static union {
struct grant_entry_v1 *v1;
- union grant_entry_v2 *v2;
void *addr;
} gnttab_shared;
* by bit operations.
*/
int (*query_foreign_access)(grant_ref_t ref);
- /*
- * Grant a domain to access a range of bytes within the page referred by
- * an available grant entry. Ref parameter is reference of a grant entry
- * which will be sub-page accessed, domid is id of grantee domain, frame
- * is frame address of subpage grant, flags is grant type and flag
- * information, page_off is offset of the range of bytes, and length is
- * length of bytes to be accessed.
- */
- void (*update_subpage_entry)(grant_ref_t ref, domid_t domid,
- unsigned long frame, int flags,
- unsigned page_off, unsigned length);
- /*
- * Redirect an available grant entry on domain A to another grant
- * reference of domain B, then allow domain C to use grant reference
- * of domain B transitively. Ref parameter is an available grant entry
- * reference on domain A, domid is id of domain C which accesses grant
- * entry transitively, flags is grant type and flag information,
- * trans_domid is id of domain B whose grant entry is finally accessed
- * transitively, trans_gref is grant entry transitive reference of
- * domain B.
- */
- void (*update_trans_entry)(grant_ref_t ref, domid_t domid, int flags,
- domid_t trans_domid, grant_ref_t trans_gref);
};
static struct gnttab_ops *gnttab_interface;
-/*This reflects status of grant entries, so act as a global value*/
-static grant_status_t *grstatus;
-
static int grant_table_version;
static int grefs_per_grant_frame;
}
/*
- * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
+ * Following applies to gnttab_update_entry_v1.
* Introducing a valid entry into the grant table:
* 1. Write ent->domid.
* 2. Write ent->frame:
gnttab_shared.v1[ref].flags = flags;
}
-static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
- unsigned long frame, unsigned flags)
-{
- gnttab_shared.v2[ref].hdr.domid = domid;
- gnttab_shared.v2[ref].full_page.frame = frame;
- wmb();
- gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags;
-}
-
/*
* Public grant-issuing interface functions
*/
}
EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
-static void gnttab_update_subpage_entry_v2(grant_ref_t ref, domid_t domid,
- unsigned long frame, int flags,
- unsigned page_off, unsigned length)
-{
- gnttab_shared.v2[ref].sub_page.frame = frame;
- gnttab_shared.v2[ref].sub_page.page_off = page_off;
- gnttab_shared.v2[ref].sub_page.length = length;
- gnttab_shared.v2[ref].hdr.domid = domid;
- wmb();
- gnttab_shared.v2[ref].hdr.flags =
- GTF_permit_access | GTF_sub_page | flags;
-}
-
-int gnttab_grant_foreign_access_subpage_ref(grant_ref_t ref, domid_t domid,
- unsigned long frame, int flags,
- unsigned page_off,
- unsigned length)
-{
- if (flags & (GTF_accept_transfer | GTF_reading |
- GTF_writing | GTF_transitive))
- return -EPERM;
-
- if (gnttab_interface->update_subpage_entry == NULL)
- return -ENOSYS;
-
- gnttab_interface->update_subpage_entry(ref, domid, frame, flags,
- page_off, length);
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_subpage_ref);
-
-int gnttab_grant_foreign_access_subpage(domid_t domid, unsigned long frame,
- int flags, unsigned page_off,
- unsigned length)
-{
- int ref, rc;
-
- ref = get_free_entries(1);
- if (unlikely(ref < 0))
- return -ENOSPC;
-
- rc = gnttab_grant_foreign_access_subpage_ref(ref, domid, frame, flags,
- page_off, length);
- if (rc < 0) {
- put_free_entry(ref);
- return rc;
- }
-
- return ref;
-}
-EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_subpage);
-
-bool gnttab_subpage_grants_available(void)
-{
- return gnttab_interface->update_subpage_entry != NULL;
-}
-EXPORT_SYMBOL_GPL(gnttab_subpage_grants_available);
-
-static void gnttab_update_trans_entry_v2(grant_ref_t ref, domid_t domid,
- int flags, domid_t trans_domid,
- grant_ref_t trans_gref)
-{
- gnttab_shared.v2[ref].transitive.trans_domid = trans_domid;
- gnttab_shared.v2[ref].transitive.gref = trans_gref;
- gnttab_shared.v2[ref].hdr.domid = domid;
- wmb();
- gnttab_shared.v2[ref].hdr.flags =
- GTF_permit_access | GTF_transitive | flags;
-}
-
-int gnttab_grant_foreign_access_trans_ref(grant_ref_t ref, domid_t domid,
- int flags, domid_t trans_domid,
- grant_ref_t trans_gref)
-{
- if (flags & (GTF_accept_transfer | GTF_reading |
- GTF_writing | GTF_sub_page))
- return -EPERM;
-
- if (gnttab_interface->update_trans_entry == NULL)
- return -ENOSYS;
-
- gnttab_interface->update_trans_entry(ref, domid, flags, trans_domid,
- trans_gref);
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_trans_ref);
-
-int gnttab_grant_foreign_access_trans(domid_t domid, int flags,
- domid_t trans_domid,
- grant_ref_t trans_gref)
-{
- int ref, rc;
-
- ref = get_free_entries(1);
- if (unlikely(ref < 0))
- return -ENOSPC;
-
- rc = gnttab_grant_foreign_access_trans_ref(ref, domid, flags,
- trans_domid, trans_gref);
- if (rc < 0) {
- put_free_entry(ref);
- return rc;
- }
-
- return ref;
-}
-EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_trans);
-
-bool gnttab_trans_grants_available(void)
-{
- return gnttab_interface->update_trans_entry != NULL;
-}
-EXPORT_SYMBOL_GPL(gnttab_trans_grants_available);
-
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);
return 1;
}
-static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly)
-{
- gnttab_shared.v2[ref].hdr.flags = 0;
- mb();
- 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);
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);
return 0;
grow_nomem:
- for ( ; i >= nr_glist_frames; i--)
+ while (i-- > nr_glist_frames)
free_page((unsigned long) gnttab_list[i]);
return -ENOMEM;
}
}
EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
-static unsigned nr_status_frames(unsigned nr_grant_frames)
-{
- BUG_ON(grefs_per_grant_frame == 0);
- return (nr_grant_frames * grefs_per_grant_frame + SPP - 1) / SPP;
-}
-
static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
{
int rc;
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(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;
.query_foreign_access = gnttab_query_foreign_access_v1,
};
-static struct gnttab_ops gnttab_v2_ops = {
- .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,
- .update_subpage_entry = gnttab_update_subpage_entry_v2,
- .update_trans_entry = gnttab_update_trans_entry_v2,
-};
-
static void gnttab_request_version(void)
{
- int rc;
- struct gnttab_set_version gsv;
+ /* 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;
- gsv.version = 1;
-
- rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
- if (rc == 0 && gsv.version == 2) {
- grant_table_version = 2;
- grefs_per_grant_frame = PAGE_SIZE / sizeof(union grant_entry_v2);
- gnttab_interface = &gnttab_v2_ops;
- } else if (grant_table_version == 2) {
- /*
- * If we've already used version 2 features,
- * but then suddenly discover that they're not
- * available (e.g. migrating to an older
- * version of Xen), almost unbounded badness
- * can happen.
- */
- panic("we need grant tables version 2, but only version 1 is available");
- } else {
- 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);
}
}
}
- ret = arch_gnttab_init(max_nr_grant_frames,
- nr_status_frames(max_nr_grant_frames));
+ ret = arch_gnttab_init(max_nr_grant_frames);
if (ret < 0)
goto ini_nomem;
projects / cascardo / linux.git / blobdiff