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Date: Sun, 2 Jan 2011 02:18:50 -0500 From: Paul Gortmaker <paul.gortmaker@...driver.com> To: stable@...nel.org, linux-kernel@...r.kernel.org Cc: stable-review@...nel.org, Xiao Guangrong <xiaoguangrong@...fujitsu.com>, Marcelo Tosatti <mtosatti@...hat.com>, Paul Gortmaker <paul.gortmaker@...driver.com> Subject: [34-longterm 234/260] KVM: MMU: fix conflict access permissions in direct sp From: Xiao Guangrong <xiaoguangrong@...fujitsu.com> commit 5fd5387c89ec99ff6cb82d2477ffeb7211b781c2 upstream. 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@...fujitsu.com> Signed-off-by: Marcelo Tosatti <mtosatti@...hat.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@...driver.com> --- 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 a535c87..2bd2b3e 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -356,6 +356,8 @@ 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; + table_gfn = gpte_to_gfn(gw->ptes[level - delta]); /* advance table_gfn when emulating 1gb pages with 4k */ if (delta == 0) -- 1.7.3.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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