From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
To: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Avi Kivity <avi@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
LKML <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
Subject: [PATCH 4/9] KVM: MMU: track the refcount when unmap the page
Date: Tue, 17 Jul 2012 21:52:52 +0800 [thread overview]
Message-ID: <50056E34.8080505@linux.vnet.ibm.com> (raw)
In-Reply-To: <50056DB8.7080702@linux.vnet.ibm.com>
It will trigger a WARN_ON if the page has been freed but it is still
used in mmu, it can help us to detect mm bug early
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
---
arch/x86/kvm/mmu.c | 8 ++++++++
1 files changed, 8 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 28c8fbc..28b12e2 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -556,6 +556,14 @@ static int mmu_spte_clear_track_bits(u64 *sptep)
return 0;
pfn = spte_to_pfn(old_spte);
+
+ /*
+ * KVM does not hold the refcount of the page used by
+ * kvm mmu, before reclaiming the page, we should
+ * unmap it from mmu first.
+ */
+ WARN_ON(!kvm_is_mmio_pfn(pfn) && !page_count(pfn_to_page(pfn)));
+
if (!shadow_accessed_mask || old_spte & shadow_accessed_mask)
kvm_set_pfn_accessed(pfn);
if (!shadow_dirty_mask || (old_spte & shadow_dirty_mask))
--
1.7.7.6
next prev parent reply other threads:[~2012-07-17 13:52 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-17 13:50 [PATCH 1/9] KVM: x86: remvoe unnecessary mark_page_dirty Xiao Guangrong
2012-07-17 13:51 ` [PATCH 2/9] KVM: x86: simplify read_emulated Xiao Guangrong
2012-07-19 23:58 ` Marcelo Tosatti
2012-07-20 2:17 ` Xiao Guangrong
2012-07-20 10:58 ` Marcelo Tosatti
2012-07-20 13:15 ` Xiao Guangrong
2012-07-20 19:52 ` Marcelo Tosatti
2012-07-23 4:23 ` Xiao Guangrong
2012-07-17 13:52 ` [PATCH 3/9] KVM: x86: introduce set_mmio_exit_info Xiao Guangrong
2012-07-20 0:03 ` Marcelo Tosatti
2012-07-20 2:24 ` Xiao Guangrong
2012-07-17 13:52 ` Xiao Guangrong [this message]
2012-07-20 0:09 ` [PATCH 4/9] KVM: MMU: track the refcount when unmap the page Marcelo Tosatti
2012-07-17 13:53 ` [PATCH 5/9] KVM: MMU: fask check write-protect for direct mmu Xiao Guangrong
2012-07-20 0:39 ` Marcelo Tosatti
2012-07-20 2:34 ` Xiao Guangrong
2012-07-20 11:09 ` Marcelo Tosatti
2012-07-20 13:33 ` Xiao Guangrong
2012-07-20 3:45 ` Xiao Guangrong
2012-07-20 11:45 ` Marcelo Tosatti
2012-07-17 13:54 ` [PATCH 6/9] KVM: using get_fault_pfn to get the fault pfn Xiao Guangrong
2012-07-17 13:54 ` [PATCH 7/9] KVM: mark do not extern bad_pfn Xiao Guangrong
2012-07-17 13:55 ` [PATCH 8/9] KVM: remove is_error_hpa Xiao Guangrong
2012-07-17 13:56 ` [PATCH 9/9] KVM: remove the unused parameter of gfn_to_pfn_memslot Xiao Guangrong
2012-07-20 0:40 ` [PATCH 1/9] KVM: x86: remvoe unnecessary mark_page_dirty Marcelo Tosatti
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