Re: [Qemu-devel] os x boot broken by commit 11948748495841bd54721b250d68c7b3cb0475ef

[Michael S. Tsirkin]

On Thu, Nov 21, 2013 at 05:02:07PM -0500, Gabriel L. Somlo wrote:
> Added qemu-devel, since that is where this stuff belongs now. Everyone
> else, sorry for the dupe...
> 
> On Thu, Nov 21, 2013 at 07:14:27PM +0100, Paolo Bonzini wrote:
> > Can you remind us about your DSDT modifications?  It should be possible
> > to patch the HPET and applesmc bits appropriately from QEMU (or to move
> > them from the DSDT to an SSDT that is built entirely in QEMU).
> > 
> > It actually isn't impossible that Mac OS X would boot just fine with 1.8...
> 
> My current DSDT patch (against QEMU) is enclosed below. The HPET
> basically needs "IRQNoFlags() {2, 8}", which causes XP to bluescreen.
> 
> So, I've made it conditional on the SMC STA method returning success
> (0x0B).
> 
> The SMC node's STA method returns 0x0B unconditionally on real
> hardware. So I was planning on figuring out what's easier in the
> context of the most recent QEMU code base:
> 
>       1. dynamically generating (during qemu runtime initialization)
>        a DSDT entry for SMC with hardcoded 0x0B STA method, whenever
>       "--device isa-applesmc" is present on the qemu command line
> 
> or
> 
>       2. writing a static (compile-time) SMC node but with a slightly
>       smarter _STA method, which returns 0x0B when "--device isa-applesmc"
>       was given on the cmdline, or which returns 0x00 in the absence
>       of "--device isa-applesmc".
> 
> Either 1. or 2. could be used with HPET -- I can make inclusion of
> IRQNoFlags dependent on either the success or on the presence of
> SMC._STA() :)
> 
> Let me know what you think.
> 
> Thanks,
> --Gabriel

Without discussing whether this is the right thing to do,
main options to implement this would be:

        - write code in ASL, supply entry in ACPI always, patch some
          fields
          to enable/disable it dynamically

        see how pvpanic entry is disabled for an example

        - write code in ASL append it to ACPI if necessary

        see how CPU entries are added depending on number of CPUs for an example

        - generate code in AML directly

        see acpi based pci hotplug on pci branch in my tree for an example