Commit ae4c51a5 authored by Oleksandr Andrushchenko's avatar Oleksandr Andrushchenko Committed by Boris Ostrovsky
Browse files

xen/balloon: Share common memory reservation routines 



Memory {increase|decrease}_reservation and VA mappings update/reset
code used in balloon driver can be made common, so other drivers can
also re-use the same functionality without open-coding.
Create a dedicated file for the shared code and export corresponding
symbols for other kernel modules.

Signed-off-by: default avatarOleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
parent 8c3799ee

drivers/xen/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -2,6 +2,7 @@ 
obj-$(CONFIG_HOTPLUG_CPU)		+= cpu_hotplug.o

obj-$(CONFIG_X86)			+= fallback.o

obj-y	+= grant-table.o features.o balloon.o manage.o preempt.o time.o

obj-y	+= mem-reservation.o

obj-y	+= events/

obj-y	+= xenbus/

drivers/xen/balloon.c

+6 −69
Original line number Diff line number Diff line
@@ -71,6 +71,7 @@ 
#include <xen/balloon.h>

#include <xen/features.h>

#include <xen/page.h>

#include <xen/mem-reservation.h>



static int xen_hotplug_unpopulated;
@@ -157,13 +158,6 @@ static DECLARE_DELAYED_WORK(balloon_worker, balloon_process); 
#define GFP_BALLOON \

	(GFP_HIGHUSER | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC)



static void scrub_page(struct page *page)

{

#ifdef CONFIG_XEN_SCRUB_PAGES

	clear_highpage(page);

#endif

}



/* balloon_append: add the given page to the balloon. */

static void __balloon_append(struct page *page)

{
@@ -463,11 +457,6 @@ static enum bp_state increase_reservation(unsigned long nr_pages) 
	int rc;

	unsigned long i;

	struct page   *page;

	struct xen_memory_reservation reservation = {

		.address_bits = 0,

		.extent_order = EXTENT_ORDER,

		.domid        = DOMID_SELF

	};



	if (nr_pages > ARRAY_SIZE(frame_list))

		nr_pages = ARRAY_SIZE(frame_list);
@@ -479,16 +468,11 @@ static enum bp_state increase_reservation(unsigned long nr_pages) 
			break;

		}



		/* XENMEM_populate_physmap requires a PFN based on Xen

		 * granularity.

		 */

		frame_list[i] = page_to_xen_pfn(page);

		page = balloon_next_page(page);

	}



	set_xen_guest_handle(reservation.extent_start, frame_list);

	reservation.nr_extents = nr_pages;

	rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation);

	rc = xenmem_reservation_increase(nr_pages, frame_list);

	if (rc <= 0)

		return BP_EAGAIN;
@@ -496,29 +480,7 @@ static enum bp_state increase_reservation(unsigned long nr_pages) 
		page = balloon_retrieve(false);

		BUG_ON(page == NULL);



#ifdef CONFIG_XEN_HAVE_PVMMU

		/*

		 * We don't support PV MMU when Linux and Xen is using

		 * different page granularity.

		 */

		BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);



		if (!xen_feature(XENFEAT_auto_translated_physmap)) {

			unsigned long pfn = page_to_pfn(page);



			set_phys_to_machine(pfn, frame_list[i]);



			/* Link back into the page tables if not highmem. */

			if (!PageHighMem(page)) {

				int ret;

				ret = HYPERVISOR_update_va_mapping(

						(unsigned long)__va(pfn << PAGE_SHIFT),

						mfn_pte(frame_list[i], PAGE_KERNEL),

						0);

				BUG_ON(ret);

			}

		}

#endif

		xenmem_reservation_va_mapping_update(1, &page, &frame_list[i]);



		/* Relinquish the page back to the allocator. */

		free_reserved_page(page);
@@ -535,11 +497,6 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) 
	unsigned long i;

	struct page *page, *tmp;

	int ret;

	struct xen_memory_reservation reservation = {

		.address_bits = 0,

		.extent_order = EXTENT_ORDER,

		.domid        = DOMID_SELF

	};

	LIST_HEAD(pages);



	if (nr_pages > ARRAY_SIZE(frame_list))
@@ -553,7 +510,7 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) 
			break;

		}

		adjust_managed_page_count(page, -1);

		scrub_page(page);

		xenmem_reservation_scrub_page(page);

		list_add(&page->lru, &pages);

	}
@@ -572,28 +529,10 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) 
	 */

	i = 0;

	list_for_each_entry_safe(page, tmp, &pages, lru) {

		/* XENMEM_decrease_reservation requires a GFN */

		frame_list[i++] = xen_page_to_gfn(page);



#ifdef CONFIG_XEN_HAVE_PVMMU

		/*

		 * We don't support PV MMU when Linux and Xen is using

		 * different page granularity.

		 */

		BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);



		if (!xen_feature(XENFEAT_auto_translated_physmap)) {

			unsigned long pfn = page_to_pfn(page);

		xenmem_reservation_va_mapping_reset(1, &page);



			if (!PageHighMem(page)) {

				ret = HYPERVISOR_update_va_mapping(

						(unsigned long)__va(pfn << PAGE_SHIFT),

						__pte_ma(0), 0);

				BUG_ON(ret);

			}

			__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);

		}

#endif

		list_del(&page->lru);



		balloon_append(page);
@@ -601,9 +540,7 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) 


	flush_tlb_all();



	set_xen_guest_handle(reservation.extent_start, frame_list);

	reservation.nr_extents   = nr_pages;

	ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation);

	ret = xenmem_reservation_decrease(nr_pages, frame_list);

	BUG_ON(ret != nr_pages);



	balloon_stats.current_pages -= nr_pages;

drivers/xen/mem-reservation.c

0 → 100644
+118 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



/******************************************************************************

 * Xen memory reservation utilities.

 *

 * Copyright (c) 2003, B Dragovic

 * Copyright (c) 2003-2004, M Williamson, K Fraser

 * Copyright (c) 2005 Dan M. Smith, IBM Corporation

 * Copyright (c) 2010 Daniel Kiper

 * Copyright (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.

 */



#include <asm/xen/hypercall.h>



#include <xen/interface/memory.h>

#include <xen/mem-reservation.h>



/*

 * Use one extent per PAGE_SIZE to avoid to break down the page into

 * multiple frame.

 */

#define EXTENT_ORDER (fls(XEN_PFN_PER_PAGE) - 1)



#ifdef CONFIG_XEN_HAVE_PVMMU

void __xenmem_reservation_va_mapping_update(unsigned long count,

					    struct page **pages,

					    xen_pfn_t *frames)

{

	int i;



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

		struct page *page = pages[i];

		unsigned long pfn = page_to_pfn(page);



		BUG_ON(!page);



		/*

		 * We don't support PV MMU when Linux and Xen is using

		 * different page granularity.

		 */

		BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);



		set_phys_to_machine(pfn, frames[i]);



		/* Link back into the page tables if not highmem. */

		if (!PageHighMem(page)) {

			int ret;



			ret = HYPERVISOR_update_va_mapping(

					(unsigned long)__va(pfn << PAGE_SHIFT),

					mfn_pte(frames[i], PAGE_KERNEL),

					0);

			BUG_ON(ret);

		}

	}

}

EXPORT_SYMBOL_GPL(__xenmem_reservation_va_mapping_update);



void __xenmem_reservation_va_mapping_reset(unsigned long count,

					   struct page **pages)

{

	int i;



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

		struct page *page = pages[i];

		unsigned long pfn = page_to_pfn(page);



		/*

		 * We don't support PV MMU when Linux and Xen are using

		 * different page granularity.

		 */

		BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);



		if (!PageHighMem(page)) {

			int ret;



			ret = HYPERVISOR_update_va_mapping(

					(unsigned long)__va(pfn << PAGE_SHIFT),

					__pte_ma(0), 0);

			BUG_ON(ret);

		}

		__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);

	}

}

EXPORT_SYMBOL_GPL(__xenmem_reservation_va_mapping_reset);

#endif /* CONFIG_XEN_HAVE_PVMMU */



/* @frames is an array of PFNs */

int xenmem_reservation_increase(int count, xen_pfn_t *frames)

{

	struct xen_memory_reservation reservation = {

		.address_bits = 0,

		.extent_order = EXTENT_ORDER,

		.domid        = DOMID_SELF

	};



	/* XENMEM_populate_physmap requires a PFN based on Xen granularity. */

	set_xen_guest_handle(reservation.extent_start, frames);

	reservation.nr_extents = count;

	return HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation);

}

EXPORT_SYMBOL_GPL(xenmem_reservation_increase);



/* @frames is an array of GFNs */

int xenmem_reservation_decrease(int count, xen_pfn_t *frames)

{

	struct xen_memory_reservation reservation = {

		.address_bits = 0,

		.extent_order = EXTENT_ORDER,

		.domid        = DOMID_SELF

	};



	/* XENMEM_decrease_reservation requires a GFN */

	set_xen_guest_handle(reservation.extent_start, frames);

	reservation.nr_extents = count;

	return HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation);

}

EXPORT_SYMBOL_GPL(xenmem_reservation_decrease);

include/xen/mem-reservation.h

0 → 100644
+59 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */



/*

 * Xen memory reservation utilities.

 *

 * Copyright (c) 2003, B Dragovic

 * Copyright (c) 2003-2004, M Williamson, K Fraser

 * Copyright (c) 2005 Dan M. Smith, IBM Corporation

 * Copyright (c) 2010 Daniel Kiper

 * Copyright (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.

 */



#ifndef _XENMEM_RESERVATION_H

#define _XENMEM_RESERVATION_H



#include <linux/highmem.h>



#include <xen/page.h>



static inline void xenmem_reservation_scrub_page(struct page *page)

{

#ifdef CONFIG_XEN_SCRUB_PAGES

	clear_highpage(page);

#endif

}



#ifdef CONFIG_XEN_HAVE_PVMMU

void __xenmem_reservation_va_mapping_update(unsigned long count,

					    struct page **pages,

					    xen_pfn_t *frames);



void __xenmem_reservation_va_mapping_reset(unsigned long count,

					   struct page **pages);

#endif



static inline void xenmem_reservation_va_mapping_update(unsigned long count,

							struct page **pages,

							xen_pfn_t *frames)

{

#ifdef CONFIG_XEN_HAVE_PVMMU

	if (!xen_feature(XENFEAT_auto_translated_physmap))

		__xenmem_reservation_va_mapping_update(count, pages, frames);

#endif

}



static inline void xenmem_reservation_va_mapping_reset(unsigned long count,

						       struct page **pages)

{

#ifdef CONFIG_XEN_HAVE_PVMMU

	if (!xen_feature(XENFEAT_auto_translated_physmap))

		__xenmem_reservation_va_mapping_reset(count, pages);

#endif

}



int xenmem_reservation_increase(int count, xen_pfn_t *frames);



int xenmem_reservation_decrease(int count, xen_pfn_t *frames);



#endif

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