qemu-kvm/kvm-s390-kvm-adjust-diag318-resets-to-retain-data.patch

From 3c7bc4319d4e475c820a63176d18afb7b4b2ed78 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= <clg@redhat.com>
Date: Tue, 23 May 2023 12:34:33 +0200
Subject: [PATCH 02/22] s390: kvm: adjust diag318 resets to retain data
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RH-Author: Cédric Le Goater <clg@redhat.com>
RH-MergeRequest: 279: Backport latest s390x-related fixes from upstream QEMU for qemu-kvm in RHEL 8.9
RH-Bugzilla: 2169308 2209605
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: David Hildenbrand <david@redhat.com>
RH-Acked-by: Cornelia Huck <cohuck@redhat.com>
RH-Commit: [1/21] 16f2ff166efdd26a3be98d7c97d3b184598d1ca4

Bugzilla: https://bugzilla.redhat.com/2169308

commit c35aff184b2ed5be930da671ea25c857713555af
Author: Collin L. Walling <walling@linux.ibm.com>
Date:   Wed Nov 17 10:23:03 2021 -0500

    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>

Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 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 ca3845d023..a75e559134 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 d36b44f32a..8d36c377b5 100644
--- a/target/s390x/kvm/kvm.c
+++ b/target/s390x/kvm/kvm.c
@@ -1598,6 +1598,10 @@ 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.
+         */
     }
 }
 
-- 
2.37.3