spapr: Pass the maximum number of vCPUs to the KVM interrupt controller

The XIVE and XICS-on-XIVE KVM devices on POWER9 hosts can greatly reduce
their consumption of some scarce HW resources, namely Virtual Presenter
identifiers, if they know the maximum number of vCPUs that may run in the
VM.

Prepare ground for this by passing the value down to xics_kvm_connect()
and kvmppc_xive_connect(). This is purely mechanical, no functional
change.

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <157478678301.67101.2717368060417156338.stgit@bahia.tlslab.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

5 files changed, 16 insertions, 9 deletions

diff --git a/hw/intc/spapr_xive.c b/hw/intc/spapr_xive.c
index bb3b2df..18a043a 100644
--- a/hw/intc/spapr_xive.c
+++ b/hw/intc/spapr_xive.c
@@ -697,12 +697,14 @@ static void spapr_xive_dt(SpaprInterruptController *intc, uint32_t nr_servers,
                      plat_res_int_priorities, sizeof(plat_res_int_priorities)));
 }
 
-static int spapr_xive_activate(SpaprInterruptController *intc, Error **errp)
+static int spapr_xive_activate(SpaprInterruptController *intc,
+                               uint32_t nr_servers, Error **errp)
 {
     SpaprXive *xive = SPAPR_XIVE(intc);
 
     if (kvm_enabled()) {
-        int rc = spapr_irq_init_kvm(kvmppc_xive_connect, intc, errp);
+        int rc = spapr_irq_init_kvm(kvmppc_xive_connect, intc, nr_servers,
+                                    errp);
         if (rc < 0) {
             return rc;
         }
diff --git a/hw/intc/spapr_xive_kvm.c b/hw/intc/spapr_xive_kvm.c
index 69e7355..46c7609 100644
--- a/hw/intc/spapr_xive_kvm.c
+++ b/hw/intc/spapr_xive_kvm.c
@@ -728,7 +728,8 @@ static void *kvmppc_xive_mmap(SpaprXive *xive, int pgoff, size_t len,
  * All the XIVE memory regions are now backed by mappings from the KVM
  * XIVE device.
  */
-int kvmppc_xive_connect(SpaprInterruptController *intc, Error **errp)
+int kvmppc_xive_connect(SpaprInterruptController *intc, uint32_t nr_servers,
+                        Error **errp)
 {
     SpaprXive *xive = SPAPR_XIVE(intc);
     XiveSource *xsrc = &xive->source;
diff --git a/hw/intc/xics_kvm.c b/hw/intc/xics_kvm.c
index 954c424..a1f1b7b 100644
--- a/hw/intc/xics_kvm.c
+++ b/hw/intc/xics_kvm.c
@@ -342,7 +342,8 @@ void ics_kvm_set_irq(ICSState *ics, int srcno, int val)
     }
 }
 
-int xics_kvm_connect(SpaprInterruptController *intc, Error **errp)
+int xics_kvm_connect(SpaprInterruptController *intc, uint32_t nr_servers,
+                     Error **errp)
 {
     ICSState *ics = ICS_SPAPR(intc);
     int rc;
diff --git a/hw/intc/xics_spapr.c b/hw/intc/xics_spapr.c
index b3705da..8ae4f41 100644
--- a/hw/intc/xics_spapr.c
+++ b/hw/intc/xics_spapr.c
@@ -422,10 +422,11 @@ static int xics_spapr_post_load(SpaprInterruptController *intc, int version_id)
     return 0;
 }
 
-static int xics_spapr_activate(SpaprInterruptController *intc, Error **errp)
+static int xics_spapr_activate(SpaprInterruptController *intc,
+                               uint32_t nr_servers, Error **errp)
 {
     if (kvm_enabled()) {
-        return spapr_irq_init_kvm(xics_kvm_connect, intc, errp);
+        return spapr_irq_init_kvm(xics_kvm_connect, intc, nr_servers, errp);
     }
     return 0;
 }
diff --git a/hw/ppc/spapr_irq.c b/hw/ppc/spapr_irq.c
index d4a54af..07e08d6 100644
--- a/hw/ppc/spapr_irq.c
+++ b/hw/ppc/spapr_irq.c
@@ -70,15 +70,16 @@ void spapr_irq_msi_free(SpaprMachineState *spapr, int irq, uint32_t num)
     bitmap_clear(spapr->irq_map, irq - SPAPR_IRQ_MSI, num);
 }
 
-int spapr_irq_init_kvm(int (*fn)(SpaprInterruptController *, Error **),
+int spapr_irq_init_kvm(SpaprInterruptControllerInitKvm fn,
                        SpaprInterruptController *intc,
+                       uint32_t nr_servers,
                        Error **errp)
 {
     MachineState *machine = MACHINE(qdev_get_machine());
     Error *local_err = NULL;
 
     if (kvm_enabled() && machine_kernel_irqchip_allowed(machine)) {
-        if (fn(intc, &local_err) < 0) {
+        if (fn(intc, nr_servers, &local_err) < 0) {
             if (machine_kernel_irqchip_required(machine)) {
                 error_prepend(&local_err,
                               "kernel_irqchip requested but unavailable: ");
@@ -481,6 +482,7 @@ static void set_active_intc(SpaprMachineState *spapr,
                             SpaprInterruptController *new_intc)
 {
     SpaprInterruptControllerClass *sicc;
+    uint32_t nr_servers = spapr_max_server_number(spapr);
 
     assert(new_intc);
 
@@ -498,7 +500,7 @@ static void set_active_intc(SpaprMachineState *spapr,
 
     sicc = SPAPR_INTC_GET_CLASS(new_intc);
     if (sicc->activate) {
-        sicc->activate(new_intc, &error_fatal);
+        sicc->activate(new_intc, nr_servers, &error_fatal);
     }
 
     spapr->active_intc = new_intc;