ppc/xive: Force the Physical CAM line value to group mode

ppc/xive: Force the Physical CAM line value to group mode

When an interrupt needs to be delivered, the XIVE interrupt controller
presenter scans the CAM lines of the thread interrupt contexts of the
HW threads of the chip to find a matching vCPU. The interrupt context
is composed of 4 different sets of registers: Physical, HV, OS and
User.

The encoding of the Physical CAM line depends on the mode in which the
interrupt controller is operating: CAM mode or block group mode.
Block group mode being the default configuration today on POWER9 and
the only one available on the next POWER10 generation, enforce this
encoding in the Physical CAM line :

    chip << 19 | 0000000 0 0001 thread (7Bit)

It fits the overall encoding of the NVT ids and simplifies the matching
algorithm in the presenter.

Fixes: d514c48d41fb ("ppc/xive: hardwire the Physical CAM line of the thread context")
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190630204601.30574-2-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>