[PATCH v3] s390x: Add missing vcpu reset functions

[Janosch Frank <frankja@linux.ibm.com>]

Up to now we only had an ioctl to reset vcpu data QEMU couldn't reach
for the initial reset, which was also called for the clear reset. To
be architecture compliant, we also need to clear local interrupts on a
normal reset.

Because of this and the upcoming protvirt support we need to add
ioctls for the missing clear and normal resets.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
---
 target/s390x/cpu.c       | 14 ++++++++++++--
 target/s390x/kvm-stub.c  | 10 +++++++++-
 target/s390x/kvm.c       | 42 ++++++++++++++++++++++++++++++++--------
 target/s390x/kvm_s390x.h |  4 +++-
 4 files changed, 58 insertions(+), 12 deletions(-)

diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
index 829ce6ad54..906285888e 100644
--- a/target/s390x/cpu.c
+++ b/target/s390x/cpu.c
@@ -139,8 +139,18 @@ static void s390_cpu_reset(CPUState *s, cpu_reset_type type)
     }
 
     /* Reset state inside the kernel that we cannot access yet from QEMU. */
-    if (kvm_enabled() && type != S390_CPU_RESET_NORMAL) {
-        kvm_s390_reset_vcpu(cpu);
+    if (kvm_enabled()) {
+        switch (type) {
+        case S390_CPU_RESET_CLEAR:
+            kvm_s390_reset_vcpu_clear(cpu);
+            break;
+        case S390_CPU_RESET_INITIAL:
+            kvm_s390_reset_vcpu_initial(cpu);
+            break;
+        case S390_CPU_RESET_NORMAL:
+            kvm_s390_reset_vcpu_normal(cpu);
+            break;
+        }
     }
 }
 
diff --git a/target/s390x/kvm-stub.c b/target/s390x/kvm-stub.c
index 5152e2bdf1..c4cd497f85 100644
--- a/target/s390x/kvm-stub.c
+++ b/target/s390x/kvm-stub.c
@@ -83,7 +83,15 @@ void kvm_s390_cmma_reset(void)
 {
 }
 
-void kvm_s390_reset_vcpu(S390CPU *cpu)
+void kvm_s390_reset_vcpu_initial(S390CPU *cpu)
+{
+}
+
+void kvm_s390_reset_vcpu_clear(S390CPU *cpu)
+{
+}
+
+void kvm_s390_reset_vcpu_normal(S390CPU *cpu)
 {
 }
 
diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index ad6e38c876..f633472980 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -151,6 +151,7 @@ static int cap_s390_irq;
 static int cap_ri;
 static int cap_gs;
 static int cap_hpage_1m;
+static int cap_vcpu_resets;
 
 static int active_cmma;
 
@@ -342,6 +343,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
     cap_async_pf = kvm_check_extension(s, KVM_CAP_ASYNC_PF);
     cap_mem_op = kvm_check_extension(s, KVM_CAP_S390_MEM_OP);
     cap_s390_irq = kvm_check_extension(s, KVM_CAP_S390_INJECT_IRQ);
+    cap_vcpu_resets = kvm_check_extension(s, KVM_CAP_S390_VCPU_RESETS);
 
     if (!kvm_check_extension(s, KVM_CAP_S390_GMAP)
         || !kvm_check_extension(s, KVM_CAP_S390_COW)) {
@@ -403,17 +405,41 @@ int kvm_arch_destroy_vcpu(CPUState *cs)
     return 0;
 }
 
-void kvm_s390_reset_vcpu(S390CPU *cpu)
+static void kvm_s390_reset_vcpu(S390CPU *cpu, unsigned long type)
 {
     CPUState *cs = CPU(cpu);
 
-    /* The initial reset call is needed here to reset in-kernel
-     * vcpu data that we can't access directly from QEMU
-     * (i.e. with older kernels which don't support sync_regs/ONE_REG).
-     * Before this ioctl cpu_synchronize_state() is called in common kvm
-     * code (kvm-all) */
-    if (kvm_vcpu_ioctl(cs, KVM_S390_INITIAL_RESET, NULL)) {
-        error_report("Initial CPU reset failed on CPU %i", cs->cpu_index);
+    /*
+     * The reset call is needed here to reset in-kernel vcpu data that
+     * we can't access directly from QEMU (i.e. with older kernels
+     * which don't support sync_regs/ONE_REG).  Before this ioctl
+     * cpu_synchronize_state() is called in common kvm code
+     * (kvm-all).
+     */
+    if (kvm_vcpu_ioctl(cs, type)) {
+        error_report("CPU reset failed on CPU %i type %lx",
+                     cs->cpu_index, type);
+    }
+}
+
+void kvm_s390_reset_vcpu_initial(S390CPU *cpu)
+{
+    kvm_s390_reset_vcpu(cpu, KVM_S390_INITIAL_RESET);
+}
+
+void kvm_s390_reset_vcpu_clear(S390CPU *cpu)
+{
+    if (cap_vcpu_resets) {
+        kvm_s390_reset_vcpu(cpu, KVM_S390_CLEAR_RESET);
+    } else {
+        kvm_s390_reset_vcpu(cpu, KVM_S390_INITIAL_RESET);
+    }
+}
+
+void kvm_s390_reset_vcpu_normal(S390CPU *cpu)
+{
+    if (cap_vcpu_resets) {
+        kvm_s390_reset_vcpu(cpu, KVM_S390_NORMAL_RESET);
     }
 }
 
diff --git a/target/s390x/kvm_s390x.h b/target/s390x/kvm_s390x.h
index caf985955b..0b21789796 100644
--- a/target/s390x/kvm_s390x.h
+++ b/target/s390x/kvm_s390x.h
@@ -34,7 +34,9 @@ int kvm_s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch,
                                     int vq, bool assign);
 int kvm_s390_cmma_active(void);
 void kvm_s390_cmma_reset(void);
-void kvm_s390_reset_vcpu(S390CPU *cpu);
+void kvm_s390_reset_vcpu_clear(S390CPU *cpu);
+void kvm_s390_reset_vcpu_normal(S390CPU *cpu);
+void kvm_s390_reset_vcpu_initial(S390CPU *cpu);
 int kvm_s390_set_mem_limit(uint64_t new_limit, uint64_t *hw_limit);
 void kvm_s390_set_max_pagesize(uint64_t pagesize, Error **errp);
 void kvm_s390_crypto_reset(void);
-- 
2.20.1