s390: sclp base support

This adds a more generic infrastructure for handling Service-Call
requests on s390. Currently we only support a small subset of Read
SCP Info directly in target-s390x. This patch provides the base
infrastructure for supporting more commands and moves Read SCP
Info.
In the future we could add additional commands for hotplug, call
home and event handling.

Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

3 files changed, 195 insertions, 0 deletions

diff --git a/hw/s390x/Makefile.objs b/hw/s390x/Makefile.objs
index dcdcac8a81..1c14b96687 100644
--- a/hw/s390x/Makefile.objs
+++ b/hw/s390x/Makefile.objs
@@ -1,3 +1,4 @@
 obj-y = s390-virtio-bus.o s390-virtio.o
 
 obj-y := $(addprefix ../,$(obj-y))
+obj-y += sclp.o
diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
new file mode 100644
index 0000000000..d902a66261
--- /dev/null
+++ b/hw/s390x/sclp.c
@@ -0,0 +1,118 @@
+/*
+ * SCLP Support
+ *
+ * Copyright IBM, Corp. 2012
+ *
+ * Authors:
+ *  Christian Borntraeger <borntraeger@de.ibm.com>
+ *  Heinz Graalfs <graalfs@linux.vnet.ibm.com>
+ *
+ * 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.
+ *
+ */
+
+#include "cpu.h"
+#include "kvm.h"
+#include "memory.h"
+
+#include "sclp.h"
+
+/* Provide information about the configuration, CPUs and storage */
+static void read_SCP_info(SCCB *sccb)
+{
+    ReadInfo *read_info = (ReadInfo *) sccb;
+    int shift = 0;
+
+    while ((ram_size >> (20 + shift)) > 65535) {
+        shift++;
+    }
+    read_info->rnmax = cpu_to_be16(ram_size >> (20 + shift));
+    read_info->rnsize = 1 << shift;
+    sccb->h.response_code = cpu_to_be16(SCLP_RC_NORMAL_READ_COMPLETION);
+}
+
+static void sclp_execute(SCCB *sccb, uint64_t code)
+{
+    switch (code) {
+    case SCLP_CMDW_READ_SCP_INFO:
+    case SCLP_CMDW_READ_SCP_INFO_FORCED:
+        read_SCP_info(sccb);
+        break;
+    default:
+        sccb->h.response_code = cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND);
+        break;
+    }
+}
+
+int sclp_service_call(uint32_t sccb, uint64_t code)
+{
+    int r = 0;
+    SCCB work_sccb;
+
+    hwaddr sccb_len = sizeof(SCCB);
+
+    /* first some basic checks on program checks */
+    if (cpu_physical_memory_is_io(sccb)) {
+        r = -PGM_ADDRESSING;
+        goto out;
+    }
+    if (sccb & ~0x7ffffff8ul) {
+        r = -PGM_SPECIFICATION;
+        goto out;
+    }
+
+    /*
+     * we want to work on a private copy of the sccb, to prevent guests
+     * from playing dirty tricks by modifying the memory content after
+     * the host has checked the values
+     */
+    cpu_physical_memory_read(sccb, &work_sccb, sccb_len);
+
+    /* Valid sccb sizes */
+    if (be16_to_cpu(work_sccb.h.length) < sizeof(SCCBHeader) ||
+        be16_to_cpu(work_sccb.h.length) > SCCB_SIZE) {
+        r = -PGM_SPECIFICATION;
+        goto out;
+    }
+
+    sclp_execute((SCCB *)&work_sccb, code);
+
+    cpu_physical_memory_write(sccb, &work_sccb,
+                              be16_to_cpu(work_sccb.h.length));
+
+    sclp_service_interrupt(sccb);
+
+out:
+    return r;
+}
+
+void sclp_service_interrupt(uint32_t sccb)
+{
+    s390_sclp_extint(sccb & ~3);
+}
+
+/* qemu object creation and initialization functions */
+
+static void s390_sclp_device_class_init(ObjectClass *klass, void *data)
+{
+    SysBusDeviceClass *dc = SYS_BUS_DEVICE_CLASS(klass);
+
+    dc->init = s390_sclp_dev_init;
+}
+
+static TypeInfo s390_sclp_device_info = {
+    .name = TYPE_DEVICE_S390_SCLP,
+    .parent = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(S390SCLPDevice),
+    .class_init = s390_sclp_device_class_init,
+    .class_size = sizeof(S390SCLPDeviceClass),
+    .abstract = true,
+};
+
+static void s390_sclp_register_types(void)
+{
+    type_register_static(&s390_sclp_device_info);
+}
+
+type_init(s390_sclp_register_types)
diff --git a/hw/s390x/sclp.h b/hw/s390x/sclp.h
new file mode 100644
index 0000000000..e9ad42bec2
--- /dev/null
+++ b/hw/s390x/sclp.h
@@ -0,0 +1,76 @@
+/*
+ * SCLP Support
+ *
+ * Copyright IBM, Corp. 2012
+ *
+ * Authors:
+ *  Christian Borntraeger <borntraeger@de.ibm.com>
+ *
+ * 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.
+ *
+ */
+
+#ifndef HW_S390_SCLP_H
+#define HW_S390_SCLP_H
+
+#include <hw/sysbus.h>
+#include <hw/qdev.h>
+
+/* SCLP command codes */
+#define SCLP_CMDW_READ_SCP_INFO                 0x00020001
+#define SCLP_CMDW_READ_SCP_INFO_FORCED          0x00120001
+
+/* SCLP response codes */
+#define SCLP_RC_NORMAL_READ_COMPLETION          0x0010
+#define SCLP_RC_INVALID_SCLP_COMMAND            0x01f0
+
+/* Service Call Control Block (SCCB) and its elements */
+
+#define SCCB_SIZE 4096
+
+/*
+ * Normally packed structures are not the right thing to do, since all code
+ * must take care of endianess. We cant use ldl_phys and friends for two
+ * reasons, though:
+ * - some of the embedded structures below the SCCB can appear multiple times
+ *   at different locations, so there is no fixed offset
+ * - we work on a private copy of the SCCB, since there are several length
+ *   fields, that would cause a security nightmare if we allow the guest to
+ *   alter the structure while we parse it. We cannot use ldl_p and friends
+ *   either without doing pointer arithmetics
+ * So we have to double check that all users of sclp data structures use the
+ * right endianess wrappers.
+ */
+typedef struct SCCBHeader {
+    uint16_t length;
+    uint8_t function_code;
+    uint8_t control_mask[3];
+    uint16_t response_code;
+} QEMU_PACKED SCCBHeader;
+
+#define SCCB_DATA_LEN (SCCB_SIZE - sizeof(SCCBHeader))
+
+typedef struct ReadInfo {
+    SCCBHeader h;
+    uint16_t rnmax;
+    uint8_t rnsize;
+} QEMU_PACKED ReadInfo;
+
+typedef struct SCCB {
+    SCCBHeader h;
+    char data[SCCB_DATA_LEN];
+ } QEMU_PACKED SCCB;
+
+typedef struct S390SCLPDevice {
+    SysBusDevice busdev;
+} S390SCLPDevice;
+
+typedef struct S390SCLPDeviceClass {
+    DeviceClass qdev;
+    int (*init)(S390SCLPDevice *sdev);
+} S390SCLPDeviceClass;
+
+void sclp_service_interrupt(uint32_t sccb);
+
+#endif