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 uint8_t usage_map[0]; // This must be the last structure member
78 static inline void set_index_usage(struct swap_state * swap, uint32_t index, int used) {
79 int major = index / 8;
80 int minor = index % 8;
83 swap->usage_map[major] |= (1 << minor);
85 swap->usage_map[major] &= ~(1 << minor);
89 static inline int get_index_usage(struct swap_state * swap, uint32_t index) {
90 int major = index / 8;
91 int minor = index % 8;
93 return (swap->usage_map[major] & (1 << minor));
97 static inline uint32_t get_swap_index_from_offset(uint32_t offset) {
98 // CAREFUL: The index might be offset by 1, because the first 4K is the header
99 return (offset / 4096);
104 static inline uint32_t get_swap_index(uint32_t offset) {
105 // CAREFUL: The index might be offset by 1, because the first 4K is the header
106 return (swap_addr - swap->swap_space) / 4096;
111 static inline void * get_swap_entry(uint32_t pg_index, void * private_data) {
112 struct vm_device * dev = (struct vm_device *)private_data;
113 struct swap_state * swap = (struct swap_state *)(dev->private_data);
114 void * pg_addr = NULL;
117 // if ((ret = get_index_usage(swap, pg_index))) {
118 // CAREFUL: The index might be offset by 1, because the first 4K is the header
119 pg_addr = (void *)(swap->swap_space + (pg_index * 4096));
127 static uint64_t swap_get_capacity(void * private_data) {
128 struct vm_device * dev = (struct vm_device *)private_data;
129 struct swap_state * swap = (struct swap_state *)(dev->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 vm_device * dev = (struct vm_device *)private_data;
145 struct swap_state * swap = (struct swap_state *)(dev->private_data);
146 uint32_t offset = lba;
147 uint32_t length = num_bytes;
151 PrintDebug("SymSwap: Reading %d bytes to %p from %p\n", length,
152 buf, (void *)(swap->swap_space + offset));
156 PrintError("Swapping in length that is not a page multiple\n");
159 memcpy(buf, swap->swap_space + offset, length);
161 swap->unswapped_pages += (length / 4096);
163 if ((swap->active == 1) && (offset != 0)) {
165 // Notify the shadow paging layer
167 #ifdef CONFIG_SYMBIOTIC_SWAP_TELEMETRY
168 swap->pages_in += length / 4096;
171 for (i = 0; i < length; i += 4096) {
172 set_index_usage(swap, get_swap_index_from_offset(offset + i), 0);
173 v3_swap_in_notify(dev->vm, get_swap_index_from_offset(offset + i), swap->hdr->info.type);
183 static int swap_write(uint8_t * buf, uint64_t lba, uint64_t num_bytes, void * private_data) {
184 struct vm_device * dev = (struct vm_device *)private_data;
185 struct swap_state * swap = (struct swap_state *)(dev->private_data);
186 uint32_t offset = lba;
187 uint32_t length = num_bytes;
190 PrintDebug("SymSwap: Writing %d bytes to %p from %p\n", length,
191 (void *)(swap->swap_space + offset), buf);
195 PrintError("Swapping out length that is not a page multiple\n");
198 if ((swap->active == 0) && (offset == 0)) {
199 // This is the swap header page
201 if (length != 4096) {
202 PrintError("Initializing Swap space by not writing page multiples. This sucks...\n");
208 PrintDebug("Swap Type=%d (magic=%s)\n", swap->hdr->info.type, swap->hdr->magic.magic);
210 if (v3_register_swap_disk(dev->vm, swap->hdr->info.type, &swap_ops, dev) == -1) {
211 PrintError("Error registering symbiotic swap disk\n");
216 memcpy(swap->swap_space + offset, buf, length);
218 swap->swapped_pages += (length / 4096);
220 if ((swap->active == 1) && (offset != 0)) {
223 #ifdef CONFIG_SYMBIOTIC_SWAP_TELEMETRY
224 swap->pages_out += length / 4096;
227 for (i = 0; i < length; i += 4096) {
228 set_index_usage(swap, get_swap_index_from_offset(offset + i), 1);
236 static int swap_free(struct vm_device * dev) {
241 static struct v3_dev_blk_ops blk_ops = {
244 .get_capacity = swap_get_capacity,
249 static struct v3_device_ops dev_ops = {
257 #ifdef CONFIG_SYMBIOTIC_SWAP_TELEMETRY
258 static void telemetry_cb(struct guest_info * info, void * private_data, char * hdr) {
259 struct vm_device * dev = (struct vm_device *)private_data;
260 struct swap_state * swap = (struct swap_state *)(dev->private_data);
262 V3_Print("%sSwap Device:\n", hdr);
263 V3_Print("%s\tPages Swapped in=%d\n", hdr, swap->pages_in);
264 V3_Print("%s\tPages Swapped out=%d\n", hdr, swap->pages_out);
273 static int swap_init(struct guest_info * vm, v3_cfg_tree_t * cfg) {
274 struct swap_state * swap = NULL;
275 v3_cfg_tree_t * frontend_cfg = v3_cfg_subtree(cfg, "frontend");
276 uint32_t capacity = atoi(v3_cfg_val(cfg, "size")) * 1024 * 1024;
277 char * name = v3_cfg_val(cfg, "name");
280 PrintError("Initializing sym swap without a frontend device\n");
284 PrintDebug("Creating Swap Device\n");
286 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)