[Qemu-devel] [PATCH 2/2] s390x/kvm: implement floating-interrupt controller device

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

This patch implements a floating-interrupt controller device (flic)
which interacts with the s390 flic kvm_device.

It provides functionality to:
    * clear all pending floating interrupts in the kernel at device reset
    * inject/retrieve interrupts into the kernel (used for migration)

Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>

---
 default-configs/s390x-softmmu.mak |   1 +
 hw/intc/Makefile.objs             |   1 +
 hw/intc/s390_flic.c               | 164 ++++++++++++++++++++++++++++++++++++++
 hw/s390x/s390-virtio-ccw.c        |   8 +-
 hw/s390x/s390-virtio.c            |   2 +
 include/hw/s390x/s390_flic.h      |  31 +++++++
 6 files changed, 206 insertions(+), 1 deletion(-)

diff --git a/default-configs/s390x-softmmu.mak b/default-configs/s390x-softmmu.mak
index 81fbc68..d843dc0 100644
--- a/default-configs/s390x-softmmu.mak
+++ b/default-configs/s390x-softmmu.mak
@@ -1,2 +1,3 @@
 CONFIG_VIRTIO=y
 CONFIG_SCLPCONSOLE=y
+CONFIG_S390_FLIC=$(CONFIG_KVM)
diff --git a/hw/intc/Makefile.objs b/hw/intc/Makefile.objs
index 2851eed..b2305aa 100644
--- a/hw/intc/Makefile.objs
+++ b/hw/intc/Makefile.objs
@@ -23,3 +23,4 @@ obj-$(CONFIG_OMAP) += omap_intc.o
 obj-$(CONFIG_OPENPIC_KVM) += openpic_kvm.o
 obj-$(CONFIG_SH4) += sh_intc.o
 obj-$(CONFIG_XICS) += xics.o
+obj-$(CONFIG_S390_FLIC) += s390_flic.o
diff --git a/hw/intc/s390_flic.c b/hw/intc/s390_flic.c
new file mode 100644
index 0000000..9dfaafa
--- /dev/null
+++ b/hw/intc/s390_flic.c
@@ -0,0 +1,164 @@
+/*
+ * QEMU S390x KVM floating interrupt controller (flic)
+ *
+ * Copyright 2013 IBM Corp.
+ * Author(s): Jens Freimann <jfrei@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 <sys/ioctl.h>
+#include "hw/sysbus.h"
+#include "sysemu/kvm.h"
+#include "migration/qemu-file.h"
+#include "hw/s390x/s390_flic.h"
+
+void s390_flic_init(void)
+{
+    DeviceState *dev;
+
+    if (kvm_enabled()) {
+        dev = qdev_create(NULL, "s390-flic");
+        object_property_add_child(qdev_get_machine(), "s390-flic",
+                                  OBJECT(dev), NULL);
+        qdev_init_nofail(dev);
+    }
+}
+
+static int flic_dequeue_irq(QEMUFile *f, struct kvm_s390_irq *s390irq,
+                            KVMS390FLICState *flic)
+{
+    struct kvm_device_attr attr;
+    int rc;
+
+    attr.group = KVM_DEV_FLIC_DEQUEUE;
+    attr.addr = (uint64_t) s390irq;
+
+    rc = ioctl(flic->fd, KVM_GET_DEVICE_ATTR, &attr);
+
+    return rc ? -errno : 0;
+}
+
+static int flic_enqueue_irq(QEMUFile *f, struct kvm_s390_irq *s390irq,
+                            KVMS390FLICState *flic)
+{
+    int rc;
+    struct kvm_device_attr attr;
+
+    attr.group = KVM_DEV_FLIC_ENQUEUE;
+    attr.addr = (uint64_t) s390irq;
+
+    rc = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
+
+    return rc ? -errno : 0;
+}
+
+/* Save pending floating interrupts. */
+static void kvm_floating_interrupt_save(QEMUFile *f, void *opaque)
+{
+    struct kvm_s390_irq s390irq = {0};
+    int r = 0;
+
+    while (!r) {
+        r = flic_dequeue_irq(f, &s390irq, opaque);
+        if (r == -ENODATA) {
+            /* At end of list: write special marker */
+            memset(&s390irq, 0, sizeof(s390irq));
+            s390irq.type = 0xffffffff;
+        }
+        qemu_put_buffer(f, (uint8_t *) &s390irq, sizeof(s390irq));
+    }
+}
+
+/* Load pending floating interrupts. */
+static int kvm_floating_interrupt_load(QEMUFile *f, void *opaque, int version_id)
+{
+    int r = 0;
+    struct kvm_s390_irq s390irq = {0};
+
+    while (!r) {
+        qemu_get_buffer(f, (uint8_t *) &s390irq, sizeof(s390irq));
+        /* Watch for marker indicating end of list */
+        if (s390irq.type == 0xffffffff) {
+            return 0;
+        }
+        r = flic_enqueue_irq(f, &s390irq, (struct KVMS390FLICState *) opaque);
+    }
+
+    return r;
+}
+
+static void kvm_s390_flic_realize(DeviceState *dev, Error **errp)
+{
+    KVMS390FLICState *flic_state = KVM_S390_FLIC(dev);
+    struct kvm_create_device cd = {0};
+    int ret;
+
+    flic_state->fd = -1;
+    if (!kvm_check_extension(kvm_state, KVM_CAP_DEVICE_CTRL)) {
+        return;
+    }
+
+    cd.type = KVM_DEV_TYPE_FLIC;
+    ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_DEVICE, &cd);
+    if (ret < 0) {
+        perror("flic: couldn't create kvm_device");
+        return;
+    }
+    flic_state->fd = cd.fd;
+
+    /* Register savevm handler for floating interrupts */
+    register_savevm(NULL, "floatingint", 0, 1, kvm_floating_interrupt_save,
+                    kvm_floating_interrupt_load, (void *) flic_state);
+}
+
+static void kvm_s390_flic_unrealize(DeviceState *dev, Error **errp)
+{
+    KVMS390FLICState *flic_state = KVM_S390_FLIC(dev);
+
+    unregister_savevm(DEVICE(flic_state), "floatingint", flic_state);
+}
+
+static void kvm_s390_flic_reset(DeviceState *dev)
+{
+    KVMS390FLICState *flic = KVM_S390_FLIC(dev);
+    struct kvm_device_attr attr;
+    int rc = 0;
+
+    if (flic->fd == -1) {
+        return;
+    }
+
+    attr.group = KVM_DEV_FLIC_CLEAR_IRQS;
+
+    rc = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
+    if (rc) {
+        perror("flic: reset failed");
+    }
+}
+
+static void kvm_s390_flic_class_init(ObjectClass *oc, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+
+    dc->realize = kvm_s390_flic_realize;
+    dc->unrealize = kvm_s390_flic_unrealize;
+    dc->reset = kvm_s390_flic_reset;
+    dc->no_user = 1;
+}
+
+static const TypeInfo kvm_s390_flic_info = {
+    .name          = TYPE_KVM_S390_FLIC,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(KVMS390FLICState),
+    .class_init    = kvm_s390_flic_class_init,
+};
+
+static void kvm_s390_flic_register_types(void)
+{
+    type_register_static(&kvm_s390_flic_info);
+}
+
+type_init(kvm_s390_flic_register_types)
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 733d988..0d4f6ae 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -13,13 +13,14 @@
 #include "exec/address-spaces.h"
 #include "s390-virtio.h"
 #include "hw/s390x/sclp.h"
+#include "hw/s390x/s390_flic.h"
 #include "ioinst.h"
 #include "css.h"
 #include "virtio-ccw.h"
 
 void io_subsystem_reset(void)
 {
-    DeviceState *css, *sclp;
+    DeviceState *css, *sclp, *flic;
 
     css = DEVICE(object_resolve_path_type("", "virtual-css-bridge", NULL));
     if (css) {
@@ -30,6 +31,10 @@ void io_subsystem_reset(void)
     if (sclp) {
         qdev_reset_all(sclp);
     }
+    flic = DEVICE(object_resolve_path_type("", "s390-flic", NULL));
+    if (flic) {
+        qdev_reset_all(flic);
+    }
 }
 
 static int virtio_ccw_hcall_notify(const uint64_t *args)
@@ -99,6 +104,7 @@ static void ccw_init(QEMUMachineInitArgs *args)
     s390_sclp_init();
     s390_init_ipl_dev(args->kernel_filename, args->kernel_cmdline,
                       args->initrd_filename, "s390-ccw.img");
+    s390_flic_init();
 
     /* register hypercalls */
     virtio_ccw_register_hcalls();
diff --git a/hw/s390x/s390-virtio.c b/hw/s390x/s390-virtio.c
index 7adf92a..5b54af7 100644
--- a/hw/s390x/s390-virtio.c
+++ b/hw/s390x/s390-virtio.c
@@ -36,6 +36,7 @@
 
 #include "hw/s390x/s390-virtio-bus.h"
 #include "hw/s390x/sclp.h"
+#include "hw/s390x/s390_flic.h"
 #include "hw/s390x/s390-virtio.h"
 
 //#define DEBUG_S390
@@ -251,6 +252,7 @@ static void s390_init(QEMUMachineInitArgs *args)
     s390_sclp_init();
     s390_init_ipl_dev(args->kernel_filename, args->kernel_cmdline,
                       args->initrd_filename, ZIPL_FILENAME);
+    s390_flic_init();
 
     /* register hypercalls */
     s390_virtio_register_hcalls();
diff --git a/include/hw/s390x/s390_flic.h b/include/hw/s390x/s390_flic.h
new file mode 100644
index 0000000..2b83f35
--- /dev/null
+++ b/include/hw/s390x/s390_flic.h
@@ -0,0 +1,31 @@
+/*
+ * QEMU S390x KVM floating interrupt controller (flic)
+ *
+ * Copyright 2013 IBM Corp.
+ * Author(s): Jens Freimann <jfrei@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.
+ */
+
+#ifndef __KVM_S390_FLIC_H
+#define __KVM_S390_FLIC_H
+
+#define TYPE_KVM_S390_FLIC "s390-flic"
+#define KVM_S390_FLIC(obj) \
+    OBJECT_CHECK(KVMS390FLICState, (obj), TYPE_KVM_S390_FLIC)
+
+typedef struct KVMS390FLICState {
+    DeviceState parent_obj;
+
+    uint32_t fd;
+} KVMS390FLICState;
+
+#ifdef CONFIG_KVM
+void s390_flic_init(void);
+#else
+static inline void s390_flic_init(void) { }
+#endif
+
+#endif /* __KVM_S390_FLIC_H */
-- 
1.8.3.4