[PATCH RFCv3 4/9] s390x: prepare for more diag500 hypercalls

[David Hildenbrand <david@redhat.com>]

Let's generalize, abstacting the virtio bits. diag500 is now a generic
hypercall to handle QEMU/KVM specific things. Explicitly specify all
already defined subcodes, including legacy ones (so we know what we can
use for new hypercalls). While at it, move exception handling into the
handler.

We'll rename the files separately, so git properly detects the rename.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 hw/s390x/s390-virtio-hcall.c | 14 +++++++-------
 hw/s390x/s390-virtio-hcall.h | 12 ++++++------
 target/s390x/kvm.c           | 15 +++------------
 target/s390x/misc_helper.c   |  3 ++-
 4 files changed, 18 insertions(+), 26 deletions(-)

diff --git a/hw/s390x/s390-virtio-hcall.c b/hw/s390x/s390-virtio-hcall.c
index 5e14bd49b7..7c4ca5d3b2 100644
--- a/hw/s390x/s390-virtio-hcall.c
+++ b/hw/s390x/s390-virtio-hcall.c
@@ -1,5 +1,5 @@
 /*
- * Support for virtio hypercalls on s390
+ * Support for QEMU/KVM-specific hypercalls on s390
  *
  * Copyright 2012 IBM Corp.
  * Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
@@ -44,18 +44,18 @@ static int handle_virtio_ccw_notify(uint64_t subch_id, uint64_t queue)
     return 0;
 }
 
-int s390_virtio_hypercall(CPUS390XState *env)
+void handle_diag_500(CPUS390XState *env, uintptr_t ra)
 {
      const uint64_t subcode = env->regs[1];
 
      switch (subcode) {
-     case KVM_S390_VIRTIO_NOTIFY:
+     case DIAG500_VIRTIO_NOTIFY:
          env->regs[2] = handle_virtio_notify(env->regs[2]);
-         return 0;
-     case KVM_S390_VIRTIO_CCW_NOTIFY:
+         break;
+     case DIAG500_VIRTIO_CCW_NOTIFY:
          env->regs[2] = handle_virtio_ccw_notify(env->regs[2], env->regs[3]);
-         return 0;
+         break;
      default:
-         return -EINVAL;
+         s390_program_interrupt(env, PGM_SPECIFICATION, ra);
      }
 }
diff --git a/hw/s390x/s390-virtio-hcall.h b/hw/s390x/s390-virtio-hcall.h
index 67e11ea39a..2214216ce8 100644
--- a/hw/s390x/s390-virtio-hcall.h
+++ b/hw/s390x/s390-virtio-hcall.h
@@ -1,5 +1,5 @@
 /*
- * Support for virtio hypercalls on s390x
+ * Support for QEMU/KVM-specific hypercalls on s390
  *
  * Copyright IBM Corp. 2012, 2017
  * Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
@@ -12,10 +12,10 @@
 #ifndef HW_S390_VIRTIO_HCALL_H
 #define HW_S390_VIRTIO_HCALL_H
 
-#include "standard-headers/asm-s390/virtio-ccw.h"
+#define DIAG500_VIRTIO_NOTIFY          0 /* legacy, implemented as a NOP */
+#define DIAG500_VIRTIO_RESET           1 /* legacy */
+#define DIAG500_VIRTIO_SET_STATUS      2 /* legacy */
+#define DIAG500_VIRTIO_CCW_NOTIFY      3 /* KVM_S390_VIRTIO_CCW_NOTIFY */
 
-/* The only thing that we need from the old kvm_virtio.h file */
-#define KVM_S390_VIRTIO_NOTIFY 0
-
-int s390_virtio_hypercall(CPUS390XState *env);
+void handle_diag_500(CPUS390XState *env, uintptr_t ra);
 #endif /* HW_S390_VIRTIO_HCALL_H */
diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index f2f75d2a57..dc00750387 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -1551,18 +1551,9 @@ static int handle_e3(S390CPU *cpu, struct kvm_run *run, uint8_t ipbl)
     return r;
 }
 
-static int handle_hypercall(S390CPU *cpu, struct kvm_run *run)
+static void handle_hypercall(S390CPU *cpu, struct kvm_run *run)
 {
-    CPUS390XState *env = &cpu->env;
-    int ret;
-
-    ret = s390_virtio_hypercall(env);
-    if (ret == -EINVAL) {
-        kvm_s390_program_interrupt(cpu, PGM_SPECIFICATION);
-        return 0;
-    }
-
-    return ret;
+    handle_diag_500(&cpu->env, RA_IGNORED);
 }
 
 static void kvm_handle_diag_288(S390CPU *cpu, struct kvm_run *run)
@@ -1621,7 +1612,7 @@ static int handle_diag(S390CPU *cpu, struct kvm_run *run, uint32_t ipb)
         kvm_handle_diag_308(cpu, run);
         break;
     case DIAG_KVM_HYPERCALL:
-        r = handle_hypercall(cpu, run);
+        handle_hypercall(cpu, run);
         break;
     case DIAG_KVM_BREAKPOINT:
         r = handle_sw_breakpoint(cpu, run);
diff --git a/target/s390x/misc_helper.c b/target/s390x/misc_helper.c
index 58dbc023eb..cfcbfbe50c 100644
--- a/target/s390x/misc_helper.c
+++ b/target/s390x/misc_helper.c
@@ -119,8 +119,9 @@ void HELPER(diag)(CPUS390XState *env, uint32_t r1, uint32_t r3, uint32_t num)
     case 0x500:
         /* KVM hypercall */
         qemu_mutex_lock_iothread();
-        r = s390_virtio_hypercall(env);
+        handle_diag_500(env, GETPC());
         qemu_mutex_unlock_iothread();
+        r = 0;
         break;
     case 0x44:
         /* yield */
-- 
2.26.2