[SeaBIOS] seabios: acpi: add _RMV control method for PCI devices
Avi Kivity
avi at redhat.com
Mon Dec 13 09:53:07 CET 2010
On 12/13/2010 10:49 AM, Gleb Natapov wrote:
> On Mon, Dec 13, 2010 at 10:41:25AM +0200, Avi Kivity wrote:
> > On 12/13/2010 02:00 AM, Marcelo Tosatti wrote:
> > >On Sat, Dec 11, 2010 at 09:39:30AM +0200, Avi Kivity wrote:
> > >> On 12/08/2010 07:08 PM, Marcelo Tosatti wrote:
> > >> >Use _RMV method to indicate whether device can be removed.
> > >> >
> > >> >Data is retrieved from QEMU via I/O port 0xae0c.
> > >> >
> > >>
> > >> Where did this port come from?
> > >
> > >Its the next available address after "PCI EJ base", used
> > >for QEMU<->ACPI hotplug communication.
> > >
> > >> What's the protocol?
> > >
> > >ACPI reads the 32-bit field indicating the return value of the _RMV
> > >method (which is used by Windows to decide removability). 1-bit per
> > >slot.
> > >
> > >More ports have to be registered if more buses are added.
> > >
> > >> Maybe we should do this via fw_cfg.
> > >
> > >I don't see a need for it? (yes, it might be possible, but i'm not
> > >familiar enough with AML).
> >
> > To avoid adding tons of undocumented I/O ports, and to allow
> > discoverability (what happens with a new seabios on old qemu)?
> >
> We already have out own mini pci hot-plug controller at io port 0xae00.
> The patch just extends its functionality a bit. Logically this
> functionality belongs there.
Well, at least it should be documented.
We could also deprecate the old port and use fwcfg for everything (try
fwcfg, fall back to ae00).
> > We could do this in two ways: by adding a fwcfg client to the DSDT,
> > or by copying the information to system memory, and referencing
> > system memory from the DSDT.
> >
> This is even worse. It requires some fixed address to be shared between
> DSDT and Seabios (or alternatively Seabios will have to generate this
> part of DSDT dynamically).
>
Could easily be something in the F segment.
--
error compiling committee.c: too many arguments to function
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