Re: [PATCH] When switching to a vm8086 task, load segments as 16-bit (v2)

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On 08/12/2009 03:11 PM, Avi Kivity wrote:
On 08/11/2009 11:57 PM, Anthony Liguori wrote:
According to 16.2.5 in the SDM, eflags.vm in the tss is consulted before loading and new segments. If eflags.vm == 1, then the segments are treated as 16-bit segments. The LDTR and TR are not normally available in vm86 mode so if they happen to somehow get loaded, they need to be treated as 32-bit segments.

This fixes an invalid vmentry failure in a custom OS that was happening after a task switch into vm8086 mode. Since the segments were being mistakenly
treated as 32-bit, we loaded garbage state.

I'm getting a Vista x64 installer failure on reboot with this. One possibility is that ->get_rflags() is returning the mangled flags state (we add vm86 for real mode), which confuses the new code.


That's indeed the case, I'm testing a patch now.

--
error compiling committee.c: too many arguments to function

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