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Re: [Qemu-devel] [RFC v3 0/2] kvm "fake DAX" device flushing
From: |
David Hildenbrand |
Subject: |
Re: [Qemu-devel] [RFC v3 0/2] kvm "fake DAX" device flushing |
Date: |
Tue, 28 Aug 2018 14:13:24 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 |
On 13.07.2018 09:52, Pankaj Gupta wrote:
> This is RFC V3 for 'fake DAX' flushing interface sharing
> for review. This patchset has two 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 RFC v2:
> - Add flush function in the nd_region in place of switching
> on a flag - Dan & Stefan
> - Add flush completion function with proper locking and wait
> for host side flush completion - Stefan & Dan
> - Keep userspace API in uapi header file - Stefan, MST
> - Use LE fields & New device id - MST
> - Indentation & spacing suggestions - MST & Eric
> - Remove extra header files & add licensing - Stefan
>
> Changes from RFC v1:
> - 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/nd.h | 1
> drivers/nvdimm/pmem.c | 4
> drivers/nvdimm/region_devs.c | 24 +++-
> drivers/virtio/Kconfig | 9 +
> drivers/virtio/Makefile | 1
> drivers/virtio/virtio_pmem.c | 190
> +++++++++++++++++++++++++++++++++++++++
> include/linux/libnvdimm.h | 5 -
> include/linux/virtio_pmem.h | 44 +++++++++
> include/uapi/linux/virtio_ids.h | 1
> include/uapi/linux/virtio_pmem.h | 40 ++++++++
> 10 files changed, 310 insertions(+), 9 deletions(-)
>
Hi Pankaj,
do you have a branch for the QEMU part somewhere available? I want to
see how this works with MemoryDevice changes.
--
Thanks,
David / dhildenb
- Re: [Qemu-devel] [RFC v3 0/2] kvm "fake DAX" device flushing,
David Hildenbrand <=