Re: [Qemu-devel] [PATCH v4 8/8] xics_kvm: Add cpu_destroy method to XICS

[Alexey Kardashevskiy]

On 06/05/2015 02:25 PM, Bharata B Rao wrote:
XICS is setup for each CPU during initialization. Provide a routine
to undo the same when CPU is unplugged. Also ensure xics reset doesn't set
irq for CPUs that are already unplugged.
This allows reboot of a VM that has undergone CPU hotplug and unplug
to work correctly.

Signed-off-by: Bharata B Rao <bhar...@linux.vnet.ibm.com>
---
  hw/intc/xics.c        | 14 ++++++++++++++
  hw/intc/xics_kvm.c    | 15 +++++++++++++--
  include/hw/ppc/xics.h |  2 ++
  3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/hw/intc/xics.c b/hw/intc/xics.c
index 924b1ae..3f87f82 100644
--- a/hw/intc/xics.c
+++ b/hw/intc/xics.c
@@ -44,6 +44,20 @@ static int get_cpu_index_by_dt_id(int cpu_dt_id)
      return -1;
  }

+void xics_cpu_destroy(XICSState *icp, PowerPCCPU *cpu)


xics_cpu_destroy() is not used by anything, may be push it later with the 
stuff which needs it?


+{
+    CPUState *cs = CPU(cpu);
+    XICSStateClass *info = XICS_COMMON_GET_CLASS(icp);
+    ICPState *ss = &icp->ss[cs->cpu_index];
+
+    assert(cs->cpu_index < icp->nr_servers);
+
+    ss->output = NULL;
+    if (info->cpu_destroy) {
+        info->cpu_destroy(icp, cpu);
+    }
+}
+
  void xics_cpu_setup(XICSState *icp, PowerPCCPU *cpu)
  {
      CPUState *cs = CPU(cpu);
diff --git a/hw/intc/xics_kvm.c b/hw/intc/xics_kvm.c
index d58729c..e35f319 100644
--- a/hw/intc/xics_kvm.c
+++ b/hw/intc/xics_kvm.c
@@ -109,8 +109,10 @@ static void icp_kvm_reset(DeviceState *dev)
      icp->pending_priority = 0xff;
      icp->mfrr = 0xff;

-    /* Make all outputs are deasserted */
-    qemu_set_irq(icp->output, 0);
+    /* Make all outputs are deasserted only if the CPU thread is in use */
+    if (icp->output) {
+        qemu_set_irq(icp->output, 0);
+    }


This feels unrelated to what the patch claims that it does. Or 
xics_cpu_destroy() somehow indirectly calls icp_kvm_reset()?



      icp_set_kvm_state(icp, 1);
  }
@@ -356,6 +358,14 @@ static void xics_kvm_cpu_setup(XICSState *icp, PowerPCCPU 
*cpu)
      }
  }

+static void xics_kvm_cpu_destroy(XICSState *icp, PowerPCCPU *cpu)
+{
+    CPUState *cs = CPU(cpu);
+    ICPState *ss = &icp->ss[cs->cpu_index];
+
+    ss->cs = NULL;
+}
+
  static void xics_kvm_set_nr_irqs(XICSState *icp, uint32_t nr_irqs, Error 
**errp)
  {
      icp->nr_irqs = icp->ics->nr_irqs = nr_irqs;
@@ -486,6 +496,7 @@ static void xics_kvm_class_init(ObjectClass *oc, void *data)

      dc->realize = xics_kvm_realize;
      xsc->cpu_setup = xics_kvm_cpu_setup;
+    xsc->cpu_destroy = xics_kvm_cpu_destroy;
      xsc->set_nr_irqs = xics_kvm_set_nr_irqs;
      xsc->set_nr_servers = xics_kvm_set_nr_servers;
  }
diff --git a/include/hw/ppc/xics.h b/include/hw/ppc/xics.h
index 355a966..2faad48 100644
--- a/include/hw/ppc/xics.h
+++ b/include/hw/ppc/xics.h
@@ -68,6 +68,7 @@ struct XICSStateClass {
      DeviceClass parent_class;

      void (*cpu_setup)(XICSState *icp, PowerPCCPU *cpu);
+    void (*cpu_destroy)(XICSState *icp, PowerPCCPU *cpu);
      void (*set_nr_irqs)(XICSState *icp, uint32_t nr_irqs, Error **errp);
      void (*set_nr_servers)(XICSState *icp, uint32_t nr_servers, Error **errp);
  };
@@ -166,5 +167,6 @@ int xics_alloc_block(XICSState *icp, int src, int num, bool 
lsi, bool align);
  void xics_free(XICSState *icp, int irq, int num);

  void xics_cpu_setup(XICSState *icp, PowerPCCPU *cpu);
+void xics_cpu_destroy(XICSState *icp, PowerPCCPU *cpu);

  #endif /* __XICS_H__ */



--
Alexey