1
linux/drivers/hv/hv_balloon.c
David Hildenbrand 503b158fc3 mm/memory_hotplug: initialize memmap of !ZONE_DEVICE with PageOffline() instead of PageReserved()
We currently initialize the memmap such that PG_reserved is set and the
refcount of the page is 1.  In virtio-mem code, we have to manually clear
that PG_reserved flag to make memory offlining with partially hotplugged
memory blocks possible: has_unmovable_pages() would otherwise bail out on
such pages.

We want to avoid PG_reserved where possible and move to typed pages
instead.  Further, we want to further enlighten memory offlining code
about PG_offline: offline pages in an online memory section.  One example
is handling managed page count adjustments in a cleaner way during memory
offlining.

So let's initialize the pages with PG_offline instead of PG_reserved. 
generic_online_page()->__free_pages_core() will now clear that flag before
handing that memory to the buddy.

Note that the page refcount is still 1 and would forbid offlining of such
memory except when special care is take during GOING_OFFLINE as currently
only implemented by virtio-mem.

With this change, we can now get non-PageReserved() pages in the XEN
balloon list.  From what I can tell, that can already happen via
decrease_reservation(), so that should be fine.

HV-balloon should not really observe a change: partial online memory
blocks still cannot get surprise-offlined, because the refcount of these
PageOffline() pages is 1.

Update virtio-mem, HV-balloon and XEN-balloon code to be aware that
hotplugged pages are now PageOffline() instead of PageReserved() before
they are handed over to the buddy.

We'll leave the ZONE_DEVICE case alone for now.

Note that self-hosted vmemmap pages will no longer be marked as
reserved.  This matches ordinary vmemmap pages allocated from the buddy
during memory hotplug.  Now, really only vmemmap pages allocated from
memblock during early boot will be marked reserved.  Existing
PageReserved() checks seem to be handling all relevant cases correctly
even after this change.

Link: https://lkml.kernel.org/r/20240607090939.89524-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Oscar Salvador <osalvador@suse.de> [generic memory-hotplug bits]
Cc: Alexander Potapenko <glider@google.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eugenio Pérez <eperezma@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Marco Elver <elver@google.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:18 -07:00

2136 lines
54 KiB
C

// 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/sizes.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 be at least 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 be at least 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 chunks equal to the
* memory block size; 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 brought 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, 0644);
MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add");
module_param(pressure_report_delay, uint, 0644);
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];
static unsigned long ha_pages_in_chunk;
#define HA_BYTES_IN_CHUNK (ha_pages_in_chunk << PAGE_SHIFT)
#define PAGES_IN_2M (2 * 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;
} else if (!PageOffline(pg))
return;
/* 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_pages_in_chunk); i++) {
start_pfn = start + (i * ha_pages_in_chunk);
scoped_guard(spinlock_irqsave, &dm_device.ha_lock) {
has->ha_end_pfn += ha_pages_in_chunk;
processed_pfn = umin(total_pfn, ha_pages_in_chunk);
total_pfn -= processed_pfn;
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_BYTES_IN_CHUNK, 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_pages_in_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;
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) {
/* Extend the region by multiples of ha_pages_in_chunk */
residual = (start_pfn + pfn_cnt - has->end_pfn);
has->end_pfn += ALIGN(residual, ha_pages_in_chunk);
}
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_pages_in_chunk that fully covers the pages
* we have.
*/
size = (has->end_pfn - has->ha_end_pfn);
if (pfn_cnt <= size) {
size = ALIGN(pfn_cnt, ha_pages_in_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) {
/*
* 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.
*/
rg_start = ALIGN_DOWN(pg_start, ha_pages_in_chunk);
rg_sz = ALIGN(pfn_cnt, ha_pages_in_chunk);
}
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 for memory hot-add. The value is
* the log base 2 of the number of megabytes in a chunk. For example,
* with 256 MiB chunks, the value is 8. The number of MiB in a chunk
* must be a power of 2.
*/
cap_msg.caps.cap_bits.hot_add_alignment =
ilog2(HA_BYTES_IN_CHUNK / SZ_1M);
/*
* 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
/*
* Hot-add must operate in chunks that are of size equal to the
* memory block size because that's what the core add_memory()
* interface requires. The Hyper-V interface requires that the memory
* block size be a power of 2, which is guaranteed by the check in
* memory_dev_init().
*/
ha_pages_in_chunk = memory_block_size_bytes() / PAGE_SIZE;
do_hot_add = hot_add;
#else
/*
* Without MEMORY_HOTPLUG, the guest returns a failure status for all
* hot add requests from Hyper-V, and the chunk size is used only to
* specify alignment to Hyper-V as required by the host/guest protocol.
* Somewhat arbitrarily, use 128 MiB.
*/
ha_pages_in_chunk = SZ_128M / PAGE_SIZE;
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");