From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pankaj Gupta Subject: Re: [Qemu-devel] [RFC v3 0/2] kvm "fake DAX" device flushing Date: Tue, 28 Aug 2018 08:39:53 -0400 (EDT) Message-ID: <16583366.7193885.1535459993521.JavaMail.zimbra@redhat.com> References: <20180713075232.9575-1-pagupta@redhat.com> <1328e543-0276-8f33-1744-8baa053023c4@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1328e543-0276-8f33-1744-8baa053023c4-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" To: David Hildenbrand Cc: kwolf-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, nilal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, jack-AlSwsSmVLrQ@public.gmane.org, xiaoguangrong eric , kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, riel-ebMLmSuQjDVBDgjK7y7TUQ@public.gmane.org, linux-nvdimm-y27Ovi1pjclAfugRpC6u6w@public.gmane.org, mst-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, ross zwisler , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, qemu-devel-qX2TKyscuCcdnm+yROfE0A@public.gmane.org, hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, pbonzini-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, stefanha-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, niteshnarayanlal-PkbjNfxxIARBDgjK7y7TUQ@public.gmane.org, imammedo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, lcapitulino-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org List-Id: linux-nvdimm@lists.01.org Hi David, > > 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. o.k I will update the guest virtio-pmem and Qemu current changes and share with you. BTW previous version is here: https://marc.info/?l=kvm&m=153146839627143&w=2 Thanks, Pankaj > > -- > > Thanks, > > David / dhildenb > >