From e23d3fef83df8e303fded0ab55b379beec0dd604 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Wed, 24 Feb 2016 09:46:06 +0100 Subject: [PATCH] KVM: MMU: check kvm_mmu_pages and mmu_page_path indices Give a special invalid index to the root of the walk, so that we can check the consistency of kvm_mmu_pages and mmu_page_path. Signed-off-by: Xiao Guangrong [Extracted from a bigger patch proposed by Guangrong. - Paolo] Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 609fa53..0a4dc9b 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1870,6 +1870,8 @@ static int __mmu_unsync_walk(struct kvm_mmu_page *sp, return nr_unsync_leaf; } +#define INVALID_INDEX (-1) + static int mmu_unsync_walk(struct kvm_mmu_page *sp, struct kvm_mmu_pages *pvec) { @@ -1877,7 +1879,7 @@ static int mmu_unsync_walk(struct kvm_mmu_page *sp, if (!sp->unsync_children) return 0; - mmu_pages_add(pvec, sp, 0); + mmu_pages_add(pvec, sp, INVALID_INDEX); return __mmu_unsync_walk(sp, pvec); } @@ -2026,6 +2028,8 @@ static int mmu_pages_first(struct kvm_mmu_pages *pvec, if (pvec->nr == 0) return 0; + WARN_ON(pvec->page[0].idx != INVALID_INDEX); + sp = pvec->page[0].sp; level = sp->role.level; WARN_ON(level == PT_PAGE_TABLE_LEVEL); @@ -2050,6 +2054,7 @@ static void mmu_pages_clear_parents(struct mmu_page_path *parents) if (!sp) return; + WARN_ON(idx == INVALID_INDEX); clear_unsync_child_bit(sp, idx); level++; } while (!sp->unsync_children); -- 2.7.4