Intel's new PKU extension introduces a bit of the page fault error code that must be dynamically computed after the PTE lookup (unlike I/D, U/S and W/R). To ease this, these two patches make permission_fault return the page fault error code.
Right now it only adds the P bit to the input parameter "pfec", but PKU can change that. Signed-off-by: Paolo Bonzini <[email protected]> --- arch/x86/kvm/mmu.h | 15 ++++++++++----- arch/x86/kvm/paging_tmpl.h | 5 ++--- 2 files changed, 12 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index 58fe98a0a526..8b2b3dfca1ae 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -141,11 +141,15 @@ static inline bool is_write_protection(struct kvm_vcpu *vcpu) } /* - * Will a fault with a given page-fault error code (pfec) cause a permission - * fault with the given access (in ACC_* format)? + * Check if a given access (described through the I/D, W/R and U/S bits of a + * page fault error code pfec) causes a permission fault with the given PTE + * access rights (in ACC_* format). + * + * Return zero if the access does not fault; return the page fault error code + * if the access faults. */ -static inline bool permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, - unsigned pte_access, unsigned pfec) +static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, + unsigned pte_access, unsigned pfec) { int cpl = kvm_x86_ops->get_cpl(vcpu); unsigned long rflags = kvm_x86_ops->get_rflags(vcpu); @@ -169,7 +173,8 @@ static inline bool permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, WARN_ON(pfec & PFERR_RSVD_MASK); - return (mmu->permissions[index] >> pte_access) & 1; + pfec |= PFERR_PRESENT_MASK; + return -((mmu->permissions[index] >> pte_access) & 1) & pfec; } void kvm_mmu_invalidate_zap_all_pages(struct kvm *kvm); diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 285858d3223b..4a6866dab848 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -370,10 +370,9 @@ retry_walk: walker->ptes[walker->level - 1] = pte; } while (!is_last_gpte(mmu, walker->level, pte)); - if (unlikely(permission_fault(vcpu, mmu, pte_access, access))) { - errcode |= PFERR_PRESENT_MASK; + errcode = permission_fault(vcpu, mmu, pte_access, errcode); + if (unlikely(errcode)) goto error; - } gfn = gpte_to_gfn_lvl(pte, walker->level); gfn += (addr & PT_LVL_OFFSET_MASK(walker->level)) >> PAGE_SHIFT; -- 1.8.3.1
