1. 02 Mar, 2019 6 commits
  2. 01 Mar, 2019 1 commit
  3. 28 Feb, 2019 1 commit
    • Alexey Kardashevskiy's avatar
      powerpc/powernv/ioda: Fix locked_vm counting for memory used by IOMMU tables · 11f5acce
      Alexey Kardashevskiy authored
      We store 2 multilevel tables in iommu_table - one for the hardware and
      one with the corresponding userspace addresses. Before allocating
      the tables, the iommu_table_group_ops::get_table_size() hook returns
      the combined size of the two and VFIO SPAPR TCE IOMMU driver adjusts
      the locked_vm counter correctly. When the table is actually allocated,
      the amount of allocated memory is stored in iommu_table::it_allocated_size
      and used to decrement the locked_vm counter when we release the memory
      used by the table; .get_table_size() and .create_table() calculate it
      independently but the result is expected to be the same.
      
      However the allocator does not add the userspace table size to
      .it_allocated_size so when we destroy the table because of VFIO PCI
      unplug (i.e. VFIO container is gone but the userspace keeps running),
      we decrement locked_vm by just a half of size of memory we are
      releasing.
      
      To make things worse, since we enabled on-demand allocation of
      indirect levels, it_allocated_size contains only the amount of memory
      actually allocated at the table creation time which can just be a
      fraction. It is not a problem with incrementing locked_vm (as
      get_table_size() value is used) but it is with decrementing.
      
      As the result, we leak locked_vm and may not be able to allocate more
      IOMMU tables after few iterations of hotplug/unplug.
      
      This sets it_allocated_size in the pnv_pci_ioda2_ops::create_table()
      hook to what pnv_pci_ioda2_get_table_size() returns so from now on we
      have a single place which calculates the maximum memory a table can
      occupy. The original meaning of it_allocated_size is somewhat lost now
      though.
      
      We do not ditch it_allocated_size whatsoever here and we do not call
      get_table_size() from vfio_iommu_spapr_tce.c when decrementing
      locked_vm as we may have multiple IOMMU groups per container and even
      though they all are supposed to have the same get_table_size()
      implementation, there is a small chance for failure or confusion.
      
      Fixes: 090bad39 ("powerpc/powernv: Add indirect levels to it_userspace")
      Signed-off-by: default avatarAlexey Kardashevskiy <aik@ozlabs.ru>
      Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      11f5acce
  4. 27 Feb, 2019 2 commits
  5. 26 Feb, 2019 9 commits
  6. 25 Feb, 2019 6 commits
  7. 23 Feb, 2019 15 commits