Add a new function to query whether hypercall buffers are always safe
to access by the hypervisor or might result in EFAULT.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
When splitting out various functionality from libxc into tools/libs/*
I attempted to make it possible to avoid callers being unnecessarily
exposed to the xentoollog interface by providing a typedef of the
xentoollog_logger handle in each of the headers.
However such typedefs are not allowed in C, instead it is necessary to
forward declare the struct and then use the struct xentoollog_logger
variant in the prototypes.
It appears that older gcc (e.g. 4.4) complains about this issue while
newer ones (e.g. 4.9) are more tolerant unless -pedantic-errors is
used, this was a deliberate change
https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=ce3765bf44e49ef0568a1ad4a0b7f807591d6412
As well as tools/libs/* it is also now necessary to give libvchan the
same treatment, since it previously inhereted the typedef via one of
tools/libs/*.
Reported-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Much like for gnttab and foreignmemory xencall hypercall buffers need
care.
Evtchn is a bit simpler (no magic mappings) but may not work from
parent + child simultaneously, document "parent only" since it is
consistent with the others.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
This behaviour has been confirmed by inspection on:
- Linux
- NetBSD & FreeBSD (NB: hcall->retval is the hypercall return value
only for values >= 0. For negative values the underlying privcmd
driver translates the value from Xen to {Net,Free}BSD errno space
and returns it as the result of the ioctl, which becomes
ret=-1/errno=EFOO in userspace)
- MiniOS (which takes care of errno in this library)
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: Roger Pau Monné <roger.pau@citrix.com>
libxencall will provide a stable API and ABI for calling hypercalls
(although those hypercalls themselves may not have a stable API). As
well as the hypercall buffer infrastructure needed in order to safely
provide pointer arguments to hypercalls.
libxenctrl encapsulates a instance of this interface, so users of that
library are not currently subjected to any actual changes. However all
hypercalls made internally by libxc now use the correct interface. It
is expected that most users of this library will be other libraries
providing a higher level interface, rather than applications directly.
Only the basic functionality to allocate hypercall safe memory is
moved, the type safe stuff and bounce buffers remain in libxc.
Note that the functionality to map foreign pages using privcmd is not
yet moved, meaning that an xc_interface will now contain two open
privcmd file descriptors. Foreign memory mapping is logically separate
functionality and will be moved into its own library.
The new library uses a version script to ensure that only expected
symbols are exported and to version them such that ABI guarantees can
be kept in the future.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
[ ijc -- updated MINIOS_UPSTREAM_REVISION and QEMU_TRADITIONAL_REVISION ]
Juergen Gross
Ian Campbell