[PATCH 07/14] xen: balloon: do not update stage 1 pagetable for autotranslated guests

[Ian Campbell <ian.campbell@citrix.com>]

This is unnecessary (since the page will be removed from the p2m) and
can be tricky if the page is in the middle of a superpage, as it is on
ARM.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
---
Also effects PVH but in a benign way I think.
---
 drivers/xen/balloon.c |   23 +++--------------------
 1 files changed, 3 insertions(+), 20 deletions(-)

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 7885a19..1b56ae0 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -357,15 +357,7 @@ static enum bp_state increase_reservation(unsigned long nr_pages)
 		BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap) &&
 		       phys_to_machine_mapping_valid(pfn));
 
-		if (xen_pv_domain() && 
-		    xen_feature(XENFEAT_auto_translated_physmap)) {
-			/* PVH: we just need to update native page table */
-			pte_t *ptep;
-			unsigned int level;
-			void *addr = __va(pfn << PAGE_SHIFT);
-			ptep = lookup_address((unsigned long)addr, &level);
-			set_pte(ptep, pfn_pte(pfn, PAGE_KERNEL));
-		} else
+		if (!xen_feature(XENFEAT_auto_translated_physmap))
 			set_phys_to_machine(pfn, frame_list[i]);
 
 		/* Link back into the page tables if not highmem. */
@@ -427,21 +419,12 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
 
 		scrub_page(page);
 
-		if (xen_pv_domain() && !PageHighMem(page)) {
-			if (xen_feature(XENFEAT_auto_translated_physmap)) {
-				unsigned int level;
-				pte_t *ptep;
-				void *addr = __va(pfn << PAGE_SHIFT);
-				ptep = lookup_address((unsigned long)addr, 
-							&level);
-				set_pte(ptep, __pte(0));
-
-			} else {
+		if (xen_pv_domain() && !PageHighMem(page) &&
+		    !xen_feature(XENFEAT_auto_translated_physmap)) {
 				ret = HYPERVISOR_update_va_mapping(
 					(unsigned long)__va(pfn << PAGE_SHIFT),
 					__pte_ma(0), 0);
 				BUG_ON(ret);
-			}
 		}
 	}
 
-- 
1.7.2.5