Subject: CVE-2021-46917: dmaengine: idxd: fix wq cleanup of WQCFG registers

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

dmaengine: idxd: fix wq cleanup of WQCFG registers

A pre-release silicon erratum workaround where wq reset does not clear
WQCFG registers was leaked into upstream code. Use wq reset command
instead of blasting the MMIO region. This also address an issue where
we clobber registers in future devices.

The Linux kernel CVE team has assigned CVE-2021-46917 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 5.8 with commit da32b28c95a7 and fixed in 5.10.32 with commit e5eb9757fe4c
	Issue introduced in 5.8 with commit da32b28c95a7 and fixed in 5.11.16 with commit f7dc8f561916
	Issue introduced in 5.8 with commit da32b28c95a7 and fixed in 5.12 with commit ea9aadc06a9f
	Issue introduced in 5.7.10 with commit 2a2df2bd10de

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2021-46917
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/dma/idxd/device.c
	drivers/dma/idxd/idxd.h
	drivers/dma/idxd/sysfs.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/e5eb9757fe4c2392e069246ae78badc573af1833
	https://git.kernel.org/stable/c/f7dc8f5619165e1fa3383d0c2519f502d9e2a1a9
	https://git.kernel.org/stable/c/ea9aadc06a9f10ad20a90edc0a484f1147d88a7a