RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 1416182 - QEMU VFIO based block driver for NVMe devices (libvirt)
Summary: QEMU VFIO based block driver for NVMe devices (libvirt)
Keywords:
Status: CLOSED WONTFIX
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: libvirt
Version: 7.3
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: ---
Assignee: Libvirt Maintainers
QA Contact: lijuan men
URL:
Whiteboard:
Depends On: 1416180 1519004
Blocks: 1519005 1590471 1590472
TreeView+ depends on / blocked
 
Reported: 2017-01-24 19:12 UTC by Ademar Reis
Modified: 2019-03-26 14:48 UTC (History)
5 users (show)

Fixed In Version:
Doc Type: Enhancement
Doc Text:
Clone Of: 1416180
: 1519005 1590471 1590472 (view as bug list)
Environment:
Last Closed: 2019-03-26 14:48:37 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)

Description Ademar Reis 2017-01-24 19:12:51 UTC 
+++ This bug was initially created as a clone of Bug #1416180 +++

This BZ tracks the upstream work currently being done by Fam to introduce a VFIO based NVMe driver to QEMU:

https://lists.gnu.org/archive/html/qemu-devel/2016-12/msg02812.html

Date: Wed, 21 Dec 2016 00:31:35 +0800
From: Fam Zheng <famz>
Subject: [Qemu-devel] [PATCH 0/4] RFC: A VFIO based block driver for NVMe device

This series adds a new protocol driver that is intended to achieve about 20%
better performance for latency bound workloads (i.e. synchronous I/O) than
linux-aio when guest is exclusively accessing a NVMe device, by talking to the
device directly instead of through kernel file system layers and its NVMe
driver.

This applies on top of Stefan's block-next tree which has the busy polling
patches - the new driver also supports it.

A git branch is also available as:

    https://github.com/famz/qemu nvme

See patch 4 for benchmark numbers.

Tests are done on QEMU's NVMe emulation and a real Intel P3700 SSD NVMe card.
Most of dd/fio/mkfs/kernel build and OS installation testings work well, but an
weird write fault looking similar to [1] is consistently seen when installing
RHEL 7.3 guest, which is still under investigation.

[1]: http://lists.infradead.org/pipermail/linux-nvme/2015-May/001840.html

Also, the ram notifier is not enough for hot plugged block device because in
that case the notifier is installed _after_ ram blocks are added so it won't
get the events.
Comment 1 Erik Skultety 2019-03-26 14:48:37 UTC 
The focus is now shifting towards RHEL8 where this is already tracked by:
https://bugzilla.redhat.com/show_bug.cgi?id=1519005

If you feel like this needs to be resolved on RHEL7 too, please re-open.
Note You need to log in before you can comment on or make changes to this bug.