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 <guangrong.xiao@linux.intel.com>
[Extracted from a bigger patch proposed by Guangrong. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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 @@
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 @@
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 @@
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 @@
if (!sp)
return;
+ WARN_ON(idx == INVALID_INDEX);
clear_unsync_child_bit(sp, idx);
level++;
} while (!sp->unsync_children);