This bug was fixed in the package linux-aws - 5.8.0-1018.20+21.04.1
---------------
linux-aws (5.8.0-1018.20+21.04.1) hirsute; urgency=medium
* Packaging resync (LP: #1786013)
- update dkms package versions
[ Ubuntu: 5.8.0-1018.20 ]
* debian/scripts/file-downloader does not handle positive failures correctly
(LP: #1878897)
- [Packaging] file-downloader not handling positive failures correctly
* Packaging resync (LP: #1786013)
- update dkms package versions
* CVE-2021-1052 // CVE-2021-1053
- [Packaging] NVIDIA -- Add the NVIDIA 460 driver
-- Thadeu Lima de Souza Cascardo <casca...@canonical.com> Thu, 07 Jan
2021 10:47:22 -0300
** Changed in: linux-aws (Ubuntu)
Status: New => Fix Released
** CVE added: https://cve.mitre.org/cgi-bin/cvename.cgi?name=2021-1052
** CVE added: https://cve.mitre.org/cgi-bin/cvename.cgi?name=2021-1053
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https://bugs.launchpad.net/bugs/1902281
Title:
aws: disable strict IOMMU TLB invalidation by default
Status in linux-aws package in Ubuntu:
Fix Released
Status in linux-aws source package in Bionic:
Fix Released
Status in linux-aws source package in Focal:
Fix Released
Status in linux-aws source package in Groovy:
Fix Released
Bug description:
[Impact]
AWS requires to relax the synchronous IOMMU TLB invalidation by
default to get a significant performance improvement on certain arm64
instance types (bare metal).
This is not the default behavior in the upstream kernel, that enforces
synchronous invalidations to provide a better isolation and
potentially prevent side-channel attacks with malicious devices that
can be registered in the same IOMMU domain.
This behavior cannot be changed at run-time and it is available only
via iommu.strict=0|1 (via kernel boot parameters - GRUB).
[Test Case]
It has been performance-tested by AWS.
[Fix]
Change iommu.strict in the kernel to be off by default. It will be
always possible to revert this change and restore the old behavior by
setting iommu.strict=1 in the GRUB parameters (and rebooting).
[Regression Potential]
The only concern about this change is that we are relaxing a security
constraint. After considerable discussion and evaluation (also with
the security team) the conclusion was that this change is not
realistically affecting the particular AWS environment in terms of
security and it can definitely provide a significant performance boost
on certain arm64 instance types.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux-aws/+bug/1902281/+subscriptions
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