From 5fd5387c89ec99ff6cb82d2477ffeb7211b781c2 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Wed, 30 Jun 2010 16:02:45 +0800 Subject: 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 Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/paging_tmpl.h | 2 ++ 1 file changed, 2 insertions(+) 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 -- cgit v1.2.3