[Qemu-devel] [PATCH 21/25] s390x/ioinst: Rework memory access in STCRW instruction

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

From: Thomas Huth <thuth@linux.vnet.ibm.com>

Change the handler for STCRW to use the new logical memory access
functions. Since STCRW is suppressed on protection/access exceptions,
we also have to make sure to re-queue the CRW in case it could not be
written to the memory.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
---
 hw/s390x/css.c        | 20 ++++++++++++++++++++
 target-s390x/cpu.h    |  1 +
 target-s390x/ioinst.c | 20 +++++++++-----------
 3 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index f6d0c0a..9a13b00 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -955,6 +955,26 @@ int css_do_stcrw(CRW *crw)
     return ret;
 }
 
+static void copy_crw_from_guest(CRW *dest, const CRW *src)
+{
+    dest->flags = be16_to_cpu(src->flags);
+    dest->rsid = be16_to_cpu(src->rsid);
+}
+
+void css_undo_stcrw(CRW *crw)
+{
+    CrwContainer *crw_cont;
+
+    crw_cont = g_try_malloc0(sizeof(CrwContainer));
+    if (!crw_cont) {
+        channel_subsys->crws_lost = true;
+        return;
+    }
+    copy_crw_from_guest(&crw_cont->crw, crw);
+
+    QTAILQ_INSERT_HEAD(&channel_subsys->pending_crws, crw_cont, sibling);
+}
+
 int css_do_tpi(IOIntCode *int_code, int lowcore)
 {
     /* No pending interrupts for !KVM. */
diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
index 7c07ca6..1f58312 100644
--- a/target-s390x/cpu.h
+++ b/target-s390x/cpu.h
@@ -458,6 +458,7 @@ int css_do_ssch(SubchDev *sch, ORB *orb);
 int css_do_tsch_get_irb(SubchDev *sch, IRB *irb, int *irb_len);
 void css_do_tsch_update_subch(SubchDev *sch);
 int css_do_stcrw(CRW *crw);
+void css_undo_stcrw(CRW *crw);
 int css_do_tpi(IOIntCode *int_code, int lowcore);
 int css_collect_chp_desc(int m, uint8_t cssid, uint8_t f_chpid, uint8_t l_chpid,
                          int rfmt, void *buf);
diff --git a/target-s390x/ioinst.c b/target-s390x/ioinst.c
index aa55ca8..157972d 100644
--- a/target-s390x/ioinst.c
+++ b/target-s390x/ioinst.c
@@ -254,10 +254,9 @@ void ioinst_handle_ssch(S390CPU *cpu, uint64_t reg1, uint32_t ipb)
 
 void ioinst_handle_stcrw(S390CPU *cpu, uint32_t ipb)
 {
-    CRW *crw;
+    CRW crw;
     uint64_t addr;
     int cc;
-    hwaddr len = sizeof(*crw);
     CPUS390XState *env = &cpu->env;
 
     addr = decode_basedisp_s(env, ipb);
@@ -265,17 +264,16 @@ void ioinst_handle_stcrw(S390CPU *cpu, uint32_t ipb)
         program_interrupt(env, PGM_SPECIFICATION, 2);
         return;
     }
-    crw = s390_cpu_physical_memory_map(env, addr, &len, 1);
-    if (!crw || len != sizeof(*crw)) {
-        program_interrupt(env, PGM_ADDRESSING, 2);
-        goto out;
-    }
-    cc = css_do_stcrw(crw);
+
+    cc = css_do_stcrw(&crw);
     /* 0 - crw stored, 1 - zeroes stored */
-    setcc(cpu, cc);
 
-out:
-    s390_cpu_physical_memory_unmap(env, crw, len, 1);
+    if (s390_cpu_virt_mem_write(cpu, addr, &crw, sizeof(crw)) == 0) {
+        setcc(cpu, cc);
+    } else if (cc == 0) {
+        /* Write failed: requeue CRW since STCRW is a suppressing instruction */
+        css_undo_stcrw(&crw);
+    }
 }
 
 void ioinst_handle_stsch(S390CPU *cpu, uint64_t reg1, uint32_t ipb)
-- 
2.1.4