s390: kvm: adjust diag318 resets to retain data

The CPNC portion of the diag318 data is erroneously reset during an
initial CPU reset caused by SIGP. Let's go ahead and relocate the
diag318_info field within the CPUS390XState struct such that it is
only zeroed during a clear reset. This way, the CPNC will be retained
for each VCPU in the configuration after the diag318 instruction
has been invoked.

The s390_machine_reset code already takes care of zeroing the diag318
data on VM resets, which also cover resets caused by diag308.

Fixes: fabdada9357b ("s390: guest support for diagnose 0x318")
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Collin Walling <walling@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Message-Id: <20211117152303.627969-1-walling@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index ca3845d02358d292979de1fcdd418d2180e8434c..a75e559134cca94cc5084e40db78ce85adb4eccd 100644 (file)
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -63,6 +63,8 @@ struct CPUS390XState {
     uint64_t etoken;       /* etoken */
     uint64_t etoken_extension; /* etoken extension */
 
+    uint64_t diag318_info;
+
     /* Fields up to this point are not cleared by initial CPU reset */
     struct {} start_initial_reset_fields;
 
@@ -118,8 +120,6 @@ struct CPUS390XState {
     uint16_t external_call_addr;
     DECLARE_BITMAP(emergency_signals, S390_MAX_CPUS);
 
-    uint64_t diag318_info;
-
 #if !defined(CONFIG_USER_ONLY)
     uint64_t tlb_fill_tec;   /* translation exception code during tlb_fill */
     int tlb_fill_exc;        /* exception number seen during tlb_fill */

diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
index 5b1fdb55c47747f1145fe72af88391b0d92515b8..6acf14d5ecb4ca8a407724146380b37f8e7e65d4 100644 (file)
--- a/target/s390x/kvm/kvm.c
+++ b/target/s390x/kvm/kvm.c
@@ -1585,6 +1585,10 @@ void kvm_s390_set_diag318(CPUState *cs, uint64_t diag318_info)
         env->diag318_info = diag318_info;
         cs->kvm_run->s.regs.diag318 = diag318_info;
         cs->kvm_run->kvm_dirty_regs |= KVM_SYNC_DIAG318;
+        /*
+         * diag 318 info is zeroed during a clear reset and
+         * diag 308 IPL subcodes.
+         */
     }
 }