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authorXiao Guangrong <xiaoguangrong@cn.fujitsu.com>2010-06-30 16:02:45 +0800
committerAvi Kivity <avi@redhat.com>2010-08-01 10:47:23 +0300
commit5fd5387c89ec99ff6cb82d2477ffeb7211b781c2 (patch)
treea3896c883dca431512110870f31d32c431814f12 /arch/x86/kvm
parent36a2e6774bfb5f32a0f23bb155f1f960321f291b (diff)
KVM: MMU: fix conflict access permissions in direct sp
In no-direct mapping, we mark sp is 'direct' when we mapping the guest's larger page, but its access is encoded form upper page-struct entire not include the last mapping, it will cause access conflict. For example, have this mapping: [W] / PDE1 -> |---| P[W] | | LPA \ PDE2 -> |---| [R] P have two children, PDE1 and PDE2, both PDE1 and PDE2 mapping the same lage page(LPA). The P's access is WR, PDE1's access is WR, PDE2's access is RO(just consider read-write permissions here) When guest access PDE1, we will create a direct sp for LPA, the sp's access is from P, is W, then we will mark the ptes is W in this sp. Then, guest access PDE2, we will find LPA's shadow page, is the same as PDE's, and mark the ptes is RO. So, if guest access PDE1, the incorrect #PF is occured. Fixed by encode the last mapping access into direct shadow page Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/paging_tmpl.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index a21a86ef9e2..f4e4aaa65ff 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -339,6 +339,8 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
direct = 1;
if (!is_dirty_gpte(gw->ptes[level - delta]))
access &= ~ACC_WRITE_MASK;
+ access &= gw->pte_access;
+
/*
* It is a large guest pages backed by small host pages,
* So we set @direct(@sp->role.direct)=1, and set