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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.1 MIME-Version: 1.0 In-Reply-To: <20200203131957.383915-22-borntraeger@de.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Content-Transfer-Encoding: quoted-printable Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org > #ifdef CONFIG_KVM_S390_PROTECTED_VIRTUALIZATION_HOST > +static long kvm_s390_guest_sida_op(struct kvm_vcpu *vcpu, > + struct kvm_s390_mem_op *mop) > +{ > + int r =3D 0; > + void __user *uaddr =3D (void __user *)mop->buf; Reverse christmas tree :) > + > + if (mop->flags || !mop->size) > + return -EINVAL; > + > + if (mop->size > sida_size(vcpu->arch.sie_block)) > + return -E2BIG; Should be caught by the check below as well (or is this an implicit overflow check? - see below). > + > + if (mop->size + mop->offset > sida_size(vcpu->arch.sie_block)) > + return -E2BIG; > + Do we have to care about overflows? (at least the offset is 32-bit, didn't check the size :)) > + switch (mop->op) { > + case KVM_S390_MEMOP_SIDA_READ: > + r =3D 0; > + if (copy_to_user(uaddr, (void *)sida_origin(vcpu->arch.sie_block) + > + mop->offset, mop->size)) > + r =3D -EFAULT; > + > + break; > + case KVM_S390_MEMOP_SIDA_WRITE: > + r =3D 0; > + if (copy_from_user((void *)vcpu->arch.sie_block->sidad + > + mop->offset, uaddr, mop->size)) > + r =3D -EFAULT; > + break; > + } > + return r; > +} > + > static int kvm_s390_handle_pv_vcpu(struct kvm_vcpu *vcpu, > struct kvm_pv_cmd *cmd) > { > @@ -4708,6 +4743,20 @@ long kvm_arch_vcpu_ioctl(struct file *filp, > r =3D kvm_s390_handle_pv_vcpu(vcpu, &args); > break; > } > + case KVM_S390_SIDA_OP: { > + struct kvm_s390_mem_op mem_op; > + > + if (!kvm_s390_pv_is_protected(vcpu->kvm)) { > + r =3D -EINVAL; > + break; > + } Could we race against a VM_DESTROY? Should we protect somehow? [...] > -/* for KVM_S390_MEM_OP */ > +/* for KVM_S390_MEM_OP and KVM_S390_SIDA_OP */ > struct kvm_s390_mem_op { > /* in */ > __u64 gaddr; /* the guest address */ > @@ -475,11 +475,17 @@ struct kvm_s390_mem_op { > __u32 op; /* type of operation */ > __u64 buf; /* buffer in userspace */ > __u8 ar; /* the access register number */ > - __u8 reserved[31]; /* should be set to 0 */ > + __u8 reserved21[3]; /* should be set to 0 */ > + __u32 offset; /* offset into the sida */ maybe "side_offset"? or define a union, overlying the ar (because that obviously doesn't apply to this memop). So eventually different layout for different memop. --=20 Thanks, David / dhildenb