On 14/11/2019 17.21, Janosch Frank wrote:
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> ---
> arch/s390/kvm/kvm-s390.c | 19 +++++++++++++------
> 1 file changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 0fa7c6d9ed0e..9820fde04887 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -4432,13 +4432,21 @@ static long kvm_s390_guest_mem_op(struct kvm_vcpu *vcpu,
> if (mop->size > MEM_OP_MAX_SIZE)
> return -E2BIG;
>
> - /* Protected guests move instruction data over the satellite
> + /*
> + * Protected guests move instruction data over the satellite
> * block which has its own size limit
> */
> if (kvm_s390_pv_is_protected(vcpu->kvm) &&
> - mop->size > ((vcpu->arch.sie_block->sidad & 0x0f) + 1) * PAGE_SIZE)
> + mop->size > ((vcpu->arch.sie_block->sidad & 0xff) + 1) * PAGE_SIZE)
> return -E2BIG;
>
> + /* We can currently only offset into the one SIDA page. */
> + if (kvm_s390_pv_is_protected(vcpu->kvm)) {
> + mop->gaddr &= ~PAGE_MASK;
> + if (mop->gaddr + mop->size > PAGE_SIZE)
> + return -EINVAL;
> + }
> +
> if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) {
> tmpbuf = vmalloc(mop->size);
> if (!tmpbuf)
> @@ -4451,6 +4459,7 @@ static long kvm_s390_guest_mem_op(struct kvm_vcpu *vcpu,
> case KVM_S390_MEMOP_LOGICAL_READ:
> if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) {
> if (kvm_s390_pv_is_protected(vcpu->kvm)) {
> + /* We can always copy into the SIDA */
> r = 0;
> break;
> }
> @@ -4461,8 +4470,7 @@ static long kvm_s390_guest_mem_op(struct kvm_vcpu *vcpu,
> if (kvm_s390_pv_is_protected(vcpu->kvm)) {
> r = 0;
> if (copy_to_user(uaddr, (void *)vcpu->arch.sie_block->sidad +
> - (mop->gaddr & ~PAGE_MASK),
> - mop->size))
> + mop->gaddr, mop->size))
> r = -EFAULT;
> break;
> }
> @@ -4485,8 +4493,7 @@ static long kvm_s390_guest_mem_op(struct kvm_vcpu *vcpu,
> if (kvm_s390_pv_is_protected(vcpu->kvm)) {
> r = 0;
> if (copy_from_user((void *)vcpu->arch.sie_block->sidad +
> - (mop->gaddr & ~PAGE_MASK), uaddr,
> - mop->size))
> + mop->gaddr, uaddr, mop->size))
> r = -EFAULT;
> break;
> }
>
That looks better, indeed.
Still, is there a way you could also verify that gaddr references the
right page that is mirrored in the sidad?
Thomas
