On 09/01/2009 04:47 PM, Jan Kiszka wrote:
btw, something else I've considered was not to do any emulation for 'mov
dr' but instead load the debug registers and disable the intercept. So
far the only issue I've seen is that we lose support for real mode guest
self-debug on intel (pre-unrestricted guest). What do you think of this?
I think you can't have both: optimized dr save/restore on vmentry/exit
and optimized dr access. If you drop on-demand dr register
readout/update, you need to deal with this on every vmentry/exit. My
feeling is that this would be awfully slower, even slower than what we
currently have without your patches.
I'll clarify:
In the normal case, we'll have #DB and MOV DR intercepted.
On #DB, update vcpu->dr6.
On MOV DR, disable MOV DR interception, enable dr swap, and let the
guest execute; on the next exit, reenable MOV DR interception and
disable dr swap.
It's similar to the fpu code where we don't emulate fpu instructions.
It doesn't really buy us a lot.
--
error compiling committee.c: too many arguments to function
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