[Bug 292798] bhyve: VMX triple fault in efi windows bootloader

From: <bugzilla-noreply_at_freebsd.org>
Date: Thu, 05 Feb 2026 03:57:19 UTC 
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=292798

Mykola K. <nikolaytihonov2022@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|New                         |Closed
         Resolution|---                         |FIXED

--- Comment #5 from Mykola K. <nikolaytihonov2022@gmail.com> ---
Case solved. 

For Windows you need Data Execution Prevention, or NX in cpu flags. CPU leaf
0x80000001 EDX bit 20. If dmesg doesn't report NX flag in AMD Extended Features
- then you don't have it.

If you don't have NX, Windows Bootloader will try force it and triple fault.
Bhyve doesn't make up any NX flags, unlike KVM does - that confirms why I had
this exact VM working in past. 

If you facing same problem on Z440 please go to BIOS, somewhere in Legacy
settings there will be Data Execution Prevention - ENABLE it!

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