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Commit 7a8f1a74 authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Avi Kivity
Browse files

KVM: MMU: clear unsync_child_bitmap completely 



In current code, some page's unsync_child_bitmap is not cleared completely
in mmu_sync_children(), for example, if two PDPEs shard one PDT, one of
PDPE's unsync_child_bitmap is not cleared.

Currently, it not harm anything just little overload, but it's the prepare
work for the later patch

Signed-off-by: default avatarXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent ebdea638

arch/x86/kvm/mmu.c

+29 −24
Original line number Diff line number Diff line
@@ -1149,10 +1149,12 @@ static int __mmu_unsync_walk(struct kvm_mmu_page *sp, 
	int i, ret, nr_unsync_leaf = 0;



	for_each_unsync_children(sp->unsync_child_bitmap, i) {

		struct kvm_mmu_page *child;

		u64 ent = sp->spt[i];



		if (is_shadow_present_pte(ent) && !is_large_pte(ent)) {

			struct kvm_mmu_page *child;

		if (!is_shadow_present_pte(ent) || is_large_pte(ent))

			goto clear_child_bitmap;



		child = page_header(ent & PT64_BASE_ADDR_MASK);



		if (child->unsync_children) {
@@ -1160,22 +1162,25 @@ static int __mmu_unsync_walk(struct kvm_mmu_page *sp, 
				return -ENOSPC;



			ret = __mmu_unsync_walk(child, pvec);

				if (!ret) {

					__clear_bit(i, sp->unsync_child_bitmap);

					sp->unsync_children--;

					WARN_ON((int)sp->unsync_children < 0);

				} else if (ret > 0)

			if (!ret)

				goto clear_child_bitmap;

			else if (ret > 0)

				nr_unsync_leaf += ret;

			else

				return ret;

			}



			if (child->unsync) {

		} else if (child->unsync) {

			nr_unsync_leaf++;

			if (mmu_pages_add(pvec, child, i))

				return -ENOSPC;

			}

		}

		} else

			 goto clear_child_bitmap;



		continue;



clear_child_bitmap:

		__clear_bit(i, sp->unsync_child_bitmap);

		sp->unsync_children--;

		WARN_ON((int)sp->unsync_children < 0);

	}