This is RFC V2 for 'fake DAX' flushing interface sharing for review. This patchset has two main parts: - Guest virtio-pmem driver Guest driver reads persistent memory range from paravirt device and registers with 'nvdimm_bus'. 'nvdimm/pmem' driver uses this information to allocate persistent memory range. Also, we have implemented guest side of VIRTIO flushing interface. - Qemu virtio-pmem device It exposes a persistent memory range to KVM guest which at host side is file backed memory and works as persistent memory device. In addition to this it provides virtio device handling of flushing interface. KVM guest performs Qemu side asynchronous sync using this interface. Changes from previous RFC[1]: - Reuse existing 'pmem' code for registering persistent memory and other operations instead of creating an entirely new block driver. - Use VIRTIO driver to register memory information with nvdimm_bus and create region_type accordingly. - Call VIRTIO flush from existing pmem driver. Details of project idea for 'fake DAX' flushing interface is shared [2] & [3]. Pankaj Gupta (2): Add virtio-pmem guest driver pmem: device flush over VIRTIO [1] https://marc.info/?l=linux-mm&m=150782346802290&w=2 [2] https://www.spinics.net/lists/kvm/msg149761.html [3] https://www.spinics.net/lists/kvm/msg153095.html drivers/nvdimm/region_devs.c | 7 ++ drivers/virtio/Kconfig | 12 +++ drivers/virtio/Makefile | 1 drivers/virtio/virtio_pmem.c | 118 +++++++++++++++++++++++++++++++++++++++ include/linux/libnvdimm.h | 4 + include/uapi/linux/virtio_ids.h | 1 include/uapi/linux/virtio_pmem.h | 58 +++++++++++++++++++ 7 files changed, 201 insertions(+)
