From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <Ian.Campbell@citrix.com>
Subject: Re: [Xen-devel] Re: [PATCH v2] xen network backend driver
Date: Fri, 25 Feb 2011 15:35:53 +0000
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On Thu, 2011-02-24 at 13:23 +0000, Ian Campbell wrote:
> 
> > > +
> > > +     if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op,
> 1))
> > > +             BUG();
> > 
> > How about something less severe? Say return the error code?
> 
> Yes, I folded this into the following check of op.status. 

I revisited this and HYPERVISOR_grant_table_op has multicall like
semantics and a failure of the hypercall itself is a serious bug in the
calling kernel, akin to a page fault on kernel memory or similar so I
think a BUG() is the appropriate response.

Failures of the type which a guest may cause are the GNTST_* error codes
found in the op.status field an are handled appropriately gracefully.

Ian.