Hello,
This is Non-RFC patch series for guest_memfd preservation. After
having multiple discussion across hypervisor liveupdate meeting,
guest_memfd bi-weekly meeting, the design for the basic support of
guest_memfd preservation is final. This series is going to include
guest_memfd which are fully shared and does not support private mem
and backed by PAGE_SIZE pages.
Steps to test:
1. Compile Kernel with CONFIG_LIVEUPDATE_GUEST_MEMFD=y
2. boot kernel with command line: kho=on liveupdate=on
3. run the following kselftest
$ .selftests/kvm/guest_memfd_preservation_test --stage 1
$ <kexec> --reuse-cmdline
$ .selftests/kvm/guest_memfd_preservation_test --stage 2
NOTE: Assert the following:
$ ls /dev/liveupdate
$ ls /dev/kvm
$ dmesg | grep liveupdate # (should have kvm_vm_luo &&
# guest_memfd_luo handler registered)
The changes are rebased on:
kvm/next + liveupdate/next (merge) + [3] + [4] + [5]
Where,
[3]: luo: conversion of serialized_data to KHOSER_PTR
[4]: luo: APIs to retrieve file internally from session
[5]: selftests: liveupdate sefltests library
Here is the github repo:
https://github.com/tar-unix/linux/tree/gmem-pre
V3 <- RFC V2 [2]
1. Finalize the design
2. resolve sashiko reported bugs
3. Use of KHOSER_PTR instead of raw serialized_data as per [3]
RFC V2 [2] <- RFC V1 [1]
1. Removed mem_attr_array as it is not needed for fully-shared
2. Removed pre-faulted condition
3. Added vm_type preservation for ARM64.
4. Removed liveupdate_get_file_incoming api patch as it is sent
separately [4] by Samiullah.
[1] https://lore.kernel.org/all/[email protected]/
[2]
https://lore.kernel.org/all/c054ba0fb2639932bbe354420d3f4f84cce84905.1780676742.git.taruns...@google.com/
[3] https://lore.kernel.org/all/[email protected]/
[4] https://lore.kernel.org/all/[email protected]/
[5] https://lore.kernel.org/all/[email protected]/
Tarun Sahu (9):
liveupdate: Add LIVEUPDATE_GUEST_MEMFD config option
kvm: Prepare core VM structs and helpers for LUO support
kvm: kvm_luo: Allow kvm preservation with LUO
kvm: guest_memfd: Move internal definitions and helper to new header
kvm: guest_memfd: Add support for freezing and unfreezing mappings
kvm: guest_memfd_luo: add support for guest_memfd preservation
docs: add documentation for guest_memfd preservation via LUO
selftests: kvm: Split ____vm_create() to expose init helpers
selftests: kvm: Add guest_memfd_preservation_test
Documentation/core-api/liveupdate.rst | 1 +
Documentation/liveupdate/vmm.rst | 107 ++++
MAINTAINERS | 14 +
include/linux/kho/abi/kvm.h | 106 ++++
include/linux/kvm_host.h | 14 +
kernel/liveupdate/Kconfig | 15 +
tools/testing/selftests/kvm/Makefile.kvm | 6 +-
.../kvm/guest_memfd_preservation_test.c | 236 +++++++++
.../testing/selftests/kvm/include/kvm_util.h | 2 +
tools/testing/selftests/kvm/lib/kvm_util.c | 26 +-
virt/kvm/Makefile.kvm | 1 +
virt/kvm/guest_memfd.c | 185 +++++--
virt/kvm/guest_memfd.h | 44 ++
virt/kvm/guest_memfd_luo.c | 497 ++++++++++++++++++
virt/kvm/kvm_luo.c | 195 +++++++
virt/kvm/kvm_main.c | 94 +++-
virt/kvm/kvm_mm.h | 15 +
17 files changed, 1477 insertions(+), 81 deletions(-)
create mode 100644 Documentation/liveupdate/vmm.rst
create mode 100644 include/linux/kho/abi/kvm.h
create mode 100644 tools/testing/selftests/kvm/guest_memfd_preservation_test.c
create mode 100644 virt/kvm/guest_memfd.h
create mode 100644 virt/kvm/guest_memfd_luo.c
create mode 100644 virt/kvm/kvm_luo.c
--
2.55.0.rc0.786.g65d90a0328-goog
