[PATCH v2 1/2] spapr: Introduce a interrupt presenter reset handler

["Cédric Le Goater" <clg@kaod.org>]

The interrupt presenters are created by a machine handler at the core
level and are reseted independently. This is not consistent and it
raises some issues when it comes to handle hot-plugged CPUs. These are
reseted from the realize handler of the core and the presenters are
not. This is less of an issue in XICS, although a zero MFFR could be a
concern, but in XIVE, the OS CAM line is not set and this breaks the
presenting algorithm. The current code has workarounds which need a
global cleanup.

Extend the sPAPR IRQ backend with a new cpu_intc_reset() handler which
will be called by the CPU reset handler and remove the XiveTCTX reset
handler which is redundant.

spapr_realize_vcpu() is modified to call the CPU reset only after the
intc presenter has been created.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
---

 The change of order of the CPU reset and the intc creation could be
 in its own patch for bisect. This is fragile.
 
 include/hw/ppc/spapr_irq.h |  2 ++
 include/hw/ppc/xics.h      |  1 +
 include/hw/ppc/xive.h      |  1 +
 hw/intc/spapr_xive.c       |  7 +++++++
 hw/intc/xics.c             |  8 ++------
 hw/intc/xics_spapr.c       |  7 +++++++
 hw/intc/xive.c             | 12 +-----------
 hw/ppc/spapr_cpu_core.c    | 14 ++++++++++----
 hw/ppc/spapr_irq.c         | 14 ++++++++++++++
 9 files changed, 45 insertions(+), 21 deletions(-)

diff --git a/include/hw/ppc/spapr_irq.h b/include/hw/ppc/spapr_irq.h
index 5e150a667902..09232999b07e 100644
--- a/include/hw/ppc/spapr_irq.h
+++ b/include/hw/ppc/spapr_irq.h
@@ -52,6 +52,7 @@ typedef struct SpaprInterruptControllerClass {
      */
     int (*cpu_intc_create)(SpaprInterruptController *intc,
                             PowerPCCPU *cpu, Error **errp);
+    void (*cpu_intc_reset)(SpaprInterruptController *intc, PowerPCCPU *cpu);
     int (*claim_irq)(SpaprInterruptController *intc, int irq, bool lsi,
                      Error **errp);
     void (*free_irq)(SpaprInterruptController *intc, int irq);
@@ -68,6 +69,7 @@ void spapr_irq_update_active_intc(SpaprMachineState *spapr);
 
 int spapr_irq_cpu_intc_create(SpaprMachineState *spapr,
                               PowerPCCPU *cpu, Error **errp);
+void spapr_irq_cpu_intc_reset(SpaprMachineState *spapr, PowerPCCPU *cpu);
 void spapr_irq_print_info(SpaprMachineState *spapr, Monitor *mon);
 void spapr_irq_dt(SpaprMachineState *spapr, uint32_t nr_servers,
                   void *fdt, uint32_t phandle);
diff --git a/include/hw/ppc/xics.h b/include/hw/ppc/xics.h
index 1e6a9300eb2b..602173c12250 100644
--- a/include/hw/ppc/xics.h
+++ b/include/hw/ppc/xics.h
@@ -161,6 +161,7 @@ void icp_set_mfrr(ICPState *icp, uint8_t mfrr);
 uint32_t icp_accept(ICPState *ss);
 uint32_t icp_ipoll(ICPState *ss, uint32_t *mfrr);
 void icp_eoi(ICPState *icp, uint32_t xirr);
+void icp_reset(ICPState *icp);
 
 void ics_write_xive(ICSState *ics, int nr, int server,
                     uint8_t priority, uint8_t saved_priority);
diff --git a/include/hw/ppc/xive.h b/include/hw/ppc/xive.h
index fd3319bd3202..99381639f50c 100644
--- a/include/hw/ppc/xive.h
+++ b/include/hw/ppc/xive.h
@@ -415,6 +415,7 @@ uint64_t xive_tctx_tm_read(XiveTCTX *tctx, hwaddr offset, unsigned size);
 
 void xive_tctx_pic_print_info(XiveTCTX *tctx, Monitor *mon);
 Object *xive_tctx_create(Object *cpu, XiveRouter *xrtr, Error **errp);
+void xive_tctx_reset(XiveTCTX *tctx);
 
 static inline uint32_t xive_nvt_cam_line(uint8_t nvt_blk, uint32_t nvt_idx)
 {
diff --git a/hw/intc/spapr_xive.c b/hw/intc/spapr_xive.c
index ba32d2cc5b0f..258b1c5fb5ff 100644
--- a/hw/intc/spapr_xive.c
+++ b/hw/intc/spapr_xive.c
@@ -553,6 +553,12 @@ static int spapr_xive_cpu_intc_create(SpaprInterruptController *intc,
     return 0;
 }
 
+static void spapr_xive_cpu_intc_reset(SpaprInterruptController *intc,
+                                     PowerPCCPU *cpu)
+{
+    xive_tctx_reset(spapr_cpu_state(cpu)->tctx);
+}
+
 static void spapr_xive_set_irq(SpaprInterruptController *intc, int irq, int val)
 {
     SpaprXive *xive = SPAPR_XIVE(intc);
@@ -697,6 +703,7 @@ static void spapr_xive_class_init(ObjectClass *klass, void *data)
     sicc->activate = spapr_xive_activate;
     sicc->deactivate = spapr_xive_deactivate;
     sicc->cpu_intc_create = spapr_xive_cpu_intc_create;
+    sicc->cpu_intc_reset = spapr_xive_cpu_intc_reset;
     sicc->claim_irq = spapr_xive_claim_irq;
     sicc->free_irq = spapr_xive_free_irq;
     sicc->set_irq = spapr_xive_set_irq;
diff --git a/hw/intc/xics.c b/hw/intc/xics.c
index b5ac408f7b74..6da05763f9db 100644
--- a/hw/intc/xics.c
+++ b/hw/intc/xics.c
@@ -274,10 +274,8 @@ static const VMStateDescription vmstate_icp_server = {
     },
 };
 
-static void icp_reset_handler(void *dev)
+void icp_reset(ICPState *icp)
 {
-    ICPState *icp = ICP(dev);
-
     icp->xirr = 0;
     icp->pending_priority = 0xff;
     icp->mfrr = 0xff;
@@ -288,7 +286,7 @@ static void icp_reset_handler(void *dev)
     if (kvm_irqchip_in_kernel()) {
         Error *local_err = NULL;
 
-        icp_set_kvm_state(ICP(dev), &local_err);
+        icp_set_kvm_state(icp, &local_err);
         if (local_err) {
             error_report_err(local_err);
         }
@@ -351,7 +349,6 @@ static void icp_realize(DeviceState *dev, Error **errp)
         }
     }
 
-    qemu_register_reset(icp_reset_handler, dev);
     vmstate_register(NULL, icp->cs->cpu_index, &vmstate_icp_server, icp);
 }
 
@@ -360,7 +357,6 @@ static void icp_unrealize(DeviceState *dev, Error **errp)
     ICPState *icp = ICP(dev);
 
     vmstate_unregister(NULL, &vmstate_icp_server, icp);
-    qemu_unregister_reset(icp_reset_handler, dev);
 }
 
 static void icp_class_init(ObjectClass *klass, void *data)
diff --git a/hw/intc/xics_spapr.c b/hw/intc/xics_spapr.c
index 4f64b9a9fc66..7418fb9f370c 100644
--- a/hw/intc/xics_spapr.c
+++ b/hw/intc/xics_spapr.c
@@ -346,6 +346,12 @@ static int xics_spapr_cpu_intc_create(SpaprInterruptController *intc,
     return 0;
 }
 
+static void xics_spapr_cpu_intc_reset(SpaprInterruptController *intc,
+                                     PowerPCCPU *cpu)
+{
+    icp_reset(spapr_cpu_state(cpu)->icp);
+}
+
 static int xics_spapr_claim_irq(SpaprInterruptController *intc, int irq,
                                 bool lsi, Error **errp)
 {
@@ -433,6 +439,7 @@ static void ics_spapr_class_init(ObjectClass *klass, void *data)
     sicc->activate = xics_spapr_activate;
     sicc->deactivate = xics_spapr_deactivate;
     sicc->cpu_intc_create = xics_spapr_cpu_intc_create;
+    sicc->cpu_intc_reset = xics_spapr_cpu_intc_reset;
     sicc->claim_irq = xics_spapr_claim_irq;
     sicc->free_irq = xics_spapr_free_irq;
     sicc->set_irq = xics_spapr_set_irq;
diff --git a/hw/intc/xive.c b/hw/intc/xive.c
index d420c6571e14..f066be5eb5e3 100644
--- a/hw/intc/xive.c
+++ b/hw/intc/xive.c
@@ -547,10 +547,8 @@ void xive_tctx_pic_print_info(XiveTCTX *tctx, Monitor *mon)
     }
 }
 
-static void xive_tctx_reset(void *dev)
+void xive_tctx_reset(XiveTCTX *tctx)
 {
-    XiveTCTX *tctx = XIVE_TCTX(dev);
-
     memset(tctx->regs, 0, sizeof(tctx->regs));
 
     /* Set some defaults */
@@ -607,13 +605,6 @@ static void xive_tctx_realize(DeviceState *dev, Error **errp)
             return;
         }
     }
-
-    qemu_register_reset(xive_tctx_reset, dev);
-}
-
-static void xive_tctx_unrealize(DeviceState *dev, Error **errp)
-{
-    qemu_unregister_reset(xive_tctx_reset, dev);
 }
 
 static int vmstate_xive_tctx_pre_save(void *opaque)
@@ -668,7 +659,6 @@ static void xive_tctx_class_init(ObjectClass *klass, void *data)
 
     dc->desc = "XIVE Interrupt Thread Context";
     dc->realize = xive_tctx_realize;
-    dc->unrealize = xive_tctx_unrealize;
     dc->vmsd = &vmstate_xive_tctx;
     /*
      * Reason: part of XIVE interrupt controller, needs to be wired up
diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
index 3e4302c7d596..d04baa7cde4f 100644
--- a/hw/ppc/spapr_cpu_core.c
+++ b/hw/ppc/spapr_cpu_core.c
@@ -33,6 +33,7 @@ static void spapr_cpu_reset(void *opaque)
     PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu);
     SpaprCpuState *spapr_cpu = spapr_cpu_state(cpu);
     target_ulong lpcr;
+    SpaprMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
 
     cpu_reset(cs);
 
@@ -77,9 +78,11 @@ static void spapr_cpu_reset(void *opaque)
     spapr_cpu->dtl_addr = 0;
     spapr_cpu->dtl_size = 0;
 
-    spapr_caps_cpu_apply(SPAPR_MACHINE(qdev_get_machine()), cpu);
+    spapr_caps_cpu_apply(spapr, cpu);
 
     kvm_check_mmu(cpu, &error_fatal);
+
+    spapr_irq_cpu_intc_reset(spapr, cpu);
 }
 
 void spapr_cpu_set_entry_state(PowerPCCPU *cpu, target_ulong nip, target_ulong r3)
@@ -234,13 +237,16 @@ static void spapr_realize_vcpu(PowerPCCPU *cpu, SpaprMachineState *spapr,
     cpu_ppc_set_vhyp(cpu, PPC_VIRTUAL_HYPERVISOR(spapr));
     kvmppc_set_papr(cpu);
 
-    qemu_register_reset(spapr_cpu_reset, cpu);
-    spapr_cpu_reset(cpu);
-
     if (spapr_irq_cpu_intc_create(spapr, cpu, &local_err) < 0) {
         goto error_unregister;
     }
 
+    /*
+     * Hot-plugged CPUs are not reseted. Do it here.
+     */
+    qemu_register_reset(spapr_cpu_reset, cpu);
+    spapr_cpu_reset(cpu);
+
     if (!sc->pre_3_0_migration) {
         vmstate_register(NULL, cs->cpu_index, &vmstate_spapr_cpu_state,
                          cpu->machine_data);
diff --git a/hw/ppc/spapr_irq.c b/hw/ppc/spapr_irq.c
index 234d1073e518..b941608b69ba 100644
--- a/hw/ppc/spapr_irq.c
+++ b/hw/ppc/spapr_irq.c
@@ -220,6 +220,20 @@ int spapr_irq_cpu_intc_create(SpaprMachineState *spapr,
     return 0;
 }
 
+void spapr_irq_cpu_intc_reset(SpaprMachineState *spapr, PowerPCCPU *cpu)
+{
+    SpaprInterruptController *intcs[] = ALL_INTCS(spapr);
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(intcs); i++) {
+        SpaprInterruptController *intc = intcs[i];
+        if (intc) {
+            SpaprInterruptControllerClass *sicc = SPAPR_INTC_GET_CLASS(intc);
+            sicc->cpu_intc_reset(intc, cpu);
+        }
+    }
+}
+
 static void spapr_set_irq(void *opaque, int irq, int level)
 {
     SpaprMachineState *spapr = SPAPR_MACHINE(opaque);
-- 
2.21.0