diff options
Diffstat (limited to 'arch/powerpc/kvm/book3s_64_vio.c')
| -rw-r--r-- | arch/powerpc/kvm/book3s_64_vio.c | 94 |
1 files changed, 67 insertions, 27 deletions
diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c index 9a3f2646ecc7e..62a8d03ba7e96 100644 --- a/arch/powerpc/kvm/book3s_64_vio.c +++ b/arch/powerpc/kvm/book3s_64_vio.c @@ -363,6 +363,40 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, return ret; } +static long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt, + unsigned long tce) +{ + unsigned long gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE); + enum dma_data_direction dir = iommu_tce_direction(tce); + struct kvmppc_spapr_tce_iommu_table *stit; + unsigned long ua = 0; + + /* Allow userspace to poison TCE table */ + if (dir == DMA_NONE) + return H_SUCCESS; + + if (iommu_tce_check_gpa(stt->page_shift, gpa)) + return H_TOO_HARD; + + if (kvmppc_tce_to_ua(stt->kvm, tce, &ua, NULL)) + return H_TOO_HARD; + + list_for_each_entry_rcu(stit, &stt->iommu_tables, next) { + unsigned long hpa = 0; + struct mm_iommu_table_group_mem_t *mem; + long shift = stit->tbl->it_page_shift; + + mem = mm_iommu_lookup(stt->kvm->mm, ua, 1ULL << shift); + if (!mem) + return H_TOO_HARD; + + if (mm_iommu_ua_to_hpa(mem, ua, shift, &hpa)) + return H_TOO_HARD; + } + + return H_SUCCESS; +} + static void kvmppc_clear_tce(struct iommu_table *tbl, unsigned long entry) { unsigned long hpa = 0; @@ -376,11 +410,10 @@ static long kvmppc_tce_iommu_mapped_dec(struct kvm *kvm, { struct mm_iommu_table_group_mem_t *mem = NULL; const unsigned long pgsize = 1ULL << tbl->it_page_shift; - __be64 *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry); + __be64 *pua = IOMMU_TABLE_USERSPACE_ENTRY_RO(tbl, entry); if (!pua) - /* it_userspace allocation might be delayed */ - return H_TOO_HARD; + return H_SUCCESS; mem = mm_iommu_lookup(kvm->mm, be64_to_cpu(*pua), pgsize); if (!mem) @@ -401,7 +434,7 @@ static long kvmppc_tce_iommu_do_unmap(struct kvm *kvm, long ret; if (WARN_ON_ONCE(iommu_tce_xchg(tbl, entry, &hpa, &dir))) - return H_HARDWARE; + return H_TOO_HARD; if (dir == DMA_NONE) return H_SUCCESS; @@ -449,15 +482,15 @@ long kvmppc_tce_iommu_do_map(struct kvm *kvm, struct iommu_table *tbl, return H_TOO_HARD; if (WARN_ON_ONCE(mm_iommu_ua_to_hpa(mem, ua, tbl->it_page_shift, &hpa))) - return H_HARDWARE; + return H_TOO_HARD; if (mm_iommu_mapped_inc(mem)) - return H_CLOSED; + return H_TOO_HARD; ret = iommu_tce_xchg(tbl, entry, &hpa, &dir); if (WARN_ON_ONCE(ret)) { mm_iommu_mapped_dec(mem); - return H_HARDWARE; + return H_TOO_HARD; } if (dir != DMA_NONE) @@ -517,8 +550,7 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn, idx = srcu_read_lock(&vcpu->kvm->srcu); - if ((dir != DMA_NONE) && kvmppc_gpa_to_ua(vcpu->kvm, - tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), &ua, NULL)) { + if ((dir != DMA_NONE) && kvmppc_tce_to_ua(vcpu->kvm, tce, &ua, NULL)) { ret = H_PARAMETER; goto unlock_exit; } @@ -533,14 +565,10 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn, ret = kvmppc_tce_iommu_map(vcpu->kvm, stt, stit->tbl, entry, ua, dir); - if (ret == H_SUCCESS) - continue; - - if (ret == H_TOO_HARD) + if (ret != H_SUCCESS) { + kvmppc_clear_tce(stit->tbl, entry); goto unlock_exit; - - WARN_ON_ONCE(1); - kvmppc_clear_tce(stit->tbl, entry); + } } kvmppc_tce_put(stt, entry, tce); @@ -583,7 +611,7 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu, return ret; idx = srcu_read_lock(&vcpu->kvm->srcu); - if (kvmppc_gpa_to_ua(vcpu->kvm, tce_list, &ua, NULL)) { + if (kvmppc_tce_to_ua(vcpu->kvm, tce_list, &ua, NULL)) { ret = H_TOO_HARD; goto unlock_exit; } @@ -599,10 +627,26 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu, ret = kvmppc_tce_validate(stt, tce); if (ret != H_SUCCESS) goto unlock_exit; + } + + for (i = 0; i < npages; ++i) { + /* + * This looks unsafe, because we validate, then regrab + * the TCE from userspace which could have been changed by + * another thread. + * + * But it actually is safe, because the relevant checks will be + * re-executed in the following code. If userspace tries to + * change this dodgily it will result in a messier failure mode + * but won't threaten the host. + */ + if (get_user(tce, tces + i)) { + ret = H_TOO_HARD; + goto unlock_exit; + } + tce = be64_to_cpu(tce); - if (kvmppc_gpa_to_ua(vcpu->kvm, - tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), - &ua, NULL)) + if (kvmppc_tce_to_ua(vcpu->kvm, tce, &ua, NULL)) return H_PARAMETER; list_for_each_entry_lockless(stit, &stt->iommu_tables, next) { @@ -610,14 +654,10 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu, stit->tbl, entry + i, ua, iommu_tce_direction(tce)); - if (ret == H_SUCCESS) - continue; - - if (ret == H_TOO_HARD) + if (ret != H_SUCCESS) { + kvmppc_clear_tce(stit->tbl, entry); goto unlock_exit; - - WARN_ON_ONCE(1); - kvmppc_clear_tce(stit->tbl, entry); + } } kvmppc_tce_put(stt, entry + i, tce); |