Hello Paolo, On Mon, Aug 16, 2021 at 04:58:02PM +0200, Paolo Bonzini wrote: > On 16/08/21 16:44, Ashish Kalra wrote: > > I think that once the mirror VM starts booting and running the UEFI > > code, it might be only during the PEI or DXE phase where it will > > start actually running the MH code, so mirror VM probably still need > > to handles KVM_EXIT_IO when SEC phase does I/O, I can see PIC > > accesses and Debug Agent initialization stuff in SEC startup code. > > That may be a design of the migration helper code that you were working > with, but it's not necessary. > Actually my comments are about a more generic MH code. > The migration helper can be just some code that the guest "donates" to > the host. The entry point need not be the usual 0xfffffff0; it can be > booted directly in 64-bit mode with a CR3 and EIP that the guest > provides to the guest---for example with a UEFI GUIDed structure. Yes, this is consistent with the MH code we are currently testing, it boots directly into 64-bit mode. This is what Tobin's response is also pointing out to. Thanks, Ashish > > In fact, the migration helper can run even before the guest has booted > and while the guest is paused, so I don't think that it is possible to > make use of any device emulation code in it. > > Paolo >
