Il 25/06/2014 11:50, Chen, Tiejun ha scritto:
For past devices, we know which BARs they use. For future devices, it
would be nice if the PCH/MCH backdoor was specified so that we know they
will leave a free BAR for virtualization.
Now I'm a bit confused about BAR here.
You're saying we will reserve a free BAR to address those information to
expose to guest, but which device does this free BAR belong to? The
video device? Or PCH/MCH?
The video device. If the host device does not have the BAR (which will
be the common case), QEMU can emulate it like this:
- offsets 0x0000..0x0fff map to configuration space of the host MCH
- offsets 0x1000..0x1fff map to configuration space of the host PCH
Of course this is only limited to offsets that are needed by the driver.
Paolo
