[PATCH v2] s390x/gdb: Split s390-virt.xml

[Ilya Leoshkevich]

Both TCG and KVM emulate ckc, cputm, last_break and prefix, and it's
quite useful to have them during debugging. Right now they are grouped
together with KVM-only pp, pfault_token, pfault_select and
pfault_compare in s390-virt.xml, and are not available when debugging
TCG-emulated code.

Move KVM-only registers into the new s390-virt-kvm.xml file. Advertise
s390-virt.xml always, and the new s390-virt-kvm.xml only for KVM.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20230313211614.98739-1-iii@linux.ibm.com>
---

v1: https://lists.gnu.org/archive/html/qemu-devel/2023-03/msg04307.html
v1 -> v2: Improve the naming and the commit message (Christian).

 configs/targets/s390x-linux-user.mak |  2 +-
 configs/targets/s390x-softmmu.mak    |  2 +-
 gdb-xml/s390-virt-kvm.xml            | 14 ++++++
 gdb-xml/s390-virt.xml                |  4 --
 target/s390x/gdbstub.c               | 65 +++++++++++++++++++---------
 5 files changed, 61 insertions(+), 26 deletions(-)
 create mode 100644 gdb-xml/s390-virt-kvm.xml

diff --git a/configs/targets/s390x-linux-user.mak 
b/configs/targets/s390x-linux-user.mak
index e2978248ede..24c04c85894 100644
--- a/configs/targets/s390x-linux-user.mak
+++ b/configs/targets/s390x-linux-user.mak
@@ -2,4 +2,4 @@ TARGET_ARCH=s390x
 TARGET_SYSTBL_ABI=common,64
 TARGET_SYSTBL=syscall.tbl
 TARGET_BIG_ENDIAN=y
-TARGET_XML_FILES= gdb-xml/s390x-core64.xml gdb-xml/s390-acr.xml 
gdb-xml/s390-fpr.xml gdb-xml/s390-vx.xml gdb-xml/s390-cr.xml 
gdb-xml/s390-virt.xml gdb-xml/s390-gs.xml
+TARGET_XML_FILES= gdb-xml/s390x-core64.xml gdb-xml/s390-acr.xml 
gdb-xml/s390-fpr.xml gdb-xml/s390-vx.xml gdb-xml/s390-cr.xml 
gdb-xml/s390-virt.xml gdb-xml/s390-virt-kvm.xml gdb-xml/s390-gs.xml
diff --git a/configs/targets/s390x-softmmu.mak 
b/configs/targets/s390x-softmmu.mak
index 258b4cf3582..70d2f9f0ba0 100644
--- a/configs/targets/s390x-softmmu.mak
+++ b/configs/targets/s390x-softmmu.mak
@@ -1,4 +1,4 @@
 TARGET_ARCH=s390x
 TARGET_BIG_ENDIAN=y
 TARGET_SUPPORTS_MTTCG=y
-TARGET_XML_FILES= gdb-xml/s390x-core64.xml gdb-xml/s390-acr.xml 
gdb-xml/s390-fpr.xml gdb-xml/s390-vx.xml gdb-xml/s390-cr.xml 
gdb-xml/s390-virt.xml gdb-xml/s390-gs.xml
+TARGET_XML_FILES= gdb-xml/s390x-core64.xml gdb-xml/s390-acr.xml 
gdb-xml/s390-fpr.xml gdb-xml/s390-vx.xml gdb-xml/s390-cr.xml 
gdb-xml/s390-virt.xml gdb-xml/s390-virt-kvm.xml gdb-xml/s390-gs.xml
diff --git a/gdb-xml/s390-virt-kvm.xml b/gdb-xml/s390-virt-kvm.xml
new file mode 100644
index 00000000000..a256eddaf57
--- /dev/null
+++ b/gdb-xml/s390-virt-kvm.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0"?>
+<!-- Copyright 2023 IBM Corp.
+
+     This work is licensed under the terms of the GNU GPL, version 2 or
+     (at your option) any later version. See the COPYING file in the
+     top-level directory. -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.s390.virt.kvm">
+  <reg name="pp" bitsize="64" type="uint64" group="system"/>
+  <reg name="pfault_token" bitsize="64" type="uint64" group="system"/>
+  <reg name="pfault_select" bitsize="64" type="uint64" group="system"/>
+  <reg name="pfault_compare" bitsize="64" type="uint64" group="system"/>
+</feature>
diff --git a/gdb-xml/s390-virt.xml b/gdb-xml/s390-virt.xml
index e2e9a7ad3cc..438eb68aabe 100644
--- a/gdb-xml/s390-virt.xml
+++ b/gdb-xml/s390-virt.xml
@@ -11,8 +11,4 @@
   <reg name="cputm" bitsize="64" type="uint64" group="system"/>
   <reg name="last_break" bitsize="64" type="code_ptr" group="system"/>
   <reg name="prefix" bitsize="64" type="data_ptr" group="system"/>
-  <reg name="pp" bitsize="64" type="uint64" group="system"/>
-  <reg name="pfault_token" bitsize="64" type="uint64" group="system"/>
-  <reg name="pfault_select" bitsize="64" type="uint64" group="system"/>
-  <reg name="pfault_compare" bitsize="64" type="uint64" group="system"/>
 </feature>
diff --git a/target/s390x/gdbstub.c b/target/s390x/gdbstub.c
index a5d69d0e0bc..e1153f5dc4a 100644
--- a/target/s390x/gdbstub.c
+++ b/target/s390x/gdbstub.c
@@ -205,12 +205,8 @@ static int cpu_write_c_reg(CPUS390XState *env, uint8_t 
*mem_buf, int n)
 #define S390_VIRT_CPUTM_REGNUM  1
 #define S390_VIRT_BEA_REGNUM    2
 #define S390_VIRT_PREFIX_REGNUM 3
-#define S390_VIRT_PP_REGNUM     4
-#define S390_VIRT_PFT_REGNUM    5
-#define S390_VIRT_PFS_REGNUM    6
-#define S390_VIRT_PFC_REGNUM    7
 /* total number of registers in s390-virt.xml */
-#define S390_NUM_VIRT_REGS 8
+#define S390_NUM_VIRT_REGS 4
 
 static int cpu_read_virt_reg(CPUS390XState *env, GByteArray *mem_buf, int n)
 {
@@ -223,14 +219,6 @@ static int cpu_read_virt_reg(CPUS390XState *env, 
GByteArray *mem_buf, int n)
         return gdb_get_regl(mem_buf, env->gbea);
     case S390_VIRT_PREFIX_REGNUM:
         return gdb_get_regl(mem_buf, env->psa);
-    case S390_VIRT_PP_REGNUM:
-        return gdb_get_regl(mem_buf, env->pp);
-    case S390_VIRT_PFT_REGNUM:
-        return gdb_get_regl(mem_buf, env->pfault_token);
-    case S390_VIRT_PFS_REGNUM:
-        return gdb_get_regl(mem_buf, env->pfault_select);
-    case S390_VIRT_PFC_REGNUM:
-        return gdb_get_regl(mem_buf, env->pfault_compare);
     default:
         return 0;
     }
@@ -255,19 +243,51 @@ static int cpu_write_virt_reg(CPUS390XState *env, uint8_t 
*mem_buf, int n)
         env->psa = ldtul_p(mem_buf);
         cpu_synchronize_post_init(env_cpu(env));
         return 8;
-    case S390_VIRT_PP_REGNUM:
+    default:
+        return 0;
+    }
+}
+
+/* the values represent the positions in s390-virt-kvm.xml */
+#define S390_VIRT_KVM_PP_REGNUM     0
+#define S390_VIRT_KVM_PFT_REGNUM    1
+#define S390_VIRT_KVM_PFS_REGNUM    2
+#define S390_VIRT_KVM_PFC_REGNUM    3
+/* total number of registers in s390-virt-kvm.xml */
+#define S390_NUM_VIRT_KVM_REGS 4
+
+static int cpu_read_virt_kvm_reg(CPUS390XState *env, GByteArray *mem_buf, int 
n)
+{
+    switch (n) {
+    case S390_VIRT_KVM_PP_REGNUM:
+        return gdb_get_regl(mem_buf, env->pp);
+    case S390_VIRT_KVM_PFT_REGNUM:
+        return gdb_get_regl(mem_buf, env->pfault_token);
+    case S390_VIRT_KVM_PFS_REGNUM:
+        return gdb_get_regl(mem_buf, env->pfault_select);
+    case S390_VIRT_KVM_PFC_REGNUM:
+        return gdb_get_regl(mem_buf, env->pfault_compare);
+    default:
+        return 0;
+    }
+}
+
+static int cpu_write_virt_kvm_reg(CPUS390XState *env, uint8_t *mem_buf, int n)
+{
+    switch (n) {
+    case S390_VIRT_KVM_PP_REGNUM:
         env->pp = ldtul_p(mem_buf);
         cpu_synchronize_post_init(env_cpu(env));
         return 8;
-    case S390_VIRT_PFT_REGNUM:
+    case S390_VIRT_KVM_PFT_REGNUM:
         env->pfault_token = ldtul_p(mem_buf);
         cpu_synchronize_post_init(env_cpu(env));
         return 8;
-    case S390_VIRT_PFS_REGNUM:
+    case S390_VIRT_KVM_PFS_REGNUM:
         env->pfault_select = ldtul_p(mem_buf);
         cpu_synchronize_post_init(env_cpu(env));
         return 8;
-    case S390_VIRT_PFC_REGNUM:
+    case S390_VIRT_KVM_PFC_REGNUM:
         env->pfault_compare = ldtul_p(mem_buf);
         cpu_synchronize_post_init(env_cpu(env));
         return 8;
@@ -320,10 +340,15 @@ void s390_cpu_gdb_init(CPUState *cs)
                              cpu_write_c_reg,
                              S390_NUM_C_REGS, "s390-cr.xml", 0);
 
+    gdb_register_coprocessor(cs, cpu_read_virt_reg,
+                             cpu_write_virt_reg,
+                             S390_NUM_VIRT_REGS, "s390-virt.xml", 0);
+
     if (kvm_enabled()) {
-        gdb_register_coprocessor(cs, cpu_read_virt_reg,
-                                 cpu_write_virt_reg,
-                                 S390_NUM_VIRT_REGS, "s390-virt.xml", 0);
+        gdb_register_coprocessor(cs, cpu_read_virt_kvm_reg,
+                                 cpu_write_virt_kvm_reg,
+                                 S390_NUM_VIRT_KVM_REGS, "s390-virt-kvm.xml",
+                                 0);
     }
 #endif
 }
-- 
2.39.2