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Commit fd951457 authored by Takuya Yoshikawa's avatar Takuya Yoshikawa Committed by Paolo Bonzini
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KVM: x86: MMU: Add helper function to clear a bit in unsync child bitmap 



Both __mmu_unsync_walk() and mmu_pages_clear_parents() have three line
code which clears a bit in the unsync child bitmap; the former places it
inside a loop block and uses a few goto statements to jump to it.

A new helper function, clear_unsync_child_bit(), makes the code cleaner.

Signed-off-by: default avatarTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 7ee0e5b2

arch/x86/kvm/mmu.c

+18 −18
Original line number Diff line number Diff line
@@ -1809,6 +1809,13 @@ static int mmu_pages_add(struct kvm_mmu_pages *pvec, struct kvm_mmu_page *sp, 
	return (pvec->nr == KVM_PAGE_ARRAY_NR);

}



static inline void clear_unsync_child_bit(struct kvm_mmu_page *sp, int idx)

{

	--sp->unsync_children;

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

	__clear_bit(idx, sp->unsync_child_bitmap);

}



static int __mmu_unsync_walk(struct kvm_mmu_page *sp,

			   struct kvm_mmu_pages *pvec)

{
@@ -1818,8 +1825,10 @@ static int __mmu_unsync_walk(struct kvm_mmu_page *sp, 
		struct kvm_mmu_page *child;

		u64 ent = sp->spt[i];



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

			goto clear_child_bitmap;

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

			clear_unsync_child_bit(sp, i);

			continue;

		}



		child = page_header(ent & PT64_BASE_ADDR_MASK);
@@ -1828,28 +1837,21 @@ static int __mmu_unsync_walk(struct kvm_mmu_page *sp, 
				return -ENOSPC;



			ret = __mmu_unsync_walk(child, pvec);

			if (!ret)

				goto clear_child_bitmap;

			else if (ret > 0)

			if (!ret) {

				clear_unsync_child_bit(sp, i);

				continue;

			} else if (ret > 0) {

				nr_unsync_leaf += ret;

			else

			} else

				return ret;

		} 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);

			clear_unsync_child_bit(sp, i);

	}





	return nr_unsync_leaf;

}
@@ -2012,9 +2014,7 @@ static void mmu_pages_clear_parents(struct mmu_page_path *parents) 
		if (!sp)

			return;



		--sp->unsync_children;

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

		__clear_bit(idx, sp->unsync_child_bitmap);

		clear_unsync_child_bit(sp, idx);

		level++;

	} while (level < PT64_ROOT_LEVEL-1 && !sp->unsync_children);

}