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| author | Xiao Guangrong <guangrong.xiao@linux.intel.com> | 2015-05-07 16:20:15 +0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2015-05-11 17:17:23 +0200 |
| commit | 7cbeed9bce7580479bb97457dad220cb3594b875 (patch) | |
| tree | b38bc1552670fc368b60fa5788ae3e66f23316eb /arch/x86 | |
| parent | 17d489019c5249d059768184c80e9b2b0269b81e (diff) | |
| download | linux-7cbeed9bce7580479bb97457dad220cb3594b875.tar.bz2 | |
KVM: MMU: fix smap permission check
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@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/mmu.h | 2 | ||||
| -rw-r--r-- | arch/x86/kvm/paging_tmpl.h | 7 |
2 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index c7d65637c851..06eb2fc1bab8 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -166,6 +166,8 @@ 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 fd49c867b25a..6e6d115fe9b5 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -718,6 +718,13 @@ 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); |