diff options
Diffstat (limited to 'drivers/hv/hv_balloon.c')
| -rw-r--r-- | drivers/hv/hv_balloon.c | 1616 |
1 files changed, 1616 insertions, 0 deletions
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c new file mode 100644 index 000000000..cb5b7dc97 --- /dev/null +++ b/drivers/hv/hv_balloon.c @@ -0,0 +1,1616 @@ +/* + * Copyright (c) 2012, Microsoft Corporation. + * + * Author: + * K. Y. Srinivasan <kys@microsoft.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published + * by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for more + * details. + * + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/kernel.h> +#include <linux/jiffies.h> +#include <linux/mman.h> +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/kthread.h> +#include <linux/completion.h> +#include <linux/memory_hotplug.h> +#include <linux/memory.h> +#include <linux/notifier.h> +#include <linux/percpu_counter.h> + +#include <linux/hyperv.h> + +/* + * We begin with definitions supporting the Dynamic Memory protocol + * with the host. + * + * Begin protocol definitions. + */ + + + +/* + * Protocol versions. The low word is the minor version, the high word the major + * version. + * + * History: + * Initial version 1.0 + * Changed to 0.1 on 2009/03/25 + * Changes to 0.2 on 2009/05/14 + * Changes to 0.3 on 2009/12/03 + * Changed to 1.0 on 2011/04/05 + */ + +#define DYNMEM_MAKE_VERSION(Major, Minor) ((__u32)(((Major) << 16) | (Minor))) +#define DYNMEM_MAJOR_VERSION(Version) ((__u32)(Version) >> 16) +#define DYNMEM_MINOR_VERSION(Version) ((__u32)(Version) & 0xff) + +enum { + DYNMEM_PROTOCOL_VERSION_1 = DYNMEM_MAKE_VERSION(0, 3), + DYNMEM_PROTOCOL_VERSION_2 = DYNMEM_MAKE_VERSION(1, 0), + + DYNMEM_PROTOCOL_VERSION_WIN7 = DYNMEM_PROTOCOL_VERSION_1, + DYNMEM_PROTOCOL_VERSION_WIN8 = DYNMEM_PROTOCOL_VERSION_2, + + DYNMEM_PROTOCOL_VERSION_CURRENT = DYNMEM_PROTOCOL_VERSION_WIN8 +}; + + + +/* + * Message Types + */ + +enum dm_message_type { + /* + * Version 0.3 + */ + DM_ERROR = 0, + DM_VERSION_REQUEST = 1, + DM_VERSION_RESPONSE = 2, + DM_CAPABILITIES_REPORT = 3, + DM_CAPABILITIES_RESPONSE = 4, + DM_STATUS_REPORT = 5, + DM_BALLOON_REQUEST = 6, + DM_BALLOON_RESPONSE = 7, + DM_UNBALLOON_REQUEST = 8, + DM_UNBALLOON_RESPONSE = 9, + DM_MEM_HOT_ADD_REQUEST = 10, + DM_MEM_HOT_ADD_RESPONSE = 11, + DM_VERSION_03_MAX = 11, + /* + * Version 1.0. + */ + DM_INFO_MESSAGE = 12, + DM_VERSION_1_MAX = 12 +}; + + +/* + * Structures defining the dynamic memory management + * protocol. + */ + +union dm_version { + struct { + __u16 minor_version; + __u16 major_version; + }; + __u32 version; +} __packed; + + +union dm_caps { + struct { + __u64 balloon:1; + __u64 hot_add:1; + /* + * To support guests that may have alignment + * limitations on hot-add, the guest can specify + * its alignment requirements; a value of n + * represents an alignment of 2^n in mega bytes. + */ + __u64 hot_add_alignment:4; + __u64 reservedz:58; + } cap_bits; + __u64 caps; +} __packed; + +union dm_mem_page_range { + struct { + /* + * The PFN number of the first page in the range. + * 40 bits is the architectural limit of a PFN + * number for AMD64. + */ + __u64 start_page:40; + /* + * The number of pages in the range. + */ + __u64 page_cnt:24; + } finfo; + __u64 page_range; +} __packed; + + + +/* + * The header for all dynamic memory messages: + * + * type: Type of the message. + * size: Size of the message in bytes; including the header. + * trans_id: The guest is responsible for manufacturing this ID. + */ + +struct dm_header { + __u16 type; + __u16 size; + __u32 trans_id; +} __packed; + +/* + * A generic message format for dynamic memory. + * Specific message formats are defined later in the file. + */ + +struct dm_message { + struct dm_header hdr; + __u8 data[]; /* enclosed message */ +} __packed; + + +/* + * Specific message types supporting the dynamic memory protocol. + */ + +/* + * Version negotiation message. Sent from the guest to the host. + * The guest is free to try different versions until the host + * accepts the version. + * + * dm_version: The protocol version requested. + * is_last_attempt: If TRUE, this is the last version guest will request. + * reservedz: Reserved field, set to zero. + */ + +struct dm_version_request { + struct dm_header hdr; + union dm_version version; + __u32 is_last_attempt:1; + __u32 reservedz:31; +} __packed; + +/* + * Version response message; Host to Guest and indicates + * if the host has accepted the version sent by the guest. + * + * is_accepted: If TRUE, host has accepted the version and the guest + * should proceed to the next stage of the protocol. FALSE indicates that + * guest should re-try with a different version. + * + * reservedz: Reserved field, set to zero. + */ + +struct dm_version_response { + struct dm_header hdr; + __u64 is_accepted:1; + __u64 reservedz:63; +} __packed; + +/* + * Message reporting capabilities. This is sent from the guest to the + * host. + */ + +struct dm_capabilities { + struct dm_header hdr; + union dm_caps caps; + __u64 min_page_cnt; + __u64 max_page_number; +} __packed; + +/* + * Response to the capabilities message. This is sent from the host to the + * guest. This message notifies if the host has accepted the guest's + * capabilities. If the host has not accepted, the guest must shutdown + * the service. + * + * is_accepted: Indicates if the host has accepted guest's capabilities. + * reservedz: Must be 0. + */ + +struct dm_capabilities_resp_msg { + struct dm_header hdr; + __u64 is_accepted:1; + __u64 reservedz:63; +} __packed; + +/* + * This message is used to report memory pressure from the guest. + * This message is not part of any transaction and there is no + * response to this message. + * + * num_avail: Available memory in pages. + * num_committed: Committed memory in pages. + * page_file_size: The accumulated size of all page files + * in the system in pages. + * zero_free: The nunber of zero and free pages. + * page_file_writes: The writes to the page file in pages. + * io_diff: An indicator of file cache efficiency or page file activity, + * calculated as File Cache Page Fault Count - Page Read Count. + * This value is in pages. + * + * Some of these metrics are Windows specific and fortunately + * the algorithm on the host side that computes the guest memory + * pressure only uses num_committed value. + */ + +struct dm_status { + struct dm_header hdr; + __u64 num_avail; + __u64 num_committed; + __u64 page_file_size; + __u64 zero_free; + __u32 page_file_writes; + __u32 io_diff; +} __packed; + + +/* + * Message to ask the guest to allocate memory - balloon up message. + * This message is sent from the host to the guest. The guest may not be + * able to allocate as much memory as requested. + * + * num_pages: number of pages to allocate. + */ + +struct dm_balloon { + struct dm_header hdr; + __u32 num_pages; + __u32 reservedz; +} __packed; + + +/* + * Balloon response message; this message is sent from the guest + * to the host in response to the balloon message. + * + * reservedz: Reserved; must be set to zero. + * more_pages: If FALSE, this is the last message of the transaction. + * if TRUE there will atleast one more message from the guest. + * + * range_count: The number of ranges in the range array. + * + * range_array: An array of page ranges returned to the host. + * + */ + +struct dm_balloon_response { + struct dm_header hdr; + __u32 reservedz; + __u32 more_pages:1; + __u32 range_count:31; + union dm_mem_page_range range_array[]; +} __packed; + +/* + * Un-balloon message; this message is sent from the host + * to the guest to give guest more memory. + * + * more_pages: If FALSE, this is the last message of the transaction. + * if TRUE there will atleast one more message from the guest. + * + * reservedz: Reserved; must be set to zero. + * + * range_count: The number of ranges in the range array. + * + * range_array: An array of page ranges returned to the host. + * + */ + +struct dm_unballoon_request { + struct dm_header hdr; + __u32 more_pages:1; + __u32 reservedz:31; + __u32 range_count; + union dm_mem_page_range range_array[]; +} __packed; + +/* + * Un-balloon response message; this message is sent from the guest + * to the host in response to an unballoon request. + * + */ + +struct dm_unballoon_response { + struct dm_header hdr; +} __packed; + + +/* + * Hot add request message. Message sent from the host to the guest. + * + * mem_range: Memory range to hot add. + * + * On Linux we currently don't support this since we cannot hot add + * arbitrary granularity of memory. + */ + +struct dm_hot_add { + struct dm_header hdr; + union dm_mem_page_range range; +} __packed; + +/* + * Hot add response message. + * This message is sent by the guest to report the status of a hot add request. + * If page_count is less than the requested page count, then the host should + * assume all further hot add requests will fail, since this indicates that + * the guest has hit an upper physical memory barrier. + * + * Hot adds may also fail due to low resources; in this case, the guest must + * not complete this message until the hot add can succeed, and the host must + * not send a new hot add request until the response is sent. + * If VSC fails to hot add memory DYNMEM_NUMBER_OF_UNSUCCESSFUL_HOTADD_ATTEMPTS + * times it fails the request. + * + * + * page_count: number of pages that were successfully hot added. + * + * result: result of the operation 1: success, 0: failure. + * + */ + +struct dm_hot_add_response { + struct dm_header hdr; + __u32 page_count; + __u32 result; +} __packed; + +/* + * Types of information sent from host to the guest. + */ + +enum dm_info_type { + INFO_TYPE_MAX_PAGE_CNT = 0, + MAX_INFO_TYPE +}; + + +/* + * Header for the information message. + */ + +struct dm_info_header { + enum dm_info_type type; + __u32 data_size; +} __packed; + +/* + * This message is sent from the host to the guest to pass + * some relevant information (win8 addition). + * + * reserved: no used. + * info_size: size of the information blob. + * info: information blob. + */ + +struct dm_info_msg { + struct dm_header hdr; + __u32 reserved; + __u32 info_size; + __u8 info[]; +}; + +/* + * End protocol definitions. + */ + +/* + * State to manage hot adding memory into the guest. + * The range start_pfn : end_pfn specifies the range + * that the host has asked us to hot add. The range + * start_pfn : ha_end_pfn specifies the range that we have + * currently hot added. We hot add in multiples of 128M + * chunks; it is possible that we may not be able to bring + * online all the pages in the region. The range + * covered_end_pfn defines the pages that can + * be brough online. + */ + +struct hv_hotadd_state { + struct list_head list; + unsigned long start_pfn; + unsigned long covered_end_pfn; + unsigned long ha_end_pfn; + unsigned long end_pfn; +}; + +struct balloon_state { + __u32 num_pages; + struct work_struct wrk; +}; + +struct hot_add_wrk { + union dm_mem_page_range ha_page_range; + union dm_mem_page_range ha_region_range; + struct work_struct wrk; +}; + +static bool hot_add = true; +static bool do_hot_add; +/* + * Delay reporting memory pressure by + * the specified number of seconds. + */ +static uint pressure_report_delay = 45; + +/* + * The last time we posted a pressure report to host. + */ +static unsigned long last_post_time; + +module_param(hot_add, bool, (S_IRUGO | S_IWUSR)); +MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add"); + +module_param(pressure_report_delay, uint, (S_IRUGO | S_IWUSR)); +MODULE_PARM_DESC(pressure_report_delay, "Delay in secs in reporting pressure"); +static atomic_t trans_id = ATOMIC_INIT(0); + +static int dm_ring_size = (5 * PAGE_SIZE); + +/* + * Driver specific state. + */ + +enum hv_dm_state { + DM_INITIALIZING = 0, + DM_INITIALIZED, + DM_BALLOON_UP, + DM_BALLOON_DOWN, + DM_HOT_ADD, + DM_INIT_ERROR +}; + + +static __u8 recv_buffer[PAGE_SIZE]; +static __u8 *send_buffer; +#define PAGES_IN_2M 512 +#define HA_CHUNK (32 * 1024) + +struct hv_dynmem_device { + struct hv_device *dev; + enum hv_dm_state state; + struct completion host_event; + struct completion config_event; + + /* + * Number of pages we have currently ballooned out. + */ + unsigned int num_pages_ballooned; + unsigned int num_pages_onlined; + unsigned int num_pages_added; + + /* + * State to manage the ballooning (up) operation. + */ + struct balloon_state balloon_wrk; + + /* + * State to execute the "hot-add" operation. + */ + struct hot_add_wrk ha_wrk; + + /* + * This state tracks if the host has specified a hot-add + * region. + */ + bool host_specified_ha_region; + + /* + * State to synchronize hot-add. + */ + struct completion ol_waitevent; + bool ha_waiting; + /* + * This thread handles hot-add + * requests from the host as well as notifying + * the host with regards to memory pressure in + * the guest. + */ + struct task_struct *thread; + + struct mutex ha_region_mutex; + + /* + * A list of hot-add regions. + */ + struct list_head ha_region_list; + + /* + * We start with the highest version we can support + * and downgrade based on the host; we save here the + * next version to try. + */ + __u32 next_version; +}; + +static struct hv_dynmem_device dm_device; + +static void post_status(struct hv_dynmem_device *dm); + +#ifdef CONFIG_MEMORY_HOTPLUG +static int hv_memory_notifier(struct notifier_block *nb, unsigned long val, + void *v) +{ + struct memory_notify *mem = (struct memory_notify *)v; + + switch (val) { + case MEM_GOING_ONLINE: + mutex_lock(&dm_device.ha_region_mutex); + break; + + case MEM_ONLINE: + dm_device.num_pages_onlined += mem->nr_pages; + case MEM_CANCEL_ONLINE: + mutex_unlock(&dm_device.ha_region_mutex); + if (dm_device.ha_waiting) { + dm_device.ha_waiting = false; + complete(&dm_device.ol_waitevent); + } + break; + + case MEM_OFFLINE: + mutex_lock(&dm_device.ha_region_mutex); + dm_device.num_pages_onlined -= mem->nr_pages; + mutex_unlock(&dm_device.ha_region_mutex); + break; + case MEM_GOING_OFFLINE: + case MEM_CANCEL_OFFLINE: + break; + } + return NOTIFY_OK; +} + +static struct notifier_block hv_memory_nb = { + .notifier_call = hv_memory_notifier, + .priority = 0 +}; + + +static void hv_bring_pgs_online(unsigned long start_pfn, unsigned long size) +{ + int i; + + for (i = 0; i < size; i++) { + struct page *pg; + pg = pfn_to_page(start_pfn + i); + __online_page_set_limits(pg); + __online_page_increment_counters(pg); + __online_page_free(pg); + } +} + +static void hv_mem_hot_add(unsigned long start, unsigned long size, + unsigned long pfn_count, + struct hv_hotadd_state *has) +{ + int ret = 0; + int i, nid; + unsigned long start_pfn; + unsigned long processed_pfn; + unsigned long total_pfn = pfn_count; + + for (i = 0; i < (size/HA_CHUNK); i++) { + start_pfn = start + (i * HA_CHUNK); + has->ha_end_pfn += HA_CHUNK; + + if (total_pfn > HA_CHUNK) { + processed_pfn = HA_CHUNK; + total_pfn -= HA_CHUNK; + } else { + processed_pfn = total_pfn; + total_pfn = 0; + } + + has->covered_end_pfn += processed_pfn; + + init_completion(&dm_device.ol_waitevent); + dm_device.ha_waiting = true; + + mutex_unlock(&dm_device.ha_region_mutex); + nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn)); + ret = add_memory(nid, PFN_PHYS((start_pfn)), + (HA_CHUNK << PAGE_SHIFT)); + + if (ret) { + pr_info("hot_add memory failed error is %d\n", ret); + if (ret == -EEXIST) { + /* + * This error indicates that the error + * is not a transient failure. This is the + * case where the guest's physical address map + * precludes hot adding memory. Stop all further + * memory hot-add. + */ + do_hot_add = false; + } + has->ha_end_pfn -= HA_CHUNK; + has->covered_end_pfn -= processed_pfn; + mutex_lock(&dm_device.ha_region_mutex); + break; + } + + /* + * Wait for the memory block to be onlined. + * Since the hot add has succeeded, it is ok to + * proceed even if the pages in the hot added region + * have not been "onlined" within the allowed time. + */ + wait_for_completion_timeout(&dm_device.ol_waitevent, 5*HZ); + mutex_lock(&dm_device.ha_region_mutex); + post_status(&dm_device); + } + + return; +} + +static void hv_online_page(struct page *pg) +{ + struct list_head *cur; + struct hv_hotadd_state *has; + unsigned long cur_start_pgp; + unsigned long cur_end_pgp; + + list_for_each(cur, &dm_device.ha_region_list) { + has = list_entry(cur, struct hv_hotadd_state, list); + cur_start_pgp = (unsigned long)pfn_to_page(has->start_pfn); + cur_end_pgp = (unsigned long)pfn_to_page(has->covered_end_pfn); + + if (((unsigned long)pg >= cur_start_pgp) && + ((unsigned long)pg < cur_end_pgp)) { + /* + * This frame is currently backed; online the + * page. + */ + __online_page_set_limits(pg); + __online_page_increment_counters(pg); + __online_page_free(pg); + } + } +} + +static bool pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt) +{ + struct list_head *cur; + struct hv_hotadd_state *has; + unsigned long residual, new_inc; + + if (list_empty(&dm_device.ha_region_list)) + return false; + + list_for_each(cur, &dm_device.ha_region_list) { + has = list_entry(cur, struct hv_hotadd_state, list); + + /* + * If the pfn range we are dealing with is not in the current + * "hot add block", move on. + */ + if ((start_pfn >= has->end_pfn)) + continue; + /* + * If the current hot add-request extends beyond + * our current limit; extend it. + */ + if ((start_pfn + pfn_cnt) > has->end_pfn) { + residual = (start_pfn + pfn_cnt - has->end_pfn); + /* + * Extend the region by multiples of HA_CHUNK. + */ + new_inc = (residual / HA_CHUNK) * HA_CHUNK; + if (residual % HA_CHUNK) + new_inc += HA_CHUNK; + + has->end_pfn += new_inc; + } + + /* + * If the current start pfn is not where the covered_end + * is, update it. + */ + + if (has->covered_end_pfn != start_pfn) + has->covered_end_pfn = start_pfn; + + return true; + + } + + return false; +} + +static unsigned long handle_pg_range(unsigned long pg_start, + unsigned long pg_count) +{ + unsigned long start_pfn = pg_start; + unsigned long pfn_cnt = pg_count; + unsigned long size; + struct list_head *cur; + struct hv_hotadd_state *has; + unsigned long pgs_ol = 0; + unsigned long old_covered_state; + + if (list_empty(&dm_device.ha_region_list)) + return 0; + + list_for_each(cur, &dm_device.ha_region_list) { + has = list_entry(cur, struct hv_hotadd_state, list); + + /* + * If the pfn range we are dealing with is not in the current + * "hot add block", move on. + */ + if ((start_pfn >= has->end_pfn)) + continue; + + old_covered_state = has->covered_end_pfn; + + if (start_pfn < has->ha_end_pfn) { + /* + * This is the case where we are backing pages + * in an already hot added region. Bring + * these pages online first. + */ + pgs_ol = has->ha_end_pfn - start_pfn; + if (pgs_ol > pfn_cnt) + pgs_ol = pfn_cnt; + + /* + * Check if the corresponding memory block is already + * online by checking its last previously backed page. + * In case it is we need to bring rest (which was not + * backed previously) online too. + */ + if (start_pfn > has->start_pfn && + !PageReserved(pfn_to_page(start_pfn - 1))) + hv_bring_pgs_online(start_pfn, pgs_ol); + + has->covered_end_pfn += pgs_ol; + pfn_cnt -= pgs_ol; + } + + if ((has->ha_end_pfn < has->end_pfn) && (pfn_cnt > 0)) { + /* + * We have some residual hot add range + * that needs to be hot added; hot add + * it now. Hot add a multiple of + * of HA_CHUNK that fully covers the pages + * we have. + */ + size = (has->end_pfn - has->ha_end_pfn); + if (pfn_cnt <= size) { + size = ((pfn_cnt / HA_CHUNK) * HA_CHUNK); + if (pfn_cnt % HA_CHUNK) + size += HA_CHUNK; + } else { + pfn_cnt = size; + } + hv_mem_hot_add(has->ha_end_pfn, size, pfn_cnt, has); + } + /* + * If we managed to online any pages that were given to us, + * we declare success. + */ + return has->covered_end_pfn - old_covered_state; + + } + + return 0; +} + +static unsigned long process_hot_add(unsigned long pg_start, + unsigned long pfn_cnt, + unsigned long rg_start, + unsigned long rg_size) +{ + struct hv_hotadd_state *ha_region = NULL; + + if (pfn_cnt == 0) + return 0; + + if (!dm_device.host_specified_ha_region) + if (pfn_covered(pg_start, pfn_cnt)) + goto do_pg_range; + + /* + * If the host has specified a hot-add range; deal with it first. + */ + + if (rg_size != 0) { + ha_region = kzalloc(sizeof(struct hv_hotadd_state), GFP_KERNEL); + if (!ha_region) + return 0; + + INIT_LIST_HEAD(&ha_region->list); + + list_add_tail(&ha_region->list, &dm_device.ha_region_list); + ha_region->start_pfn = rg_start; + ha_region->ha_end_pfn = rg_start; + ha_region->covered_end_pfn = pg_start; + ha_region->end_pfn = rg_start + rg_size; + } + +do_pg_range: + /* + * Process the page range specified; bringing them + * online if possible. + */ + return handle_pg_range(pg_start, pfn_cnt); +} + +#endif + +static void hot_add_req(struct work_struct *dummy) +{ + struct dm_hot_add_response resp; +#ifdef CONFIG_MEMORY_HOTPLUG + unsigned long pg_start, pfn_cnt; + unsigned long rg_start, rg_sz; +#endif + struct hv_dynmem_device *dm = &dm_device; + + memset(&resp, 0, sizeof(struct dm_hot_add_response)); + resp.hdr.type = DM_MEM_HOT_ADD_RESPONSE; + resp.hdr.size = sizeof(struct dm_hot_add_response); + +#ifdef CONFIG_MEMORY_HOTPLUG + mutex_lock(&dm_device.ha_region_mutex); + pg_start = dm->ha_wrk.ha_page_range.finfo.start_page; + pfn_cnt = dm->ha_wrk.ha_page_range.finfo.page_cnt; + + rg_start = dm->ha_wrk.ha_region_range.finfo.start_page; + rg_sz = dm->ha_wrk.ha_region_range.finfo.page_cnt; + + if ((rg_start == 0) && (!dm->host_specified_ha_region)) { + unsigned long region_size; + unsigned long region_start; + + /* + * The host has not specified the hot-add region. + * Based on the hot-add page range being specified, + * compute a hot-add region that can cover the pages + * that need to be hot-added while ensuring the alignment + * and size requirements of Linux as it relates to hot-add. + */ + region_start = pg_start; + region_size = (pfn_cnt / HA_CHUNK) * HA_CHUNK; + if (pfn_cnt % HA_CHUNK) + region_size += HA_CHUNK; + + region_start = (pg_start / HA_CHUNK) * HA_CHUNK; + + rg_start = region_start; + rg_sz = region_size; + } + + if (do_hot_add) + resp.page_count = process_hot_add(pg_start, pfn_cnt, + rg_start, rg_sz); + + dm->num_pages_added += resp.page_count; + mutex_unlock(&dm_device.ha_region_mutex); +#endif + /* + * The result field of the response structure has the + * following semantics: + * + * 1. If all or some pages hot-added: Guest should return success. + * + * 2. If no pages could be hot-added: + * + * If the guest returns success, then the host + * will not attempt any further hot-add operations. This + * signifies a permanent failure. + * + * If the guest returns failure, then this failure will be + * treated as a transient failure and the host may retry the + * hot-add operation after some delay. + */ + if (resp.page_count > 0) + resp.result = 1; + else if (!do_hot_add) + resp.result = 1; + else + resp.result = 0; + + if (!do_hot_add || (resp.page_count == 0)) + pr_info("Memory hot add failed\n"); + + dm->state = DM_INITIALIZED; + resp.hdr.trans_id = atomic_inc_return(&trans_id); + vmbus_sendpacket(dm->dev->channel, &resp, + sizeof(struct dm_hot_add_response), + (unsigned long)NULL, + VM_PKT_DATA_INBAND, 0); +} + +static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg) +{ + struct dm_info_header *info_hdr; + + info_hdr = (struct dm_info_header *)msg->info; + + switch (info_hdr->type) { + case INFO_TYPE_MAX_PAGE_CNT: + pr_info("Received INFO_TYPE_MAX_PAGE_CNT\n"); + pr_info("Data Size is %d\n", info_hdr->data_size); + break; + default: + pr_info("Received Unknown type: %d\n", info_hdr->type); + } +} + +static unsigned long compute_balloon_floor(void) +{ + unsigned long min_pages; +#define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT)) + /* Simple continuous piecewiese linear function: + * max MiB -> min MiB gradient + * 0 0 + * 16 16 + * 32 24 + * 128 72 (1/2) + * 512 168 (1/4) + * 2048 360 (1/8) + * 8192 744 (1/16) + * 32768 1512 (1/32) + */ + if (totalram_pages < MB2PAGES(128)) + min_pages = MB2PAGES(8) + (totalram_pages >> 1); + else if (totalram_pages < MB2PAGES(512)) + min_pages = MB2PAGES(40) + (totalram_pages >> 2); + else if (totalram_pages < MB2PAGES(2048)) + min_pages = MB2PAGES(104) + (totalram_pages >> 3); + else if (totalram_pages < MB2PAGES(8192)) + min_pages = MB2PAGES(232) + (totalram_pages >> 4); + else + min_pages = MB2PAGES(488) + (totalram_pages >> 5); +#undef MB2PAGES + return min_pages; +} + +/* + * Post our status as it relates memory pressure to the + * host. Host expects the guests to post this status + * periodically at 1 second intervals. + * + * The metrics specified in this protocol are very Windows + * specific and so we cook up numbers here to convey our memory + * pressure. + */ + +static void post_status(struct hv_dynmem_device *dm) +{ + struct dm_status status; + struct sysinfo val; + unsigned long now = jiffies; + unsigned long last_post = last_post_time; + + if (pressure_report_delay > 0) { + --pressure_report_delay; + return; + } + + if (!time_after(now, (last_post_time + HZ))) + return; + + si_meminfo(&val); + memset(&status, 0, sizeof(struct dm_status)); + status.hdr.type = DM_STATUS_REPORT; + status.hdr.size = sizeof(struct dm_status); + status.hdr.trans_id = atomic_inc_return(&trans_id); + + /* + * The host expects the guest to report free and committed memory. + * Furthermore, the host expects the pressure information to include + * the ballooned out pages. For a given amount of memory that we are + * managing we need to compute a floor below which we should not + * balloon. Compute this and add it to the pressure report. + * We also need to report all offline pages (num_pages_added - + * num_pages_onlined) as committed to the host, otherwise it can try + * asking us to balloon them out. + */ + status.num_avail = val.freeram; + status.num_committed = vm_memory_committed() + + dm->num_pages_ballooned + + (dm->num_pages_added > dm->num_pages_onlined ? + dm->num_pages_added - dm->num_pages_onlined : 0) + + compute_balloon_floor(); + + /* + * If our transaction ID is no longer current, just don't + * send the status. This can happen if we were interrupted + * after we picked our transaction ID. + */ + if (status.hdr.trans_id != atomic_read(&trans_id)) + return; + + /* + * If the last post time that we sampled has changed, + * we have raced, don't post the status. + */ + if (last_post != last_post_time) + return; + + last_post_time = jiffies; + vmbus_sendpacket(dm->dev->channel, &status, + sizeof(struct dm_status), + (unsigned long)NULL, + VM_PKT_DATA_INBAND, 0); + +} + +static void free_balloon_pages(struct hv_dynmem_device *dm, + union dm_mem_page_range *range_array) +{ + int num_pages = range_array->finfo.page_cnt; + __u64 start_frame = range_array->finfo.start_page; + struct page *pg; + int i; + + for (i = 0; i < num_pages; i++) { + pg = pfn_to_page(i + start_frame); + __free_page(pg); + dm->num_pages_ballooned--; + } +} + + + +static unsigned int alloc_balloon_pages(struct hv_dynmem_device *dm, + unsigned int num_pages, + struct dm_balloon_response *bl_resp, + int alloc_unit) +{ + unsigned int i = 0; + struct page *pg; + + if (num_pages < alloc_unit) + return 0; + + for (i = 0; (i * alloc_unit) < num_pages; i++) { + if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) > + PAGE_SIZE) + return i * alloc_unit; + + /* + * We execute this code in a thread context. Furthermore, + * we don't want the kernel to try too hard. + */ + pg = alloc_pages(GFP_HIGHUSER | __GFP_NORETRY | + __GFP_NOMEMALLOC | __GFP_NOWARN, + get_order(alloc_unit << PAGE_SHIFT)); + + if (!pg) + return i * alloc_unit; + + dm->num_pages_ballooned += alloc_unit; + + /* + * If we allocatted 2M pages; split them so we + * can free them in any order we get. + */ + + if (alloc_unit != 1) + split_page(pg, get_order(alloc_unit << PAGE_SHIFT)); + + bl_resp->range_count++; + bl_resp->range_array[i].finfo.start_page = + page_to_pfn(pg); + bl_resp->range_array[i].finfo.page_cnt = alloc_unit; + bl_resp->hdr.size += sizeof(union dm_mem_page_range); + + } + + return num_pages; +} + + + +static void balloon_up(struct work_struct *dummy) +{ + unsigned int num_pages = dm_device.balloon_wrk.num_pages; + unsigned int num_ballooned = 0; + struct dm_balloon_response *bl_resp; + int alloc_unit; + int ret; + bool done = false; + int i; + struct sysinfo val; + unsigned long floor; + + /* The host balloons pages in 2M granularity. */ + WARN_ON_ONCE(num_pages % PAGES_IN_2M != 0); + + /* + * We will attempt 2M allocations. However, if we fail to + * allocate 2M chunks, we will go back to 4k allocations. + */ + alloc_unit = 512; + + si_meminfo(&val); + floor = compute_balloon_floor(); + + /* Refuse to balloon below the floor, keep the 2M granularity. */ + if (val.freeram < num_pages || val.freeram - num_pages < floor) { + num_pages = val.freeram > floor ? (val.freeram - floor) : 0; + num_pages -= num_pages % PAGES_IN_2M; + } + + while (!done) { + bl_resp = (struct dm_balloon_response *)send_buffer; + memset(send_buffer, 0, PAGE_SIZE); + bl_resp->hdr.type = DM_BALLOON_RESPONSE; + bl_resp->hdr.size = sizeof(struct dm_balloon_response); + bl_resp->more_pages = 1; + + + num_pages -= num_ballooned; + num_ballooned = alloc_balloon_pages(&dm_device, num_pages, + bl_resp, alloc_unit); + + if (alloc_unit != 1 && num_ballooned == 0) { + alloc_unit = 1; + continue; + } + + if (num_ballooned == 0 || num_ballooned == num_pages) { + bl_resp->more_pages = 0; + done = true; + dm_device.state = DM_INITIALIZED; + } + + /* + * We are pushing a lot of data through the channel; + * deal with transient failures caused because of the + * lack of space in the ring buffer. + */ + + do { + bl_resp->hdr.trans_id = atomic_inc_return(&trans_id); + ret = vmbus_sendpacket(dm_device.dev->channel, + bl_resp, + bl_resp->hdr.size, + (unsigned long)NULL, + VM_PKT_DATA_INBAND, 0); + + if (ret == -EAGAIN) + msleep(20); + post_status(&dm_device); + } while (ret == -EAGAIN); + + if (ret) { + /* + * Free up the memory we allocatted. + */ + pr_info("Balloon response failed\n"); + + for (i = 0; i < bl_resp->range_count; i++) + free_balloon_pages(&dm_device, + &bl_resp->range_array[i]); + + done = true; + } + } + +} + +static void balloon_down(struct hv_dynmem_device *dm, + struct dm_unballoon_request *req) +{ + union dm_mem_page_range *range_array = req->range_array; + int range_count = req->range_count; + struct dm_unballoon_response resp; + int i; + + for (i = 0; i < range_count; i++) { + free_balloon_pages(dm, &range_array[i]); + complete(&dm_device.config_event); + } + + if (req->more_pages == 1) + return; + + memset(&resp, 0, sizeof(struct dm_unballoon_response)); + resp.hdr.type = DM_UNBALLOON_RESPONSE; + resp.hdr.trans_id = atomic_inc_return(&trans_id); + resp.hdr.size = sizeof(struct dm_unballoon_response); + + vmbus_sendpacket(dm_device.dev->channel, &resp, + sizeof(struct dm_unballoon_response), + (unsigned long)NULL, + VM_PKT_DATA_INBAND, 0); + + dm->state = DM_INITIALIZED; +} + +static void balloon_onchannelcallback(void *context); + +static int dm_thread_func(void *dm_dev) +{ + struct hv_dynmem_device *dm = dm_dev; + + while (!kthread_should_stop()) { + wait_for_completion_interruptible_timeout( + &dm_device.config_event, 1*HZ); + /* + * The host expects us to post information on the memory + * pressure every second. + */ + reinit_completion(&dm_device.config_event); + post_status(dm); + } + + return 0; +} + + +static void version_resp(struct hv_dynmem_device *dm, + struct dm_version_response *vresp) +{ + struct dm_version_request version_req; + int ret; + + if (vresp->is_accepted) { + /* + * We are done; wakeup the + * context waiting for version + * negotiation. + */ + complete(&dm->host_event); + return; + } + /* + * If there are more versions to try, continue + * with negotiations; if not + * shutdown the service since we are not able + * to negotiate a suitable version number + * with the host. + */ + if (dm->next_version == 0) + goto version_error; + + dm->next_version = 0; + memset(&version_req, 0, sizeof(struct dm_version_request)); + version_req.hdr.type = DM_VERSION_REQUEST; + version_req.hdr.size = sizeof(struct dm_version_request); + version_req.hdr.trans_id = atomic_inc_return(&trans_id); + version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN7; + version_req.is_last_attempt = 1; + + ret = vmbus_sendpacket(dm->dev->channel, &version_req, + sizeof(struct dm_version_request), + (unsigned long)NULL, + VM_PKT_DATA_INBAND, 0); + + if (ret) + goto version_error; + + return; + +version_error: + dm->state = DM_INIT_ERROR; + complete(&dm->host_event); +} + +static void cap_resp(struct hv_dynmem_device *dm, + struct dm_capabilities_resp_msg *cap_resp) +{ + if (!cap_resp->is_accepted) { + pr_info("Capabilities not accepted by host\n"); + dm->state = DM_INIT_ERROR; + } + complete(&dm->host_event); +} + +static void balloon_onchannelcallback(void *context) +{ + struct hv_device *dev = context; + u32 recvlen; + u64 requestid; + struct dm_message *dm_msg; + struct dm_header *dm_hdr; + struct hv_dynmem_device *dm = hv_get_drvdata(dev); + struct dm_balloon *bal_msg; + struct dm_hot_add *ha_msg; + union dm_mem_page_range *ha_pg_range; + union dm_mem_page_range *ha_region; + + memset(recv_buffer, 0, sizeof(recv_buffer)); + vmbus_recvpacket(dev->channel, recv_buffer, + PAGE_SIZE, &recvlen, &requestid); + + if (recvlen > 0) { + dm_msg = (struct dm_message *)recv_buffer; + dm_hdr = &dm_msg->hdr; + + switch (dm_hdr->type) { + case DM_VERSION_RESPONSE: + version_resp(dm, + (struct dm_version_response *)dm_msg); + break; + + case DM_CAPABILITIES_RESPONSE: + cap_resp(dm, + (struct dm_capabilities_resp_msg *)dm_msg); + break; + + case DM_BALLOON_REQUEST: + if (dm->state == DM_BALLOON_UP) + pr_warn("Currently ballooning\n"); + bal_msg = (struct dm_balloon *)recv_buffer; + dm->state = DM_BALLOON_UP; + dm_device.balloon_wrk.num_pages = bal_msg->num_pages; + schedule_work(&dm_device.balloon_wrk.wrk); + break; + + case DM_UNBALLOON_REQUEST: + dm->state = DM_BALLOON_DOWN; + balloon_down(dm, + (struct dm_unballoon_request *)recv_buffer); + break; + + case DM_MEM_HOT_ADD_REQUEST: + if (dm->state == DM_HOT_ADD) + pr_warn("Currently hot-adding\n"); + dm->state = DM_HOT_ADD; + ha_msg = (struct dm_hot_add *)recv_buffer; + if (ha_msg->hdr.size == sizeof(struct dm_hot_add)) { + /* + * This is a normal hot-add request specifying + * hot-add memory. + */ + ha_pg_range = &ha_msg->range; + dm->ha_wrk.ha_page_range = *ha_pg_range; + dm->ha_wrk.ha_region_range.page_range = 0; + } else { + /* + * Host is specifying that we first hot-add + * a region and then partially populate this + * region. + */ + dm->host_specified_ha_region = true; + ha_pg_range = &ha_msg->range; + ha_region = &ha_pg_range[1]; + dm->ha_wrk.ha_page_range = *ha_pg_range; + dm->ha_wrk.ha_region_range = *ha_region; + } + schedule_work(&dm_device.ha_wrk.wrk); + break; + + case DM_INFO_MESSAGE: + process_info(dm, (struct dm_info_msg *)dm_msg); + break; + + default: + pr_err("Unhandled message: type: %d\n", dm_hdr->type); + + } + } + +} + +static int balloon_probe(struct hv_device *dev, + const struct hv_vmbus_device_id *dev_id) +{ + int ret; + unsigned long t; + struct dm_version_request version_req; + struct dm_capabilities cap_msg; + + do_hot_add = hot_add; + + /* + * First allocate a send buffer. + */ + + send_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); + if (!send_buffer) + return -ENOMEM; + + ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0, + balloon_onchannelcallback, dev); + + if (ret) + goto probe_error0; + + dm_device.dev = dev; + dm_device.state = DM_INITIALIZING; + dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN7; + init_completion(&dm_device.host_event); + init_completion(&dm_device.config_event); + INIT_LIST_HEAD(&dm_device.ha_region_list); + mutex_init(&dm_device.ha_region_mutex); + INIT_WORK(&dm_device.balloon_wrk.wrk, balloon_up); + INIT_WORK(&dm_device.ha_wrk.wrk, hot_add_req); + dm_device.host_specified_ha_region = false; + + dm_device.thread = + kthread_run(dm_thread_func, &dm_device, "hv_balloon"); + if (IS_ERR(dm_device.thread)) { + ret = PTR_ERR(dm_device.thread); + goto probe_error1; + } + +#ifdef CONFIG_MEMORY_HOTPLUG + set_online_page_callback(&hv_online_page); + register_memory_notifier(&hv_memory_nb); +#endif + + hv_set_drvdata(dev, &dm_device); + /* + * Initiate the hand shake with the host and negotiate + * a version that the host can support. We start with the + * highest version number and go down if the host cannot + * support it. + */ + memset(&version_req, 0, sizeof(struct dm_version_request)); + version_req.hdr.type = DM_VERSION_REQUEST; + version_req.hdr.size = sizeof(struct dm_version_request); + version_req.hdr.trans_id = atomic_inc_return(&trans_id); + version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN8; + version_req.is_last_attempt = 0; + + ret = vmbus_sendpacket(dev->channel, &version_req, + sizeof(struct dm_version_request), + (unsigned long)NULL, + VM_PKT_DATA_INBAND, 0); + if (ret) + goto probe_error2; + + t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); + if (t == 0) { + ret = -ETIMEDOUT; + goto probe_error2; + } + + /* + * If we could not negotiate a compatible version with the host + * fail the probe function. + */ + if (dm_device.state == DM_INIT_ERROR) { + ret = -ETIMEDOUT; + goto probe_error2; + } + /* + * Now submit our capabilities to the host. + */ + memset(&cap_msg, 0, sizeof(struct dm_capabilities)); + cap_msg.hdr.type = DM_CAPABILITIES_REPORT; + cap_msg.hdr.size = sizeof(struct dm_capabilities); + cap_msg.hdr.trans_id = atomic_inc_return(&trans_id); + + cap_msg.caps.cap_bits.balloon = 1; + cap_msg.caps.cap_bits.hot_add = 1; + + /* + * Specify our alignment requirements as it relates + * memory hot-add. Specify 128MB alignment. + */ + cap_msg.caps.cap_bits.hot_add_alignment = 7; + + /* + * Currently the host does not use these + * values and we set them to what is done in the + * Windows driver. + */ + cap_msg.min_page_cnt = 0; + cap_msg.max_page_number = -1; + + ret = vmbus_sendpacket(dev->channel, &cap_msg, + sizeof(struct dm_capabilities), + (unsigned long)NULL, + VM_PKT_DATA_INBAND, 0); + if (ret) + goto probe_error2; + + t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); + if (t == 0) { + ret = -ETIMEDOUT; + goto probe_error2; + } + + /* + * If the host does not like our capabilities, + * fail the probe function. + */ + if (dm_device.state == DM_INIT_ERROR) { + ret = -ETIMEDOUT; + goto probe_error2; + } + + dm_device.state = DM_INITIALIZED; + + return 0; + +probe_error2: +#ifdef CONFIG_MEMORY_HOTPLUG + restore_online_page_callback(&hv_online_page); +#endif + kthread_stop(dm_device.thread); + +probe_error1: + vmbus_close(dev->channel); +probe_error0: + kfree(send_buffer); + return ret; +} + +static int balloon_remove(struct hv_device *dev) +{ + struct hv_dynmem_device *dm = hv_get_drvdata(dev); + struct list_head *cur, *tmp; + struct hv_hotadd_state *has; + + if (dm->num_pages_ballooned != 0) + pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned); + + cancel_work_sync(&dm->balloon_wrk.wrk); + cancel_work_sync(&dm->ha_wrk.wrk); + + vmbus_close(dev->channel); + kthread_stop(dm->thread); + kfree(send_buffer); +#ifdef CONFIG_MEMORY_HOTPLUG + restore_online_page_callback(&hv_online_page); + unregister_memory_notifier(&hv_memory_nb); +#endif + list_for_each_safe(cur, tmp, &dm->ha_region_list) { + has = list_entry(cur, struct hv_hotadd_state, list); + list_del(&has->list); + kfree(has); + } + + return 0; +} + +static const struct hv_vmbus_device_id id_table[] = { + /* Dynamic Memory Class ID */ + /* 525074DC-8985-46e2-8057-A307DC18A502 */ + { HV_DM_GUID, }, + { }, +}; + +MODULE_DEVICE_TABLE(vmbus, id_table); + +static struct hv_driver balloon_drv = { + .name = "hv_balloon", + .id_table = id_table, + .probe = balloon_probe, + .remove = balloon_remove, +}; + +static int __init init_balloon_drv(void) +{ + + return vmbus_driver_register(&balloon_drv); +} + +module_init(init_balloon_drv); + +MODULE_DESCRIPTION("Hyper-V Balloon"); +MODULE_LICENSE("GPL"); |