2 * This file is part of the Palacios Virtual Machine Monitor developed
3 * by the V3VEE Project with funding from the United States National
4 * Science Foundation and the Department of Energy.
6 * The V3VEE Project is a joint project between Northwestern University
7 * and the University of New Mexico. You can find out more at
10 * Copyright (c) 2008, Jack Lange <jarusl@cs.northwestern.edu>
11 * Copyright (c) 2008, The V3VEE Project <http://www.v3vee.org>
12 * All rights reserved.
14 * Author: Jack Lange <jarusl@cs.northwestern.edu>
16 * This is free software. You are permitted to use,
17 * redistribute, and modify it as specified in the file "V3VEE_LICENSE".
20 #include <palacios/vmm.h>
21 #include <palacios/vmm_dev_mgr.h>
22 #include <palacios/vmm_sym_swap.h>
25 #ifdef CONFIG_SYMBIOTIC_SWAP_TELEMETRY
26 #include <palacios/vmm_telemetry.h>
30 /* This is the first page that linux writes to the swap area */
31 /* Taken from Linux */
34 char reserved[PAGE_SIZE - 10];
35 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
38 char bootbits[1024]; /* Space for disklabel etc. */
42 unsigned char sws_uuid[16];
43 unsigned char sws_volume[16];
44 uint32_t type; // The index into the swap_map
45 uint32_t padding[116];
46 // uint32_t padding[117];
57 uint_t unswapped_pages;
60 union swap_header * hdr;
62 #ifdef CONFIG_SYMBIOTIC_SWAP_TELEMETRY
70 addr_t swap_base_addr;
72 struct guest_info * vm;
74 uint8_t usage_map[0]; // This must be the last structure member
80 static inline void set_index_usage(struct swap_state * swap, uint32_t index, int used) {
81 int major = index / 8;
82 int minor = index % 8;
85 swap->usage_map[major] |= (1 << minor);
87 swap->usage_map[major] &= ~(1 << minor);
91 static inline int get_index_usage(struct swap_state * swap, uint32_t index) {
92 int major = index / 8;
93 int minor = index % 8;
95 return (swap->usage_map[major] & (1 << minor));
99 static inline uint32_t get_swap_index_from_offset(uint32_t offset) {
100 // CAREFUL: The index might be offset by 1, because the first 4K is the header
101 return (offset / 4096);
106 static inline uint32_t get_swap_index(uint32_t offset) {
107 // CAREFUL: The index might be offset by 1, because the first 4K is the header
108 return (swap_addr - swap->swap_space) / 4096;
113 static inline void * get_swap_entry(uint32_t pg_index, void * private_data) {
114 struct swap_state * swap = (struct swap_state *)private_data;
115 void * pg_addr = NULL;
118 // if ((ret = get_index_usage(swap, pg_index))) {
119 // CAREFUL: The index might be offset by 1, because the first 4K is the header
120 pg_addr = (void *)(swap->swap_space + (pg_index * 4096));
128 static uint64_t swap_get_capacity(void * private_data) {
129 struct swap_state * swap = (struct swap_state *)private_data;
131 PrintDebug("SymSwap: Getting Capacity %d\n", (uint32_t)(swap->capacity));
133 return swap->capacity;
137 static struct v3_swap_ops swap_ops = {
138 .get_swap_entry = get_swap_entry,
143 static int swap_read(uint8_t * buf, uint64_t lba, uint64_t num_bytes, void * private_data) {
144 struct swap_state * swap = (struct swap_state *)private_data;
145 uint32_t offset = lba;
146 uint32_t length = num_bytes;
150 PrintDebug("SymSwap: Reading %d bytes to %p from %p\n", length,
151 buf, (void *)(swap->swap_space + offset));
155 PrintError("Swapping in length that is not a page multiple\n");
158 memcpy(buf, swap->swap_space + offset, length);
160 swap->unswapped_pages += (length / 4096);
162 if ((swap->active == 1) && (offset != 0)) {
164 // Notify the shadow paging layer
166 #ifdef CONFIG_SYMBIOTIC_SWAP_TELEMETRY
167 swap->pages_in += length / 4096;
170 for (i = 0; i < length; i += 4096) {
171 set_index_usage(swap, get_swap_index_from_offset(offset + i), 0);
172 v3_swap_in_notify(swap->vm, get_swap_index_from_offset(offset + i), swap->hdr->info.type);
182 static int swap_write(uint8_t * buf, uint64_t lba, uint64_t num_bytes, void * private_data) {
183 struct swap_state * swap = (struct swap_state *)private_data;
184 uint32_t offset = lba;
185 uint32_t length = num_bytes;
188 PrintDebug("SymSwap: Writing %d bytes to %p from %p\n", length,
189 (void *)(swap->swap_space + offset), buf);
193 PrintError("Swapping out length that is not a page multiple\n");
196 if ((swap->active == 0) && (offset == 0)) {
197 // This is the swap header page
199 if (length != 4096) {
200 PrintError("Initializing Swap space by not writing page multiples. This sucks...\n");
206 PrintDebug("Swap Type=%d (magic=%s)\n", swap->hdr->info.type, swap->hdr->magic.magic);
208 if (v3_register_swap_disk(swap->vm, swap->hdr->info.type, &swap_ops, swap) == -1) {
209 PrintError("Error registering symbiotic swap disk\n");
214 memcpy(swap->swap_space + offset, buf, length);
216 swap->swapped_pages += (length / 4096);
218 if ((swap->active == 1) && (offset != 0)) {
221 #ifdef CONFIG_SYMBIOTIC_SWAP_TELEMETRY
222 swap->pages_out += length / 4096;
225 for (i = 0; i < length; i += 4096) {
226 set_index_usage(swap, get_swap_index_from_offset(offset + i), 1);
234 static int swap_free(struct vm_device * dev) {
239 static struct v3_dev_blk_ops blk_ops = {
242 .get_capacity = swap_get_capacity,
247 static struct v3_device_ops dev_ops = {
255 #ifdef CONFIG_SYMBIOTIC_SWAP_TELEMETRY
256 static void telemetry_cb(struct guest_info * info, void * private_data, char * hdr) {
257 struct vm_device * dev = (struct vm_device *)private_data;
258 struct swap_state * swap = (struct swap_state *)(dev->private_data);
260 V3_Print("%sSwap Device:\n", hdr);
261 V3_Print("%s\tPages Swapped in=%d\n", hdr, swap->pages_in);
262 V3_Print("%s\tPages Swapped out=%d\n", hdr, swap->pages_out);
271 static int swap_init(struct guest_info * vm, v3_cfg_tree_t * cfg) {
272 struct swap_state * swap = NULL;
273 v3_cfg_tree_t * frontend_cfg = v3_cfg_subtree(cfg, "frontend");
274 uint32_t capacity = atoi(v3_cfg_val(cfg, "size")) * 1024 * 1024;
275 char * name = v3_cfg_val(cfg, "name");
278 PrintError("Initializing sym swap without a frontend device\n");
282 PrintDebug("Creating Swap Device (size=%dMB)\n", capacity / (1024 * 1024));
284 swap = (struct swap_state *)V3_Malloc(sizeof(struct swap_state) + ((capacity / 4096) / 8));
288 swap->capacity = capacity;
290 swap->swapped_pages = 0;
291 swap->unswapped_pages = 0;
294 swap->hdr = (union swap_header *)swap;
296 swap->swap_base_addr = (addr_t)V3_AllocPages(swap->capacity / 4096);
297 swap->swap_space = (uint8_t *)V3_VAddr((void *)(swap->swap_base_addr));
298 memset(swap->swap_space, 0, swap->capacity);
300 memset(swap->usage_map, 0, ((swap->capacity / 4096) / 8));
302 struct vm_device * dev = v3_allocate_device(name, &dev_ops, swap);
304 if (v3_attach_device(vm, dev) == -1) {
305 PrintError("Could not attach device %s\n", name);
309 if (v3_dev_connect_blk(vm, v3_cfg_val(frontend_cfg, "tag"),
310 &blk_ops, frontend_cfg, swap) == -1) {
311 PrintError("Could not connect %s to frontend %s\n",
312 name, v3_cfg_val(frontend_cfg, "tag"));
316 #ifdef CONFIG_SYMBIOTIC_SWAP_TELEMETRY
317 if (vm->enable_telemetry) {
318 v3_add_telemetry_cb(vm, telemetry_cb, dev);
325 device_register("SYM_SWAP", swap_init)