |
| 111 | gmfn, 0, 0, 0); |
| 112 | } |
| 113 | |
| 114 | static int xen_tmem_flush_page(u32 pool_id, struct tmem_oid oid, u32 index) |
| 115 | { |
| 116 | return xen_tmem_op(TMEM_FLUSH_PAGE, pool_id, oid, index, |
| 117 | 0, 0, 0, 0); |
| 118 | } |
| 119 | |
| 120 | static int xen_tmem_flush_object(u32 pool_id, struct tmem_oid oid) |
| 121 | { |
| 122 | return xen_tmem_op(TMEM_FLUSH_OBJECT, pool_id, oid, 0, 0, 0, 0, 0); |
| 123 | } |
| 124 | |
| 125 | static int xen_tmem_destroy_pool(u32 pool_id) |
| 126 | { |
| 127 | struct tmem_oid oid = { { 0 } }; |
| 128 | |
| 129 | return xen_tmem_op(TMEM_DESTROY_POOL, pool_id, oid, 0, 0, 0, 0, 0); |
| 130 | } |
| 131 | |
| 132 | int tmem_enabled; |
| 133 | |
| 134 | static int __init enable_tmem(char *s) |
| 135 | { |
| 136 | tmem_enabled = 1; |
| 137 | return 1; |
| 138 | } |
| 139 | |
| 140 | __setup("tmem", enable_tmem); |
| 141 | |
| 142 | /* cleancache ops */ |
| 143 | |
| 144 | static void tmem_cleancache_put_page(int pool, struct cleancache_filekey key, |
| 145 | pgoff_t index, struct page *page) |
| 146 | { |
| 147 | u32 ind = (u32) index; |
| 148 | struct tmem_oid oid = *(struct tmem_oid *)&key; |
| 149 | unsigned long pfn = page_to_pfn(page); |
| 150 | |
| 151 | if (pool < 0) |
| 152 | return; |
| 153 | if (ind != index) |
| 154 | return; |
| 155 | mb(); /* ensure page is quiescent; tmem may address it with an alias */ |
| 156 | (void)xen_tmem_put_page((u32)pool, oid, ind, pfn); |
| 157 | } |
| 158 | |
| 159 | static int tmem_cleancache_get_page(int pool, struct cleancache_filekey key, |
| 160 | pgoff_t index, struct page *page) |
| 161 | { |
| 162 | u32 ind = (u32) index; |
| 163 | struct tmem_oid oid = *(struct tmem_oid *)&key; |
| 164 | unsigned long pfn = page_to_pfn(page); |
| 165 | int ret; |
| 166 | |
| 167 | /* translate return values to linux semantics */ |
| 168 | if (pool < 0) |
| 169 | return -1; |
| 170 | if (ind != index) |
| 171 | return -1; |
| 172 | ret = xen_tmem_get_page((u32)pool, oid, ind, pfn); |
| 173 | if (ret == 1) |
| 174 | return 0; |
| 175 | else |
| 176 | return -1; |
| 177 | } |
| 178 | |
| 179 | static void tmem_cleancache_flush_page(int pool, struct cleancache_filekey key, |
| 180 | pgoff_t index) |
| 181 | { |
| 182 | u32 ind = (u32) index; |
| 183 | struct tmem_oid oid = *(struct tmem_oid *)&key; |
| 184 | |
| 185 | if (pool < 0) |
| 186 | return; |
| 187 | if (ind != index) |
| 188 | return; |
| 189 | (void)xen_tmem_flush_page((u32)pool, oid, ind); |
| 190 | } |
| 191 | |
| 192 | static void tmem_cleancache_flush_inode(int pool, struct cleancache_filekey key) |
| 193 | { |
| 194 | struct tmem_oid oid = *(struct tmem_oid *)&key; |
| 195 | |
| 196 | if (pool < 0) |
| 197 | return; |
| 198 | (void)xen_tmem_flush_object((u32)pool, oid); |
| 199 | } |
| 200 | |
| 201 | static void tmem_cleancache_flush_fs(int pool) |
| 202 | { |
| 203 | if (pool < 0) |
| 204 | return; |
| 205 | (void)xen_tmem_destroy_pool((u32)pool); |
| 206 | } |
| 207 | |
| 208 | static int tmem_cleancache_init_fs(size_t pagesize) |
| 209 | { |
| 210 | struct tmem_pool_uuid uuid_private = TMEM_POOL_PRIVATE_UUID; |
| 211 | |
| 212 | return xen_tmem_new_pool(uuid_private, 0, pagesize); |
| 213 | } |
| 214 | |
| 215 | static int tmem_cleancache_init_shared_fs(char *uuid, size_t pagesize) |
| 216 | { |
| 217 | struct tmem_pool_uuid shared_uuid; |
| 218 | |
| 219 | shared_uuid.uuid_lo = *(u64 *)uuid; |
| 220 | shared_uuid.uuid_hi = *(u64 *)(&uuid[8]); |
| 221 | return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize); |
| 222 | } |
| 223 | |
| 224 | static int use_cleancache = 1; |
| 225 | |
| 226 | static int __init no_cleancache(char *s) |
| 227 | { |
| 228 | use_cleancache = 0; |
| 229 | return 1; |
| 230 | } |
| 231 | |
| 232 | __setup("nocleancache", no_cleancache); |
| 233 | |
| 234 | static struct cleancache_ops tmem_cleancache_ops = { |
| 235 | .put_page = tmem_cleancache_put_page, |
| 236 | .get_page = tmem_cleancache_get_page, |
| 237 | .flush_page = tmem_cleancache_flush_page, |
| 238 | .flush_inode = tmem_cleancache_flush_inode, |
| 239 | .flush_fs = tmem_cleancache_flush_fs, |
| 240 | .init_shared_fs = tmem_cleancache_init_shared_fs, |
| 241 | .init_fs = tmem_cleancache_init_fs |
| 242 | }; |
| 243 | |
| 244 | static int __init xen_tmem_init(void) |
| 245 | { |
| 246 | struct cleancache_ops old_ops; |
| 247 | |
| 248 | if (!xen_domain()) |
| 249 | return 0; |
| 250 | #ifdef CONFIG_CLEANCACHE |
| 251 | BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid)); |
| 252 | if (tmem_enabled && use_cleancache) { |
| 253 | char *s = ""; |
| 254 | old_ops = cleancache_register_ops(&tmem_cleancache_ops); |
| 255 | if (old_ops.init_fs != NULL) |
| 256 | s = " (WARNING: cleancache_ops overridden)"; |
| 257 | printk(KERN_INFO "cleancache enabled, RAM provided by " |
| 258 | "Xen Transcendent Memory%s\n", s); |
| 259 | } |
| 260 | #endif |
| 261 | return 0; |
| 262 | } |
| 263 | |
| 264 | module_init(xen_tmem_init) |