--- /dev/null
+/*
+ * This file is part of the Palacios Virtual Machine Monitor developed
+ * by the V3VEE Project with funding from the United States National
+ * Science Foundation and the Department of Energy.
+ *
+ * The V3VEE Project is a joint project between Northwestern University
+ * and the University of New Mexico. You can find out more at
+ * http://www.v3vee.org
+ *
+ * Copyright (c) 2008, Jack Lange <jarusl@cs.northwestern.edu>
+ * Copyright (c) 2008, The V3VEE Project <http://www.v3vee.org>
+ * All rights reserved.
+ *
+ * Author: Jack Lange <jarusl@cs.northwestern.edu>
+ *
+ * This is free software. You are permitted to use,
+ * redistribute, and modify it as specified in the file "V3VEE_LICENSE".
+ */
+
+#include <palacios/vmm.h>
+#include <palacios/vmm_dev_mgr.h>
+#include <palacios/vmm_sym_swap.h>
+#include <palacios/vm_guest.h>
+#include <palacios/vmm_hashtable.h>
+
+
+#ifdef CONFIG_SYMBIOTIC_SWAP_TELEMETRY
+#include <palacios/vmm_telemetry.h>
+#endif
+
+
+#undef PrintDebug
+#define PrintDebug(fmt, ...)
+
+
+/* This is the first page that linux writes to the swap area */
+/* Taken from Linux */
+union swap_header {
+ struct {
+ char reserved[PAGE_SIZE - 10];
+ char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
+ } magic;
+ struct {
+ char bootbits[1024]; /* Space for disklabel etc. */
+ uint32_t version;
+ uint32_t last_page;
+ uint32_t nr_badpages;
+ unsigned char sws_uuid[16];
+ unsigned char sws_volume[16];
+ uint32_t type; // The index into the swap_map
+ uint32_t padding[116];
+
+ uint32_t badpages[1];
+ } info;
+};
+
+
+struct cache_entry {
+ uint32_t disk_index;
+ struct list_head cache_node;
+};
+
+// Per instance data structure
+struct swap_state {
+ int active;
+ int disabled;
+
+ struct guest_info * vm;
+ struct swap_state * swap_info;
+
+ int symbiotic;
+
+ union swap_header hdr;
+
+ uint_t swapped_pages;
+ uint_t unswapped_pages;
+ uint32_t disk_writes;
+ uint32_t disk_reads;
+
+
+ uint32_t seek_usecs;
+
+ struct v3_dev_blk_ops * ops;
+ void * private_data;
+
+#ifdef CONFIG_SYMBIOTIC_SWAP_TELEMETRY
+ uint32_t pages_in;
+ uint32_t pages_out;
+#endif
+
+ int io_flag;
+
+ uint64_t cache_size;
+ uint8_t * cache;
+ uint64_t cache_base_addr;
+ uint_t pages_in_cache;
+
+ struct cache_entry * entry_map;
+ struct list_head entry_list;
+ struct list_head free_list;
+
+ struct hashtable * entry_ht;
+};
+
+
+
+void __udelay(unsigned long usecs);
+
+static uint_t cache_hash_fn(addr_t key) {
+ return v3_hash_long(key, 32);
+}
+
+
+static int cache_eq_fn(addr_t key1, addr_t key2) {
+ return (key1 == key2);
+}
+
+
+
+
+
+static inline uint32_t get_swap_index_from_offset(uint32_t offset) {
+ // CAREFUL: The index might be offset by 1, because the first 4K is the header
+ return (offset / 4096);
+}
+
+static inline uint32_t get_swap_offset_from_index(uint32_t index) {
+ // CAREFUL: The index might be offset by 1, because the first 4K is the header
+ return (index * 4096);
+}
+
+
+static inline uint32_t get_cache_entry_index(struct swap_state * swap, struct cache_entry * entry) {
+ return (entry - swap->entry_map); // / sizeof(struct cache_entry);
+}
+
+
+
+
+
+static inline void * get_swap_entry(uint32_t pg_index, void * private_data) {
+ struct swap_state * swap = (struct swap_state *)private_data;
+ struct cache_entry * entry = NULL;
+ void * pg_addr = NULL;
+ uint32_t swap_index = pg_index * 4096;
+
+ if (swap->disabled) {
+ return NULL;
+ }
+
+ PrintDebug("Getting swap entry for index %d\n", pg_index);
+
+ entry = (struct cache_entry *)v3_htable_search(swap->entry_ht, swap_index);
+
+ if (entry != NULL) {
+ uint32_t cache_index = get_cache_entry_index(swap, entry);
+ PrintDebug("Found cached entry (%d)\n", cache_index);
+ pg_addr = swap->cache + (cache_index * 4096);
+ }
+
+ return pg_addr;
+}
+
+
+
+static int read_disk(uint8_t * buf, uint64_t lba, uint64_t num_bytes, struct swap_state * swap) {
+ if ((swap->io_flag == 0) && (swap->seek_usecs > 0)) {
+ __udelay(swap->seek_usecs);
+ swap->io_flag = 1;
+ }
+
+ swap->disk_reads += num_bytes / 4096;
+ return swap->ops->read(buf, lba, num_bytes, swap->private_data);
+
+}
+
+
+static int write_disk(uint8_t * buf, uint64_t lba, uint64_t num_bytes, struct swap_state * swap) {
+ if ((swap->io_flag == 0) && (swap->seek_usecs > 0)) {
+ __udelay(swap->seek_usecs);
+ swap->io_flag = 1;
+ }
+
+ swap->disk_writes += num_bytes / 4096;
+
+
+ return swap->ops->write(buf, lba, num_bytes, swap->private_data);
+}
+
+
+static uint64_t swap_get_capacity(void * private_data) {
+ struct swap_state * swap = (struct swap_state *)private_data;
+ return swap->ops->get_capacity(swap->private_data);
+}
+
+
+static struct v3_swap_ops swap_ops = {
+ .get_swap_entry = get_swap_entry,
+};
+
+
+
+static int buf_read(uint8_t * buf, uint64_t lba, uint64_t num_bytes, void * private_data) {
+ struct swap_state * swap = (struct swap_state *)private_data;
+ uint32_t offset = lba;
+ uint32_t length = num_bytes;
+
+ swap->io_flag = 0;
+
+ if (length % 4096) {
+ PrintError("Swapping in length that is not a page multiple\n");
+ }
+
+ if (swap->disabled) {
+ return read_disk(buf, lba, num_bytes, swap);
+ }
+
+
+ PrintDebug("SymSwap: Reading %d bytes to %p (lba=%p)\n", (uint32_t)num_bytes, buf, (void *)(addr_t)lba);
+
+
+ if (length % 4096) {
+ PrintError("Swapping in length that is not a page multiple\n");
+ return -1;
+ }
+
+
+ if ((swap->active == 1) && (offset >= 4096)) {
+ int i = 0;
+ int read_pages = (length / 4096);
+
+
+ // Notify the shadow paging layer
+
+ swap->unswapped_pages += (length / 4096);
+
+
+#ifdef CONFIG_SYMBIOTIC_SWAP_TELEMETRY
+ swap->pages_in += length / 4096;
+#endif
+
+ for (i = 0; i < read_pages; i++) {
+ uint32_t swap_index = offset + (i * 4096);
+ uint32_t cache_index = 0;
+ struct cache_entry * entry = NULL;
+
+ if (swap->symbiotic == 1) {
+ v3_swap_in_notify(swap->vm, get_swap_index_from_offset(offset + i), swap->hdr.info.type);
+ }
+
+ PrintDebug("Searching for swap index %d\n", swap_index);
+
+ entry = (struct cache_entry *)v3_htable_search(swap->entry_ht, (addr_t)swap_index);
+
+ if (entry != NULL) {
+
+ cache_index = get_cache_entry_index(swap, entry);
+
+ PrintDebug("Reading from cache entry %d\n", cache_index);
+
+ memcpy(buf, swap->cache + (cache_index * 4096), 4096);
+
+ } else {
+ PrintDebug("Reading from disk offset = %p\n", (void *)(addr_t)offset);
+
+ if (read_disk(buf, offset, 4096, swap) == -1) {
+ PrintError("Error reading disk\n");
+ return -1;
+ }
+ }
+
+ offset += 4096;
+ buf += 4096;
+ }
+ } else {
+ return read_disk(buf, lba, num_bytes, swap);
+ }
+
+
+ return 0;
+}
+
+
+static int flush_cache(struct swap_state * swap, int num_to_flush) {
+ int i;
+
+ PrintDebug("Flushing %d pages\n", num_to_flush);
+
+ for (i = 0; i < num_to_flush; i++) {
+ struct cache_entry * entry = NULL;
+ uint32_t entry_index = 0;
+
+ entry = list_first_entry(&(swap->entry_list), struct cache_entry, cache_node);
+
+ entry_index = get_cache_entry_index(swap, entry);
+ PrintDebug("Flushing cache entry %d\n", entry_index);
+
+ if (write_disk(swap->cache + (entry_index * 4096), entry->disk_index, 4096, swap) == -1) {
+ PrintError("Error in disk write\n");
+ return -1;
+ }
+
+
+ if (swap->symbiotic == 1) {
+ v3_swap_in_notify(swap->vm, entry->disk_index / 4096, swap->hdr.info.type);
+ }
+
+ // invalidate swap entry
+
+
+ v3_htable_remove(swap->entry_ht, entry->disk_index, 0);
+
+ list_move(&(entry->cache_node), &(swap->free_list));
+
+ swap->pages_in_cache--;
+ }
+
+ return 0;
+}
+
+
+
+
+
+
+
+
+static int buf_write(uint8_t * buf, uint64_t lba, uint64_t num_bytes, void * private_data) {
+ struct swap_state * swap = (struct swap_state *)private_data;
+ uint32_t offset = lba;
+ uint32_t length = num_bytes;
+
+ swap->io_flag = 0;
+
+
+
+ if (swap->disabled) {
+ return write_disk(buf, lba, num_bytes, swap);
+ }
+
+
+ /*
+ PrintDebug("SymSwap: Writing %d bytes to %p from %p\n", length,
+ (void *)(swap->swap_space + offset), buf);
+ */
+
+
+ if ((swap->active == 0) && (offset == 0)) {
+ // This is the swap header page
+
+ swap->active = 1;
+
+ // store a local copy
+ memcpy(&(swap->hdr), buf, sizeof(union swap_header));
+
+
+ PrintError("Swap Type=%d (magic=%s)\n", swap->hdr.info.type, swap->hdr.magic.magic);
+
+ if (swap->symbiotic == 1) {
+ if (v3_register_swap_disk(swap->vm, swap->hdr.info.type, &swap_ops, swap) == -1) {
+ PrintError("Error registering symbiotic swap disk\n");
+ return -1;
+ }
+
+ PrintError("Swap disk registered\n");
+ }
+
+
+ if (write_disk(buf, lba, num_bytes, swap) == -1) {
+ PrintError("Error writing swap header to disk\n");
+ return -1;
+ }
+
+ PrintDebug("Wrote header to disk\n");
+
+ return 0;
+ }
+
+ if ((swap->active == 1) && (offset >= 4096)) {
+ int i = 0;
+ int written_pages = (length / 4096);
+ int avail_space = (swap->cache_size / 4096) - swap->pages_in_cache;
+
+
+ swap->swapped_pages += written_pages;
+
+#ifdef CONFIG_SYMBIOTIC_SWAP_TELEMETRY
+ swap->pages_out += length / 4096;
+#endif
+
+ PrintDebug("available cache space = %d, pages written = %d\n", avail_space, written_pages);
+
+ if (avail_space < written_pages) {
+ flush_cache(swap, written_pages - avail_space);
+ }
+
+
+ for (i = 0; i < written_pages; i += 1) {
+ // set_index_usage(swap, get_swap_index_from_offset(offset + i), 1);
+ struct cache_entry * new_entry = NULL;
+ uint32_t swap_index = offset + (i * 4096);
+ uint32_t cache_index = 0;
+
+ new_entry = (struct cache_entry *)v3_htable_search(swap->entry_ht, (addr_t)swap_index);
+
+ if (new_entry == NULL) {
+ new_entry = list_tail_entry(&(swap->free_list), struct cache_entry, cache_node);
+
+ new_entry->disk_index = swap_index;
+
+ list_move_tail(&(new_entry->cache_node), &(swap->entry_list));
+
+ v3_htable_insert(swap->entry_ht, (addr_t)swap_index, (addr_t)new_entry);
+
+ swap->pages_in_cache++;
+ }
+
+ cache_index = get_cache_entry_index(swap, new_entry);
+
+ PrintDebug("Writing to cache entry %d\n", cache_index);
+
+ memcpy(swap->cache + (cache_index * 4096), buf, 4096);
+
+ buf += 4096;
+ }
+ } else {
+ if (write_disk(buf, lba, num_bytes, swap) == -1) {
+ PrintError("Error writing swap header to disk\n");
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+
+
+
+static uint8_t write_buf[4096];
+
+
+static int swap_write(uint8_t * buf, uint64_t lba, uint64_t num_bytes, void * private_data) {
+ int idx = lba % 4096;
+
+ if (num_bytes != 512) {
+ PrintError("Write for %d bytes\n", (uint32_t)num_bytes);
+ return -1;
+ }
+
+
+ memcpy(write_buf + idx, buf, num_bytes);
+
+ if (idx + num_bytes == 4096) {
+ return buf_write(write_buf, lba - idx, 4096, private_data);
+ }
+
+ return 0;
+}
+
+
+
+static uint8_t read_buf[4096];
+
+
+
+static int swap_read(uint8_t * buf, uint64_t lba, uint64_t num_bytes, void * private_data) {
+ int idx = lba % 4096;
+
+
+ if (num_bytes != 512) {
+ PrintError("Read for %d bytes\n", (uint32_t)num_bytes);
+ return -1;
+ }
+
+ if (idx == 0) {
+ if (buf_read(read_buf, lba - idx, 4096, private_data) == -1) {
+ PrintError("Error reading buffer\n");
+ return -1;
+ }
+ }
+
+ memcpy(buf, read_buf + idx, num_bytes);
+
+ return 0;
+}
+
+
+static int swap_free(struct vm_device * dev) {
+ return -1;
+}
+
+
+static struct v3_dev_blk_ops blk_ops = {
+ .read = swap_read,
+ .write = swap_write,
+ .get_capacity = swap_get_capacity,
+};
+
+
+
+static struct v3_device_ops dev_ops = {
+ .free = swap_free,
+ .reset = NULL,
+ .start = NULL,
+ .stop = NULL,
+};
+
+
+#ifdef CONFIG_SYMBIOTIC_SWAP_TELEMETRY
+static void telemetry_cb(struct guest_info * info, void * private_data, char * hdr) {
+ struct swap_state * swap = (struct swap_state *)private_data;
+
+ V3_Print("%sSwap Device:\n", hdr);
+ V3_Print("%s\tPages Swapped in=%d\n", hdr, swap->pages_in);
+ V3_Print("%s\tPages Swapped out=%d\n", hdr, swap->pages_out);
+ V3_Print("%s\tPages Written to Disk=%d\n", hdr, swap->disk_writes);
+ V3_Print("%s\tPages Read from Disk=%d\n", hdr, swap->disk_reads);
+}
+#endif
+
+
+static int connect_fn(struct guest_info * info,
+ void * frontend_data,
+ struct v3_dev_blk_ops * ops,
+ v3_cfg_tree_t * cfg,
+ void * private_data) {
+ v3_cfg_tree_t * frontend_cfg = v3_cfg_subtree(cfg, "frontend");
+ uint32_t cache_size = atoi(v3_cfg_val(cfg, "cache_size")) * 1024 * 1024;
+ uint32_t seek_us = atoi(v3_cfg_val(cfg, "seek_us"));
+ int symbiotic = atoi(v3_cfg_val(cfg, "symbiotic"));
+ struct swap_state * swap = NULL;
+ int i;
+
+ if (!frontend_cfg) {
+ PrintError("Initializing sym swap without a frontend device\n");
+ return -1;
+ }
+
+ PrintError("Creating Swap filter (cache size=%dMB)\n", cache_size / (1024 * 1024));
+
+ swap = (struct swap_state *)V3_Malloc(sizeof(struct swap_state));
+
+ swap->vm = info;
+ swap->cache_size = cache_size;
+ swap->io_flag = 0;
+ swap->seek_usecs = seek_us;
+ swap->symbiotic = symbiotic;
+
+ swap->ops = ops;
+ swap->private_data = private_data;
+
+ swap->swapped_pages = 0;
+ swap->unswapped_pages = 0;
+ // swap->cached_pages = 0;
+
+ if (cache_size == 0) {
+ swap->disabled = 1;
+ } else {
+ swap->disabled = 0;
+
+ INIT_LIST_HEAD(&(swap->entry_list));
+ INIT_LIST_HEAD(&(swap->free_list));
+ swap->entry_map = (struct cache_entry *)V3_Malloc(sizeof(struct cache_entry) * (cache_size / 4096));
+
+ for (i = 0; i < (cache_size / 4096); i++) {
+ list_add(&(swap->entry_map[i].cache_node), &(swap->free_list));
+ }
+
+ swap->entry_ht = v3_create_htable(0, cache_hash_fn, cache_eq_fn);
+
+ swap->active = 0;
+
+ swap->cache_base_addr = (addr_t)V3_AllocPages(swap->cache_size / 4096);
+ swap->cache = (uint8_t *)V3_VAddr((void *)(swap->cache_base_addr));
+ memset(swap->cache, 0, swap->cache_size);
+ }
+
+ if (v3_dev_connect_blk(info, v3_cfg_val(frontend_cfg, "tag"),
+ &blk_ops, frontend_cfg, swap) == -1) {
+ PrintError("Could not connect to frontend %s\n",
+ v3_cfg_val(frontend_cfg, "tag"));
+ return -1;
+ }
+
+
+#ifdef CONFIG_SYMBIOTIC_SWAP_TELEMETRY
+
+ if (info->enable_telemetry == 1) {
+ v3_add_telemetry_cb(info, telemetry_cb, swap);
+ }
+
+#endif
+
+ return 0;
+}
+
+
+
+
+static int swap_init(struct guest_info * vm, v3_cfg_tree_t * cfg) {
+
+ char * name = v3_cfg_val(cfg, "name");
+
+ struct vm_device * dev = v3_allocate_device(name, &dev_ops, NULL);
+
+ if (v3_attach_device(vm, dev) == -1) {
+ PrintError("Could not attach device %s\n", name);
+ return -1;
+ }
+
+ if (v3_dev_add_blk_frontend(vm, name, connect_fn, NULL) == -1) {
+ PrintError("Could not register %s as block frontend\n", name);
+ return -1;
+ }
+
+
+ return 0;
+}
+
+device_register("SWAPCACHE", swap_init)
