On Mon, Oct 25, 2021 at 09:45:35PM +0200, Alexander Graf wrote: > > On 25.10.21 17:10, Daniel P. Berrangé wrote: > > On Mon, Oct 25, 2021 at 04:53:57PM +0200, Alexander Graf wrote: > > > On 25.10.21 16:47, Daniel P. Berrangé wrote: > > > > On Mon, Oct 25, 2021 at 04:42:22PM +0200, Alexander Graf wrote: > > > > > On 25.10.21 16:22, Daniel P. Berrangé wrote: > > > > > > On Mon, Oct 25, 2021 at 12:13:32PM +0200, Alexander Graf wrote: > > > > > > > On 22.10.21 18:14, Vladislav Yaroshchuk wrote: > > > > > > > > On Apple hosts we can read AppleSMC OSK key directly from host's > > > > > > > > SMC and forward this value to QEMU Guest. > > > > > > > > > > > > > > > > Usage: > > > > > > > > `-device isa-applesmc,hostosk=on` > > > > > > > > > > > > > > > > Apple licence allows use and run up to two additional copies > > > > > > > > or instances of macOS operating within virtual operating system > > > > > > > > environments on each Apple-branded computer that is already > > > > > > > > running > > > > > > > > the Apple Software, for purposes of: > > > > > > > > - software development > > > > > > > > - testing during software development > > > > > > > > - using macOS Server > > > > > > > > - personal, non-commercial use > > > > > > > > > > > > > > > > Guest macOS requires AppleSMC with correct OSK. The most legal > > > > > > > > way to pass it to the Guest is to forward the key from host SMC > > > > > > > > without any value exposion. > > > > > > > > > > > > > > > > Based on > > > > > > > > https://web.archive.org/web/20200103161737/osxbook.com/book/bonus/chapter7/tpmdrmmyth/ > > > > > > > > > > > > > > > > Signed-off-by: Vladislav Yaroshchuk <[email protected]> > > > > > > > > @@ -331,6 +464,25 @@ static void > > > > > > > > applesmc_isa_realize(DeviceState *dev, Error **errp) > > > > > > > > isa_register_ioport(&s->parent_obj, &s->io_err, > > > > > > > > s->iobase + APPLESMC_ERR_PORT); > > > > > > > > + if (s->hostosk_flag) { > > > > > > > > + /* > > > > > > > > + * Property 'hostosk' has higher priority than 'osk' > > > > > > > > + * and shadows it. > > > > > > > > + * Free user-provided 'osk' property value > > > > > > > > + */ > > > > > > > > + if (s->osk) { > > > > > > > > + warn_report("isa-applesmc.osk is shadowed " > > > > > > > > + "by isa-applesmc.hostosk"); > > > > > > > > + g_free(s->osk); > > > > > > > > + } > > > > > > > > + > > > > > > > > + if (!applesmc_read_host_osk(&s->osk, &err)) { > > > > > > > > + /* On host OSK retrieval error report a warning */ > > > > > > > > + error_report_err(err); > > > > > > > > + s->osk = default_osk; > > > > > > > > + } > > > > > > > > + } > > > > > > > This part is yucky. A few things: > > > > > > > > > > > > > > 1) QEMU in general does not fail user requested operations > > > > > > > silently. If the > > > > > > > user explicitly asked to read the host OSK and we couldn't, it > > > > > > > must > > > > > > > propagate that error. > > > > > > > 2) In tandem to the above, I think the only consistent CX is to > > > > > > > make both > > > > > > > options mutually exclusive. The easiest way to achieve that IMHO > > > > > > > would be to > > > > > > > overload the "osk" property. If it is "host", then use the host > > > > > > > one. > > > > > > > 3) Should we make "osk"="host" the default on macOS as well then? > > > > > > > Of course, > > > > > > > that one should *not* fail hard when it can't read the key, > > > > > > > because it's an > > > > > > > implicit request rather than an explicit one. > > > > > > The problem with using a magic string value for the existing "osk" > > > > > > parameter is that this is not introspectable by management apps. > > > > > What introspectability would you like to have? > > > > Essentially to answer the question > > > > > > > > "Does this QEMU support OSK passthrough from the host" > > > > > > > > Mgmt apps like libvirt introspect using various query-XXX QMP commands. > > > > For devices, the typical approach is to ask for the list of properties > > > > the device supports. If we're just accepting a new magic value on an > > > > existing property there is no way to query for existance of that > > > > feature. > > > > If we add a "host-osk=bool" parameter introspectability is trivially > > > > satisfied. > > > > > > Ok, the only flow that remains sensible in that case to me sounds like the > > > following: > > Just need an extra check upfront: > > > > if (s->osk && s->use_hoist_osk) > > error_setg(errp, ...) > > else > > > if (s->osk) { > > > /* Use osk */ > > This should fail hard if the provided value is the wrong length - currently > > it falls back with a warning IIUC. > > > > > } else if (s->use_host_osk) { > > > /* Use host OSK. Fail hard if we can't find it */ > > > } else if (can_use_host_osk) { > > > /* See if we can extract the key from the host. If not, fall back to > > > old > > > behavior */ > > > } else { > > > /* Old fallback behavior */ > > Was this old fallback behaviour actually useful ? IIUC it means it is using > > > > > > static char default_osk[64] = "This is a dummy key. Enter the real key " > > "using the -osk parameter"; > > > > which obviously isn't a valid key that will work with any gust OS that > > cares. I guess it at least let QEMU startup, but any the guest OS that > > checks the key will be unhappy. > > > > If if don't think default_osk is actually useful, then we could simplify > > further to > > > > if (s->osk && s->use_host_osk) { > > error_setg(errp, ...) > > } else if (s->osk) { > > /* Use osk. Fail hard if invalid (ie wrong length) */ > > } else if (s->use_host_osk) { > > /* Use host OSK. Fail hard if we can't find it */ > > } else { > > /* try to use host OSK, fail hard if we can't find it or non-OS-X > > build */ > > } > > > In the example above, use_host_osk=on and use_host_osk=off yield the exact > same behavior, so we don't need the switch, no?
Hmm, I forgot about machine type back compat. From a strict pov, if we change the default it should only be for the 6.2.0 machine type, with old machines keeping the current 'default_osk' behaviour. IOW, for 6.2.0 machine use_host_osk=on as default, and for < 6.2.0, use_host_osk=off as default . Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
