diff options
Diffstat (limited to 'drivers/hv/hv_balloon.c')
| -rw-r--r-- | drivers/hv/hv_balloon.c | 2166 |
1 files changed, 2166 insertions, 0 deletions
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c new file mode 100644 index 0000000000..e000fa3b9f --- /dev/null +++ b/drivers/hv/hv_balloon.c @@ -0,0 +1,2166 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2012, Microsoft Corporation. + * + * Author: + * K. Y. Srinivasan <kys@microsoft.com> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/cleanup.h> +#include <linux/kernel.h> +#include <linux/jiffies.h> +#include <linux/mman.h> +#include <linux/debugfs.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/count_zeros.h> +#include <linux/memory_hotplug.h> +#include <linux/memory.h> +#include <linux/notifier.h> +#include <linux/percpu_counter.h> +#include <linux/page_reporting.h> + +#include <linux/hyperv.h> +#include <asm/hyperv-tlfs.h> + +#include <asm/mshyperv.h> + +#define CREATE_TRACE_POINTS +#include "hv_trace_balloon.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_3 = DYNMEM_MAKE_VERSION(2, 0), + + DYNMEM_PROTOCOL_VERSION_WIN7 = DYNMEM_PROTOCOL_VERSION_1, + DYNMEM_PROTOCOL_VERSION_WIN8 = DYNMEM_PROTOCOL_VERSION_2, + DYNMEM_PROTOCOL_VERSION_WIN10 = DYNMEM_PROTOCOL_VERSION_3, + + DYNMEM_PROTOCOL_VERSION_CURRENT = DYNMEM_PROTOCOL_VERSION_WIN10 +}; + + + +/* + * 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 number 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. + * + */ + +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_start_pfn: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_start_pfn; + unsigned long covered_end_pfn; + unsigned long ha_end_pfn; + unsigned long end_pfn; + /* + * A list of gaps. + */ + struct list_head gap_list; +}; + +struct hv_hotadd_gap { + struct list_head list; + unsigned long start_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 allow_hibernation; +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; +extern unsigned int page_reporting_order; +#define HV_MAX_FAILURES 2 + +/* + * The last time we posted a pressure report to host. + */ +static unsigned long last_post_time; + +static int hv_hypercall_multi_failure; + +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 = VMBUS_RING_SIZE(16 * 1024); + +/* + * 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[HV_HYP_PAGE_SIZE]; +static __u8 balloon_up_send_buffer[HV_HYP_PAGE_SIZE]; +#define PAGES_IN_2M (2 * 1024 * 1024 / PAGE_SIZE) +#define HA_CHUNK (128 * 1024 * 1024 / PAGE_SIZE) + +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; + /* + * 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; + + /* + * Protects ha_region_list, num_pages_onlined counter and individual + * regions from ha_region_list. + */ + spinlock_t ha_lock; + + /* + * 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; + + /* + * The negotiated version agreed by host. + */ + __u32 version; + + struct page_reporting_dev_info pr_dev_info; + + /* + * Maximum number of pages that can be hot_add-ed + */ + __u64 max_dynamic_page_count; +}; + +static struct hv_dynmem_device dm_device; + +static void post_status(struct hv_dynmem_device *dm); + +static void enable_page_reporting(void); + +static void disable_page_reporting(void); + +#ifdef CONFIG_MEMORY_HOTPLUG +static inline bool has_pfn_is_backed(struct hv_hotadd_state *has, + unsigned long pfn) +{ + struct hv_hotadd_gap *gap; + + /* The page is not backed. */ + if ((pfn < has->covered_start_pfn) || (pfn >= has->covered_end_pfn)) + return false; + + /* Check for gaps. */ + list_for_each_entry(gap, &has->gap_list, list) { + if ((pfn >= gap->start_pfn) && (pfn < gap->end_pfn)) + return false; + } + + return true; +} + +static unsigned long hv_page_offline_check(unsigned long start_pfn, + unsigned long nr_pages) +{ + unsigned long pfn = start_pfn, count = 0; + struct hv_hotadd_state *has; + bool found; + + while (pfn < start_pfn + nr_pages) { + /* + * Search for HAS which covers the pfn and when we find one + * count how many consequitive PFNs are covered. + */ + found = false; + list_for_each_entry(has, &dm_device.ha_region_list, list) { + while ((pfn >= has->start_pfn) && + (pfn < has->end_pfn) && + (pfn < start_pfn + nr_pages)) { + found = true; + if (has_pfn_is_backed(has, pfn)) + count++; + pfn++; + } + } + + /* + * This PFN is not in any HAS (e.g. we're offlining a region + * which was present at boot), no need to account for it. Go + * to the next one. + */ + if (!found) + pfn++; + } + + return count; +} + +static int hv_memory_notifier(struct notifier_block *nb, unsigned long val, + void *v) +{ + struct memory_notify *mem = (struct memory_notify *)v; + unsigned long pfn_count; + + switch (val) { + case MEM_ONLINE: + case MEM_CANCEL_ONLINE: + complete(&dm_device.ol_waitevent); + break; + + case MEM_OFFLINE: + scoped_guard(spinlock_irqsave, &dm_device.ha_lock) { + pfn_count = hv_page_offline_check(mem->start_pfn, + mem->nr_pages); + if (pfn_count <= dm_device.num_pages_onlined) { + dm_device.num_pages_onlined -= pfn_count; + } else { + /* + * We're offlining more pages than we + * managed to online. This is + * unexpected. In any case don't let + * num_pages_onlined wrap around zero. + */ + WARN_ON_ONCE(1); + dm_device.num_pages_onlined = 0; + } + } + break; + case MEM_GOING_ONLINE: + 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 +}; + +/* Check if the particular page is backed and can be onlined and online it. */ +static void hv_page_online_one(struct hv_hotadd_state *has, struct page *pg) +{ + if (!has_pfn_is_backed(has, page_to_pfn(pg))) { + if (!PageOffline(pg)) + __SetPageOffline(pg); + return; + } + if (PageOffline(pg)) + __ClearPageOffline(pg); + + /* This frame is currently backed; online the page. */ + generic_online_page(pg, 0); + + lockdep_assert_held(&dm_device.ha_lock); + dm_device.num_pages_onlined++; +} + +static void hv_bring_pgs_online(struct hv_hotadd_state *has, + unsigned long start_pfn, unsigned long size) +{ + int i; + + pr_debug("Online %lu pages starting at pfn 0x%lx\n", size, start_pfn); + for (i = 0; i < size; i++) + hv_page_online_one(has, pfn_to_page(start_pfn + i)); +} + +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); + + scoped_guard(spinlock_irqsave, &dm_device.ha_lock) { + 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; + } + + reinit_completion(&dm_device.ol_waitevent); + + nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn)); + ret = add_memory(nid, PFN_PHYS((start_pfn)), + (HA_CHUNK << PAGE_SHIFT), MHP_MERGE_RESOURCE); + + if (ret) { + pr_err("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; + } + scoped_guard(spinlock_irqsave, &dm_device.ha_lock) { + has->ha_end_pfn -= HA_CHUNK; + has->covered_end_pfn -= processed_pfn; + } + break; + } + + /* + * Wait for memory to get onlined. If the kernel onlined the + * memory when adding it, this will return directly. Otherwise, + * it will wait for user space to online the memory. This helps + * to avoid adding memory faster than it is getting onlined. As + * adding succeeded, it is ok to proceed even if the memory was + * not onlined in time. + */ + wait_for_completion_timeout(&dm_device.ol_waitevent, 5 * HZ); + post_status(&dm_device); + } +} + +static void hv_online_page(struct page *pg, unsigned int order) +{ + struct hv_hotadd_state *has; + unsigned long pfn = page_to_pfn(pg); + + guard(spinlock_irqsave)(&dm_device.ha_lock); + list_for_each_entry(has, &dm_device.ha_region_list, list) { + /* The page belongs to a different HAS. */ + if ((pfn < has->start_pfn) || + (pfn + (1UL << order) > has->end_pfn)) + continue; + + hv_bring_pgs_online(has, pfn, 1UL << order); + break; + } +} + +static int pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt) +{ + struct hv_hotadd_state *has; + struct hv_hotadd_gap *gap; + unsigned long residual, new_inc; + int ret = 0; + + guard(spinlock_irqsave)(&dm_device.ha_lock); + list_for_each_entry(has, &dm_device.ha_region_list, list) { + /* + * If the pfn range we are dealing with is not in the current + * "hot add block", move on. + */ + if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn) + continue; + + /* + * If the current start pfn is not where the covered_end + * is, create a gap and update covered_end_pfn. + */ + if (has->covered_end_pfn != start_pfn) { + gap = kzalloc(sizeof(struct hv_hotadd_gap), GFP_ATOMIC); + if (!gap) { + ret = -ENOMEM; + break; + } + + INIT_LIST_HEAD(&gap->list); + gap->start_pfn = has->covered_end_pfn; + gap->end_pfn = start_pfn; + list_add_tail(&gap->list, &has->gap_list); + + has->covered_end_pfn = start_pfn; + } + + /* + * 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; + } + + ret = 1; + break; + } + + return ret; +} + +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 hv_hotadd_state *has; + unsigned long pgs_ol = 0; + unsigned long old_covered_state; + unsigned long res = 0, flags; + + pr_debug("Hot adding %lu pages starting at pfn 0x%lx.\n", pg_count, + pg_start); + + spin_lock_irqsave(&dm_device.ha_lock, flags); + list_for_each_entry(has, &dm_device.ha_region_list, list) { + /* + * If the pfn range we are dealing with is not in the current + * "hot add block", move on. + */ + if (start_pfn < has->start_pfn || 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; + + has->covered_end_pfn += pgs_ol; + pfn_cnt -= pgs_ol; + /* + * Check if the corresponding memory block is already + * online. It is possible to observe struct pages still + * being uninitialized here so check section instead. + * In case the section is online we need to bring the + * rest of pfns (which were not backed previously) + * online too. + */ + if (start_pfn > has->start_pfn && + online_section_nr(pfn_to_section_nr(start_pfn))) + hv_bring_pgs_online(has, start_pfn, 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 + * 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; + } + spin_unlock_irqrestore(&dm_device.ha_lock, flags); + hv_mem_hot_add(has->ha_end_pfn, size, pfn_cnt, has); + spin_lock_irqsave(&dm_device.ha_lock, flags); + } + /* + * If we managed to online any pages that were given to us, + * we declare success. + */ + res = has->covered_end_pfn - old_covered_state; + break; + } + spin_unlock_irqrestore(&dm_device.ha_lock, flags); + + return res; +} + +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; + int covered; + + if (pfn_cnt == 0) + return 0; + + if (!dm_device.host_specified_ha_region) { + covered = pfn_covered(pg_start, pfn_cnt); + if (covered < 0) + return 0; + + if (covered) + 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); + INIT_LIST_HEAD(&ha_region->gap_list); + + ha_region->start_pfn = rg_start; + ha_region->ha_end_pfn = rg_start; + ha_region->covered_start_pfn = pg_start; + ha_region->covered_end_pfn = pg_start; + ha_region->end_pfn = rg_start + rg_size; + + scoped_guard(spinlock_irqsave, &dm_device.ha_lock) { + list_add_tail(&ha_region->list, &dm_device.ha_region_list); + } + } + +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 + 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_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; +#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) { + if (!allow_hibernation) + pr_err("Memory hot add failed\n"); + else + pr_info("Ignore hot-add request!\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: + if (info_hdr->data_size == sizeof(__u64)) { + __u64 *max_page_count = (__u64 *)&info_hdr[1]; + + pr_info("Max. dynamic memory size: %llu MB\n", + (*max_page_count) >> (20 - HV_HYP_PAGE_SHIFT)); + dm->max_dynamic_page_count = *max_page_count; + } + + break; + default: + pr_warn("Received Unknown type: %d\n", info_hdr->type); + } +} + +static unsigned long compute_balloon_floor(void) +{ + unsigned long min_pages; + unsigned long nr_pages = totalram_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 (nr_pages < MB2PAGES(128)) + min_pages = MB2PAGES(8) + (nr_pages >> 1); + else if (nr_pages < MB2PAGES(512)) + min_pages = MB2PAGES(40) + (nr_pages >> 2); + else if (nr_pages < MB2PAGES(2048)) + min_pages = MB2PAGES(104) + (nr_pages >> 3); + else if (nr_pages < MB2PAGES(8192)) + min_pages = MB2PAGES(232) + (nr_pages >> 4); + else + min_pages = MB2PAGES(488) + (nr_pages >> 5); +#undef MB2PAGES + return min_pages; +} + +/* + * Compute total committed memory pages + */ + +static unsigned long get_pages_committed(struct hv_dynmem_device *dm) +{ + return 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(); +} + +/* + * 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; + unsigned long now = jiffies; + unsigned long last_post = last_post_time; + unsigned long num_pages_avail, num_pages_committed; + + if (pressure_report_delay > 0) { + --pressure_report_delay; + return; + } + + if (!time_after(now, (last_post_time + HZ))) + return; + + 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. + */ + num_pages_avail = si_mem_available(); + num_pages_committed = get_pages_committed(dm); + + trace_balloon_status(num_pages_avail, num_pages_committed, + vm_memory_committed(), dm->num_pages_ballooned, + dm->num_pages_added, dm->num_pages_onlined); + + /* Convert numbers of pages into numbers of HV_HYP_PAGEs. */ + status.num_avail = num_pages_avail * NR_HV_HYP_PAGES_IN_PAGE; + status.num_committed = num_pages_committed * NR_HV_HYP_PAGES_IN_PAGE; + + /* + * 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); + __ClearPageOffline(pg); + __free_page(pg); + dm->num_pages_ballooned--; + adjust_managed_page_count(pg, 1); + } +} + + + +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, j; + struct page *pg; + + for (i = 0; i < num_pages / alloc_unit; i++) { + if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) > + HV_HYP_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)); + + /* mark all pages offline */ + for (j = 0; j < alloc_unit; j++) { + __SetPageOffline(pg + j); + adjust_managed_page_count(pg + j, -1); + } + + 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 i * alloc_unit; +} + +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; + long avail_pages; + unsigned long floor; + + /* + * We will attempt 2M allocations. However, if we fail to + * allocate 2M chunks, we will go back to PAGE_SIZE allocations. + */ + alloc_unit = PAGES_IN_2M; + + avail_pages = si_mem_available(); + floor = compute_balloon_floor(); + + /* Refuse to balloon below the floor. */ + if (avail_pages < num_pages || avail_pages - num_pages < floor) { + pr_info("Balloon request will be partially fulfilled. %s\n", + avail_pages < num_pages ? "Not enough memory." : + "Balloon floor reached."); + + num_pages = avail_pages > floor ? (avail_pages - floor) : 0; + } + + while (!done) { + memset(balloon_up_send_buffer, 0, HV_HYP_PAGE_SIZE); + bl_resp = (struct dm_balloon_response *)balloon_up_send_buffer; + 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) { + pr_debug("Ballooned %u out of %u requested pages.\n", + num_pages, dm_device.balloon_wrk.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_err("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; + unsigned int prev_pages_ballooned = dm->num_pages_ballooned; + + for (i = 0; i < range_count; i++) { + free_balloon_pages(dm, &range_array[i]); + complete(&dm_device.config_event); + } + + pr_debug("Freed %u ballooned pages.\n", + prev_pages_ballooned - dm->num_pages_ballooned); + + 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); + /* + * disable free page reporting if multiple hypercall + * failure flag set. It is not done in the page_reporting + * callback context as that causes a deadlock between + * page_reporting_process() and page_reporting_unregister() + */ + if (hv_hypercall_multi_failure >= HV_MAX_FAILURES) { + pr_err("Multiple failures in cold memory discard hypercall, disabling page reporting\n"); + disable_page_reporting(); + /* Reset the flag after disabling reporting */ + hv_hypercall_multi_failure = 0; + } + } + + 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; + + 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 = dm->next_version; + dm->version = version_req.version.version; + + /* + * Set the next version to try in case current version fails. + * Win7 protocol ought to be the last one to try. + */ + switch (version_req.version.version) { + case DYNMEM_PROTOCOL_VERSION_WIN8: + dm->next_version = DYNMEM_PROTOCOL_VERSION_WIN7; + version_req.is_last_attempt = 0; + break; + default: + dm->next_version = 0; + 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_err("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, + HV_HYP_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 (allow_hibernation) { + pr_info("Ignore balloon-up request!\n"); + break; + } + + 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: + if (allow_hibernation) { + pr_info("Ignore balloon-down request!\n"); + break; + } + + 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. + */ + dm->host_specified_ha_region = false; + 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_warn_ratelimited("Unhandled message: type: %d\n", dm_hdr->type); + + } + } + +} + +#define HV_LARGE_REPORTING_ORDER 9 +#define HV_LARGE_REPORTING_LEN (HV_HYP_PAGE_SIZE << \ + HV_LARGE_REPORTING_ORDER) +static int hv_free_page_report(struct page_reporting_dev_info *pr_dev_info, + struct scatterlist *sgl, unsigned int nents) +{ + unsigned long flags; + struct hv_memory_hint *hint; + int i, order; + u64 status; + struct scatterlist *sg; + + WARN_ON_ONCE(nents > HV_MEMORY_HINT_MAX_GPA_PAGE_RANGES); + WARN_ON_ONCE(sgl->length < (HV_HYP_PAGE_SIZE << page_reporting_order)); + local_irq_save(flags); + hint = *this_cpu_ptr(hyperv_pcpu_input_arg); + if (!hint) { + local_irq_restore(flags); + return -ENOSPC; + } + + hint->type = HV_EXT_MEMORY_HEAT_HINT_TYPE_COLD_DISCARD; + hint->reserved = 0; + for_each_sg(sgl, sg, nents, i) { + union hv_gpa_page_range *range; + + range = &hint->ranges[i]; + range->address_space = 0; + order = get_order(sg->length); + /* + * Hyper-V expects the additional_pages field in the units + * of one of these 3 sizes, 4Kbytes, 2Mbytes or 1Gbytes. + * This is dictated by the values of the fields page.largesize + * and page_size. + * This code however, only uses 4Kbytes and 2Mbytes units + * and not 1Gbytes unit. + */ + + /* page reporting for pages 2MB or higher */ + if (order >= HV_LARGE_REPORTING_ORDER ) { + range->page.largepage = 1; + range->page_size = HV_GPA_PAGE_RANGE_PAGE_SIZE_2MB; + range->base_large_pfn = page_to_hvpfn( + sg_page(sg)) >> HV_LARGE_REPORTING_ORDER; + range->page.additional_pages = + (sg->length / HV_LARGE_REPORTING_LEN) - 1; + } else { + /* Page reporting for pages below 2MB */ + range->page.basepfn = page_to_hvpfn(sg_page(sg)); + range->page.largepage = false; + range->page.additional_pages = + (sg->length / HV_HYP_PAGE_SIZE) - 1; + } + + } + + status = hv_do_rep_hypercall(HV_EXT_CALL_MEMORY_HEAT_HINT, nents, 0, + hint, NULL); + local_irq_restore(flags); + if (!hv_result_success(status)) { + + pr_err("Cold memory discard hypercall failed with status %llx\n", + status); + if (hv_hypercall_multi_failure > 0) + hv_hypercall_multi_failure++; + + if (hv_result(status) == HV_STATUS_INVALID_PARAMETER) { + pr_err("Underlying Hyper-V does not support order less than 9. Hypercall failed\n"); + pr_err("Defaulting to page_reporting_order %d\n", + pageblock_order); + page_reporting_order = pageblock_order; + hv_hypercall_multi_failure++; + return -EINVAL; + } + + return -EINVAL; + } + + return 0; +} + +static void enable_page_reporting(void) +{ + int ret; + + if (!hv_query_ext_cap(HV_EXT_CAPABILITY_MEMORY_COLD_DISCARD_HINT)) { + pr_debug("Cold memory discard hint not supported by Hyper-V\n"); + return; + } + + BUILD_BUG_ON(PAGE_REPORTING_CAPACITY > HV_MEMORY_HINT_MAX_GPA_PAGE_RANGES); + dm_device.pr_dev_info.report = hv_free_page_report; + /* + * We let the page_reporting_order parameter decide the order + * in the page_reporting code + */ + dm_device.pr_dev_info.order = 0; + ret = page_reporting_register(&dm_device.pr_dev_info); + if (ret < 0) { + dm_device.pr_dev_info.report = NULL; + pr_err("Failed to enable cold memory discard: %d\n", ret); + } else { + pr_info("Cold memory discard hint enabled with order %d\n", + page_reporting_order); + } +} + +static void disable_page_reporting(void) +{ + if (dm_device.pr_dev_info.report) { + page_reporting_unregister(&dm_device.pr_dev_info); + dm_device.pr_dev_info.report = NULL; + } +} + +static int ballooning_enabled(void) +{ + /* + * Disable ballooning if the page size is not 4k (HV_HYP_PAGE_SIZE), + * since currently it's unclear to us whether an unballoon request can + * make sure all page ranges are guest page size aligned. + */ + if (PAGE_SIZE != HV_HYP_PAGE_SIZE) { + pr_info("Ballooning disabled because page size is not 4096 bytes\n"); + return 0; + } + + return 1; +} + +static int hot_add_enabled(void) +{ + /* + * Disable hot add on ARM64, because we currently rely on + * memory_add_physaddr_to_nid() to get a node id of a hot add range, + * however ARM64's memory_add_physaddr_to_nid() always return 0 and + * DM_MEM_HOT_ADD_REQUEST doesn't have the NUMA node information for + * add_memory(). + */ + if (IS_ENABLED(CONFIG_ARM64)) { + pr_info("Memory hot add disabled on ARM64\n"); + return 0; + } + + return 1; +} + +static int balloon_connect_vsp(struct hv_device *dev) +{ + struct dm_version_request version_req; + struct dm_capabilities cap_msg; + unsigned long t; + int ret; + + /* + * max_pkt_size should be large enough for one vmbus packet header plus + * our receive buffer size. Hyper-V sends messages up to + * HV_HYP_PAGE_SIZE bytes long on balloon channel. + */ + dev->channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2; + + ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0, + balloon_onchannelcallback, dev); + if (ret) + return ret; + + /* + * 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_WIN10; + version_req.is_last_attempt = 0; + dm_device.version = version_req.version.version; + + ret = vmbus_sendpacket(dev->channel, &version_req, + sizeof(struct dm_version_request), + (unsigned long)NULL, VM_PKT_DATA_INBAND, 0); + if (ret) + goto out; + + t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); + if (t == 0) { + ret = -ETIMEDOUT; + goto out; + } + + /* + * If we could not negotiate a compatible version with the host + * fail the probe function. + */ + if (dm_device.state == DM_INIT_ERROR) { + ret = -EPROTO; + goto out; + } + + pr_info("Using Dynamic Memory protocol version %u.%u\n", + DYNMEM_MAJOR_VERSION(dm_device.version), + DYNMEM_MINOR_VERSION(dm_device.version)); + + /* + * 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); + + /* + * When hibernation (i.e. virtual ACPI S4 state) is enabled, the host + * currently still requires the bits to be set, so we have to add code + * to fail the host's hot-add and balloon up/down requests, if any. + */ + cap_msg.caps.cap_bits.balloon = ballooning_enabled(); + cap_msg.caps.cap_bits.hot_add = hot_add_enabled(); + + /* + * 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 out; + + t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); + if (t == 0) { + ret = -ETIMEDOUT; + goto out; + } + + /* + * If the host does not like our capabilities, + * fail the probe function. + */ + if (dm_device.state == DM_INIT_ERROR) { + ret = -EPROTO; + goto out; + } + + return 0; +out: + vmbus_close(dev->channel); + return ret; +} + +/* + * DEBUGFS Interface + */ +#ifdef CONFIG_DEBUG_FS + +/** + * hv_balloon_debug_show - shows statistics of balloon operations. + * @f: pointer to the &struct seq_file. + * @offset: ignored. + * + * Provides the statistics that can be accessed in hv-balloon in the debugfs. + * + * Return: zero on success or an error code. + */ +static int hv_balloon_debug_show(struct seq_file *f, void *offset) +{ + struct hv_dynmem_device *dm = f->private; + char *sname; + + seq_printf(f, "%-22s: %u.%u\n", "host_version", + DYNMEM_MAJOR_VERSION(dm->version), + DYNMEM_MINOR_VERSION(dm->version)); + + seq_printf(f, "%-22s:", "capabilities"); + if (ballooning_enabled()) + seq_puts(f, " enabled"); + + if (hot_add_enabled()) + seq_puts(f, " hot_add"); + + seq_puts(f, "\n"); + + seq_printf(f, "%-22s: %u", "state", dm->state); + switch (dm->state) { + case DM_INITIALIZING: + sname = "Initializing"; + break; + case DM_INITIALIZED: + sname = "Initialized"; + break; + case DM_BALLOON_UP: + sname = "Balloon Up"; + break; + case DM_BALLOON_DOWN: + sname = "Balloon Down"; + break; + case DM_HOT_ADD: + sname = "Hot Add"; + break; + case DM_INIT_ERROR: + sname = "Error"; + break; + default: + sname = "Unknown"; + } + seq_printf(f, " (%s)\n", sname); + + /* HV Page Size */ + seq_printf(f, "%-22s: %ld\n", "page_size", HV_HYP_PAGE_SIZE); + + /* Pages added with hot_add */ + seq_printf(f, "%-22s: %u\n", "pages_added", dm->num_pages_added); + + /* pages that are "onlined"/used from pages_added */ + seq_printf(f, "%-22s: %u\n", "pages_onlined", dm->num_pages_onlined); + + /* pages we have given back to host */ + seq_printf(f, "%-22s: %u\n", "pages_ballooned", dm->num_pages_ballooned); + + seq_printf(f, "%-22s: %lu\n", "total_pages_committed", + get_pages_committed(dm)); + + seq_printf(f, "%-22s: %llu\n", "max_dynamic_page_count", + dm->max_dynamic_page_count); + + return 0; +} + +DEFINE_SHOW_ATTRIBUTE(hv_balloon_debug); + +static void hv_balloon_debugfs_init(struct hv_dynmem_device *b) +{ + debugfs_create_file("hv-balloon", 0444, NULL, b, + &hv_balloon_debug_fops); +} + +static void hv_balloon_debugfs_exit(struct hv_dynmem_device *b) +{ + debugfs_lookup_and_remove("hv-balloon", NULL); +} + +#else + +static inline void hv_balloon_debugfs_init(struct hv_dynmem_device *b) +{ +} + +static inline void hv_balloon_debugfs_exit(struct hv_dynmem_device *b) +{ +} + +#endif /* CONFIG_DEBUG_FS */ + +static int balloon_probe(struct hv_device *dev, + const struct hv_vmbus_device_id *dev_id) +{ + int ret; + + allow_hibernation = hv_is_hibernation_supported(); + if (allow_hibernation) + hot_add = false; + +#ifdef CONFIG_MEMORY_HOTPLUG + do_hot_add = hot_add; +#else + do_hot_add = false; +#endif + dm_device.dev = dev; + dm_device.state = DM_INITIALIZING; + dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN8; + init_completion(&dm_device.host_event); + init_completion(&dm_device.config_event); + INIT_LIST_HEAD(&dm_device.ha_region_list); + spin_lock_init(&dm_device.ha_lock); + 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; + +#ifdef CONFIG_MEMORY_HOTPLUG + set_online_page_callback(&hv_online_page); + init_completion(&dm_device.ol_waitevent); + register_memory_notifier(&hv_memory_nb); +#endif + + hv_set_drvdata(dev, &dm_device); + + ret = balloon_connect_vsp(dev); + if (ret != 0) + goto connect_error; + + enable_page_reporting(); + dm_device.state = DM_INITIALIZED; + + 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_error; + } + + hv_balloon_debugfs_init(&dm_device); + + return 0; + +probe_error: + dm_device.state = DM_INIT_ERROR; + dm_device.thread = NULL; + disable_page_reporting(); + vmbus_close(dev->channel); +connect_error: +#ifdef CONFIG_MEMORY_HOTPLUG + unregister_memory_notifier(&hv_memory_nb); + restore_online_page_callback(&hv_online_page); +#endif + return ret; +} + +static void balloon_remove(struct hv_device *dev) +{ + struct hv_dynmem_device *dm = hv_get_drvdata(dev); + struct hv_hotadd_state *has, *tmp; + struct hv_hotadd_gap *gap, *tmp_gap; + + if (dm->num_pages_ballooned != 0) + pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned); + + hv_balloon_debugfs_exit(dm); + + cancel_work_sync(&dm->balloon_wrk.wrk); + cancel_work_sync(&dm->ha_wrk.wrk); + + kthread_stop(dm->thread); + + /* + * This is to handle the case when balloon_resume() + * call has failed and some cleanup has been done as + * a part of the error handling. + */ + if (dm_device.state != DM_INIT_ERROR) { + disable_page_reporting(); + vmbus_close(dev->channel); +#ifdef CONFIG_MEMORY_HOTPLUG + unregister_memory_notifier(&hv_memory_nb); + restore_online_page_callback(&hv_online_page); +#endif + } + + guard(spinlock_irqsave)(&dm_device.ha_lock); + list_for_each_entry_safe(has, tmp, &dm->ha_region_list, list) { + list_for_each_entry_safe(gap, tmp_gap, &has->gap_list, list) { + list_del(&gap->list); + kfree(gap); + } + list_del(&has->list); + kfree(has); + } +} + +static int balloon_suspend(struct hv_device *hv_dev) +{ + struct hv_dynmem_device *dm = hv_get_drvdata(hv_dev); + + tasklet_disable(&hv_dev->channel->callback_event); + + cancel_work_sync(&dm->balloon_wrk.wrk); + cancel_work_sync(&dm->ha_wrk.wrk); + + if (dm->thread) { + kthread_stop(dm->thread); + dm->thread = NULL; + vmbus_close(hv_dev->channel); + } + + tasklet_enable(&hv_dev->channel->callback_event); + + return 0; + +} + +static int balloon_resume(struct hv_device *dev) +{ + int ret; + + dm_device.state = DM_INITIALIZING; + + ret = balloon_connect_vsp(dev); + + if (ret != 0) + goto out; + + dm_device.thread = + kthread_run(dm_thread_func, &dm_device, "hv_balloon"); + if (IS_ERR(dm_device.thread)) { + ret = PTR_ERR(dm_device.thread); + dm_device.thread = NULL; + goto close_channel; + } + + dm_device.state = DM_INITIALIZED; + return 0; +close_channel: + vmbus_close(dev->channel); +out: + dm_device.state = DM_INIT_ERROR; + disable_page_reporting(); +#ifdef CONFIG_MEMORY_HOTPLUG + unregister_memory_notifier(&hv_memory_nb); + restore_online_page_callback(&hv_online_page); +#endif + return ret; +} + +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, + .suspend = balloon_suspend, + .resume = balloon_resume, + .driver = { + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + }, +}; + +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"); |