[RFC PATCH kvmtool v1 00/32] Add support for restricted guest memory in kvmtool

[Fuad Tabba <tabba@google.com>]

The main goal of this patch series is to add support for the the
restricted guest memory proposali (V9) [1] to kvmtool (V10 was
released today [2]). This proposal is still being discussed, but
it seems to be close to its final form. The intention is that
the restricted guest memory would be used in various confidential
computing environments, such as TDX and pKVM.

This series is intended to work with the kernel in of the
V9 proposal [1], in addition to work to port it to
pKVM [3]. It has been tested on qemu/arm64.

The patch series is divided as follows:

Patches 1--4:
General fixes and tidying up

Patches 5--18:
Move kvmtool from allocating guest vm memory using anonymous mmap
to using memfd/ftruncate. The main motivation is to support the
fd-based kvm guest memory proposal [1, 2]. It also facilitates using
ipc memory sharing should that be needed in the future. It also
moves kvmtool to using only a file based backend for guest memory
allocation, with the file descriptor being the canonical
reference to guest memory. The idea is to refer to all allocated
guest memory via a file descriptor.

Patches 19--28:
Add architecture-independent framework to support restricted
guest memory.

Patches 29--32:
Add pKVM-specific (arm64) support for restricted guest memory.

I had posted a subset of this series earlier covering patches
1--18  [4]. This series incorporates fixes and suggestions from
Alex into those patches.

Cheers,
/fuad

[1] https://lore.kernel.org/all/20221025151344.3784230-1-chao.p.peng@linux.intel.com/
[2] https://lore.kernel.org/all/20221202061347.1070246-1-chao.p.peng@linux.intel.com/
[3] https://android-kvm.googlesource.com/kvmtool/+/refs/heads/tabba/fdmem-v9-core
[4] https://lore.kernel.org/all/20221115111549.2784927-1-tabba@google.com/

Fuad Tabba (31):
  Initialize the return value in kvm__for_each_mem_bank()
  Remove newline from end of die() aborts
  Make mmap_hugetlbfs() static
  Rename parameter in mmap_anon_or_hugetlbfs()
  Add hostmem va to debug print
  Factor out getting the hugetlb block size
  Use memfd for hugetlbfs when allocating guest ram
  Make blk_size a parameter and pass it to mmap_hugetlbfs()
  Use memfd for all guest ram allocations
  Allocate pvtime memory with memfd
  Allocate vesa memory with memfd
  Add a function that allocates aligned memory if specified
  Use new function to align memory
  Remove struct fields and code used for alignment
  Replace kvm__arch_delete_ram() with kvm__delete_ram()
  Remove no-longer used macro
  Factor out set_user_memory_region code
  Pass the memory file descriptor and offset when registering ram
  Add memfd_restricted system call
  Add kvm linux headers and structure extensions for restricted_fd
  Add option for enabling restricted memory for guests
  Change guest ram mapping from private to shared
  Change pvtime mapping from private to shared
  Change vesa mapping from private to shared
  Allocate guest memory as restricted if needed
  Use the new fd-based extended memory region
  Track the memfd in the bank
  Add functions for mapping/unmapping guest memory
  pkvm: Enable exit hypercall capability if supported
  pkvm: Handle (un)share hypercalls coming from the guest
  pkvm: Unmap all guest memory after initialization

Will Deacon (1):
  pkvm: Add option to spawn a protected vm in pkvm

 arm/aarch32/include/kvm/kvm-arch.h |   1 +
 arm/aarch64/include/asm/kvm.h      |   7 +
 arm/aarch64/include/kvm/kvm-arch.h |   1 +
 arm/aarch64/kvm.c                  |  26 +++
 arm/aarch64/pvtime.c               |  20 +-
 arm/fdt.c                          |  18 ++
 arm/include/arm-common/fdt-arch.h  |   2 +-
 arm/include/arm-common/kvm-arch.h  |   7 -
 arm/kvm-cpu.c                      |  58 ++++++
 arm/kvm.c                          |  41 ++--
 arm/pci.c                          |   3 +
 builtin-run.c                      |   7 +
 framebuffer.c                      |   2 +
 hw/cfi_flash.c                     |   4 +-
 hw/vesa.c                          |  17 +-
 include/kvm/framebuffer.h          |   1 +
 include/kvm/kvm-config.h           |   2 +
 include/kvm/kvm.h                  |  25 ++-
 include/kvm/util.h                 |   5 +-
 include/linux/kvm.h                |  19 ++
 kvm.c                              | 301 ++++++++++++++++++++++++++---
 mips/kvm.c                         |  11 +-
 powerpc/kvm.c                      |   7 +-
 riscv/include/kvm/kvm-arch.h       |   7 -
 riscv/kvm.c                        |  26 +--
 util/util.c                        | 131 ++++++++++---
 vfio/core.c                        |   3 +-
 virtio/pci-modern.c                |   3 +
 x86/kvm.c                          |  11 +-
 29 files changed, 606 insertions(+), 160 deletions(-)


base-commit: e17d182ad3f797f01947fc234d95c96c050c534b
-- 
2.39.0.rc0.267.gcb52ba06e7-goog