[Xen-devel] [PATCH v2 00/55] Switch to domheap for Xen PTEs

[Hongyan Xia <hongyax@xxxxxxxxxx>]

This series is mostly Wei's effort to switch from xenheap to domheap for
Xen page tables. In addition, I have also merged several bug fixes from
my "Remove direct map from Xen" series [1]. As the title suggests, this
series switches from xenheap to domheap for Xen PTEs.

This is needed to achieve the ultimate goal of removing the
always-mapped direct map from Xen. To work without an always-mapped
direct map, Xen PTE manipulations themselves must not rely on it.
Unfortunately, PTE APIs currently use the xenheap that does not work
without the direct map. By switching to domheap APIs, it is much easier
for us to break the reliance on the direct map later on, not only for
PTEs but for all other memory allocations as well.

I have broken down the direct map removal series into two. This series
is the first batch. The patches change the life cycle of Xen PTEs from
alloc-free to alloc-map-unmap-free, which means PTEs must be explicitly
mapped and unmapped. This also makes sense to be the first batch from a
stability PoV, since this is just an API change and the direct map has
not been actually removed. Further, the map and unmap in the release
build use the direct map as a fast path, so there is also no performance
degredation in a release build.

I have tested both debug and release build on bare-metal and nested
virtualisation. I am able to run PV and HVM guests and XTF tests without
crashes so far on x86. I am able to build on AArch64.

This series is at https://xenbits.xen.org/git-http/people/hx242/xen.git,
xen_pte_map branch.

---
Changed since v1:
- squash some commits
- merge bug fixes into this first batch
- rebase against latest master

[1]:
https://lists.xenproject.org/archives/html/xen-devel/2019-09/msg02647.html

Wei Liu (55):
  x86/mm: defer clearing page in virt_to_xen_lXe
  x86: move some xen mm function declarations
  x86: introduce a new set of APIs to manage Xen page tables
  x86/mm: introduce l{1,2}t local variables to map_pages_to_xen
  x86/mm: introduce l{1,2}t local variables to modify_xen_mappings
  x86/mm: map_pages_to_xen should have one exit path
  x86/mm: add an end_of_loop label in map_pages_to_xen
  x86/mm: make sure there is one exit path for modify_xen_mappings
  x86/mm: add an end_of_loop label in modify_xen_mappings
  x86/mm: change pl2e to l2t in virt_to_xen_l2e
  x86/mm: change pl1e to l1t in virt_to_xen_l1e
  x86/mm: change pl3e to l3t in virt_to_xen_l3e
  x86/mm: rewrite virt_to_xen_l3e
  x86/mm: rewrite xen_to_virt_l2e
  x86/mm: rewrite virt_to_xen_l1e
  x86/mm: switch to new APIs in map_pages_to_xen
  x86/mm: drop lXe_to_lYe invocations in map_pages_to_xen
  x86/mm: switch to new APIs in modify_xen_mappings
  x86/mm: drop lXe_to_lYe invocations from modify_xen_mappings
  x86/mm: switch to new APIs in arch_init_memory
  x86_64/mm: introduce pl2e in paging_init
  x86_64/mm: switch to new APIs in paging_init
  x86_64/mm: drop l4e_to_l3e invocation from paging_init
  x86_64/mm.c: remove code that serves no purpose in setup_m2p_table
  x86_64/mm: introduce pl2e in setup_m2p_table
  x86_64/mm: switch to new APIs in setup_m2p_table
  x86_64/mm: drop lXe_to_lYe invocations from setup_m2p_table
  efi: use new page table APIs in copy_mapping
  efi: avoid using global variable in copy_mapping
  efi: use new page table APIs in efi_init_memory
  efi: add emacs block to boot.c
  efi: switch EFI L4 table to use new APIs
  x86/smpboot: add emacs block
  x86/smpboot: clone_mapping should have one exit path
  x86/smpboot: switch pl3e to use new APIs in clone_mapping
  x86/smpboot: switch pl2e to use new APIs in clone_mapping
  x86/smpboot: switch pl1e to use new APIs in clone_mapping
  x86/smpboot: drop lXe_to_lYe invocations from cleanup_cpu_root_pgt
  x86: switch root_pgt to mfn_t and use new APIs
  x86/shim: map and unmap page tables in replace_va_mapping
  x86_64/mm: map and unmap page tables in m2p_mapped
  x86_64/mm: map and unmap page tables in share_hotadd_m2p_table
  x86_64/mm: map and unmap page tables in destroy_compat_m2p_mapping
  x86_64/mm: map and unmap page tables in destroy_m2p_mapping
  x86_64/mm: map and unmap page tables in setup_compat_m2p_table
  x86_64/mm: map and unmap page tables in cleanup_frame_table
  x86_64/mm: map and unmap page tables in subarch_init_memory
  x86_64/mm: map and unmap page tables in subarch_memory_op
  x86/smpboot: remove lXe_to_lYe in cleanup_cpu_root_pgt
  x86/pv: properly map and unmap page tables in mark_pv_pt_pages_rdonly
  x86/pv: properly map and unmap page table in dom0_construct_pv
  x86: remove lXe_to_lYe in __start_xen
  x86/mm: drop old page table APIs
  x86: switch to use domheap page for page tables
  x86/mm: drop _new suffix for page table APIs

 xen/arch/x86/domain.c           |  15 +-
 xen/arch/x86/domain_page.c      |  12 +-
 xen/arch/x86/efi/runtime.h      |  12 +-
 xen/arch/x86/mm.c               | 482 ++++++++++++++++++++++----------
 xen/arch/x86/pv/dom0_build.c    |  41 ++-
 xen/arch/x86/pv/domain.c        |   2 +-
 xen/arch/x86/pv/shim.c          |  20 +-
 xen/arch/x86/setup.c            |  10 +-
 xen/arch/x86/smpboot.c          | 171 +++++++----
 xen/arch/x86/x86_64/mm.c        | 267 +++++++++++++-----
 xen/common/efi/boot.c           |  84 ++++--
 xen/common/efi/efi.h            |   3 +-
 xen/common/efi/runtime.c        |   8 +-
 xen/include/asm-x86/mm.h        |  16 ++
 xen/include/asm-x86/page.h      |  10 -
 xen/include/asm-x86/processor.h |   2 +-
 16 files changed, 819 insertions(+), 336 deletions(-)

-- 
2.17.1


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