>>> On 04.09.18 at 14:23, <paul.durr...@citrix.com> wrote: >> From: Jan Beulich [mailto:jbeul...@suse.com] >> Sent: 04 September 2018 12:50 >> >> >>> On 23.08.18 at 11:47, <paul.durr...@citrix.com> wrote: >> > +int compat_one_iommu_op(compat_iommu_op_buf_t *buf) >> > +{ >> > + compat_iommu_op_t cmp; >> > + xen_iommu_op_t nat; >> > + int rc; >> > + >> > + if ( buf->size < sizeof(cmp) ) >> > + return -EFAULT; >> > + >> > + if ( copy_from_compat((void *)&cmp, buf->h, sizeof(cmp)) ) >> > + return -EFAULT; >> > + >> > + if ( cmp.pad ) >> > + return -EINVAL; >> > + >> > + rc = xsm_iommu_op(XSM_PRIV, current->domain, cmp.op); >> > + if ( rc ) >> > + return rc; >> > + >> > + XLAT_iommu_op(&nat, &cmp); >> > + >> > + iommu_op(&nat); >> > + >> > + XLAT_iommu_op(&cmp, &nat); >> > + >> > + if ( __copy_field_to_compat(compat_handle_cast(buf->h, >> > + compat_iommu_op_t), >> > + &cmp, status) ) >> >> Since you're only after the status field, perhaps better to avoid the >> full-blown reverse XLAT_iommu_op() and copy just that one field? >> > > I kind of like the fact that the two calls mirror each other so I'd prefer > to keep it.
Would you mind looking at the generated code (once you have a few sub-ops in place)? If the compiler manages to remove most of the cruft, I'd be fine keeping it as is. If, however, a whole lot of extra code gets generated, I'd really like to ask to use the shorter form. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
