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  1. Jan 29, 2016
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  4. Jan 26, 2016
    • Peter Maydell's avatar
      Merge remote-tracking branch 'remotes/sstabellini/tags/xen-20160126-2' into staging · 39c36a05
      Peter Maydell authored
      
      Xen 2016/01/26 with Signed-off-by lines.
      
      # gpg: Signature made Tue 26 Jan 2016 17:20:12 GMT using RSA key ID 70E1AE90
      # gpg: Good signature from "Stefano Stabellini <stefano.stabellini@eu.citrix.com>"
      
      * remotes/sstabellini/tags/xen-20160126-2:
        xen: make it possible to build without the Xen PV domain builder
        xen: domainbuild: reopen libxenctrl interface after forking for domain watcher.
        xen: Use stable library interfaces when they are available.
        xen: Switch uses of xc_map_foreign_{pages,bulk} to use libxenforeignmemory API.
        xen: Switch uses of xc_map_foreign_range into xc_map_foreign_pages
        xen: Switch to libxengnttab interface for compat shims.
        xen: Switch to libxenevtchn interface for compat shims.
        xen_console: correctly cleanup primary console on teardown.
      
      Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
      39c36a05
    • Ian Campbell's avatar
      xen: make it possible to build without the Xen PV domain builder · 64a7ad6f
      Ian Campbell authored
      
      Until the previous patch this relied on xc_fd(), which was only
      implemented for Xen 4.0 and earlier.
      
      Given this wasn't working since Xen 4.0 I have marked this as disabled
      by default.
      
      Removing this support drops the use of a bunch of symbols from
      libxenctrl, specifically:
      
        - xc_domain_create
        - xc_domain_destroy
        - xc_domain_getinfo
        - xc_domain_max_vcpus
        - xc_domain_setmaxmem
        - xc_domain_unpause
        - xc_evtchn_alloc_unbound
        - xc_linux_build
      
      This is another step towards only using Xen libraries which provide a
      stable inteface.
      
      Signed-off-by: default avatarIan Campbell <ian.campbell@citrix.com>
      Reviewed-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
      Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
      64a7ad6f
    • Ian Campbell's avatar
      xen: domainbuild: reopen libxenctrl interface after forking for domain watcher. · 228df5c9
      Ian Campbell authored
      
      Using an existing libxenctrl handle after a fork was never
      particularly safe (especially if foreign mappings existed at the time
      of the fork) and the xc fd has been unavailable for many releases.
      
      Reopen the handle after fork and therefore do away with xc_fd().
      
      Signed-off-by: default avatarIan Campbell <ian.campbell@citrix.com>
      Acked-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
      Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
      228df5c9
    • Ian Campbell's avatar
      xen: Use stable library interfaces when they are available. · 5eeb39c2
      Ian Campbell authored
      
      In Xen 4.7 we are refactoring parts libxenctrl into a number of
      separate libraries which will provide backward and forward API and ABI
      compatiblity.
      
      Specifically libxenevtchn, libxengnttab and libxenforeignmemory.
      
      Previous patches have already laid the groundwork for using these by
      switching the existing compatibility shims to reflect the intefaces to
      these libraries.
      
      So all which remains is to update configure to detect the libraries
      and enable their use. Although they are notionally independent we take
      an all or nothing approach to the three libraries since they were
      added at the same time.
      
      The only non-obvious bit is that we now open a proper xenforeignmemory
      handle for xen_fmem instead of reusing the xen_xc handle.
      
      Build tested with 4.0 .. 4.6 (inclusive) and the patches targetting
      4.7 which adds these libraries.
      
      This uses CONFIG_XEN_CTRL_INTERFACE_VERSION == 471 to cover the
      introduction of these new interfaces.
      
      Signed-off-by: default avatarIan Campbell <ian.campbell@citrix.com>
      Reviewed-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
      Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
      5eeb39c2
    • Ian Campbell's avatar
      xen: Switch uses of xc_map_foreign_{pages,bulk} to use libxenforeignmemory API. · e0cb42ae
      Ian Campbell authored
      
      In Xen 4.7 we are refactoring parts libxenctrl into a number of
      separate libraries which will provide backward and forward API and ABI
      compatiblity.
      
      One such library will be libxenforeignmemory which provides access to
      privileged foreign mappings and which will provide an interface
      equivalent to xc_map_foreign_{pages,bulk}.
      
      The new xenforeignmemory_map() function behaves like
      xc_map_foreign_pages() when the err argument is NULL and like
      xc_map_foreign_bulk() when err is non-NULL, which maps into the shim
      here onto checking err == NULL and calling the appropriate old
      function.
      
      Note that xenforeignmemory_map() takes the number of pages before the
      arrays themselves, in order to support potentially future use of
      variable-length-arrays in the prototype (in the future, when Xen's
      baseline toolchain requirements are new enough to ensure VLAs are
      supported).
      
      In preparation for adding support for libxenforeignmemory add support
      to the <=4.0 and <=4.6 compat code in xen_common.h to allow us to
      switch to using the new API. These shims will disappear for versions
      of Xen which include libxenforeignmemory.
      
      Since libxenforeignmemory will have its own handle type but for <= 4.6
      the functionality is provided by using a libxenctrl handle we
      introduce a new global xen_fmem alongside the existing xen_xc. In fact
      we make xen_fmem a pointer to the existing xen_xc, which then works
      correctly with both <=4.0 (xc handle is an int) and <=4.6 (xc handle
      is a pointer). In the latter case xen_fmem is actually a double
      indirect pointer, but it all falls out in the wash.
      
      Unlike libxenctrl libxenforeignmemory has an explicit unmap function,
      rather than just specifying that munmap should be used, so the unmap
      paths are updated to use xenforeignmemory_unmap, which is a shim for
      munmap on these versions of xen. The mappings in xen-hvm.c do not
      appear to be unmapped (which makes sense for a qemu-dm process)
      
      In fb_disconnect this results in a change from simply mmap over the
      existing mapping (with an implicit munmap) to expliclty unmapping with
      xenforeignmemory_unmap and then mapping the required anonymous memory
      in the same hole. I don't think this is a problem since any other
      thread which was racily touching this region would already be running
      the risk of hitting the mapping halfway through the call. If this is
      thought to be a problem then we could consider adding an extra API to
      the libxenforeignmemory interface to replace a foreign mapping with
      anonymous shared memory, but I'd prefer not to.
      
      Signed-off-by: default avatarIan Campbell <ian.campbell@citrix.com>
      Reviewed-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
      Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
      e0cb42ae
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