mirror of
https://github.com/xen-project/xen.git
synced 2026-10-28 10:11:27 +01:00
Andrew Cooper
878e684e15
Currently, VERW flushing to mitigate MDS is boot time conditional per domain
type. However, to provide mitigations for DRPW (CVE-2022-21166), we need to
conditionally use VERW based on the trustworthiness of the guest, and the
devices passed through.
Remove the PV/HVM alternatives and instead issue a VERW on the return-to-guest
path depending on the SCF_verw bit in cpuinfo spec_ctrl_flags.
Introduce spec_ctrl_init_domain() and d->arch.verw to calculate the VERW
disposition at domain creation time, and context switch the SCF_verw bit.
For now, VERW flushing is used and controlled exactly as before, but later
patches will add per-domain cases too.
No change in behaviour.
This is part of XSA-404.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit e06b95c1d4)
Sphinx documentation:
All source rendered by Sphinx is licensed under CC-BY-4.0.
You are free to:
Share:
Copy and redistribute the material in any medium or format.
Adapt:
Remix, transform, and build upon the material for any purpose, even
commercially.
Under the following terms:
Attribution:
You must give appropriate credit, provide a link to the license, and
indicate if changes were made. You may do so in any reasonable manner, but
not in any way that suggests the licensor endorses you or your use.
No additional restrictions:
You may not apply legal terms or technological measures that legally
restrict others from doing anything the license permits.
See https://creativecommons.org/licenses/by/4.0/ for full details.
This includes:
* All ReStructured Text files: docs/*/*.rst
* The Sphinx configuration file: docs/conf.py
* Content in Sphinx-exclusive subdirs: docs/*-guide/*
Other documentation:
There are a variety of text documents in various formats. These, given no
explicit license guidance, fall under Xen's default GPL-2.0 license.