s390x/tcg: Fix CPU address returned by STIDP

In qemu-user-s390x, /proc/cpuinfo contains:

	processor 0: version = 00,  identification = 000000,  machine = 8561
	processor 1: version = 00,  identification = 400000,  machine = 8561

The highest nibble is supposed to contain the CPU address, but it's off
by 2 bits. Fix the shift value and provide a symbolic constant for it.

With the fix we get:

	processor 0: version = 00,  identification = 000000,  machine = 8561
	processor 1: version = 00,  identification = 100000,  machine = 8561

Fixes: 076d4d3 ("s390x/cpumodel: wire up cpu type + id for TCG")
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20230605113950.1169228-2-iii@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

target/s390x/cpu_models.c

@@ -607,8 +607,8 @@ void s390_realize_cpu_model(CPUState *cs, Error **errp)
 #if !defined(CONFIG_USER_ONLY)
     cpu->env.cpuid = s390_cpuid_from_cpu_model(cpu->model);
     if (tcg_enabled()) {
-        /* basic mode, write the cpu address into the first 4 bit of the ID */
-        cpu->env.cpuid = deposit64(cpu->env.cpuid, 54, 4, cpu->env.core_id);
+        cpu->env.cpuid = deposit64(cpu->env.cpuid, CPU_PHYS_ADDR_SHIFT,
+                                   CPU_PHYS_ADDR_BITS, cpu->env.core_id);
     }
 #endif
 }

target/s390x/cpu_models.h

@@ -96,10 +96,18 @@ static inline bool s390_known_cpu_type(uint16_t type)
 {
     return s390_get_gen_for_cpu_type(type) != 0;
 }
+#define CPU_ID_SHIFT 32
+#define CPU_ID_BITS 24
+/*
+ * When cpu_id_format is 0 (basic mode), the leftmost 4 bits of cpu_id contain
+ * the rightmost 4 bits of the physical CPU address.
+ */
+#define CPU_PHYS_ADDR_BITS 4
+#define CPU_PHYS_ADDR_SHIFT (CPU_ID_SHIFT + CPU_ID_BITS - CPU_PHYS_ADDR_BITS)
 static inline uint64_t s390_cpuid_from_cpu_model(const S390CPUModel *model)
 {
     return ((uint64_t)model->cpu_ver << 56) |
-           ((uint64_t)model->cpu_id << 32) |
+           ((uint64_t)model->cpu_id << CPU_ID_SHIFT) |
            ((uint64_t)model->def->type << 16) |
            (model->def->gen == 7 ? 0 : (uint64_t)model->cpu_id_format << 15);
 }