Commit Graph

2 Commits

Author SHA1 Message Date
Kashyap Chamarthy
3b2c52c017 qemu-cpu-models.rst: Document -noTSX, mds-no, taa-no, and tsx-ctrl
- Add the '-noTSX' variants for CascadeLake and SkyLake.

- Document the three MSR bits: 'mds-no', 'taa-no', and 'tsx-ctrl'

  Two confusing things about 'mds-no' (and the first point applies to
  the other two MSRs too):

  (1) The 'mds-no' bit will _not_ show up in the guest's /proc/cpuinfo.
      Rather it is used to fill in the guest's sysfs:

        /sys/devices/system/cpu/vulnerabilities/mds:Not affected

      Paolo confirmed on IRC as such.

  (2) There are _three_ variants[+] of CascadeLake CPUs, with different
      stepping levels: 5, 6, and 7.  To quote wikichip.org[*]:

        "note that while steppings 6 & 7 are fully mitigated, earlier
        stepping 5 is not protected against MSBDS, MLPDS, nor MDSUM"

      The above is also indicated in the Intel's document[+], as
      indicated by "No" under the three columns of MFBDS, MSBDS, and
      MLPDS.

  I've expressed this in the docs without belabouring the details.

      [+] https://software.intel.com/security-software-guidance/insights/processors-affected-microarchitectural-data-sampling
      [*] https://en.wikichip.org/wiki/intel/microarchitectures/cascade_lake#Key_changes_from_Skylake

Signed-off-by: Kashyap Chamarthy <kchamart@redhat.com>
Message-Id: <20200225165618.6571-3-kchamart@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 23:02:25 +01:00
Kashyap Chamarthy
1bf84a1e2e docs/system: Convert qemu-cpu-models.texi to rST
This doc was originally written by Daniel P. Berrangé
<berrange@redhat.com>, introduced via commit[1]: 2544e9e4aa (docs: add
guidance on configuring CPU models for x86, 2018-06-27).

In this patch:

  - 1-1 conversion of Texinfo to rST, besides a couple of minor
    tweaks that are too trivial to mention.   (Thanks to Stephen
    Finucane on IRC for the suggestion to use rST "definition lists"
    instead of bullets in some places.)

    Further modifications will be done via a separate patch.

  - rST and related infra changes: manual page generation, Makefile
    fixes, clean up references to qemu-cpu-models.texi, update year in
    the copyright notice, etc.

[1] https://git.qemu.org/?p=qemu.git;a=commit;h=2544e9e4aa

As part of the conversion, we use a more generic 'author' attribution
for the manpage than we previously had, as agreed with the original
author Dan Berrange.

Signed-off-by: Kashyap Chamarthy <kchamart@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20200228153619.9906-16-peter.maydell@linaro.org
Message-id: 20200226113034.6741-15-pbonzini@redhat.com
[Move macros to defs.rst.inc, split in x86 and MIPS parts,
 make qemu-cpu-models.rst a standalone document. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[PMM: Move defs.rst.inc setup to its own commit;
 fix minor issues with MAINTAINERS file updates;
 drop copyright date change; keep capitalization of
 "QEMU Project developers" consistent with other uses;
 minor Makefile fixups]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2020-03-06 10:05:12 +00:00