Some hypercalls, memory-op in particular, can return values requiring
more than 31 bits to represent. Hence the underlying layers need to make
sure they won't truncate such values. (Note that for Solaris the
function also gets renamed, to match the other OSes.)
Due to them merely propagating ioctl()'s return value, this change is
benign on Linux and Solaris. IOW there's an actual effect here only for
the BSDs and MiniOS, but even then further adjustments are needed at the
xencall<N>() level.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <iwj@xenproject.org>
Make the bufdev and non-bufdev messages distinct, and always print the
non-constant argument (ie, the size).
This assists diagnosis.
CC: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Hans van Kranenburg <hans@knorrie.org>
Acked-by: Wei Liu <wei.liu2@citrix.com>
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>
Instead of using anonymous memory for hypercall buffers which is then
locked into memory, use the hypercall buffer device of the Linux
privcmd driver if available.
This has the advantage of needing just a single mmap() for allocating
the buffer and page migration or compaction can't make the buffer
unaccessible for the hypervisor.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
In some cases this replaces an FD_CLOEXEC dance, in others it is new.
Linux has had O_CLOEXEC since 2.6.23 (October 2007), so we can rely on
it from Xen 4.7 I think. Some libc headers may still lack the
definition, so we take care of that if need be by defining to 0 (on
the premise that such an old glibc might barf on O_CLOEXEC even if the
kernel may or may not be so old).
All stable versions of FreeBSD support O_CLOEXEC (10.2, 9.3 and 8.4),
and we assume the libc there does too.
Remove various comments about having to take responsibility for this
(since really it is just hygiene, politeness, not a requirement) and
the reasons for using O_CLOEXEC seem pretty straightforward.
Backends for other OSes are untouched.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Cc: Roger.Pau@citrix.com
Cc: jbeulich@suse.com
This avoids a potential issue with a fork after allocation but before
madvise.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Wei Liu <wei.liu2@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 ]
Jan Beulich
Ian Jackson
Juergen Gross
Wei Liu
Ian Campbell