/*
* 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/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_header hdr;
__u32 reserved;
__u32 info_size;
__u8 info[];
};
/*
* End protocol definitions.
*/
static bool hot_add;
static bool do_hot_add;
/*
* Delay reporting memory pressure by
* the specified number of seconds.
*/
static uint pressure_report_delay = 30;
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
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)
{
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);
}
}
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 552 (1/32)
* 32768 1320
* 131072 4392
*/
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
min_pages = MB2PAGES(296) + (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;
if (pressure_report_delay > 0) {
--pressure_report_delay;
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 memory.
* Further, 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.
*/
status.num_avail = val.freeram;
status.num_committed = vm_memory_committed() +
dm->num_pages_ballooned +
compute_balloon_floor();
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 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)
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);
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;
}
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_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;
/*
* 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_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:
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);
if (dm->num_pages_ballooned != 0)
pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned);
vmbus_close(dev->channel);
kthread_stop(dm->thread);
kfree(send_buffer);
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);
}
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");
