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ubuntu-linux-kernel/drivers/xen/grant-table.c

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/******************************************************************************
* 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/bootmem.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 <linux/ratelimit.h>
#include <linux/moduleparam.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>
#ifdef CONFIG_X86
#include <asm/xen/cpuid.h>
#endif
#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 unsigned int xen_gnttab_version;
module_param_named(version, xen_gnttab_version, uint, 0);
static union {
struct grant_entry_v1 *v1;
union grant_entry_v2 *v2;
void *addr;
} gnttab_shared;
/*This is a structure of function pointers for grant table*/
struct gnttab_ops {
/*
* Version of the grant interface.
*/
unsigned int version;
/*
* Grant refs per grant frame.
*/
unsigned int grefs_per_grant_frame;
/*
* 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);
};
struct unmap_refs_callback_data {
struct completion completion;
int result;
};
static const struct gnttab_ops *gnttab_interface;
/* This reflects status of grant entries, so act as a global value. */
static grant_status_t *grstatus;
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 and gnttab_update_entry_v2.
* 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;
}
static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
unsigned long frame, unsigned int flags)
{
gnttab_shared.v2[ref].hdr.domid = domid;
gnttab_shared.v2[ref].full_page.frame = frame;
wmb(); /* Hypervisor concurrent accesses. */
gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | 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);
}
static int gnttab_query_foreign_access_v2(grant_ref_t ref)
{
return grstatus[ref] & (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 int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly)
{
gnttab_shared.v2[ref].hdr.flags = 0;
mb(); /* Concurrent access by hypervisor. */
if (grstatus[ref] & (GTF_reading|GTF_writing)) {
return 0;
} else {
/*
* The read of grstatus needs to have acquire semantics.
* On x86, reads already have that, and we just need to
* protect against compiler reorderings.
* On other architectures we may need a full barrier.
*/
#ifdef CONFIG_X86
barrier();
#else
mb();
#endif
}
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(struct timer_list *);
static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred);
static void gnttab_handle_deferred(struct timer_list *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;
}
static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref)
{
unsigned long frame;
u16 flags;
u16 *pflags;
pflags = &gnttab_shared.v2[ref].hdr.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.v2[ref].full_page.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 unsigned int gnttab_frames(unsigned int frames, unsigned int align)
{
return (frames * gnttab_interface->grefs_per_grant_frame + align - 1) /
align;
}
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;
unsigned int grefs_per_frame;
BUG_ON(gnttab_interface == NULL);
grefs_per_frame = gnttab_interface->grefs_per_grant_frame;
new_nr_grant_frames = nr_grant_frames + more_frames;
extra_entries = more_frames * grefs_per_frame;
nr_glist_frames = gnttab_frames(nr_grant_frames, RPP);
new_nr_glist_frames = gnttab_frames(new_nr_grant_frames, 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_frame * nr_grant_frames;
i < grefs_per_frame * new_nr_grant_frames - 1; i++)
gnttab_entry(i) = i + 1;
gnttab_entry(i) = gnttab_free_head;
gnttab_free_head = grefs_per_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, XEN_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] = XEN_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);
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);
void gnttab_foreach_grant_in_range(struct page *page,
unsigned int offset,
unsigned int len,
xen_grant_fn_t fn,
void *data)
{
unsigned int goffset;
unsigned int glen;
unsigned long xen_pfn;
len = min_t(unsigned int, PAGE_SIZE - offset, len);
goffset = xen_offset_in_page(offset);
xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(offset);
while (len) {
glen = min_t(unsigned int, XEN_PAGE_SIZE - goffset, len);
fn(pfn_to_gfn(xen_pfn), goffset, glen, data);
goffset = 0;
xen_pfn++;
len -= glen;
}
}
EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
void gnttab_foreach_grant(struct page **pages,
unsigned int nr_grefs,
xen_grant_fn_t fn,
void *data)
{
unsigned int goffset = 0;
unsigned long xen_pfn = 0;
unsigned int i;
for (i = 0; i < nr_grefs; i++) {
if ((i % XEN_PFN_PER_PAGE) == 0) {
xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
goffset = 0;
}
fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
goffset += XEN_PAGE_SIZE;
xen_pfn++;
}
}
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 void unmap_refs_callback(int result,
struct gntab_unmap_queue_data *data)
{
struct unmap_refs_callback_data *d = data->data;
d->result = result;
complete(&d->completion);
}
int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
{
struct unmap_refs_callback_data data;
init_completion(&data.completion);
item->data = &data;
item->done = &unmap_refs_callback;
gnttab_unmap_refs_async(item);
wait_for_completion(&data.completion);
return data.result;
}
EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
static unsigned int nr_status_frames(unsigned int nr_grant_frames)
{
BUG_ON(gnttab_interface == NULL);
return gnttab_frames(nr_grant_frames, SPP);
}
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_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
{
uint64_t *sframes;
unsigned int nr_sframes;
struct gnttab_get_status_frames getframes;
int rc;
nr_sframes = nr_status_frames(nr_gframes);
/* No need for kzalloc as it is initialized in following hypercall
* GNTTABOP_get_status_frames.
*/
sframes = kmalloc_array(nr_sframes, sizeof(uint64_t), GFP_ATOMIC);
if (!sframes)
return -ENOMEM;
getframes.dom = DOMID_SELF;
getframes.nr_frames = nr_sframes;
set_xen_guest_handle(getframes.frame_list, sframes);
rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
&getframes, 1);
if (rc == -ENOSYS) {
kfree(sframes);
return -ENOSYS;
}
BUG_ON(rc || getframes.status);
rc = arch_gnttab_map_status(sframes, nr_sframes,
nr_status_frames(gnttab_max_grant_frames()),
&grstatus);
BUG_ON(rc);
kfree(sframes);
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_v2(void)
{
arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
arch_gnttab_unmap(grstatus, nr_status_frames(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 const struct gnttab_ops gnttab_v1_ops = {
.version = 1,
.grefs_per_grant_frame = XEN_PAGE_SIZE /
sizeof(struct grant_entry_v1),
.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 const struct gnttab_ops gnttab_v2_ops = {
.version = 2,
.grefs_per_grant_frame = XEN_PAGE_SIZE /
sizeof(union grant_entry_v2),
.map_frames = gnttab_map_frames_v2,
.unmap_frames = gnttab_unmap_frames_v2,
.update_entry = gnttab_update_entry_v2,
.end_foreign_access_ref = gnttab_end_foreign_access_ref_v2,
.end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v2,
.query_foreign_access = gnttab_query_foreign_access_v2,
};
static bool gnttab_need_v2(void)
{
#ifdef CONFIG_X86
uint32_t base, width;
if (xen_pv_domain()) {
base = xen_cpuid_base();
if (cpuid_eax(base) < 5)
return false; /* Information not available, use V1. */
width = cpuid_ebx(base + 5) &
XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
return width > 32 + PAGE_SHIFT;
}
#endif
return !!(max_possible_pfn >> 32);
}
static void gnttab_request_version(void)
{
long rc;
struct gnttab_set_version gsv;
if (gnttab_need_v2())
gsv.version = 2;
else
gsv.version = 1;
/* Boot parameter overrides automatic selection. */
if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
gsv.version = xen_gnttab_version;
rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
if (rc == 0 && gsv.version == 2)
gnttab_interface = &gnttab_v2_ops;
else
gnttab_interface = &gnttab_v1_ops;
pr_info("Grant tables using version %d layout\n",
gnttab_interface->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(gnttab_interface == NULL);
cur = nr_grant_frames;
extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) /
gnttab_interface->grefs_per_grant_frame);
if (cur + extra > gnttab_max_grant_frames()) {
pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
" cur=%u extra=%u limit=%u"
" gnttab_free_count=%u req_entries=%u\n",
cur, extra, gnttab_max_grant_frames(),
gnttab_free_count, req_entries);
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(gnttab_interface == NULL);
max_nr_glist_frames = (max_nr_grant_frames *
gnttab_interface->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 = gnttab_frames(nr_grant_frames, 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,
nr_status_frames(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 *
gnttab_interface->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)
{
if (!xen_domain())
return -ENODEV;
/* Delay grant-table initialization in the PV on HVM case */
if (xen_hvm_domain() && !xen_pvh_domain())
return 0;
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);
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