diff options
| author | Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> | 2010-06-30 16:02:45 +0800 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2010-08-01 10:47:23 +0300 |
| commit | 5fd5387c89ec99ff6cb82d2477ffeb7211b781c2 (patch) | |
| tree | a3896c883dca431512110870f31d32c431814f12 /arch/x86/kvm | |
| parent | 36a2e6774bfb5f32a0f23bb155f1f960321f291b (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.h | 2 |
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 |