The 'dual' sPAPR IRQ backend supports both interrupt mode, XIVE
exploitation mode and the legacy compatibility mode (XICS). both modes
are not supported at the same time.
The machine starts with the legacy mode and a new interrupt mode can
then be negotiated by the CAS process. In this case, the new mode is
activated after a reset to take into account the required changes in
the machine. These impact the device tree layout, the interrupt
presenter object and the exposed MMIO regions in the case of XIVE.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The qemu_irq array is now allocated at the machine level using a sPAPR
IRQ set_irq handler depending on the chosen interrupt mode. The use of
this handler is slightly inefficient today but it will become necessary
when the 'dual' interrupt mode is introduced.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Today, the interrupt presenter is linked to a CPU using the
cpu_intc_create() method of the sPAPR IRQ backend. The resulting
object is assigned to the PowerPCCPU 'intc' pointer whatever the
interrupt mode, XICS or XIVE.
To support the 'dual' interrupt mode, we will need to distinguish
between the two presenter objects and for that, we plan to introduce a
second interrupt presenter object pointer under the PowerPCCPU. The
modifications below move the assignment of the presenter object under
the cpu_intc_create() method to prepare ground for the future changes.
Both sPAPR and PowerNV machines are impacted.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The interrupt modes supported by the hypervisor are advertised to the
guest with new bits definitions of the option vector 5 of property
"ibm,arch-vec-5-platform-support. The byte 23 bits 0-1 of the OV5 are
defined as follow :
0b00 PAPR 2.7 and earlier (Legacy systems)
0b01 XIVE Exploitation mode only
0b10 Either available
If the client/guest selects the XIVE interrupt mode, it informs the
hypervisor by returning the value 0b01 in byte 23 bits 0-1. A 0b00
value indicates the use of the XICS interrupt mode (Legacy systems).
The sPAPR IRQ backend is extended with these definitions and the
values are directly used to populate the "ibm,arch-vec-5-platform-support"
property. The interrupt mode is advertised under TCG and under KVM.
Although a KVM XIVE device is not yet available, the machine can still
operate with kernel_irqchip=off. However, we apply a restriction on
the CPU which is required to be a POWER9 when a XIVE interrupt
controller is in use.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
For the time being, the XIVE reset handler updates the OS CAM line of
the vCPU as it is done under a real hypervisor when a vCPU is
scheduled to run on a HW thread. This will let the XIVE presenter
engine find a match among the NVTs dispatched on the HW threads.
This handler will become even more useful when we introduce the
machine supporting both interrupt modes, XIVE and XICS. In this
machine, the interrupt mode is chosen by the CAS negotiation process
and activated after a reset.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
[dwg: Fix style nits]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Introduce a new sPAPR IRQ handler to handle resend after migration
when the machine is using a KVM XICS interrupt controller model.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Each interrupt mode has its own specific interrupt presenter object,
that we store under the CPU object, one for XICS and one for XIVE.
Extend the sPAPR IRQ backend with a new handler to support them both.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The XIVE interface for the guest is described in the device tree under
the "interrupt-controller" node. A couple of new properties are
specific to XIVE :
- "reg"
contains the base address and size of the thread interrupt
managnement areas (TIMA), for the User level and for the Guest OS
level. Only the Guest OS level is taken into account today.
- "ibm,xive-eq-sizes"
the size of the event queues. One cell per size supported, contains
log2 of size, in ascending order.
- "ibm,xive-lisn-ranges"
the IRQ interrupt number ranges assigned to the guest for the IPIs.
and also under the root node :
- "ibm,plat-res-int-priorities"
contains a list of priorities that the hypervisor has reserved for
its own use. OPAL uses the priority 7 queue to automatically
escalate interrupts for all other queues (DD2.X POWER9). So only
priorities [0..6] are allowed for the guest.
Extend the sPAPR IRQ backend with a new handler to populate the DT
with the appropriate "interrupt-controller" node.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
[dwg: Fix style nits]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The XIVE IRQ backend uses the same layout as the new XICS backend but
covers the full range of the IRQ number space. The IRQ numbers for the
CPU IPIs are allocated at the bottom of this space, below 4K, to
preserve compatibility with XICS which does not use that range.
This should be enough given that the maximum number of CPUs is 1024
for the sPAPR machine under QEMU. For the record, the biggest POWER8
or POWER9 system has a maximum of 1536 HW threads (16 sockets, 192
cores, SMT8).
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Initialize the MSI bitmap from it as this will be necessary for the
sPAPR IRQ backend for XIVE.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The new layout using static IRQ number does not leave much space to
the dynamic MSI range, only 0x100 IRQ numbers. Increase the total
number of IRQS for newer machines and introduce a legacy XICS backend
for pre-3.1 machines to maintain compatibility.
For the old backend, provide a 'nr_msis' value covering the full IRQ
number space as it does not use the bitmap allocator to allocate MSI
interrupt numbers.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The number of MSI interrupts a sPAPR machine can allocate is in direct
relation with the number of interrupts of the sPAPRIrq backend. Define
statically this value at the sPAPRIrq class level and use it for the
"ibm,pe-total-#msi" property of the sPAPR PHB.
According to the PAPR specs, "ibm,pe-total-#msi" defines the maximum
number of MSIs that are available to the PE. We choose to advertise
the maximum number of MSIs that are available to the machine for
simplicity of the model and to avoid segmenting the MSI interrupt pool
which can be easily shared. If the pool limit is reached, it can be
extended dynamically.
Finally, remove XICS_IRQS_SPAPR which is now unused.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This proposal moves all the related IRQ routines of the sPAPR machine
behind a sPAPR IRQ backend interface 'spapr_irq' to prepare for future
changes. First of which will be to increase the size of the IRQ number
space, then, will follow a new backend for the POWER9 XIVE IRQ controller.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This proposal introduces a new IRQ number space layout using static
numbers for all devices, depending on a device index, and a bitmap
allocator for the MSI IRQ numbers which are negotiated by the guest at
runtime.
As the VIO device model does not have a device index but a "reg"
property, we introduce a formula to compute an IRQ number from a "reg"
value. It should minimize most of the collisions.
The previous layout is kept in pre-3.1 machines raising the
'legacy_irq_allocation' machine class flag.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
