[PATCH] s390/kvm: fix diag318 propagation and reset functionality

[Collin Walling]

The Control Program Name Code (CPNC) portion of the diag318
info must be set within the SIE block of each VCPU in the
configuration. The handler will iterate through each VCPU
and dirty the diag318_info reg to be synced with KVM on a
subsequent sync_regs call.

Additionally, the diag318 info resets must be handled via
userspace. As such, QEMU will reset this value for each
VCPU during a modified clear, load normal, and load clear
reset event.

Signed-off-by: Collin Walling <walling@linux.ibm.com>
---
 hw/s390x/s390-virtio-ccw.c |  5 +++++
 target/s390x/cpu.c         | 10 ++++++++++
 target/s390x/cpu.h         |  1 +
 target/s390x/kvm.c         | 10 ++++++----
 4 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 22222c4fd5..a8cebf9bff 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -427,6 +427,9 @@ static void s390_machine_reset(MachineState *machine)
         qemu_devices_reset();
         s390_crypto_reset();
 
+        CPU_FOREACH(t) {
+            run_on_cpu(t, s390_do_cpu_set_diag318, RUN_ON_CPU_HOST_ULONG(0));
+        }
         /* configure and start the ipl CPU only */
         run_on_cpu(cs, s390_do_cpu_ipl, RUN_ON_CPU_NULL);
         break;
@@ -440,6 +443,7 @@ static void s390_machine_reset(MachineState *machine)
         s390_pv_prepare_reset(ms);
         CPU_FOREACH(t) {
             run_on_cpu(t, s390_do_cpu_full_reset, RUN_ON_CPU_NULL);
+            run_on_cpu(t, s390_do_cpu_set_diag318, RUN_ON_CPU_HOST_ULONG(0));
         }
         run_on_cpu(cs, s390_do_cpu_load_normal, RUN_ON_CPU_NULL);
         break;
@@ -451,6 +455,7 @@ static void s390_machine_reset(MachineState *machine)
         subsystem_reset();
         s390_pv_prepare_reset(ms);
         CPU_FOREACH(t) {
+            run_on_cpu(t, s390_do_cpu_set_diag318, RUN_ON_CPU_HOST_ULONG(0));
             if (t == cs) {
                 continue;
             }
diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
index 66f5942b53..cb0548b4d8 100644
--- a/target/s390x/cpu.c
+++ b/target/s390x/cpu.c
@@ -447,6 +447,16 @@ void s390_enable_css_support(S390CPU *cpu)
         kvm_s390_enable_css_support(cpu);
     }
 }
+
+void s390_do_cpu_set_diag318(CPUState *cs, run_on_cpu_data arg)
+{
+    CPUS390XState *env = &S390_CPU(cs)->env;
+    uint64_t diag318_info = arg.host_ulong;
+
+    env->diag318_info = diag318_info;
+    cs->kvm_run->s.regs.diag318 = diag318_info;
+    cs->kvm_run->kvm_dirty_regs |= KVM_SYNC_DIAG318;
+}
 #endif
 
 static gchar *s390_gdb_arch_name(CPUState *cs)
diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index f875ebf0f4..60d434d5ed 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -769,6 +769,7 @@ int s390_set_memory_limit(uint64_t new_limit, uint64_t 
*hw_limit);
 void s390_set_max_pagesize(uint64_t pagesize, Error **errp);
 void s390_cmma_reset(void);
 void s390_enable_css_support(S390CPU *cpu);
+void s390_do_cpu_set_diag318(CPUState *cs, run_on_cpu_data arg);
 int s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch_id,
                                 int vq, bool assign);
 #ifndef CONFIG_USER_ONLY
diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index baa070fdf7..4b2aad009c 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -1615,6 +1615,7 @@ static void handle_diag_318(S390CPU *cpu, struct kvm_run 
*run)
 {
     uint64_t reg = (run->s390_sieic.ipa & 0x00f0) >> 4;
     uint64_t diag318_info = run->s.regs.gprs[reg];
+    CPUState *t;
 
     /*
      * DIAG 318 can only be enabled with KVM support. As such, let's
@@ -1622,13 +1623,14 @@ static void handle_diag_318(S390CPU *cpu, struct 
kvm_run *run)
      */
     if (!s390_has_feat(S390_FEAT_DIAG_318)) {
         kvm_s390_program_interrupt(cpu, PGM_SPECIFICATION);
+        return;
     }
 
-    cpu->env.diag318_info = diag318_info;
-
     if (can_sync_regs(CPU(cpu), KVM_SYNC_DIAG318)) {
-        run->s.regs.diag318 = diag318_info;
-        run->kvm_dirty_regs |= KVM_SYNC_DIAG318;
+        CPU_FOREACH(t) {
+            run_on_cpu(t, s390_do_cpu_set_diag318,
+                       RUN_ON_CPU_HOST_ULONG(diag318_info));
+        }
     }
 }
 
-- 
2.26.2