diff options
Diffstat (limited to 'drivers/hv/hv_balloon.c')
| -rw-r--r-- | drivers/hv/hv_balloon.c | 1041 |
1 files changed, 1041 insertions, 0 deletions
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c new file mode 100644 index 000000000000..bbc497373aaf --- /dev/null +++ b/drivers/hv/hv_balloon.c @@ -0,0 +1,1041 @@ +/* + * 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/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/mman.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; + __u64 reservedz:62; + } 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_info_header header; + __u32 reserved; + __u32 info_size; + __u8 info[]; +}; + +/* + * End protocol definitions. + */ + +static bool hot_add; +static bool do_hot_add; + +module_param(hot_add, bool, (S_IRUGO | S_IWUSR)); +MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add"); + +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 + +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; + + /* + * This thread handles both balloon/hot-add + * requests from the host as well as notifying + * the host with regards to memory pressure in + * the guest. + */ + struct task_struct *thread; + + /* + * 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 hot_add_req(struct hv_dynmem_device *dm, struct dm_hot_add *msg) +{ + + struct dm_hot_add_response resp; + + if (do_hot_add) { + + pr_info("Memory hot add not supported\n"); + + /* + * Currently we do not support hot add. + * Just fail the request. + */ + } + + 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); + resp.hdr.trans_id = atomic_inc_return(&trans_id); + + resp.page_count = 0; + resp.result = 0; + + dm->state = DM_INITIALIZED; + 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) +{ + switch (msg->header.type) { + case INFO_TYPE_MAX_PAGE_CNT: + pr_info("Received INFO_TYPE_MAX_PAGE_CNT\n"); + pr_info("Data Size is %d\n", msg->header.data_size); + break; + default: + pr_info("Received Unknown type: %d\n", msg->header.type); + } +} + +/* + * 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; + + + 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); + + + status.num_committed = vm_memory_committed(); + + vmbus_sendpacket(dm->dev->channel, &status, + sizeof(struct dm_status), + (unsigned long)NULL, + VM_PKT_DATA_INBAND, 0); + +} + + + +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 int alloc_balloon_pages(struct hv_dynmem_device *dm, int num_pages, + struct dm_balloon_response *bl_resp, int alloc_unit, + bool *alloc_error) +{ + 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) { + *alloc_error = true; + return i * alloc_unit; + } + + + dm->num_pages_ballooned += alloc_unit; + + 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 hv_dynmem_device *dm, struct dm_balloon *req) +{ + int num_pages = req->num_pages; + int num_ballooned = 0; + struct dm_balloon_response *bl_resp; + int alloc_unit; + int ret; + bool alloc_error = false; + bool done = false; + int i; + + + /* + * Currently, we only support 4k allocations. + */ + alloc_unit = 1; + + 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.trans_id = atomic_inc_return(&trans_id); + bl_resp->hdr.size = sizeof(struct dm_balloon_response); + bl_resp->more_pages = 1; + + + num_pages -= num_ballooned; + num_ballooned = alloc_balloon_pages(dm, num_pages, + bl_resp, alloc_unit, + &alloc_error); + + if ((alloc_error) || (num_ballooned == num_pages)) { + bl_resp->more_pages = 0; + done = true; + dm->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 { + 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); + + } 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, + &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]); + + 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; + int t; + unsigned long scan_start; + + while (!kthread_should_stop()) { + t = wait_for_completion_timeout(&dm_device.config_event, 1*HZ); + /* + * The host expects us to post information on the memory + * pressure every second. + */ + + if (t == 0) + post_status(dm); + + scan_start = jiffies; + switch (dm->state) { + case DM_BALLOON_UP: + balloon_up(dm, (struct dm_balloon *)recv_buffer); + break; + + case DM_HOT_ADD: + hot_add_req(dm, (struct dm_hot_add *)recv_buffer); + break; + default: + break; + } + + if (!time_in_range(jiffies, scan_start, scan_start + HZ)) + 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); + + 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: + dm->state = DM_BALLOON_UP; + complete(&dm->config_event); + 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: + dm->state = DM_HOT_ADD; + complete(&dm->config_event); + 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, 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) + return ret; + + 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); + + 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_error0; + } + + 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, + VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); + if (ret) + goto probe_error1; + + t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); + if (t == 0) { + ret = -ETIMEDOUT; + goto probe_error1; + } + + /* + * 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_error1; + } + /* + * 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; + /* + * While we currently don't support hot-add, + * we still advertise this capability since the + * host requires that guests partcipating in the + * dynamic memory protocol support hot add. + */ + cap_msg.caps.cap_bits.hot_add = 1; + + /* + * 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, + VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); + if (ret) + goto probe_error1; + + t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); + if (t == 0) { + ret = -ETIMEDOUT; + goto probe_error1; + } + + /* + * If the host does not like our capabilities, + * fail the probe function. + */ + if (dm_device.state == DM_INIT_ERROR) { + ret = -ETIMEDOUT; + goto probe_error1; + } + + dm_device.state = DM_INITIALIZED; + + return 0; + +probe_error1: + kthread_stop(dm_device.thread); + +probe_error0: + vmbus_close(dev->channel); + return ret; +} + +static int balloon_remove(struct hv_device *dev) +{ + struct hv_dynmem_device *dm = hv_get_drvdata(dev); + + if (dm->num_pages_ballooned != 0) + pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned); + + vmbus_close(dev->channel); + kthread_stop(dm->thread); + + return 0; +} + +static const struct hv_vmbus_device_id id_table[] = { + /* Dynamic Memory Class ID */ + /* 525074DC-8985-46e2-8057-A307DC18A502 */ + { VMBUS_DEVICE(0xdc, 0x74, 0x50, 0X52, 0x85, 0x89, 0xe2, 0x46, + 0x80, 0x57, 0xa3, 0x07, 0xdc, 0x18, 0xa5, 0x02) + }, + { }, +}; + +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); +} + +static void exit_balloon_drv(void) +{ + + vmbus_driver_unregister(&balloon_drv); +} + +module_init(init_balloon_drv); +module_exit(exit_balloon_drv); + +MODULE_DESCRIPTION("Hyper-V Balloon"); +MODULE_VERSION(HV_DRV_VERSION); +MODULE_LICENSE("GPL"); |