On Fri, 27 Sep 2019 15:50:18 +1000
David Gibson <da...@gibson.dropbear.id.au> wrote:
> spapr now has the mechanism of constructing both XICS and XIVE instances of
> the SpaprInterruptController interface. However, only one of the interrupt
> controllers will actually be active at any given time, depending on feature
> negotiation with the guest. This is handled in the current code via
> spapr_irq_current() which checks the OV5 vector from feature negotiation to
> determine the current backend.
>
> Determining the active controller at the point we need it like this
> can be pretty confusing, because it makes it very non obvious at what
> points the active controller can change. This can make it difficult
> to reason about the code and where a change of active controller could
> appear in sequence with other events.
>
> Make this mechanism more explicit by adding an 'active_intc' pointer
> and an explicit spapr_irq_update_active_intc() function to update it
> from the CAS state. We also add hooks on the intc backend which will
> get called when it is activated or deactivated.
>
> For now we just introduce the switch and hooks, later patches will
> actually start using them.
>
> Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
> ---
Reviewed-by: Greg Kurz <gr...@kaod.org>
> hw/ppc/spapr_irq.c | 51 ++++++++++++++++++++++++++++++++++++++
> include/hw/ppc/spapr.h | 5 ++--
> include/hw/ppc/spapr_irq.h | 5 ++++
> 3 files changed, 59 insertions(+), 2 deletions(-)
>
> diff --git a/hw/ppc/spapr_irq.c b/hw/ppc/spapr_irq.c
> index ea44378d8c..dfa875b7cd 100644
> --- a/hw/ppc/spapr_irq.c
> +++ b/hw/ppc/spapr_irq.c
> @@ -593,6 +593,7 @@ qemu_irq spapr_qirq(SpaprMachineState *spapr, int irq)
>
> int spapr_irq_post_load(SpaprMachineState *spapr, int version_id)
> {
> + spapr_irq_update_active_intc(spapr);
> return spapr->irq->post_load(spapr, version_id);
> }
>
> @@ -600,6 +601,8 @@ void spapr_irq_reset(SpaprMachineState *spapr, Error
> **errp)
> {
> assert(!spapr->irq_map || bitmap_empty(spapr->irq_map,
> spapr->irq_map_nr));
>
> + spapr_irq_update_active_intc(spapr);
> +
> if (spapr->irq->reset) {
> spapr->irq->reset(spapr, errp);
> }
> @@ -626,6 +629,54 @@ int spapr_irq_get_phandle(SpaprMachineState *spapr, void
> *fdt, Error **errp)
> return phandle;
> }
>
> +static void set_active_intc(SpaprMachineState *spapr,
> + SpaprInterruptController *new_intc)
> +{
> + SpaprInterruptControllerClass *sicc;
> +
> + assert(new_intc);
> +
> + if (new_intc == spapr->active_intc) {
> + /* Nothing to do */
> + return;
> + }
> +
> + if (spapr->active_intc) {
> + sicc = SPAPR_INTC_GET_CLASS(spapr->active_intc);
> + if (sicc->deactivate) {
> + sicc->deactivate(spapr->active_intc);
> + }
> + }
> +
> + sicc = SPAPR_INTC_GET_CLASS(new_intc);
> + if (sicc->activate) {
> + sicc->activate(new_intc, &error_fatal);
> + }
> +
> + spapr->active_intc = new_intc;
> +}
> +
> +void spapr_irq_update_active_intc(SpaprMachineState *spapr)
> +{
> + SpaprInterruptController *new_intc;
> +
> + if (!spapr->ics) {
> + /*
> + * XXX before we run CAS, ov5_cas is initialized empty, which
> + * indicates XICS, even if we have ic-mode=xive. TODO: clean
> + * up the CAS path so that we have a clearer way of handling
> + * this.
> + */
> + new_intc = SPAPR_INTC(spapr->xive);
> + } else if (spapr_ovec_test(spapr->ov5_cas, OV5_XIVE_EXPLOIT)) {
> + new_intc = SPAPR_INTC(spapr->xive);
> + } else {
> + new_intc = SPAPR_INTC(spapr->ics);
> + }
> +
> + set_active_intc(spapr, new_intc);
> +}
> +
> /*
> * XICS legacy routines - to deprecate one day
> */
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index cbd1a4c9f3..763da757f0 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -143,7 +143,6 @@ struct SpaprMachineState {
> struct SpaprVioBus *vio_bus;
> QLIST_HEAD(, SpaprPhbState) phbs;
> struct SpaprNvram *nvram;
> - ICSState *ics;
> SpaprRtcState rtc;
>
> SpaprResizeHpt resize_hpt;
> @@ -195,9 +194,11 @@ struct SpaprMachineState {
>
> int32_t irq_map_nr;
> unsigned long *irq_map;
> - SpaprXive *xive;
> SpaprIrq *irq;
> qemu_irq *qirqs;
> + SpaprInterruptController *active_intc;
> + ICSState *ics;
> + SpaprXive *xive;
>
> bool cmd_line_caps[SPAPR_CAP_NUM];
> SpaprCapabilities def, eff, mig;
> diff --git a/include/hw/ppc/spapr_irq.h b/include/hw/ppc/spapr_irq.h
> index 616086f9bb..3102d152b2 100644
> --- a/include/hw/ppc/spapr_irq.h
> +++ b/include/hw/ppc/spapr_irq.h
> @@ -44,6 +44,9 @@ typedef struct SpaprInterruptController
> SpaprInterruptController;
> typedef struct SpaprInterruptControllerClass {
> InterfaceClass parent;
>
> + void (*activate)(SpaprInterruptController *intc, Error **errp);
> + void (*deactivate)(SpaprInterruptController *intc);
> +
> /*
> * These methods will typically be called on all intcs, active and
> * inactive
> @@ -55,6 +58,8 @@ typedef struct SpaprInterruptControllerClass {
> void (*free_irq)(SpaprInterruptController *intc, int irq);
> } SpaprInterruptControllerClass;
>
> +void spapr_irq_update_active_intc(SpaprMachineState *spapr);
> +
> void spapr_irq_print_info(SpaprMachineState *spapr, Monitor *mon);
> void spapr_irq_dt(SpaprMachineState *spapr, uint32_t nr_servers,
> void *fdt, uint32_t phandle);
