From: Pankaj Gupta <pagupta@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
qemu-devel@nongnu.org, linux-nvdimm@ml01.01.org
Cc: jack@suse.cz, stefanha@redhat.com, dan.j.williams@intel.com,
riel@surriel.com, haozhong.zhang@intel.com, nilal@redhat.com,
kwolf@redhat.com, pbonzini@redhat.com, ross.zwisler@intel.com,
david@redhat.com, xiaoguangrong.eric@gmail.com,
hch@infradead.org, marcel@redhat.com, mst@redhat.com,
niteshnarayanlal@hotmail.com, imammedo@redhat.com,
pagupta@redhat.com
Subject: [RFC 0/2] kvm "fake DAX" device flushing
Date: Thu, 5 Apr 2018 16:18:31 +0530 [thread overview]
Message-ID: <20180405104834.10457-1-pagupta@redhat.com> (raw)
We are sharing RFC version of 'fake DAX' flushing
interface for feedback. This is still work in progress
and not yet ready for merging.
Prototype implements two major parts:
- 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 a virtio flushing interface for KVM guest to do a Qemu side sync for
guest DAX persistent memory range.
- Guest virtio-pmem 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.
Changes from previous RFC:
- Reuse existing 'pmem' code instead of creating an entirely new block driver.
- Use VIRTIO driver to register memory information with nvdimm_bus and create
region_type accordingly.
- Use VIRTIO flushing interface from existing pmem driver code based on
registered flushign mechanism.
We have done the implementation based on suggestions here [1]. Previous RFC is
shared here [2]. Details of project idea for 'fake DAX' flushing is shared
here [3] & [4].
[1] https://marc.info/?l=linux-mm&m=150782346802290&w=2
[2] https://marc.info/?l=kvm&m=151630416506527&w=2
[3] https://www.spinics.net/lists/kvm/msg149761.html
[4] https://www.spinics.net/lists/kvm/msg153095.html
Work yet to be done:
- Qemu RAM address handling independent of PC-DIMM so that memory
operations(get_free_address) can be used for VIRTIO device type as well.
(David Hildenbrand CCed has a prototype for this).
- Qemu device flush functionality trigger with guest fsync on file.
- Qemu live migration work when host page cache is used.
- Multiple virtio-pmem disks support.
- Prepare virtio spec after we get feedback on current approach.
drivers/nvdimm/region_devs.c | 7 ++
drivers/virtio/Kconfig | 12 +++
drivers/virtio/Makefile | 1
drivers/virtio/virtio_pmem.c | 122 +++++++++++++++++++++++++++++++++++++++
include/linux/libnvdimm.h | 2
include/uapi/linux/virtio_ids.h | 1
include/uapi/linux/virtio_pmem.h | 61 +++++++++++++++++++
7 files changed, 206 insertions(+)
next reply other threads:[~2018-04-05 10:48 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-05 10:48 Pankaj Gupta [this message]
[not found] ` <20180405104834.10457-1-pagupta-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2018-04-05 10:48 ` [RFC 1/2] kvm: add virtio pmem driver Pankaj Gupta
2018-04-05 10:48 ` [RFC 2/2] pmem: device flush over VIRTIO Pankaj Gupta
2018-04-05 10:48 ` [RFC] qemu: Add virtio pmem device Pankaj Gupta
[not found] ` <20180405104834.10457-4-pagupta-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2018-04-05 11:26 ` David Hildenbrand
[not found] ` <ad08ca09-71ee-08d5-3479-8b3d06380a03-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2018-04-05 12:09 ` [Qemu-devel] " Pankaj Gupta
[not found] ` <416823501.16310251.1522930166070.JavaMail.zimbra-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2018-04-05 12:19 ` David Hildenbrand
2018-04-09 3:26 ` Stefan Hajnoczi
[not found] ` <20180409032601.GA1648-lxVrvc10SDRcolVlb+j0YCZi+YwRKgec@public.gmane.org>
2018-04-09 6:42 ` David Hildenbrand
-- strict thread matches above, loose matches on Subject: below --
2017-10-12 15:50 [RFC 0/2] KVM "fake DAX" device flushing Pankaj Gupta
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180405104834.10457-1-pagupta@redhat.com \
--to=pagupta@redhat.com \
--cc=dan.j.williams@intel.com \
--cc=david@redhat.com \
--cc=haozhong.zhang@intel.com \
--cc=hch@infradead.org \
--cc=imammedo@redhat.com \
--cc=jack@suse.cz \
--cc=kvm@vger.kernel.org \
--cc=kwolf@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nvdimm@ml01.01.org \
--cc=marcel@redhat.com \
--cc=mst@redhat.com \
--cc=nilal@redhat.com \
--cc=niteshnarayanlal@hotmail.com \
--cc=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=riel@surriel.com \
--cc=ross.zwisler@intel.com \
--cc=stefanha@redhat.com \
--cc=xiaoguangrong.eric@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).