Re: [Xen-devel] [PATCH v4 1/8] public / x86: Introduce __HYPERCALL_dm_op...

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
[snip]
> > +
> > +    va_start(args, nr_bufs);
> > +    for (idx = 0; idx < nr_bufs; idx++)
> 
> Coding style.

Ah, yes.

> 
> > +
> > +int compat_dm_op(domid_t domid,
> > +                 unsigned int nr_bufs,
> > +                 COMPAT_HANDLE_PARAM(compat_dm_op_buf_t) bufs)
> > +{
> > +    struct xen_dm_op_buf *nat;
> > +    unsigned int i;
> > +    int rc = -EFAULT;
> > +
> > +    nat = xzalloc_array(struct xen_dm_op_buf, nr_bufs);
> > +    if ( !nat )
> > +        return -ENOMEM;
> > +
> > +    for ( i = 0; i < nr_bufs; i++ )
> > +    {
> > +        struct compat_dm_op_buf cmp;
> > +
> > +        if ( copy_from_compat_offset(&cmp, bufs, i, 1) )
> > +            goto out;
> > +
> > +#define XLAT_dm_op_buf_HNDL_h(_d_, _s_) \
> > +        guest_from_compat_handle((_d_)->h, (_s_)->h)
> > +
> > +        XLAT_dm_op_buf(&nat[i], &cmp);
> > +
> > +#undef XLAT_dm_op_buf_HNDL_h
> > +    }
> > +
> > +    rc = dm_op(domid, nr_bufs, nat);
> > +
> 
> Need to copy back to the original places with copy_to_compat?
> 

No. It's only the array itself that is subject to compat translation and that 
is not copied back.

  Paul

> Wei.

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