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Commit c1d15f5c authored by Stefano Stabellini's avatar Stefano Stabellini Committed by Konrad Rzeszutek Wilk
Browse files

xen/balloon: Seperate the auto-translate logic properly (v2) 



The auto-xlat logic vs the non-xlat means that we don't need to for
auto-xlat guests (like PVH, HVM or ARM):
 - use P2M
 - use scratch page.

However the code in increase_reservation does modify the p2m for
auto_translate guests, but not in decrease_reservation.

Fix that by avoiding any p2m modifications in both increase_reservation
and decrease_reservation for auto_translated guests.

And also avoid allocating or using scratch pages for auto_translated guests.

Lastly, since !auto-xlat is really another way of saying 'xen_pv'
remove the redundant 'xen_pv_domain' check.

Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
[v2: Updated the description]
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 380108d8

drivers/xen/balloon.c

+34 −29
Original line number Diff line number Diff line
@@ -350,11 +350,12 @@ static enum bp_state increase_reservation(unsigned long nr_pages) 


		pfn = page_to_pfn(page);



#ifdef CONFIG_XEN_HAVE_PVMMU

		if (!xen_feature(XENFEAT_auto_translated_physmap)) {

			set_phys_to_machine(pfn, frame_list[i]);



#ifdef CONFIG_XEN_HAVE_PVMMU

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

		if (xen_pv_domain() && !PageHighMem(page)) {

			if (!PageHighMem(page)) {

				int ret;

				ret = HYPERVISOR_update_va_mapping(

						(unsigned long)__va(pfn << PAGE_SHIFT),
@@ -362,6 +363,7 @@ static enum bp_state increase_reservation(unsigned long nr_pages) 
						0);

				BUG_ON(ret);

			}

		}

#endif



		/* Relinquish the page back to the allocator. */
@@ -378,7 +380,6 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) 
	enum bp_state state = BP_DONE;

	unsigned long  pfn, i;

	struct page   *page;

	struct page   *scratch_page;

	int ret;

	struct xen_memory_reservation reservation = {

		.address_bits = 0,
@@ -411,27 +412,29 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) 


		scrub_page(page);



#ifdef CONFIG_XEN_HAVE_PVMMU

		/*

		 * Ballooned out frames are effectively replaced with

		 * a scratch frame.  Ensure direct mappings and the

		 * p2m are consistent.

		 */

		scratch_page = get_balloon_scratch_page();

#ifdef CONFIG_XEN_HAVE_PVMMU

		if (xen_pv_domain() && !PageHighMem(page)) {

		if (!xen_feature(XENFEAT_auto_translated_physmap)) {

			unsigned long p;

			struct page   *scratch_page = get_balloon_scratch_page();



			if (!PageHighMem(page)) {

				ret = HYPERVISOR_update_va_mapping(

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

						pfn_pte(page_to_pfn(scratch_page),

							PAGE_KERNEL_RO), 0);

				BUG_ON(ret);

			}

#endif

		if (!xen_feature(XENFEAT_auto_translated_physmap)) {

			unsigned long p;

			p = page_to_pfn(scratch_page);

			__set_phys_to_machine(pfn, pfn_to_mfn(p));

		}



			put_balloon_scratch_page();

		}

#endif



		balloon_append(pfn_to_page(pfn));

	}
@@ -627,6 +630,7 @@ static int __init balloon_init(void) 
	if (!xen_domain())

		return -ENODEV;



	if (!xen_feature(XENFEAT_auto_translated_physmap)) {

		for_each_online_cpu(cpu)

		{

			per_cpu(balloon_scratch_page, cpu) = alloc_page(GFP_KERNEL);
@@ -636,6 +640,7 @@ static int __init balloon_init(void) 
			}

		}

		register_cpu_notifier(&balloon_cpu_notifier);

	}



	pr_info("Initialising balloon driver\n");