Hello, I read on the kvmwiki/TODO that there is a work in progress for extending x86 emulator to support more instructions in real mode and for changing the execution loop to call the emulator for real mode.
As I'm interested to work on this part I'd like to know what was already done. I'd like to have more information about how the execution loop need to be changed. Currently we enter/leave real mode through a call to enter_rmode()/enter_pmode(). The function sets a variable "arch.rmode.active" and also sets the bit X86_EFLAGS_VM of GUEST_RFLAGS. That means that we are using the VM mode to virtualize the real mode. I know that in virtual mode some instructions can not be used as they are in full real mode (that would have been too easy). So these instructions generate a protection fault and need to be emulated. So we handle this kind of exception in handle_exception() and we call the x86 emulator. From the emulator we read the eflags (kvm_x86_ops->get_rflags(vcpu)) and we can know if we are in real mode or not. It's the current scheme, right? My question is why the execution loop needs to be changed here. I mean isn't it possible to just extend x86 emulator to support more instructions in real mode? I think that I'm missing something here so any help, hint, advice, link are welcome. Best Regards, -- Guillaume Thouvenin ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
