xen/grant-table: remove support for V2 tables

Since 11c7ff17c9b6dbf3a4e4f36be30ad531a6cf0ec9 (xen/grant-table: Force
to use v1 of grants.) the code for V2 grant tables is not used.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

arch/arm/xen/grant-table.c

@@ -45,14 +45,7 @@ void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
 	return;
 }
 
-int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
+int arch_gnttab_init(unsigned long nr_shared)
-			   unsigned long max_nr_gframes,
-			   grant_status_t **__shared)
-{
-	return -ENOSYS;
-}
-
-int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status)
 {
 	return 0;
 }

arch/x86/xen/grant-table.c

@@ -49,7 +49,7 @@
 static struct gnttab_vm_area {
 	struct vm_struct *area;
 	pte_t **ptes;
-} gnttab_shared_vm_area, gnttab_status_vm_area;
+} gnttab_shared_vm_area;
 
 int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
 			   unsigned long max_nr_gframes,
@@ -73,43 +73,16 @@ int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
 	return 0;
 }
 
-int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
-			   unsigned long max_nr_gframes,
-			   grant_status_t **__shared)
-{
-	grant_status_t *shared = *__shared;
-	unsigned long addr;
-	unsigned long i;
-
-	if (shared == NULL)
-		*__shared = shared = gnttab_status_vm_area.area->addr;
-
-	addr = (unsigned long)shared;
-
-	for (i = 0; i < nr_gframes; i++) {
-		set_pte_at(&init_mm, addr, gnttab_status_vm_area.ptes[i],
-			   mfn_pte(frames[i], PAGE_KERNEL));
-		addr += PAGE_SIZE;
-	}
-
-	return 0;
-}
-
 void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
 {
-	pte_t **ptes;
 	unsigned long addr;
 	unsigned long i;
 
-	if (shared == gnttab_status_vm_area.area->addr)
-		ptes = gnttab_status_vm_area.ptes;
-	else
-		ptes = gnttab_shared_vm_area.ptes;
-
 	addr = (unsigned long)shared;
 
 	for (i = 0; i < nr_gframes; i++) {
-		set_pte_at(&init_mm, addr, ptes[i], __pte(0));
+		set_pte_at(&init_mm, addr, gnttab_shared_vm_area.ptes[i],
+			   __pte(0));
 		addr += PAGE_SIZE;
 	}
 }
@@ -129,35 +102,12 @@ static int arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames)
 	return 0;
 }
 
-static void arch_gnttab_vfree(struct gnttab_vm_area *area)
+int arch_gnttab_init(unsigned long nr_shared)
 {
-	free_vm_area(area->area);
-	kfree(area->ptes);
-}
-
-int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status)
-{
-	int ret;
-
 	if (!xen_pv_domain())
 		return 0;
 
-	ret = arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared);
+	return arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared);
-	if (ret < 0)
-		return ret;
-
-	/*
-	 * Always allocate the space for the status frames in case
-	 * we're migrated to a host with V2 support.
-	 */
-	ret = arch_gnttab_valloc(&gnttab_status_vm_area, nr_status);
-	if (ret < 0)
-		goto err;
-
-	return 0;
-  err:
-	arch_gnttab_vfree(&gnttab_shared_vm_area);
-	return -ENOMEM;
 }
 
 #ifdef CONFIG_XEN_PVH

drivers/xen/grant-table.c

@@ -69,7 +69,6 @@ struct grant_frames xen_auto_xlat_grant_frames;
 
 static union {
 	struct grant_entry_v1 *v1;
-	union grant_entry_v2 *v2;
 	void *addr;
 } gnttab_shared;
 
@@ -120,36 +119,10 @@ struct gnttab_ops {
 	 * 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;
 
@@ -231,7 +204,7 @@ static void put_free_entry(grant_ref_t ref)
 }
 
 /*
- * 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:
@@ -250,15 +223,6 @@ static void gnttab_update_entry_v1(grant_ref_t ref, domid_t domid,
 	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
  */
@@ -285,132 +249,11 @@ int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
 }
 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);
@@ -433,29 +276,6 @@ static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
 	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);
@@ -616,37 +436,6 @@ static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
 	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);
@@ -962,12 +751,6 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
 }
 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;
@@ -985,55 +768,6 @@ 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(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;
@@ -1101,43 +835,13 @@ static struct gnttab_ops gnttab_v1_ops = {
 	.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;
+	/* Only version 1 is used, which will always be available. */
-	struct gnttab_set_version gsv;
+	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);
 }
 
@@ -1225,8 +929,7 @@ int gnttab_init(void)
 		}
 	}
 
-	ret = arch_gnttab_init(max_nr_grant_frames,
+	ret = arch_gnttab_init(max_nr_grant_frames);
-			       nr_status_frames(max_nr_grant_frames));
 	if (ret < 0)
 		goto ini_nomem;
 

include/xen/grant_table.h

@@ -64,24 +64,6 @@ int gnttab_resume(void);
 
 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
 				int readonly);
-int gnttab_grant_foreign_access_subpage(domid_t domid, unsigned long frame,
-					int flags, unsigned page_off,
-					unsigned length);
-int gnttab_grant_foreign_access_trans(domid_t domid, int flags,
-				      domid_t trans_domid,
-				      grant_ref_t trans_gref);
-
-/*
- * Are sub-page grants available on this version of Xen?  Returns true if they
- * are, and false if they're not.
- */
-bool gnttab_subpage_grants_available(void);
-
-/*
- * Are transitive grants available on this version of Xen?  Returns true if they
- * are, and false if they're not.
- */
-bool gnttab_trans_grants_available(void);
 
 /*
  * End access through the given grant reference, iff the grant entry is no
@@ -128,13 +110,6 @@ 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);
-int gnttab_grant_foreign_access_subpage_ref(grant_ref_t ref, domid_t domid,
-					    unsigned long frame, int flags,
-					    unsigned page_off,
-					    unsigned length);
-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);
 
 void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
 				       unsigned long pfn);
@@ -170,13 +145,10 @@ gnttab_set_unmap_op(struct gnttab_unmap_grant_ref *unmap, phys_addr_t addr,
 	unmap->dev_bus_addr = 0;
 }
 
-int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status);
+int arch_gnttab_init(unsigned long nr_shared);
 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 {