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-rw-r--r--include/xen/interface/grant_table.h167
1 files changed, 162 insertions, 5 deletions
diff --git a/include/xen/interface/grant_table.h b/include/xen/interface/grant_table.h
index 39e571796e32..a17d84433e6a 100644
--- a/include/xen/interface/grant_table.h
+++ b/include/xen/interface/grant_table.h
@@ -85,12 +85,22 @@
*/
/*
+ * Reference to a grant entry in a specified domain's grant table.
+ */
+typedef uint32_t grant_ref_t;
+
+/*
* A grant table comprises a packed array of grant entries in one or more
* page frames shared between Xen and a guest.
* [XEN]: This field is written by Xen and read by the sharing guest.
* [GST]: This field is written by the guest and read by Xen.
*/
-struct grant_entry {
+
+/*
+ * Version 1 of the grant table entry structure is maintained purely
+ * for backwards compatibility. New guests should use version 2.
+ */
+struct grant_entry_v1 {
/* GTF_xxx: various type and flag information. [XEN,GST] */
uint16_t flags;
/* The domain being granted foreign privileges. [GST] */
@@ -108,10 +118,13 @@ struct grant_entry {
* GTF_permit_access: Allow @domid to map/access @frame.
* GTF_accept_transfer: Allow @domid to transfer ownership of one page frame
* to this guest. Xen writes the page number to @frame.
+ * GTF_transitive: Allow @domid to transitively access a subrange of
+ * @trans_grant in @trans_domid. No mappings are allowed.
*/
#define GTF_invalid (0U<<0)
#define GTF_permit_access (1U<<0)
#define GTF_accept_transfer (2U<<0)
+#define GTF_transitive (3U<<0)
#define GTF_type_mask (3U<<0)
/*
@@ -119,6 +132,9 @@ struct grant_entry {
* GTF_readonly: Restrict @domid to read-only mappings and accesses. [GST]
* GTF_reading: Grant entry is currently mapped for reading by @domid. [XEN]
* GTF_writing: Grant entry is currently mapped for writing by @domid. [XEN]
+ * GTF_sub_page: Grant access to only a subrange of the page. @domid
+ * will only be allowed to copy from the grant, and not
+ * map it. [GST]
*/
#define _GTF_readonly (2)
#define GTF_readonly (1U<<_GTF_readonly)
@@ -126,6 +142,8 @@ struct grant_entry {
#define GTF_reading (1U<<_GTF_reading)
#define _GTF_writing (4)
#define GTF_writing (1U<<_GTF_writing)
+#define _GTF_sub_page (8)
+#define GTF_sub_page (1U<<_GTF_sub_page)
/*
* Subflags for GTF_accept_transfer:
@@ -142,15 +160,81 @@ struct grant_entry {
#define _GTF_transfer_completed (3)
#define GTF_transfer_completed (1U<<_GTF_transfer_completed)
+/*
+ * Version 2 grant table entries. These fulfil the same role as
+ * version 1 entries, but can represent more complicated operations.
+ * Any given domain will have either a version 1 or a version 2 table,
+ * and every entry in the table will be the same version.
+ *
+ * The interface by which domains use grant references does not depend
+ * on the grant table version in use by the other domain.
+ */
-/***********************************
- * GRANT TABLE QUERIES AND USES
+/*
+ * Version 1 and version 2 grant entries share a common prefix. The
+ * fields of the prefix are documented as part of struct
+ * grant_entry_v1.
*/
+struct grant_entry_header {
+ uint16_t flags;
+ domid_t domid;
+};
/*
- * Reference to a grant entry in a specified domain's grant table.
+ * Version 2 of the grant entry structure, here is an union because three
+ * different types are suppotted: full_page, sub_page and transitive.
+ */
+union grant_entry_v2 {
+ struct grant_entry_header hdr;
+
+ /*
+ * This member is used for V1-style full page grants, where either:
+ *
+ * -- hdr.type is GTF_accept_transfer, or
+ * -- hdr.type is GTF_permit_access and GTF_sub_page is not set.
+ *
+ * In that case, the frame field has the same semantics as the
+ * field of the same name in the V1 entry structure.
+ */
+ struct {
+ struct grant_entry_header hdr;
+ uint32_t pad0;
+ uint64_t frame;
+ } full_page;
+
+ /*
+ * If the grant type is GTF_grant_access and GTF_sub_page is set,
+ * @domid is allowed to access bytes [@page_off,@page_off+@length)
+ * in frame @frame.
+ */
+ struct {
+ struct grant_entry_header hdr;
+ uint16_t page_off;
+ uint16_t length;
+ uint64_t frame;
+ } sub_page;
+
+ /*
+ * If the grant is GTF_transitive, @domid is allowed to use the
+ * grant @gref in domain @trans_domid, as if it was the local
+ * domain. Obviously, the transitive access must be compatible
+ * with the original grant.
+ */
+ struct {
+ struct grant_entry_header hdr;
+ domid_t trans_domid;
+ uint16_t pad0;
+ grant_ref_t gref;
+ } transitive;
+
+ uint32_t __spacer[4]; /* Pad to a power of two */
+};
+
+typedef uint16_t grant_status_t;
+
+/***********************************
+ * GRANT TABLE QUERIES AND USES
*/
-typedef uint32_t grant_ref_t;
/*
* Handle to track a mapping created via a grant reference.
@@ -322,6 +406,79 @@ struct gnttab_query_size {
DEFINE_GUEST_HANDLE_STRUCT(gnttab_query_size);
/*
+ * GNTTABOP_unmap_and_replace: Destroy one or more grant-reference mappings
+ * tracked by <handle> but atomically replace the page table entry with one
+ * pointing to the machine address under <new_addr>. <new_addr> will be
+ * redirected to the null entry.
+ * NOTES:
+ * 1. The call may fail in an undefined manner if either mapping is not
+ * tracked by <handle>.
+ * 2. After executing a batch of unmaps, it is guaranteed that no stale
+ * mappings will remain in the device or host TLBs.
+ */
+#define GNTTABOP_unmap_and_replace 7
+struct gnttab_unmap_and_replace {
+ /* IN parameters. */
+ uint64_t host_addr;
+ uint64_t new_addr;
+ grant_handle_t handle;
+ /* OUT parameters. */
+ int16_t status; /* GNTST_* */
+};
+DEFINE_GUEST_HANDLE_STRUCT(gnttab_unmap_and_replace);
+
+/*
+ * GNTTABOP_set_version: Request a particular version of the grant
+ * table shared table structure. This operation can only be performed
+ * once in any given domain. It must be performed before any grants
+ * are activated; otherwise, the domain will be stuck with version 1.
+ * The only defined versions are 1 and 2.
+ */
+#define GNTTABOP_set_version 8
+struct gnttab_set_version {
+ /* IN parameters */
+ uint32_t version;
+};
+DEFINE_GUEST_HANDLE_STRUCT(gnttab_set_version);
+
+/*
+ * GNTTABOP_get_status_frames: Get the list of frames used to store grant
+ * status for <dom>. In grant format version 2, the status is separated
+ * from the other shared grant fields to allow more efficient synchronization
+ * using barriers instead of atomic cmpexch operations.
+ * <nr_frames> specify the size of vector <frame_list>.
+ * The frame addresses are returned in the <frame_list>.
+ * Only <nr_frames> addresses are returned, even if the table is larger.
+ * NOTES:
+ * 1. <dom> may be specified as DOMID_SELF.
+ * 2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
+ */
+#define GNTTABOP_get_status_frames 9
+struct gnttab_get_status_frames {
+ /* IN parameters. */
+ uint32_t nr_frames;
+ domid_t dom;
+ /* OUT parameters. */
+ int16_t status; /* GNTST_* */
+ GUEST_HANDLE(uint64_t) frame_list;
+};
+DEFINE_GUEST_HANDLE_STRUCT(gnttab_get_status_frames);
+
+/*
+ * GNTTABOP_get_version: Get the grant table version which is in
+ * effect for domain <dom>.
+ */
+#define GNTTABOP_get_version 10
+struct gnttab_get_version {
+ /* IN parameters */
+ domid_t dom;
+ uint16_t pad;
+ /* OUT parameters */
+ uint32_t version;
+};
+DEFINE_GUEST_HANDLE_STRUCT(gnttab_get_version);
+
+/*
* Bitfield values for update_pin_status.flags.
*/
/* Map the grant entry for access by I/O devices. */