summaryrefslogtreecommitdiffstats
path: root/drivers/xen
diff options
context:
space:
mode:
authorAnnie Li <annie.li@oracle.com>2011-12-12 18:15:07 +0800
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-12-16 11:25:39 -0500
commit9438ce9dbbf512fd717051284f568d5cb35e5cf1 (patch)
tree53c2abe7dccbf557586cb04319a0f9c6eed3a317 /drivers/xen
parent6666754b11297526c699f8df63c52d50c24fe946 (diff)
downloadlinux-9438ce9dbbf512fd717051284f568d5cb35e5cf1.tar.bz2
xen/granttable: Support transitive grants
These allow a domain A which has been granted access on a page of domain B's memory to issue domain C with a copy-grant on the same page. This is useful e.g. for forwarding packets between domains. Signed-off-by: Annie Li <annie.li@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/grant-table.c70
1 files changed, 70 insertions, 0 deletions
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index c8312c7056f1..a3d0e1e278c1 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -131,6 +131,18 @@ struct gnttab_ops {
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;
@@ -332,6 +344,63 @@ bool gnttab_subpage_grants_available(void)
}
EXPORT_SYMBOL_GPL(gnttab_subpage_grants_available);
+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);
@@ -885,6 +954,7 @@ static struct gnttab_ops gnttab_v2_ops = {
.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)