QEMU writes to vNVDIMM backends in the vNVDIMM label emulation and live migration. If the backend is on the persistent memory, QEMU needs to take proper operations to ensure its writes persistent on the persistent memory. Otherwise, a host power failure may result in the loss the guest data on the persistent memory.
This v3 patch series is based on Marcel's patch "mem: add share parameter to memory-backend-ram" [1] because of the changes in patch 1. [1] https://lists.gnu.org/archive/html/qemu-devel/2018-02/msg03858.html Previous versions can be found at v3: https://lists.gnu.org/archive/html/qemu-devel/2018-02/msg04365.html v2: https://lists.gnu.org/archive/html/qemu-devel/2018-02/msg01579.html v1: https://lists.gnu.org/archive/html/qemu-devel/2017-12/msg05040.html Changes in v4: * (Patch 2) Fix compilation errors found by patchew. Changes in v3: * (Patch 5) Add a is_pmem flag to ram_handle_compressed() and handle PMEM writes in it, so we don't need the _common function. * (Patch 6) Expose qemu_get_buffer_common so we can remove the unnecessary qemu_get_buffer_to_pmem wrapper. * (Patch 8) Add a is_pmem flag to xbzrle_decode_buffer() and handle PMEM writes in it, so we can remove the unnecessary xbzrle_decode_buffer_{common, to_pmem}. * Move libpmem stubs to stubs/pmem.c and fix the compilation failures of test-{xbzrle,vmstate}.c. Changes in v2: * (Patch 1) Use a flags parameter in file ram allocation functions. * (Patch 2) Add a new option 'pmem' to hostmem-file. * (Patch 3) Use libpmem to operate on the persistent memory, rather than re-implementing those operations in QEMU. * (Patch 5-8) Consider the write persistence in the migration path. Haozhong Zhang (8): [1/8] memory, exec: switch file ram allocation functions to 'flags' parameters [2/8] hostmem-file: add the 'pmem' option [3/8] configure: add libpmem support [4/8] mem/nvdimm: ensure write persistence to PMEM in label emulation [5/8] migration/ram: ensure write persistence on loading zero pages to PMEM [6/8] migration/ram: ensure write persistence on loading normal pages to PMEM [7/8] migration/ram: ensure write persistence on loading compressed pages to PMEM [8/8] migration/ram: ensure write persistence on loading xbzrle pages to PMEM backends/hostmem-file.c | 27 +++++++++++++++++++- configure | 35 ++++++++++++++++++++++++++ docs/nvdimm.txt | 14 +++++++++++ exec.c | 20 ++++++++++++--- hw/mem/nvdimm.c | 9 ++++++- include/exec/memory.h | 12 +++++++-- include/exec/ram_addr.h | 28 +++++++++++++++++++-- include/migration/qemu-file-types.h | 2 ++ include/qemu/pmem.h | 27 ++++++++++++++++++++ memory.c | 8 +++--- migration/qemu-file.c | 29 ++++++++++++++-------- migration/ram.c | 49 +++++++++++++++++++++++++++---------- migration/ram.h | 2 +- migration/rdma.c | 2 +- migration/xbzrle.c | 8 ++++-- migration/xbzrle.h | 3 ++- numa.c | 2 +- qemu-options.hx | 9 ++++++- stubs/Makefile.objs | 1 + stubs/pmem.c | 37 ++++++++++++++++++++++++++++ tests/Makefile.include | 4 +-- tests/test-xbzrle.c | 4 +-- 22 files changed, 285 insertions(+), 47 deletions(-) create mode 100644 include/qemu/pmem.h create mode 100644 stubs/pmem.c -- 2.14.1
