3.16.7-ckt13 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx> commit 7cbeed9bce7580479bb97457dad220cb3594b875 upstream. Current permission check assumes that RSVD bit in PFEC is always zero, however, it is not true since MMIO #PF will use it to quickly identify MMIO access Fix it by clearing the bit if walking guest page table is needed Signed-off-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx> --- arch/x86/kvm/mmu.h | 2 ++ arch/x86/kvm/paging_tmpl.h | 7 +++++++ 2 files changed, 9 insertions(+) diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index b982112d2ca5..6baa9221829e 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -174,6 +174,8 @@ static inline bool permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, int index = (pfec >> 1) + (smap >> (X86_EFLAGS_AC_BIT - PFERR_RSVD_BIT + 1)); + WARN_ON(pfec & PFERR_RSVD_MASK); + return (mmu->permissions[index] >> pte_access) & 1; } diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 410776528265..484711d2c71f 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -706,6 +706,13 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code, mmu_is_nested(vcpu)); if (likely(r != RET_MMIO_PF_INVALID)) return r; + + /* + * page fault with PFEC.RSVD = 1 is caused by shadow + * page fault, should not be used to walk guest page + * table. + */ + error_code &= ~PFERR_RSVD_MASK; }; r = mmu_topup_memory_caches(vcpu); -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html