Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 8da7633f authored by Jennifer Herbert's avatar Jennifer Herbert Committed by David Vrabel
Browse files

xen: mark grant mapped pages as foreign 



Use the "foreign" page flag to mark pages that have a grant map.  Use
page->private to store information of the grant (the granting domain
and the grant reference).

Signed-off-by: default avatarJennifer Herbert <jennifer.herbert@citrix.com>
Reviewed-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
parent ff4b156f

arch/x86/xen/p2m.c

+0 −7
Original line number Diff line number Diff line
@@ -681,12 +681,8 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, 
		}

		pfn = page_to_pfn(pages[i]);



		WARN_ON(PagePrivate(pages[i]));

		WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned");



		SetPagePrivate(pages[i]);

		set_page_private(pages[i], mfn);



		if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) {

			ret = -ENOMEM;

			goto out;
@@ -716,9 +712,6 @@ int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, 
			goto out;

		}



		set_page_private(pages[i], INVALID_P2M_ENTRY);

		WARN_ON(!PagePrivate(pages[i]));

		ClearPagePrivate(pages[i]);

		set_phys_to_machine(pfn, INVALID_P2M_ENTRY);

	}

	if (kunmap_ops)

drivers/xen/grant-table.c

+41 −2
Original line number Diff line number Diff line
@@ -679,12 +679,27 @@ EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames); 
 */

int gnttab_alloc_pages(int nr_pages, struct page **pages)

{

	int i;

	int ret;



	ret = alloc_xenballooned_pages(nr_pages, pages, false);

	if (ret < 0)

		return ret;



	for (i = 0; i < nr_pages; i++) {

#if BITS_PER_LONG < 64

		struct xen_page_foreign *foreign;



		foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);

		if (!foreign) {

			gnttab_free_pages(nr_pages, pages);

			return -ENOMEM;

		}

		set_page_private(pages[i], (unsigned long)foreign);

#endif

		SetPagePrivate(pages[i]);

	}



	return 0;

}

EXPORT_SYMBOL(gnttab_alloc_pages);
@@ -696,6 +711,16 @@ EXPORT_SYMBOL(gnttab_alloc_pages); 
 */

void gnttab_free_pages(int nr_pages, struct page **pages)

{

	int i;



	for (i = 0; i < nr_pages; i++) {

		if (PagePrivate(pages[i])) {

#if BITS_PER_LONG < 64

			kfree((void *)page_private(pages[i]));

#endif

			ClearPagePrivate(pages[i]);

		}

	}

	free_xenballooned_pages(nr_pages, pages);

}

EXPORT_SYMBOL(gnttab_free_pages);
@@ -756,12 +781,22 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, 
	if (ret)

		return ret;



	for (i = 0; i < count; i++) {

		/* Retry eagain maps */

	for (i = 0; i < count; i++)

		if (map_ops[i].status == GNTST_eagain)

			gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i,

						&map_ops[i].status, __func__);



		if (map_ops[i].status == GNTST_okay) {

			struct xen_page_foreign *foreign;



			SetPageForeign(pages[i]);

			foreign = xen_page_foreign(pages[i]);

			foreign->domid = map_ops[i].dom;

			foreign->gref = map_ops[i].ref;

		}

	}



	return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count);

}

EXPORT_SYMBOL_GPL(gnttab_map_refs);
@@ -770,12 +805,16 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, 
		      struct gnttab_unmap_grant_ref *kunmap_ops,

		      struct page **pages, unsigned int count)

{

	unsigned int i;

	int ret;



	ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);

	if (ret)

		return ret;



	for (i = 0; i < count; i++)

		ClearPageForeign(pages[i]);



	return clear_foreign_p2m_mapping(unmap_ops, kunmap_ops, pages, count);

}

EXPORT_SYMBOL_GPL(gnttab_unmap_refs);

include/xen/grant_table.h

+20 −0
Original line number Diff line number Diff line
@@ -45,6 +45,8 @@ 
#include <asm/xen/hypervisor.h>



#include <xen/features.h>

#include <linux/mm_types.h>

#include <linux/page-flags.h>



#define GNTTAB_RESERVED_XENSTORE 1
@@ -185,4 +187,22 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, 
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

}



#endif /* __ASM_GNTTAB_H__ */