linux/drivers/xen/grant-table.c
Jennifer Herbert 3f9f1c6757 xen/grant-table: add a mechanism to safely unmap pages that are in use
Introduce gnttab_unmap_refs_async() that can be used to safely unmap
pages that may be in use (ref count > 1).  If the pages are in use the
unmap is deferred and retried later.  This polling is not very clever
but it should be good enough if the cases where the delay is necessary
are rare.

The initial delay is 5 ms and is increased linearly on each subsequent
retry (to reduce load if the page is in use for a long time).

This is needed to allow block backends using grant mapping to safely
use network storage (block or filesystem based such as iSCSI or NFS).

The network storage driver may complete a block request whilst there
is a queued network packet retry (because the ack from the remote end
races with deciding to queue the retry).  The pages for the retried
packet would be grant unmapped and the network driver (or hardware)
would access the unmapped page.

Signed-off-by: Jennifer Herbert <jennifer.herbert@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-28 14:03:14 +00:00

1087 lines
28 KiB
C

/******************************************************************************
* grant_table.c
*
* Granting foreign access to our memory reservation.
*
* Copyright (c) 2005-2006, Christopher Clark
* Copyright (c) 2004-2005, K A Fraser
*
* 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; or, when distributed
* separately from the Linux kernel or incorporated into other
* software packages, subject to the following license:
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this source file (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy, modify,
* merge, publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/hardirq.h>
#include <linux/workqueue.h>
#include <xen/xen.h>
#include <xen/interface/xen.h>
#include <xen/page.h>
#include <xen/grant_table.h>
#include <xen/interface/memory.h>
#include <xen/hvc-console.h>
#include <xen/swiotlb-xen.h>
#include <xen/balloon.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/interface.h>
#include <asm/pgtable.h>
#include <asm/sync_bitops.h>
/* External tools reserve first few grant table entries. */
#define NR_RESERVED_ENTRIES 8
#define GNTTAB_LIST_END 0xffffffff
static grant_ref_t **gnttab_list;
static unsigned int nr_grant_frames;
static int gnttab_free_count;
static grant_ref_t gnttab_free_head;
static DEFINE_SPINLOCK(gnttab_list_lock);
struct grant_frames xen_auto_xlat_grant_frames;
static union {
struct grant_entry_v1 *v1;
void *addr;
} gnttab_shared;
/*This is a structure of function pointers for grant table*/
struct gnttab_ops {
/*
* Mapping a list of frames for storing grant entries. Frames parameter
* is used to store grant table address when grant table being setup,
* nr_gframes is the number of frames to map grant table. Returning
* GNTST_okay means success and negative value means failure.
*/
int (*map_frames)(xen_pfn_t *frames, unsigned int nr_gframes);
/*
* Release a list of frames which are mapped in map_frames for grant
* entry status.
*/
void (*unmap_frames)(void);
/*
* Introducing a valid entry into the grant table, granting the frame of
* this grant entry to domain for accessing or transfering. Ref
* parameter is reference of this introduced grant entry, domid is id of
* granted domain, frame is the page frame to be granted, and flags is
* status of the grant entry to be updated.
*/
void (*update_entry)(grant_ref_t ref, domid_t domid,
unsigned long frame, unsigned flags);
/*
* Stop granting a grant entry to domain for accessing. Ref parameter is
* reference of a grant entry whose grant access will be stopped,
* readonly is not in use in this function. If the grant entry is
* currently mapped for reading or writing, just return failure(==0)
* directly and don't tear down the grant access. Otherwise, stop grant
* access for this entry and return success(==1).
*/
int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);
/*
* Stop granting a grant entry to domain for transfer. Ref parameter is
* reference of a grant entry whose grant transfer will be stopped. If
* tranfer has not started, just reclaim the grant entry and return
* failure(==0). Otherwise, wait for the transfer to complete and then
* return the frame.
*/
unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
/*
* Query the status of a grant entry. Ref parameter is reference of
* queried grant entry, return value is the status of queried entry.
* Detailed status(writing/reading) can be gotten from the return value
* by bit operations.
*/
int (*query_foreign_access)(grant_ref_t ref);
};
static struct gnttab_ops *gnttab_interface;
static int grant_table_version;
static int grefs_per_grant_frame;
static struct gnttab_free_callback *gnttab_free_callback_list;
static int gnttab_expand(unsigned int req_entries);
#define RPP (PAGE_SIZE / sizeof(grant_ref_t))
#define SPP (PAGE_SIZE / sizeof(grant_status_t))
static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
{
return &gnttab_list[(entry) / RPP][(entry) % RPP];
}
/* This can be used as an l-value */
#define gnttab_entry(entry) (*__gnttab_entry(entry))
static int get_free_entries(unsigned count)
{
unsigned long flags;
int ref, rc = 0;
grant_ref_t head;
spin_lock_irqsave(&gnttab_list_lock, flags);
if ((gnttab_free_count < count) &&
((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
spin_unlock_irqrestore(&gnttab_list_lock, flags);
return rc;
}
ref = head = gnttab_free_head;
gnttab_free_count -= count;
while (count-- > 1)
head = gnttab_entry(head);
gnttab_free_head = gnttab_entry(head);
gnttab_entry(head) = GNTTAB_LIST_END;
spin_unlock_irqrestore(&gnttab_list_lock, flags);
return ref;
}
static void do_free_callbacks(void)
{
struct gnttab_free_callback *callback, *next;
callback = gnttab_free_callback_list;
gnttab_free_callback_list = NULL;
while (callback != NULL) {
next = callback->next;
if (gnttab_free_count >= callback->count) {
callback->next = NULL;
callback->fn(callback->arg);
} else {
callback->next = gnttab_free_callback_list;
gnttab_free_callback_list = callback;
}
callback = next;
}
}
static inline void check_free_callbacks(void)
{
if (unlikely(gnttab_free_callback_list))
do_free_callbacks();
}
static void put_free_entry(grant_ref_t ref)
{
unsigned long flags;
spin_lock_irqsave(&gnttab_list_lock, flags);
gnttab_entry(ref) = gnttab_free_head;
gnttab_free_head = ref;
gnttab_free_count++;
check_free_callbacks();
spin_unlock_irqrestore(&gnttab_list_lock, flags);
}
/*
* Following applies to gnttab_update_entry_v1.
* Introducing a valid entry into the grant table:
* 1. Write ent->domid.
* 2. Write ent->frame:
* GTF_permit_access: Frame to which access is permitted.
* GTF_accept_transfer: Pseudo-phys frame slot being filled by new
* frame, or zero if none.
* 3. Write memory barrier (WMB).
* 4. Write ent->flags, inc. valid type.
*/
static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
unsigned long frame, unsigned flags)
{
gnttab_shared.v1[ref].domid = domid;
gnttab_shared.v1[ref].frame = frame;
wmb();
gnttab_shared.v1[ref].flags = flags;
}
/*
* Public grant-issuing interface functions
*/
void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
unsigned long frame, int readonly)
{
gnttab_interface->update_entry(ref, domid, frame,
GTF_permit_access | (readonly ? GTF_readonly : 0));
}
EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
int readonly)
{
int ref;
ref = get_free_entries(1);
if (unlikely(ref < 0))
return -ENOSPC;
gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
return ref;
}
EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
static int gnttab_query_foreign_access_v1(grant_ref_t ref)
{
return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
}
int gnttab_query_foreign_access(grant_ref_t ref)
{
return gnttab_interface->query_foreign_access(ref);
}
EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
{
u16 flags, nflags;
u16 *pflags;
pflags = &gnttab_shared.v1[ref].flags;
nflags = *pflags;
do {
flags = nflags;
if (flags & (GTF_reading|GTF_writing))
return 0;
} while ((nflags = sync_cmpxchg(pflags, flags, 0)) != flags);
return 1;
}
static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
{
return gnttab_interface->end_foreign_access_ref(ref, readonly);
}
int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
{
if (_gnttab_end_foreign_access_ref(ref, readonly))
return 1;
pr_warn("WARNING: g.e. %#x still in use!\n", ref);
return 0;
}
EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
struct deferred_entry {
struct list_head list;
grant_ref_t ref;
bool ro;
uint16_t warn_delay;
struct page *page;
};
static LIST_HEAD(deferred_list);
static void gnttab_handle_deferred(unsigned long);
static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred, 0, 0);
static void gnttab_handle_deferred(unsigned long unused)
{
unsigned int nr = 10;
struct deferred_entry *first = NULL;
unsigned long flags;
spin_lock_irqsave(&gnttab_list_lock, flags);
while (nr--) {
struct deferred_entry *entry
= list_first_entry(&deferred_list,
struct deferred_entry, list);
if (entry == first)
break;
list_del(&entry->list);
spin_unlock_irqrestore(&gnttab_list_lock, flags);
if (_gnttab_end_foreign_access_ref(entry->ref, entry->ro)) {
put_free_entry(entry->ref);
if (entry->page) {
pr_debug("freeing g.e. %#x (pfn %#lx)\n",
entry->ref, page_to_pfn(entry->page));
__free_page(entry->page);
} else
pr_info("freeing g.e. %#x\n", entry->ref);
kfree(entry);
entry = NULL;
} else {
if (!--entry->warn_delay)
pr_info("g.e. %#x still pending\n", entry->ref);
if (!first)
first = entry;
}
spin_lock_irqsave(&gnttab_list_lock, flags);
if (entry)
list_add_tail(&entry->list, &deferred_list);
else if (list_empty(&deferred_list))
break;
}
if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {
deferred_timer.expires = jiffies + HZ;
add_timer(&deferred_timer);
}
spin_unlock_irqrestore(&gnttab_list_lock, flags);
}
static void gnttab_add_deferred(grant_ref_t ref, bool readonly,
struct page *page)
{
struct deferred_entry *entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
const char *what = KERN_WARNING "leaking";
if (entry) {
unsigned long flags;
entry->ref = ref;
entry->ro = readonly;
entry->page = page;
entry->warn_delay = 60;
spin_lock_irqsave(&gnttab_list_lock, flags);
list_add_tail(&entry->list, &deferred_list);
if (!timer_pending(&deferred_timer)) {
deferred_timer.expires = jiffies + HZ;
add_timer(&deferred_timer);
}
spin_unlock_irqrestore(&gnttab_list_lock, flags);
what = KERN_DEBUG "deferring";
}
printk("%s g.e. %#x (pfn %#lx)\n",
what, ref, page ? page_to_pfn(page) : -1);
}
void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
unsigned long page)
{
if (gnttab_end_foreign_access_ref(ref, readonly)) {
put_free_entry(ref);
if (page != 0)
free_page(page);
} else
gnttab_add_deferred(ref, readonly,
page ? virt_to_page(page) : NULL);
}
EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
{
int ref;
ref = get_free_entries(1);
if (unlikely(ref < 0))
return -ENOSPC;
gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
return ref;
}
EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
unsigned long pfn)
{
gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);
}
EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
{
unsigned long frame;
u16 flags;
u16 *pflags;
pflags = &gnttab_shared.v1[ref].flags;
/*
* If a transfer is not even yet started, try to reclaim the grant
* reference and return failure (== 0).
*/
while (!((flags = *pflags) & GTF_transfer_committed)) {
if (sync_cmpxchg(pflags, flags, 0) == flags)
return 0;
cpu_relax();
}
/* If a transfer is in progress then wait until it is completed. */
while (!(flags & GTF_transfer_completed)) {
flags = *pflags;
cpu_relax();
}
rmb(); /* Read the frame number /after/ reading completion status. */
frame = gnttab_shared.v1[ref].frame;
BUG_ON(frame == 0);
return frame;
}
unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
{
return gnttab_interface->end_foreign_transfer_ref(ref);
}
EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
{
unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
put_free_entry(ref);
return frame;
}
EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
void gnttab_free_grant_reference(grant_ref_t ref)
{
put_free_entry(ref);
}
EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
void gnttab_free_grant_references(grant_ref_t head)
{
grant_ref_t ref;
unsigned long flags;
int count = 1;
if (head == GNTTAB_LIST_END)
return;
spin_lock_irqsave(&gnttab_list_lock, flags);
ref = head;
while (gnttab_entry(ref) != GNTTAB_LIST_END) {
ref = gnttab_entry(ref);
count++;
}
gnttab_entry(ref) = gnttab_free_head;
gnttab_free_head = head;
gnttab_free_count += count;
check_free_callbacks();
spin_unlock_irqrestore(&gnttab_list_lock, flags);
}
EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
{
int h = get_free_entries(count);
if (h < 0)
return -ENOSPC;
*head = h;
return 0;
}
EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
int gnttab_empty_grant_references(const grant_ref_t *private_head)
{
return (*private_head == GNTTAB_LIST_END);
}
EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
int gnttab_claim_grant_reference(grant_ref_t *private_head)
{
grant_ref_t g = *private_head;
if (unlikely(g == GNTTAB_LIST_END))
return -ENOSPC;
*private_head = gnttab_entry(g);
return g;
}
EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
void gnttab_release_grant_reference(grant_ref_t *private_head,
grant_ref_t release)
{
gnttab_entry(release) = *private_head;
*private_head = release;
}
EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
void gnttab_request_free_callback(struct gnttab_free_callback *callback,
void (*fn)(void *), void *arg, u16 count)
{
unsigned long flags;
struct gnttab_free_callback *cb;
spin_lock_irqsave(&gnttab_list_lock, flags);
/* Check if the callback is already on the list */
cb = gnttab_free_callback_list;
while (cb) {
if (cb == callback)
goto out;
cb = cb->next;
}
callback->fn = fn;
callback->arg = arg;
callback->count = count;
callback->next = gnttab_free_callback_list;
gnttab_free_callback_list = callback;
check_free_callbacks();
out:
spin_unlock_irqrestore(&gnttab_list_lock, flags);
}
EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
{
struct gnttab_free_callback **pcb;
unsigned long flags;
spin_lock_irqsave(&gnttab_list_lock, flags);
for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
if (*pcb == callback) {
*pcb = callback->next;
break;
}
}
spin_unlock_irqrestore(&gnttab_list_lock, flags);
}
EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
static int grow_gnttab_list(unsigned int more_frames)
{
unsigned int new_nr_grant_frames, extra_entries, i;
unsigned int nr_glist_frames, new_nr_glist_frames;
BUG_ON(grefs_per_grant_frame == 0);
new_nr_grant_frames = nr_grant_frames + more_frames;
extra_entries = more_frames * grefs_per_grant_frame;
nr_glist_frames = (nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
new_nr_glist_frames =
(new_nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
if (!gnttab_list[i])
goto grow_nomem;
}
for (i = grefs_per_grant_frame * nr_grant_frames;
i < grefs_per_grant_frame * new_nr_grant_frames - 1; i++)
gnttab_entry(i) = i + 1;
gnttab_entry(i) = gnttab_free_head;
gnttab_free_head = grefs_per_grant_frame * nr_grant_frames;
gnttab_free_count += extra_entries;
nr_grant_frames = new_nr_grant_frames;
check_free_callbacks();
return 0;
grow_nomem:
while (i-- > nr_glist_frames)
free_page((unsigned long) gnttab_list[i]);
return -ENOMEM;
}
static unsigned int __max_nr_grant_frames(void)
{
struct gnttab_query_size query;
int rc;
query.dom = DOMID_SELF;
rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
if ((rc < 0) || (query.status != GNTST_okay))
return 4; /* Legacy max supported number of frames */
return query.max_nr_frames;
}
unsigned int gnttab_max_grant_frames(void)
{
unsigned int xen_max = __max_nr_grant_frames();
static unsigned int boot_max_nr_grant_frames;
/* First time, initialize it properly. */
if (!boot_max_nr_grant_frames)
boot_max_nr_grant_frames = __max_nr_grant_frames();
if (xen_max > boot_max_nr_grant_frames)
return boot_max_nr_grant_frames;
return xen_max;
}
EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
int gnttab_setup_auto_xlat_frames(phys_addr_t addr)
{
xen_pfn_t *pfn;
unsigned int max_nr_gframes = __max_nr_grant_frames();
unsigned int i;
void *vaddr;
if (xen_auto_xlat_grant_frames.count)
return -EINVAL;
vaddr = xen_remap(addr, PAGE_SIZE * max_nr_gframes);
if (vaddr == NULL) {
pr_warn("Failed to ioremap gnttab share frames (addr=%pa)!\n",
&addr);
return -ENOMEM;
}
pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
if (!pfn) {
xen_unmap(vaddr);
return -ENOMEM;
}
for (i = 0; i < max_nr_gframes; i++)
pfn[i] = PFN_DOWN(addr) + i;
xen_auto_xlat_grant_frames.vaddr = vaddr;
xen_auto_xlat_grant_frames.pfn = pfn;
xen_auto_xlat_grant_frames.count = max_nr_gframes;
return 0;
}
EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
void gnttab_free_auto_xlat_frames(void)
{
if (!xen_auto_xlat_grant_frames.count)
return;
kfree(xen_auto_xlat_grant_frames.pfn);
xen_unmap(xen_auto_xlat_grant_frames.vaddr);
xen_auto_xlat_grant_frames.pfn = NULL;
xen_auto_xlat_grant_frames.count = 0;
xen_auto_xlat_grant_frames.vaddr = NULL;
}
EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
/**
* gnttab_alloc_pages - alloc pages suitable for grant mapping into
* @nr_pages: number of pages to alloc
* @pages: returns the pages
*/
int gnttab_alloc_pages(int nr_pages, struct page **pages)
{
int i;
int ret;
ret = alloc_xenballooned_pages(nr_pages, pages, false);
if (ret < 0)
return ret;
for (i = 0; i < nr_pages; i++) {
#if BITS_PER_LONG < 64
struct xen_page_foreign *foreign;
foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
if (!foreign) {
gnttab_free_pages(nr_pages, pages);
return -ENOMEM;
}
set_page_private(pages[i], (unsigned long)foreign);
#endif
SetPagePrivate(pages[i]);
}
return 0;
}
EXPORT_SYMBOL(gnttab_alloc_pages);
/**
* gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
* @nr_pages; number of pages to free
* @pages: the pages
*/
void gnttab_free_pages(int nr_pages, struct page **pages)
{
int i;
for (i = 0; i < nr_pages; i++) {
if (PagePrivate(pages[i])) {
#if BITS_PER_LONG < 64
kfree((void *)page_private(pages[i]));
#endif
ClearPagePrivate(pages[i]);
}
}
free_xenballooned_pages(nr_pages, pages);
}
EXPORT_SYMBOL(gnttab_free_pages);
/* Handling of paged out grant targets (GNTST_eagain) */
#define MAX_DELAY 256
static inline void
gnttab_retry_eagain_gop(unsigned int cmd, void *gop, int16_t *status,
const char *func)
{
unsigned delay = 1;
do {
BUG_ON(HYPERVISOR_grant_table_op(cmd, gop, 1));
if (*status == GNTST_eagain)
msleep(delay++);
} while ((*status == GNTST_eagain) && (delay < MAX_DELAY));
if (delay >= MAX_DELAY) {
pr_err("%s: %s eagain grant\n", func, current->comm);
*status = GNTST_bad_page;
}
}
void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count)
{
struct gnttab_map_grant_ref *op;
if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, batch, count))
BUG();
for (op = batch; op < batch + count; op++)
if (op->status == GNTST_eagain)
gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, op,
&op->status, __func__);
}
EXPORT_SYMBOL_GPL(gnttab_batch_map);
void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
{
struct gnttab_copy *op;
if (HYPERVISOR_grant_table_op(GNTTABOP_copy, batch, count))
BUG();
for (op = batch; op < batch + count; op++)
if (op->status == GNTST_eagain)
gnttab_retry_eagain_gop(GNTTABOP_copy, op,
&op->status, __func__);
}
EXPORT_SYMBOL_GPL(gnttab_batch_copy);
int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
struct gnttab_map_grant_ref *kmap_ops,
struct page **pages, unsigned int count)
{
int i, ret;
ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
if (ret)
return ret;
for (i = 0; i < count; i++) {
/* Retry eagain maps */
if (map_ops[i].status == GNTST_eagain)
gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i,
&map_ops[i].status, __func__);
if (map_ops[i].status == GNTST_okay) {
struct xen_page_foreign *foreign;
SetPageForeign(pages[i]);
foreign = xen_page_foreign(pages[i]);
foreign->domid = map_ops[i].dom;
foreign->gref = map_ops[i].ref;
}
}
return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);
}
EXPORT_SYMBOL_GPL(gnttab_map_refs);
int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
struct gnttab_unmap_grant_ref *kunmap_ops,
struct page **pages, unsigned int count)
{
unsigned int i;
int ret;
ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
if (ret)
return ret;
for (i = 0; i < count; i++)
ClearPageForeign(pages[i]);
return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);
}
EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
#define GNTTAB_UNMAP_REFS_DELAY 5
static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
static void gnttab_unmap_work(struct work_struct *work)
{
struct gntab_unmap_queue_data
*unmap_data = container_of(work,
struct gntab_unmap_queue_data,
gnttab_work.work);
if (unmap_data->age != UINT_MAX)
unmap_data->age++;
__gnttab_unmap_refs_async(unmap_data);
}
static void __gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
{
int ret;
int pc;
for (pc = 0; pc < item->count; pc++) {
if (page_count(item->pages[pc]) > 1) {
unsigned long delay = GNTTAB_UNMAP_REFS_DELAY * (item->age + 1);
schedule_delayed_work(&item->gnttab_work,
msecs_to_jiffies(delay));
return;
}
}
ret = gnttab_unmap_refs(item->unmap_ops, item->kunmap_ops,
item->pages, item->count);
item->done(ret, item);
}
void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item)
{
INIT_DELAYED_WORK(&item->gnttab_work, gnttab_unmap_work);
item->age = 0;
__gnttab_unmap_refs_async(item);
}
EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
{
int rc;
rc = arch_gnttab_map_shared(frames, nr_gframes,
gnttab_max_grant_frames(),
&gnttab_shared.addr);
BUG_ON(rc);
return 0;
}
static void gnttab_unmap_frames_v1(void)
{
arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
}
static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
{
struct gnttab_setup_table setup;
xen_pfn_t *frames;
unsigned int nr_gframes = end_idx + 1;
int rc;
if (xen_feature(XENFEAT_auto_translated_physmap)) {
struct xen_add_to_physmap xatp;
unsigned int i = end_idx;
rc = 0;
BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
/*
* Loop backwards, so that the first hypercall has the largest
* index, ensuring that the table will grow only once.
*/
do {
xatp.domid = DOMID_SELF;
xatp.idx = i;
xatp.space = XENMAPSPACE_grant_table;
xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
if (rc != 0) {
pr_warn("grant table add_to_physmap failed, err=%d\n",
rc);
break;
}
} while (i-- > start_idx);
return rc;
}
/* No need for kzalloc as it is initialized in following hypercall
* GNTTABOP_setup_table.
*/
frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC);
if (!frames)
return -ENOMEM;
setup.dom = DOMID_SELF;
setup.nr_frames = nr_gframes;
set_xen_guest_handle(setup.frame_list, frames);
rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
if (rc == -ENOSYS) {
kfree(frames);
return -ENOSYS;
}
BUG_ON(rc || setup.status);
rc = gnttab_interface->map_frames(frames, nr_gframes);
kfree(frames);
return rc;
}
static struct gnttab_ops gnttab_v1_ops = {
.map_frames = gnttab_map_frames_v1,
.unmap_frames = gnttab_unmap_frames_v1,
.update_entry = gnttab_update_entry_v1,
.end_foreign_access_ref = gnttab_end_foreign_access_ref_v1,
.end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v1,
.query_foreign_access = gnttab_query_foreign_access_v1,
};
static void gnttab_request_version(void)
{
/* Only version 1 is used, which will always be available. */
grant_table_version = 1;
grefs_per_grant_frame = PAGE_SIZE / sizeof(struct grant_entry_v1);
gnttab_interface = &gnttab_v1_ops;
pr_info("Grant tables using version %d layout\n", grant_table_version);
}
static int gnttab_setup(void)
{
unsigned int max_nr_gframes;
max_nr_gframes = gnttab_max_grant_frames();
if (max_nr_gframes < nr_grant_frames)
return -ENOSYS;
if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
if (gnttab_shared.addr == NULL) {
pr_warn("gnttab share frames (addr=0x%08lx) is not mapped!\n",
(unsigned long)xen_auto_xlat_grant_frames.vaddr);
return -ENOMEM;
}
}
return gnttab_map(0, nr_grant_frames - 1);
}
int gnttab_resume(void)
{
gnttab_request_version();
return gnttab_setup();
}
int gnttab_suspend(void)
{
if (!xen_feature(XENFEAT_auto_translated_physmap))
gnttab_interface->unmap_frames();
return 0;
}
static int gnttab_expand(unsigned int req_entries)
{
int rc;
unsigned int cur, extra;
BUG_ON(grefs_per_grant_frame == 0);
cur = nr_grant_frames;
extra = ((req_entries + (grefs_per_grant_frame-1)) /
grefs_per_grant_frame);
if (cur + extra > gnttab_max_grant_frames())
return -ENOSPC;
rc = gnttab_map(cur, cur + extra - 1);
if (rc == 0)
rc = grow_gnttab_list(extra);
return rc;
}
int gnttab_init(void)
{
int i;
unsigned long max_nr_grant_frames;
unsigned int max_nr_glist_frames, nr_glist_frames;
unsigned int nr_init_grefs;
int ret;
gnttab_request_version();
max_nr_grant_frames = gnttab_max_grant_frames();
nr_grant_frames = 1;
/* Determine the maximum number of frames required for the
* grant reference free list on the current hypervisor.
*/
BUG_ON(grefs_per_grant_frame == 0);
max_nr_glist_frames = (max_nr_grant_frames *
grefs_per_grant_frame / RPP);
gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *),
GFP_KERNEL);
if (gnttab_list == NULL)
return -ENOMEM;
nr_glist_frames = (nr_grant_frames * grefs_per_grant_frame + RPP - 1) / RPP;
for (i = 0; i < nr_glist_frames; i++) {
gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
if (gnttab_list[i] == NULL) {
ret = -ENOMEM;
goto ini_nomem;
}
}
ret = arch_gnttab_init(max_nr_grant_frames);
if (ret < 0)
goto ini_nomem;
if (gnttab_setup() < 0) {
ret = -ENODEV;
goto ini_nomem;
}
nr_init_grefs = nr_grant_frames * grefs_per_grant_frame;
for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
gnttab_entry(i) = i + 1;
gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
gnttab_free_head = NR_RESERVED_ENTRIES;
printk("Grant table initialized\n");
return 0;
ini_nomem:
for (i--; i >= 0; i--)
free_page((unsigned long)gnttab_list[i]);
kfree(gnttab_list);
return ret;
}
EXPORT_SYMBOL_GPL(gnttab_init);
static int __gnttab_init(void)
{
/* Delay grant-table initialization in the PV on HVM case */
if (xen_hvm_domain())
return 0;
if (!xen_pv_domain())
return -ENODEV;
return gnttab_init();
}
/* Starts after core_initcall so that xen_pvh_gnttab_setup can be called
* beforehand to initialize xen_auto_xlat_grant_frames. */
core_initcall_sync(__gnttab_init);