Avi Kivity wrote:
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.
While the code looks nicer with the second patch, the fact that
get_rflags() does a vmcs_read() seems 7 times more than before seems
unfortunate.
--
Regards,
Anthony Liguori
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