On Thu, 11 Jul 2019 at 16:58, Philippe Mathieu-Daudé <phi...@redhat.com> wrote: > > In the "Read Array Flowchart" the command has a value of 0xFF. > > In the document [*] the "Read Array Flowchart", the READ_ARRAY > command has a value of 0xff. > > Use the correct value in the pflash model. > > There is no change of behavior in the guest, because: > - when the guest were sending 0xFF, the reset_flash label > was setting the command value as 0x00 > - 0x00 was used internally for READ_ARRAY > > To keep migration with older versions behaving correctly, we > decide to always migrate the READ_ARRAY as 0x00. > > [*] "Common Flash Interface (CFI) and Command Sets" > (Intel Application Note 646) > Appendix B "Basic Command Set" > > Reviewed-by: John Snow <js...@redhat.com> > Reviewed-by: Alistair Francis <alistair.fran...@wdc.com> > Regression-tested-by: Laszlo Ersek <ler...@redhat.com> > Signed-off-by: Philippe Mathieu-Daudé <phi...@redhat.com> > ---
These changes look correct as far as they go, but are we sure that command value 0x00 will never be a valid command in some future version? If it ever does, then we have a problem because we can't distinguish "0xff with a silly encoding" from "really 0x00" in the incoming migration data stream. If we're 100% confident that there will never be a true command 0x00 then this approach is OK. thanks -- PMM
