Merge remote-tracking branch 'remotes/dgibson/tags/ppc-for-4.1-20190813' into staging

ppc patch queue 2019-08-13 (last minute qemu-4.1 fixes)

Here's a very, very last minute pull request for qemu-4.1.  This fixes
two nasty bugs with the XIVE interrupt controller in "dual" mode
(where the guest decides which interrupt controller it wants to use).
One occurs when resetting the guest while I/O is active, and the other
with migration of hotplugged CPUs.

The timing here is very unfortunate.  Alas, we only spotted these bugs
very late, and I was sick last week, delaying analysis and fix even
further.

This series hasn't had nearly as much testing as I'd really like, but
I'd still like to squeeze it into qemu-4.1 if possible, since
definitely fixing two bad bugs seems like an acceptable tradeoff for
the risk of introducing different bugs.

# gpg: Signature made Tue 13 Aug 2019 07:56:42 BST
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# gpg: Good signature from "David Gibson <david@gibson.dropbear.id.au>" [full]
# gpg:                 aka "David Gibson (Red Hat) <dgibson@redhat.com>" [full]
# gpg:                 aka "David Gibson (ozlabs.org) <dgibson@ozlabs.org>" [full]
# gpg:                 aka "David Gibson (kernel.org) <dwg@kernel.org>" [unknown]
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* remotes/dgibson/tags/ppc-for-4.1-20190813:
  spapr/xive: Fix migration of hot-plugged CPUs
  spapr: Reset CAS & IRQ subsystem after devices

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

4 files changed, 50 insertions, 15 deletions

diff --git a/hw/intc/spapr_xive_kvm.c b/hw/intc/spapr_xive_kvm.c
index 3bf8e7a20e..8898615c69 100644
--- a/hw/intc/spapr_xive_kvm.c
+++ b/hw/intc/spapr_xive_kvm.c
@@ -72,11 +72,17 @@ static void kvm_cpu_disable_all(void)
  * XIVE Thread Interrupt Management context (KVM)
  */
 
-static void kvmppc_xive_cpu_set_state(XiveTCTX *tctx, Error **errp)
+void kvmppc_xive_cpu_set_state(XiveTCTX *tctx, Error **errp)
 {
+    SpaprXive *xive = SPAPR_MACHINE(qdev_get_machine())->xive;
     uint64_t state[2];
     int ret;
 
+    /* The KVM XIVE device is not in use yet */
+    if (xive->fd == -1) {
+        return;
+    }
+
     /* word0 and word1 of the OS ring. */
     state[0] = *((uint64_t *) &tctx->regs[TM_QW1_OS]);
 
@@ -655,7 +661,16 @@ int kvmppc_xive_post_load(SpaprXive *xive, int version_id)
         }
     }
 
-    /* Restore the thread interrupt contexts */
+    /*
+     * Restore the thread interrupt contexts of initial CPUs.
+     *
+     * The context of hotplugged CPUs is restored later, by the
+     * 'post_load' handler of the XiveTCTX model because they are not
+     * available at the time the SpaprXive 'post_load' method is
+     * called. We can not restore the context of all CPUs in the
+     * 'post_load' handler of XiveTCTX because the machine is not
+     * necessarily connected to the KVM device at that time.
+     */
     CPU_FOREACH(cs) {
         PowerPCCPU *cpu = POWERPC_CPU(cs);
 
diff --git a/hw/intc/xive.c b/hw/intc/xive.c
index cf77bdb7d3..da148e9f6f 100644
--- a/hw/intc/xive.c
+++ b/hw/intc/xive.c
@@ -615,12 +615,31 @@ static int vmstate_xive_tctx_pre_save(void *opaque)
     return 0;
 }
 
+static int vmstate_xive_tctx_post_load(void *opaque, int version_id)
+{
+    Error *local_err = NULL;
+
+    if (kvm_irqchip_in_kernel()) {
+        /*
+         * Required for hotplugged CPU, for which the state comes
+         * after all states of the machine.
+         */
+        kvmppc_xive_cpu_set_state(XIVE_TCTX(opaque), &local_err);
+        if (local_err) {
+            error_report_err(local_err);
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
 static const VMStateDescription vmstate_xive_tctx = {
     .name = TYPE_XIVE_TCTX,
     .version_id = 1,
     .minimum_version_id = 1,
     .pre_save = vmstate_xive_tctx_pre_save,
-    .post_load = NULL, /* handled by the sPAPRxive model */
+    .post_load = vmstate_xive_tctx_post_load,
     .fields = (VMStateField[]) {
         VMSTATE_BUFFER(regs, XiveTCTX),
         VMSTATE_END_OF_LIST()
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 821f0d4a49..12ed4b065c 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1727,6 +1727,18 @@ static void spapr_machine_reset(MachineState *machine)
     }
 
     /*
+     * NVLink2-connected GPU RAM needs to be placed on a separate NUMA node.
+     * We assign a new numa ID per GPU in spapr_pci_collect_nvgpu() which is
+     * called from vPHB reset handler so we initialize the counter here.
+     * If no NUMA is configured from the QEMU side, we start from 1 as GPU RAM
+     * must be equally distant from any other node.
+     * The final value of spapr->gpu_numa_id is going to be written to
+     * max-associativity-domains in spapr_build_fdt().
+     */
+    spapr->gpu_numa_id = MAX(1, nb_numa_nodes);
+    qemu_devices_reset();
+
+    /*
      * If this reset wasn't generated by CAS, we should reset our
      * negotiated options and start from scratch
      */
@@ -1742,18 +1754,6 @@ static void spapr_machine_reset(MachineState *machine)
     }
 
     /*
-     * NVLink2-connected GPU RAM needs to be placed on a separate NUMA node.
-     * We assign a new numa ID per GPU in spapr_pci_collect_nvgpu() which is
-     * called from vPHB reset handler so we initialize the counter here.
-     * If no NUMA is configured from the QEMU side, we start from 1 as GPU RAM
-     * must be equally distant from any other node.
-     * The final value of spapr->gpu_numa_id is going to be written to
-     * max-associativity-domains in spapr_build_fdt().
-     */
-    spapr->gpu_numa_id = MAX(1, nb_numa_nodes);
-    qemu_devices_reset();
-
-    /*
      * This is fixing some of the default configuration of the XIVE
      * devices. To be called after the reset of the machine devices.
      */
diff --git a/include/hw/ppc/xive.h b/include/hw/ppc/xive.h
index 55c53c7417..736335174a 100644
--- a/include/hw/ppc/xive.h
+++ b/include/hw/ppc/xive.h
@@ -438,5 +438,6 @@ void kvmppc_xive_source_set_irq(void *opaque, int srcno, int val);
 void kvmppc_xive_cpu_connect(XiveTCTX *tctx, Error **errp);
 void kvmppc_xive_cpu_synchronize_state(XiveTCTX *tctx, Error **errp);
 void kvmppc_xive_cpu_get_state(XiveTCTX *tctx, Error **errp);
+void kvmppc_xive_cpu_set_state(XiveTCTX *tctx, Error **errp);
 
 #endif /* PPC_XIVE_H */