OS-8008: bhyve on AMD should report SVM as disabled


Issue Type:Bug
Priority:4 - Normal
Created at:2019-10-04T17:41:13.529Z
Updated at:2019-10-23T16:30:58.385Z


Created by:Michael Zeller
Reported by:Michael Zeller
Assigned to:Michael Zeller


Fixed: A fix for this issue is checked into the tree and tested.
(Resolution Date: 2019-10-23T16:30:58.374Z)

Fix Versions

2019-10-24 Double Dip (Release Date: 2019-10-24)

Related Links




As reported in https://github.com/joyent/smartos-live/issues/843 a Windows guest will hang at boot on AMD boxes without the "-w" command line flag (Ignore accesses to unimplemented Model Specific Registers).

Looking at this it seems Windows tries to read VM_CR MSR (C001_0114h).

rdmsr to register 0xc0010114 on vcpu 3

It seems that Windows ignores the cpuid bits here and attempts to poke the MSR anyways.


Comment by Michael Zeller
Created at 2019-10-23T16:12:08.537Z

To test this change I ran a DEBUG platform with the change on our AMD Epyc lab box and confirmed I was able to boot a Windows bhyve instance without the "-w" flag. I also got confirmation that the user who reported the original issue was able to do the same on their hardware with the provided patched platform.

Comment by Jira Bot
Created at 2019-10-23T16:28:46.013Z

illumos-joyent commit c76cd14c4b928c713e29e8db8ad0889f08810f5d (branch master, by Mike Zeller)

OS-8008 bhyve on AMD should report SVM as disabled
Reviewed by: Patrick Mooney <pmooney@pfmooney.com>
Reviewed by: Jason King <jason.king@joyent.com>
Approved by: Jason King <jason.king@joyent.com>