Due to the missing HLT (halt) instruction emulation in the VMXAssist real-mode emulator, certain versions of the SYSLINUX boot loader could have caused the guest operating system (domU) to stop responding. With this update, the HLT instruction emulation has been added, and all versions of SYSLINUX now boot properly.
Created attachment 405569[details]
Patch to add HLT instruction emulation support
This is the patch to add HLT instruction emulation support to VMXAssist in Xen. It basically adds HLT opcode (0xF4) to the emulated opcodes for vm86. This allows emulated real-mode use halt instruction without hanging the guest.
Michal
Created attachment 405915[details]
New version of HLT instruction emulation support patch
This is the new version of HLT instruction emulation support patch for VMXAssist not adding fetch8() part to VMXAssist panic if the instruction is unknown since it could return bad EIP since fetch8() function increments the instruction pointer.
Michal
Comment 8Miroslav Rezanina
2010-05-12 11:35:26 UTC
*** Bug 591475 has been marked as a duplicate of this bug. ***
Comment 11Jaromir Hradilek
2010-07-07 08:55:28 UTC
Technical note added. If any revisions are required, please edit the "Technical Notes" field
accordingly. All revisions will be proofread by the Engineering Content Services team.
New Contents:
Due to the missing HLT (halt) instruction emulation in the VMXAssist real-mode emulator, certain versions of the SYSLINUX boot loader could have caused the guest operating system (domU) to stop responding. With this update, the HLT instruction emulation has been added, and all versions of SYSLINUX now boot properly.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.
http://rhn.redhat.com/errata/RHBA-2011-0031.html
Created attachment 405569 [details] Patch to add HLT instruction emulation support This is the patch to add HLT instruction emulation support to VMXAssist in Xen. It basically adds HLT opcode (0xF4) to the emulated opcodes for vm86. This allows emulated real-mode use halt instruction without hanging the guest. Michal