[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH v4] s390: kvm: adjust diag318 resets to retain data

From: Christian Borntraeger
Subject: Re: [PATCH v4] s390: kvm: adjust diag318 resets to retain data
Date: Tue, 23 Nov 2021 10:28:53 +0100
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0

Am 17.11.21 um 16:23 schrieb Collin Walling:
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.

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

Thomas, I think this is good to go. Will you take it via your tree?



     - fixed up commit message and added r-b's

     - reverted changes from previous versions
     - simply relocate diag318_info in CPU State struct
     - add comment in set_diag318 to explain resets

     - handler uses run_on_cpu again
     - reworded commit message slightly
     - added fixes and reported-by tags

     - nixed code reduction changes
     - added a comment to diag318 handler to briefly describe
         when relevent data is zeroed

  target/s390x/cpu.h     | 4 ++--
  target/s390x/kvm/kvm.c | 4 ++++
  2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index 3153d053e9..88aace36ff 100644
--- 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 5b1fdb55c4..6acf14d5ec 100644
--- 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 
          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.
+         */

reply via email to

[Prev in Thread] Current Thread [Next in Thread]