[Qemu-devel] [PATCH 2/3] s390: clear registers, psw and prefix at vcpu reset

[Jens Freimann <jfrei@linux.vnet.ibm.com>]

When resetting vcpus on s390/kvm we have to clear registers, psw
and prefix as described in the z/Architecture PoP, otherwise a
reboot won't work. IPL PSW and prefix are set later on by the
s390-ipl device reset code.

Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
---
 target-s390x/kvm.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index 94de764..b1b791e 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -85,7 +85,31 @@ int kvm_arch_init_vcpu(CPUS390XState *env)
 
 void kvm_arch_reset_vcpu(CPUS390XState *env)
 {
-    /* FIXME: add code to reset vcpu. */
+    int i;
+
+    /* The initial reset call is needed here to reset in-kernel
+     * vcpu data that we can't access directly from QEMU. Before
+     * this ioctl cpu_synchronize_state() is called in common kvm
+     * code (kvm-all). What remains is clearing registers and psw
+     * in QEMU cpu state */
+    if (kvm_vcpu_ioctl(env, KVM_S390_INITIAL_RESET, NULL)) {
+        perror("Can't reset vcpu\n");
+    }
+    env->halted = 1;
+    env->exception_index = EXCP_HLT;
+    for (i = 0; i < 16; i++) {
+        env->regs[i] = 0;
+        env->aregs[i] = 0;
+        env->cregs[i] = 0;
+        env->fregs[i].ll = 0;
+    }
+    /* architectured initial values for CR 0 and 14 */
+    env->cregs[0] = 0xE0UL;
+    env->cregs[14] = 0xC2000000UL;
+    env->fpc = 0;
+    env->psw.mask = 0;
+    env->psw.addr = 0;
+    env->psa = 0;
 }
 
 int kvm_arch_put_registers(CPUS390XState *env, int level)
-- 
1.7.12.4