[Xen-devel] [RFC][PATCH 3/6] HVM PCI Passthrough (non-IOMMU)

["Guy Zana" <guy@xxxxxxxxxxxx>]

1to1.patch:

    - Added functionality in libxc / Hypervisor in order to populate a
HVM P2M
      table in a 1:1 fashion. This is imperative for DMA to function
correctly.
    - Early setup of the e820 memory map table is done in order to
"steal"      
      memory from dom0 and mark that stolen memory as NEO_1TO1, later
those  
      would be given to NativeDom.
    - The first 12MB of NativDom are remapped, because Xen resides in
      this region in x86_32. If a DMA address is to be allocated in that

      region, there could be unpredicted result. This could be solved by
moving 
      Xen up in the x86_32 arch, or by abandoning it and using x86_64
where Xen 
      is already relocated to high memory (currently, Neocleus' patches
support 
      x86_32).
    - Memory protection: Regions that are marked "usable" for Dom0, are
being 
      marked "reserved" for NativeDom and the corresponding mfns are not
being 
      populated in NativeDom's P2M table, whenever the guest accesses
those 
      addresses, a mm_access callback is called, which is calling 
      domain_crash_synchronic: this is used for debugging purposes only.
A more 
      mature implementation should inject a #GPF or crash the NativeDom.
    - New hypercalls: 
        HVMOP_copy_nativedom_e820_map
        XENMEM_populate_1to1_physmap
    - Known bugs: 
        - domain destruction isn't handled, so you have only one chance 
          to launch NativeDom on each boot.
        - Known issue: this haven't been figured out completely yet, but
it 
          seems that the 32bit bios relocation code exceeds available
memory. 
          Search for "NEO TODO: (hack) malloc size multipled by 20" to
see the 
          temporary hack that overcomes this...

Signed-off-by: Guy Zana <guy@xxxxxxxxxxxx>

Attachment: 1to1.patch
Description: 1to1.patch

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