linux/include/xen/grant_table.h
Jan Beulich bce21a2b48 Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}
It's not helpful if every driver has to cook its own. Generalize
xenbus'es INVALID_GRANT_HANDLE and pcifront's INVALID_GRANT_REF (which
shouldn't have expanded to zero to begin with). Use the constants in
p2m.c and gntdev.c right away, and update field types where necessary so
they would match with the constants' types (albeit without touching
struct ioctl_gntdev_grant_ref's ref field, as that's part of the public
interface of the kernel and would require introducing a dependency on
Xen's grant_table.h public header).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/db7c38a5-0d75-d5d1-19de-e5fe9f0b9c48@suse.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2021-03-10 16:39:29 -06:00

334 lines
10 KiB
C

/******************************************************************************
* grant_table.h
*
* Two sets of functionality:
* 1. Granting foreign access to our memory reservation.
* 2. Accessing others' memory reservations via grant references.
* (i.e., mechanisms for both sender and recipient of grant references)
*
* Copyright (c) 2004-2005, K A Fraser
* Copyright (c) 2005, Christopher Clark
*
* 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.
*/
#ifndef __ASM_GNTTAB_H__
#define __ASM_GNTTAB_H__
#include <asm/page.h>
#include <xen/interface/xen.h>
#include <xen/interface/grant_table.h>
#include <asm/xen/hypervisor.h>
#include <xen/features.h>
#include <xen/page.h>
#include <linux/mm_types.h>
#include <linux/page-flags.h>
#include <linux/kernel.h>
/*
* Technically there's no reliably invalid grant reference or grant handle,
* so pick the value that is the most unlikely one to be observed valid.
*/
#define INVALID_GRANT_REF ((grant_ref_t)-1)
#define INVALID_GRANT_HANDLE ((grant_handle_t)-1)
#define GNTTAB_RESERVED_XENSTORE 1
/* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */
#define NR_GRANT_FRAMES 4
struct gnttab_free_callback {
struct gnttab_free_callback *next;
void (*fn)(void *);
void *arg;
u16 count;
};
struct gntab_unmap_queue_data;
typedef void (*gnttab_unmap_refs_done)(int result, struct gntab_unmap_queue_data *data);
struct gntab_unmap_queue_data
{
struct delayed_work gnttab_work;
void *data;
gnttab_unmap_refs_done done;
struct gnttab_unmap_grant_ref *unmap_ops;
struct gnttab_unmap_grant_ref *kunmap_ops;
struct page **pages;
unsigned int count;
unsigned int age;
};
int gnttab_init(void);
int gnttab_suspend(void);
int gnttab_resume(void);
int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
int readonly);
/*
* End access through the given grant reference, iff the grant entry is no
* longer in use. Return 1 if the grant entry was freed, 0 if it is still in
* use.
*/
int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly);
/*
* Eventually end access through the given grant reference, and once that
* access has been ended, free the given page too. Access will be ended
* immediately iff the grant entry is not in use, otherwise it will happen
* some time later. page may be 0, in which case no freeing will occur.
*/
void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
unsigned long page);
int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn);
unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref);
unsigned long gnttab_end_foreign_transfer(grant_ref_t ref);
int gnttab_query_foreign_access(grant_ref_t ref);
/*
* operations on reserved batches of grant references
*/
int gnttab_alloc_grant_references(u16 count, grant_ref_t *pprivate_head);
void gnttab_free_grant_reference(grant_ref_t ref);
void gnttab_free_grant_references(grant_ref_t head);
int gnttab_empty_grant_references(const grant_ref_t *pprivate_head);
int gnttab_claim_grant_reference(grant_ref_t *pprivate_head);
void gnttab_release_grant_reference(grant_ref_t *private_head,
grant_ref_t release);
void gnttab_request_free_callback(struct gnttab_free_callback *callback,
void (*fn)(void *), void *arg, u16 count);
void gnttab_cancel_free_callback(struct gnttab_free_callback *callback);
void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
unsigned long frame, int readonly);
/* Give access to the first 4K of the page */
static inline void gnttab_page_grant_foreign_access_ref_one(
grant_ref_t ref, domid_t domid,
struct page *page, int readonly)
{
gnttab_grant_foreign_access_ref(ref, domid, xen_page_to_gfn(page),
readonly);
}
void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
unsigned long pfn);
static inline void
gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr,
uint32_t flags, grant_ref_t ref, domid_t domid)
{
if (flags & GNTMAP_contains_pte)
map->host_addr = addr;
else if (xen_feature(XENFEAT_auto_translated_physmap))
map->host_addr = __pa(addr);
else
map->host_addr = addr;
map->flags = flags;
map->ref = ref;
map->dom = domid;
map->status = 1; /* arbitrary positive value */
}
static inline void
gnttab_set_unmap_op(struct gnttab_unmap_grant_ref *unmap, phys_addr_t addr,
uint32_t flags, grant_handle_t handle)
{
if (flags & GNTMAP_contains_pte)
unmap->host_addr = addr;
else if (xen_feature(XENFEAT_auto_translated_physmap))
unmap->host_addr = __pa(addr);
else
unmap->host_addr = addr;
unmap->handle = handle;
unmap->dev_bus_addr = 0;
}
int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status);
int arch_gnttab_map_shared(xen_pfn_t *frames, unsigned long nr_gframes,
unsigned long max_nr_gframes,
void **__shared);
int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
unsigned long max_nr_gframes,
grant_status_t **__shared);
void arch_gnttab_unmap(void *shared, unsigned long nr_gframes);
struct grant_frames {
xen_pfn_t *pfn;
unsigned int count;
void *vaddr;
};
extern struct grant_frames xen_auto_xlat_grant_frames;
unsigned int gnttab_max_grant_frames(void);
int gnttab_setup_auto_xlat_frames(phys_addr_t addr);
void gnttab_free_auto_xlat_frames(void);
#define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
int gnttab_alloc_pages(int nr_pages, struct page **pages);
void gnttab_free_pages(int nr_pages, struct page **pages);
struct gnttab_page_cache {
spinlock_t lock;
#ifdef CONFIG_XEN_UNPOPULATED_ALLOC
struct page *pages;
#else
struct list_head pages;
#endif
unsigned int num_pages;
};
void gnttab_page_cache_init(struct gnttab_page_cache *cache);
int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page);
void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
unsigned int num);
void gnttab_page_cache_shrink(struct gnttab_page_cache *cache,
unsigned int num);
#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
struct gnttab_dma_alloc_args {
/* Device for which DMA memory will be/was allocated. */
struct device *dev;
/* If set then DMA buffer is coherent and write-combine otherwise. */
bool coherent;
int nr_pages;
struct page **pages;
xen_pfn_t *frames;
void *vaddr;
dma_addr_t dev_bus_addr;
};
int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args);
int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args);
#endif
int gnttab_pages_set_private(int nr_pages, struct page **pages);
void gnttab_pages_clear_private(int nr_pages, struct page **pages);
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 gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
struct gnttab_unmap_grant_ref *kunmap_ops,
struct page **pages, unsigned int count);
void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item);
/* Perform a batch of grant map/copy operations. Retry every batch slot
* for which the hypervisor returns GNTST_eagain. This is typically due
* to paged out target frames.
*
* Will retry for 1, 2, ... 255 ms, i.e. 256 times during 32 seconds.
*
* Return value in each iand every status field of the batch guaranteed
* to not be GNTST_eagain.
*/
void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count);
void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count);
struct xen_page_foreign {
domid_t domid;
grant_ref_t gref;
};
static inline struct xen_page_foreign *xen_page_foreign(struct page *page)
{
if (!PageForeign(page))
return NULL;
#if BITS_PER_LONG < 64
return (struct xen_page_foreign *)page->private;
#else
BUILD_BUG_ON(sizeof(struct xen_page_foreign) > BITS_PER_LONG);
return (struct xen_page_foreign *)&page->private;
#endif
}
/* Split Linux page in chunk of the size of the grant and call fn
*
* Parameters of fn:
* gfn: guest frame number
* offset: offset in the grant
* len: length of the data in the grant.
* data: internal information
*/
typedef void (*xen_grant_fn_t)(unsigned long gfn, unsigned int offset,
unsigned int len, void *data);
void gnttab_foreach_grant_in_range(struct page *page,
unsigned int offset,
unsigned int len,
xen_grant_fn_t fn,
void *data);
/* Helper to get to call fn only on the first "grant chunk" */
static inline void gnttab_for_one_grant(struct page *page, unsigned int offset,
unsigned len, xen_grant_fn_t fn,
void *data)
{
/* The first request is limited to the size of one grant */
len = min_t(unsigned int, XEN_PAGE_SIZE - (offset & ~XEN_PAGE_MASK),
len);
gnttab_foreach_grant_in_range(page, offset, len, fn, data);
}
/* Get @nr_grefs grants from an array of page and call fn for each grant */
void gnttab_foreach_grant(struct page **pages,
unsigned int nr_grefs,
xen_grant_fn_t fn,
void *data);
/* Get the number of grant in a specified region
*
* start: Offset from the beginning of the first page
* len: total length of data (can cross multiple page)
*/
static inline unsigned int gnttab_count_grant(unsigned int start,
unsigned int len)
{
return XEN_PFN_UP(xen_offset_in_page(start) + len);
}
#endif /* __ASM_GNTTAB_H__ */