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Feature #13835

closed

bhyve should not zero lowmem on reboot

Added by Patrick Mooney 18 days ago. Updated 10 days ago.

Status:
Closed
Priority:
Normal
Category:
bhyve
Start date:
Due date:
% Done:

100%

Estimated time:
Difficulty:
Medium
Tags:
Gerrit CR:

Description

During the porting effort for bhyve, some erroneous behavior with an old version of the bootrom was worked around by explicitly zeroing lowmem (< 3GB) during instance reinit (as done for reboot). Upstream bhyve has never needed anything like this, although that may be due to less usage of that specific bootrom. (ROM-less bhyveload boot, and the uefi-only ROM seem much more common there). It would be nice to revisit this workaround and remove it if possible.


Related issues

Related to illumos gate - Feature #13840: bhyve hostbridge should feign PAM0 emulationClosedPatrick Mooney

Actions
Actions #1

Updated by Electric Monk 17 days ago

  • Gerrit CR set to 1523
Actions #2

Updated by Patrick Mooney 11 days ago

  • Related to Feature #13840: bhyve hostbridge should feign PAM0 emulation added
Actions #3

Updated by Patrick Mooney 10 days ago

With #13840 diagnosed and addressed with a work-around to include with this change, I set out to test the typical battery of guests on AMD and Intel hardware. (Hitting both vendors here is particularly pertinent, given that the Tianocore bootrom chooses different code paths depending on CPU vendor) The usual guests booted and rebooted fine without incident. A specially configured Alpine guest using the CSM-enabled ROM was also able to boot and reboot successfully.

Actions #4

Updated by Patrick Mooney 10 days ago

Mike Zeller tested this with several guests on SmartOS as well.

Actions #5

Updated by Electric Monk 10 days ago

  • Status changed from In Progress to Closed
  • % Done changed from 0 to 100

git commit 9e6c6f2f3ab9c8f1f042b97c0432e8ccc9650309

commit  9e6c6f2f3ab9c8f1f042b97c0432e8ccc9650309
Author: Patrick Mooney <pmooney@pfmooney.com>
Date:   2021-06-03T01:52:27.000Z

    13835 bhyve should not zero lowmem on reboot
    13840 bhyve hostbridge should feign PAM0 emulation
    Reviewed by: Andy Fiddaman <andy@omnios.org>
    Reviewed by: Dan Cross <cross@oxidecomputer.com>
    Approved by: Robert Mustacchi <rm@fingolfin.org>

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