spapr/irq: add KVM support to the 'dual' machine

The interrupt mode is chosen by the CAS negotiation process and
activated after a reset to take into account the required changes in
the machine. This brings new constraints on how the associated KVM IRQ
device is initialized.

Currently, each model takes care of the initialization of the KVM
device in their realize method but this is not possible anymore as the
initialization needs to be done globaly when the interrupt mode is
known, i.e. when machine is reseted. It also means that we need a way
to delete a KVM device when another mode is chosen.

Also, to support migration, the QEMU objects holding the state to
transfer should always be available but not necessarily activated.

The overall approach of this proposal is to initialize both interrupt
mode at the QEMU level to keep the IRQ number space in sync and to
allow switching from one mode to another. For the KVM side of things,
the whole initialization of the KVM device, sources and presenters, is
grouped in a single routine. The XICS and XIVE sPAPR IRQ reset
handlers are modified accordingly to handle the init and the delete
sequences of the KVM device.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <20190513084245.25755-15-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 38 insertions, 20 deletions

diff --git a/hw/ppc/spapr_irq.c b/hw/ppc/spapr_irq.c
index d1e8757..3156daf 100644
--- a/hw/ppc/spapr_irq.c
+++ b/hw/ppc/spapr_irq.c
@@ -102,12 +102,6 @@ static void spapr_irq_init_xics(SpaprMachineState *spapr, int nr_irqs,
     Object *obj;
     Error *local_err = NULL;
 
-    spapr_irq_init_device(spapr, &spapr_irq_xics, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
-        return;
-    }
-
     obj = object_new(TYPE_ICS_SIMPLE);
     object_property_add_child(OBJECT(spapr), "ics", obj, &error_abort);
     object_property_add_const_link(obj, ICS_PROP_XICS, OBJECT(spapr),
@@ -226,7 +220,13 @@ static void spapr_irq_set_irq_xics(void *opaque, int srcno, int val)
 
 static void spapr_irq_reset_xics(SpaprMachineState *spapr, Error **errp)
 {
-    /* TODO: create the KVM XICS device */
+    Error *local_err = NULL;
+
+    spapr_irq_init_device(spapr, &spapr_irq_xics, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
 }
 
 static const char *spapr_irq_get_nodename_xics(SpaprMachineState *spapr)
@@ -279,7 +279,6 @@ static void spapr_irq_init_xive(SpaprMachineState *spapr, int nr_irqs,
     uint32_t nr_servers = spapr_max_server_number(spapr);
     DeviceState *dev;
     int i;
-    Error *local_err = NULL;
 
     dev = qdev_create(NULL, TYPE_SPAPR_XIVE);
     qdev_prop_set_uint32(dev, "nr-irqs", nr_irqs);
@@ -297,12 +296,6 @@ static void spapr_irq_init_xive(SpaprMachineState *spapr, int nr_irqs,
     }
 
     spapr_xive_hcall_init(spapr);
-
-    spapr_irq_init_device(spapr, &spapr_irq_xive, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
-        return;
-    }
 }
 
 static int spapr_irq_claim_xive(SpaprMachineState *spapr, int irq, bool lsi,
@@ -382,6 +375,7 @@ static int spapr_irq_post_load_xive(SpaprMachineState *spapr, int version_id)
 static void spapr_irq_reset_xive(SpaprMachineState *spapr, Error **errp)
 {
     CPUState *cs;
+    Error *local_err = NULL;
 
     CPU_FOREACH(cs) {
         PowerPCCPU *cpu = POWERPC_CPU(cs);
@@ -390,6 +384,12 @@ static void spapr_irq_reset_xive(SpaprMachineState *spapr, Error **errp)
         spapr_xive_set_tctx_os_cam(spapr_cpu_state(cpu)->tctx);
     }
 
+    spapr_irq_init_device(spapr, &spapr_irq_xive, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
     /* Activate the XIVE MMIOs */
     spapr_xive_mmio_set_enabled(spapr->xive, true);
 }
@@ -472,14 +472,8 @@ static SpaprIrq *spapr_irq_current(SpaprMachineState *spapr)
 static void spapr_irq_init_dual(SpaprMachineState *spapr, int nr_irqs,
                                 Error **errp)
 {
-    MachineState *machine = MACHINE(spapr);
     Error *local_err = NULL;
 
-    if (kvm_enabled() && machine_kernel_irqchip_allowed(machine)) {
-        error_setg(errp, "No KVM support for the 'dual' machine");
-        return;
-    }
-
     spapr_irq_xics.init(spapr, spapr_irq_xics.nr_irqs, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
@@ -558,6 +552,9 @@ static int spapr_irq_post_load_dual(SpaprMachineState *spapr, int version_id)
      * defaults to XICS at startup.
      */
     if (spapr_ovec_test(spapr->ov5_cas, OV5_XIVE_EXPLOIT)) {
+        if (kvm_irqchip_in_kernel()) {
+            xics_kvm_disconnect(spapr, &error_fatal);
+        }
         spapr_irq_xive.reset(spapr, &error_fatal);
     }
 
@@ -566,12 +563,30 @@ static int spapr_irq_post_load_dual(SpaprMachineState *spapr, int version_id)
 
 static void spapr_irq_reset_dual(SpaprMachineState *spapr, Error **errp)
 {
+    Error *local_err = NULL;
+
     /*
      * Deactivate the XIVE MMIOs. The XIVE backend will reenable them
      * if selected.
      */
     spapr_xive_mmio_set_enabled(spapr->xive, false);
 
+    /* Destroy all KVM devices */
+    if (kvm_irqchip_in_kernel()) {
+        xics_kvm_disconnect(spapr, &local_err);
+        if (local_err) {
+            error_propagate(errp, local_err);
+            error_prepend(errp, "KVM XICS disconnect failed: ");
+            return;
+        }
+        kvmppc_xive_disconnect(spapr->xive, &local_err);
+        if (local_err) {
+            error_propagate(errp, local_err);
+            error_prepend(errp, "KVM XIVE disconnect failed: ");
+            return;
+        }
+    }
+
     spapr_irq_current(spapr)->reset(spapr, errp);
 }
 
@@ -809,6 +824,9 @@ SpaprIrq spapr_irq_xics_legacy = {
     .dt_populate = spapr_dt_xics,
     .cpu_intc_create = spapr_irq_cpu_intc_create_xics,
     .post_load   = spapr_irq_post_load_xics,
+    .reset       = spapr_irq_reset_xics,
     .set_irq     = spapr_irq_set_irq_xics,
     .get_nodename = spapr_irq_get_nodename_xics,
+    .init_emu    = spapr_irq_init_emu_xics,
+    .init_kvm    = spapr_irq_init_kvm_xics,
 };