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Commit 853d0289 authored by David Vrabel's avatar David Vrabel
Browse files

xen/grant-table: pre-populate kernel unmap ops for xen_gnttab_unmap_refs() 



When unmapping grants, instead of converting the kernel map ops to
unmap ops on the fly, pre-populate the set of unmap ops.

This allows the grant unmap for the kernel mappings to be trivially
batched in the future.

Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Reviewed-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
parent d8ac3dd4

arch/arm/include/asm/xen/page.h

+1 −1
Original line number Diff line number Diff line
@@ -92,7 +92,7 @@ extern int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, 
				   struct page **pages, unsigned int count);



extern int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,

				     struct gnttab_map_grant_ref *kmap_ops,

				     struct gnttab_unmap_grant_ref *kunmap_ops,

				     struct page **pages, unsigned int count);



bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);

arch/arm/xen/p2m.c

+1 −1
Original line number Diff line number Diff line
@@ -102,7 +102,7 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, 
EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping);



int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,

			      struct gnttab_map_grant_ref *kmap_ops,

			      struct gnttab_unmap_grant_ref *kunmap_ops,

			      struct page **pages, unsigned int count)

{

	int i;

arch/x86/include/asm/xen/page.h

+1 −1
Original line number Diff line number Diff line
@@ -55,7 +55,7 @@ extern int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, 
				   struct gnttab_map_grant_ref *kmap_ops,

				   struct page **pages, unsigned int count);

extern int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,

				     struct gnttab_map_grant_ref *kmap_ops,

				     struct gnttab_unmap_grant_ref *kunmap_ops,

				     struct page **pages, unsigned int count);

extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);

arch/x86/xen/p2m.c

+10 −11
Original line number Diff line number Diff line
@@ -816,7 +816,7 @@ static struct page *m2p_find_override(unsigned long mfn) 
}



static int m2p_remove_override(struct page *page,

			       struct gnttab_map_grant_ref *kmap_op,

			       struct gnttab_unmap_grant_ref *kunmap_op,

			       unsigned long mfn)

{

	unsigned long flags;
@@ -840,7 +840,7 @@ static int m2p_remove_override(struct page *page, 
	list_del(&page->lru);

	spin_unlock_irqrestore(&m2p_override_lock, flags);



	if (kmap_op != NULL) {

	if (kunmap_op != NULL) {

		if (!PageHighMem(page)) {

			struct multicall_space mcs;

			struct gnttab_unmap_and_replace *unmap_op;
@@ -855,13 +855,13 @@ static int m2p_remove_override(struct page *page, 
			 * issued. In this case handle is going to -1 because

			 * it hasn't been modified yet.

			 */

			if (kmap_op->handle == -1)

			if (kunmap_op->handle == -1)

				xen_mc_flush();

			/*

			 * Now if kmap_op->handle is negative it means that the

			 * hypercall actually returned an error.

			 */

			if (kmap_op->handle == GNTST_general_error) {

			if (kunmap_op->handle == GNTST_general_error) {

				pr_warn("m2p_remove_override: pfn %lx mfn %lx, failed to modify kernel mappings",

					pfn, mfn);

				put_balloon_scratch_page();
@@ -873,9 +873,9 @@ static int m2p_remove_override(struct page *page, 
			mcs = __xen_mc_entry(

				sizeof(struct gnttab_unmap_and_replace));

			unmap_op = mcs.args;

			unmap_op->host_addr = kmap_op->host_addr;

			unmap_op->host_addr = kunmap_op->host_addr;

			unmap_op->new_addr = scratch_page_address;

			unmap_op->handle = kmap_op->handle;

			unmap_op->handle = kunmap_op->handle;



			MULTI_grant_table_op(mcs.mc,

				GNTTABOP_unmap_and_replace, unmap_op, 1);
@@ -887,7 +887,6 @@ static int m2p_remove_override(struct page *page, 


			xen_mc_issue(PARAVIRT_LAZY_MMU);



			kmap_op->host_addr = 0;

			put_balloon_scratch_page();

		}

	}
@@ -912,7 +911,7 @@ static int m2p_remove_override(struct page *page, 
}



int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,

			      struct gnttab_map_grant_ref *kmap_ops,

			      struct gnttab_unmap_grant_ref *kunmap_ops,

			      struct page **pages, unsigned int count)

{

	int i, ret = 0;
@@ -921,7 +920,7 @@ int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, 
	if (xen_feature(XENFEAT_auto_translated_physmap))

		return 0;



	if (kmap_ops &&

	if (kunmap_ops &&

	    !in_interrupt() &&

	    paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {

		arch_enter_lazy_mmu_mode();
@@ -942,8 +941,8 @@ int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, 
		ClearPagePrivate(pages[i]);

		set_phys_to_machine(pfn, pages[i]->index);



		if (kmap_ops)

			ret = m2p_remove_override(pages[i], &kmap_ops[i], mfn);

		if (kunmap_ops)

			ret = m2p_remove_override(pages[i], &kunmap_ops[i], mfn);

		if (ret)

			goto out;

	}

drivers/xen/gntdev.c

+14 −6
Original line number Diff line number Diff line
@@ -91,6 +91,7 @@ struct grant_map { 
	struct gnttab_map_grant_ref   *map_ops;

	struct gnttab_unmap_grant_ref *unmap_ops;

	struct gnttab_map_grant_ref   *kmap_ops;

	struct gnttab_unmap_grant_ref *kunmap_ops;

	struct page **pages;

};
@@ -124,6 +125,7 @@ static void gntdev_free_map(struct grant_map *map) 
	kfree(map->map_ops);

	kfree(map->unmap_ops);

	kfree(map->kmap_ops);

	kfree(map->kunmap_ops);

	kfree(map);

}
@@ -140,11 +142,13 @@ static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count) 
	add->map_ops   = kcalloc(count, sizeof(add->map_ops[0]), GFP_KERNEL);

	add->unmap_ops = kcalloc(count, sizeof(add->unmap_ops[0]), GFP_KERNEL);

	add->kmap_ops  = kcalloc(count, sizeof(add->kmap_ops[0]), GFP_KERNEL);

	add->kunmap_ops = kcalloc(count, sizeof(add->kunmap_ops[0]), GFP_KERNEL);

	add->pages     = kcalloc(count, sizeof(add->pages[0]), GFP_KERNEL);

	if (NULL == add->grants    ||

	    NULL == add->map_ops   ||

	    NULL == add->unmap_ops ||

	    NULL == add->kmap_ops  ||

	    NULL == add->kunmap_ops ||

	    NULL == add->pages)

		goto err;
@@ -155,6 +159,7 @@ static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count) 
		add->map_ops[i].handle = -1;

		add->unmap_ops[i].handle = -1;

		add->kmap_ops[i].handle = -1;

		add->kunmap_ops[i].handle = -1;

	}



	add->index = 0;
@@ -280,6 +285,8 @@ static int map_grant_pages(struct grant_map *map) 
				map->flags | GNTMAP_host_map,

				map->grants[i].ref,

				map->grants[i].domid);

			gnttab_set_unmap_op(&map->kunmap_ops[i], address,

				map->flags | GNTMAP_host_map, -1);

		}

	}
@@ -290,13 +297,14 @@ static int map_grant_pages(struct grant_map *map) 
		return err;



	for (i = 0; i < map->count; i++) {

		if (map->map_ops[i].status)

		if (map->map_ops[i].status) {

			err = -EINVAL;

		else {

			BUG_ON(map->map_ops[i].handle == -1);

			map->unmap_ops[i].handle = map->map_ops[i].handle;

			pr_debug("map handle=%d\n", map->map_ops[i].handle);

			continue;

		}



		map->unmap_ops[i].handle = map->map_ops[i].handle;

		if (use_ptemod)

			map->kunmap_ops[i].handle = map->kmap_ops[i].handle;

	}

	return err;

}
@@ -316,7 +324,7 @@ static int __unmap_grant_pages(struct grant_map *map, int offset, int pages) 
	}



	err = gnttab_unmap_refs(map->unmap_ops + offset,

			use_ptemod ? map->kmap_ops + offset : NULL, map->pages + offset,

			use_ptemod ? map->kunmap_ops + offset : NULL, map->pages + offset,

			pages);

	if (err)

		return err;