On Mon, Aug 05, 2013 at 06:46:06PM +0200, Paolo Bonzini wrote: > On 08/05/2013 06:18 PM, Michael S. Tsirkin wrote: > >>>>Depending on the management, "management" could just be the user. > >>>>Most of the time the user simply says to use virtio in the XML. > >>>> > >>>>If it had to be specified manually every time, pvpanic would be > >>>>just another knob that nobody uses. > >>> > >>>Management tools already set XML appropriately depending > >>>on the guest. If users are happy to leave the device alone, > >>>we are also happy. > >> > >>What if the guest is upgraded? How does the user know they have > >>to add a magic device? > > > >Device is useless without a driver anyway. > > Who cares? It doesn't eat valuable resources. (20 bytes in the > DSDT are not valuable, a PCI slot is).
IO ports are a bit more valuable. But I was responding to what you said "how does the user know they have to add a magic device" - in the same way that they know they need a driver. > >How does user know there's need to install a driver? > > Apparently that was not a problem in Vista and later, when Microsoft > stopped bugging users with the wizard by default. And it's never > been a problem in Linux. > > But they don't need to know that, since probably no one will write a > driver for pvpanic that runs on Windows XP (6 months before EOL) or > 2003 (18 months before EOL). > > >So let's add -device pvpanic to QEMU, same as any device, if > >you think everyone absolutely wants this device explain this > >to libvirt guys and they'll add it by default, they > >are much closer to real users and can treat this appropriately. > > It will be exactly the same problem, just thrown further from where > you can find a real solution---which is not QEMU and is not libvirt, > it is in the firmware. > > >>Really, all guests handle the missing driver without asking the user. > > > >Did you really check them all? > > All those that have a GUI that runs by default, and manage drivers > in said GUI... What does GUI have to do with it? Guests can log errors or fail in a variety of ways. GUI is not required. > >>At some point MSFT even issued a hotfix to disable the pesky Found > >>New Hardware wizard. Let's treat it as a guest bug, hide the device > >>altogether with _OSI (detecting Vista or 2008 or Linux), > >>and declare > >>that Windows 2000/XP/2003 lack support for pvpanic. > > > >Sounds like you merely mean all windows guests. > > ... which means all Windows guests, yes. > > Paolo Which are the ones where we noticed there's a problem. But there could be other guests which are problematic. If you see a mouse in a room, how likely is it that there's a single mouse there? This is a PV technology which to me looks like it was rushed through and not only set on by default, but without a way to disable it - apparently on the assumption there's 0 chance it can cause any damage. Now that we do know the chance it's not there, why not go back to the standard interface, and why not give users a chance to enable/disable it? In other words, let's do the standard thing, and make the new device available with -device pvpanic. And in BIOS, let's just obey what QEMU tells us to do, and not create the device if it's not there. -- MST _______________________________________________ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
