• Cédric Le Goater's avatar
    powerpc/xive: guest exploitation of the XIVE interrupt controller · eac1e731
    Cédric Le Goater authored
    This is the framework for using XIVE in a PowerVM guest. The support
    is very similar to the native one in a much simpler form.
    
    Each source is associated with an Event State Buffer (ESB). This is a
    two bit state machine which is used to trigger events. The bits are
    named "P" (pending) and "Q" (queued) and can be controlled by MMIO.
    The Guest OS registers event (or notifications) queues on which the HW
    will post event data for a target to notify.
    
    Instead of OPAL calls, a set of Hypervisors call are used to configure
    the interrupt sources and the event/notification queues of the guest:
    
     - H_INT_GET_SOURCE_INFO
    
       used to obtain the address of the MMIO page of the Event State
       Buffer (PQ bits) entry associated with the source.
    
     - H_INT_SET_SOURCE_CONFIG
    
       assigns a source to a "target".
    
     - H_INT_GET_SOURCE_CONFIG
    
       determines to which "target" and "priority" is assigned to a source
    
     - H_INT_GET_QUEUE_INFO
    
       returns the address of the notification management page associated
       with the specified "target" and "priority".
    
     - H_INT_SET_QUEUE_CONFIG
    
       sets or resets the event queue for a given "target" and "priority".
       It is also used to set the notification config associated with the
       queue, only unconditional notification for the moment.  Reset is
       performed with a queue size of 0 and queueing is disabled in that
       case.
    
     - H_INT_GET_QUEUE_CONFIG
    
       returns the queue settings for a given "target" and "priority".
    
     - H_INT_RESET
    
       resets all of the partition's interrupt exploitation structures to
       their initial state, losing all configuration set via the hcalls
       H_INT_SET_SOURCE_CONFIG and H_INT_SET_QUEUE_CONFIG.
    
     - H_INT_SYNC
    
       issue a synchronisation on a source to make sure sure all
       notifications have reached their queue.
    
    As for XICS, 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), also called rings, 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 interrupt numbers ranges assigned to the guest. These are
       allocated using a simple bitmap.
    
    and also :
    
     - "/ibm,plat-res-int-priorities"
    
       contains a list of priorities that the hypervisor has reserved for
       its own use.
    
    Tested with a QEMU XIVE model for pseries and with the Power hypervisor.
    Signed-off-by: default avatarCédric Le Goater <clg@kaod.org>
    Acked-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
    Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
    eac1e731
kexec.c 1.49 KB