s390x/ipl: Extend the IplParameterBlock struct

The IplParameterBlock struct currently has only 200 bytes filled, but it
can be up to 4K.

This patch converts the struct to union with a fully populated struct
inside it and second struct with old values.

For compatibility reasons we disable migration of the extended iplb
field for pre-2.7 machines. Also a guest still can read/write only the
first 200 bytes of IPLB for now.

Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

hw/s390x/ipl.c

@@ -30,6 +30,24 @@
 #define ZIPL_IMAGE_START                0x009000UL
 #define IPL_PSW_MASK                    (PSW_MASK_32 | PSW_MASK_64)
 
+static bool iplb_extended_needed(void *opaque)
+{
+    S390IPLState *ipl = S390_IPL(object_resolve_path(TYPE_S390_IPL, NULL));
+
+    return ipl->iplbext_migration;
+}
+
+static const VMStateDescription vmstate_iplb_extended = {
+    .name = "ipl/iplb_extended",
+    .version_id = 0,
+    .minimum_version_id = 0,
+    .needed = iplb_extended_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT8_ARRAY(reserved_ext, IplParameterBlock, 4096 - 200),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static const VMStateDescription vmstate_iplb = {
     .name = "ipl/iplb",
     .version_id = 0,
@@ -39,6 +57,10 @@ static const VMStateDescription vmstate_iplb = {
         VMSTATE_UINT16(devno, IplParameterBlock),
         VMSTATE_UINT8_ARRAY(reserved2, IplParameterBlock, 88),
         VMSTATE_END_OF_LIST()
+    },
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_iplb_extended,
+        NULL
     }
 };
 
@@ -181,6 +203,8 @@ static Property s390_ipl_properties[] = {
     DEFINE_PROP_STRING("cmdline", S390IPLState, cmdline),
     DEFINE_PROP_STRING("firmware", S390IPLState, firmware),
     DEFINE_PROP_BOOL("enforce_bios", S390IPLState, enforce_bios, false),
+    DEFINE_PROP_BOOL("iplbext_migration", S390IPLState, iplbext_migration,
+                     true),
     DEFINE_PROP_END_OF_LIST(),
 };
 

hw/s390x/ipl.h

@@ -15,11 +15,59 @@
 #include "hw/qdev.h"
 #include "cpu.h"
 
-typedef struct IplParameterBlock {
-      uint8_t  reserved1[110];
-      uint16_t devno;
-      uint8_t  reserved2[88];
-} IplParameterBlock;
+struct IplBlockCcw {
+    uint8_t  reserved0[86];
+    uint16_t devno;
+    uint8_t  vm_flags;
+    uint8_t  reserved3[3];
+    uint32_t vm_parm_len;
+    uint8_t  nss_name[8];
+    uint8_t  vm_parm[64];
+    uint8_t  reserved4[8];
+} QEMU_PACKED;
+typedef struct IplBlockCcw IplBlockCcw;
+
+struct IplBlockFcp {
+    uint8_t  reserved1[305 - 1];
+    uint8_t  opt;
+    uint8_t  reserved2[3];
+    uint16_t reserved3;
+    uint16_t devno;
+    uint8_t  reserved4[4];
+    uint64_t wwpn;
+    uint64_t lun;
+    uint32_t bootprog;
+    uint8_t  reserved5[12];
+    uint64_t br_lba;
+    uint32_t scp_data_len;
+    uint8_t  reserved6[260];
+    uint8_t  scp_data[];
+} QEMU_PACKED;
+typedef struct IplBlockFcp IplBlockFcp;
+
+union IplParameterBlock {
+    struct {
+        uint32_t len;
+        uint8_t  reserved0[3];
+        uint8_t  version;
+        uint32_t blk0_len;
+        uint8_t  pbt;
+        uint8_t  flags;
+        uint16_t reserved01;
+        uint8_t  loadparm[8];
+        union {
+            IplBlockCcw ccw;
+            IplBlockFcp fcp;
+        };
+    } QEMU_PACKED;
+    struct {
+        uint8_t  reserved1[110];
+        uint16_t devno;
+        uint8_t  reserved2[88];
+        uint8_t  reserved_ext[4096 - 200];
+    } QEMU_PACKED;
+} QEMU_PACKED;
+typedef union IplParameterBlock IplParameterBlock;
 
 void s390_ipl_update_diag308(IplParameterBlock *iplb);
 void s390_ipl_prepare_cpu(S390CPU *cpu);
@@ -47,7 +95,10 @@ struct S390IPLState {
     uint8_t cssid;
     uint8_t ssid;
     uint16_t devno;
+    bool iplbext_migration;
 };
 typedef struct S390IPLState S390IPLState;
 
+#define S390_IPLB_MIN_CCW_LEN 200
+
 #endif

hw/s390x/s390-virtio-ccw.c

@@ -25,6 +25,7 @@
 #include "s390-pci-bus.h"
 #include "hw/s390x/storage-keys.h"
 #include "hw/compat.h"
+#include "ipl.h"
 #include "hw/s390x/s390-virtio-ccw.h"
 
 static const char *const reset_dev_types[] = {
@@ -317,7 +318,12 @@ static const TypeInfo ccw_machine_info = {
     type_init(ccw_machine_register_##suffix)
 
 #define CCW_COMPAT_2_6 \
-        HW_COMPAT_2_6
+        HW_COMPAT_2_6 \
+        {\
+            .driver   = TYPE_S390_IPL,\
+            .property = "iplbext_migration",\
+            .value    = "off",\
+        },
 
 #define CCW_COMPAT_2_5 \
         CCW_COMPAT_2_6 \

target-s390x/misc_helper.c

@@ -232,8 +232,8 @@ void handle_diag_308(CPUS390XState *env, uint64_t r1, uint64_t r3)
             program_interrupt(env, PGM_ADDRESSING, ILEN_LATER_INC);
             return;
         }
-        iplb = g_malloc0(sizeof(struct IplParameterBlock));
-        cpu_physical_memory_read(addr, iplb, sizeof(struct IplParameterBlock));
+        iplb = g_malloc0(sizeof(IplParameterBlock));
+        cpu_physical_memory_read(addr, iplb, S390_IPLB_MIN_CCW_LEN);
         s390_ipl_update_diag308(iplb);
         env->regs[r1 + 1] = DIAG_308_RC_OK;
         g_free(iplb);
@@ -250,8 +250,7 @@ void handle_diag_308(CPUS390XState *env, uint64_t r1, uint64_t r3)
         }
         iplb = s390_ipl_get_iplb();
         if (iplb) {
-            cpu_physical_memory_write(addr, iplb,
-                                      sizeof(struct IplParameterBlock));
+            cpu_physical_memory_write(addr, iplb, S390_IPLB_MIN_CCW_LEN);
             env->regs[r1 + 1] = DIAG_308_RC_OK;
         } else {
             env->regs[r1 + 1] = DIAG_308_RC_NO_CONF;