hw/misc: add vmcoreinfo device

See docs/specs/vmcoreinfo.txt for details.

"etc/vmcoreinfo" fw_cfg entry is added when using "-device vmcoreinfo".

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

2 files changed, 97 insertions, 0 deletions

diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
index e8f0a02f35..19202d90cf 100644
--- a/hw/misc/Makefile.objs
+++ b/hw/misc/Makefile.objs
@@ -9,6 +9,7 @@ common-obj-$(CONFIG_PCI_TESTDEV) += pci-testdev.o
 common-obj-$(CONFIG_EDU) += edu.o
 
 common-obj-y += unimp.o
+common-obj-y += vmcoreinfo.o
 
 obj-$(CONFIG_VMPORT) += vmport.o
 
diff --git a/hw/misc/vmcoreinfo.c b/hw/misc/vmcoreinfo.c
new file mode 100644
index 0000000000..a618e12677
--- /dev/null
+++ b/hw/misc/vmcoreinfo.c
@@ -0,0 +1,96 @@
+/*
+ * Virtual Machine coreinfo device
+ *
+ * Copyright (C) 2017 Red Hat, Inc.
+ *
+ * Authors: Marc-André Lureau <marcandre.lureau@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "hw/nvram/fw_cfg.h"
+#include "hw/misc/vmcoreinfo.h"
+
+static void fw_cfg_vmci_write(void *dev, off_t offset, size_t len)
+{
+    VMCoreInfoState *s = VMCOREINFO(dev);
+
+    s->has_vmcoreinfo = offset == 0 && len == sizeof(s->vmcoreinfo)
+        && s->vmcoreinfo.guest_format != VMCOREINFO_FORMAT_NONE;
+}
+
+static void vmcoreinfo_reset(void *dev)
+{
+    VMCoreInfoState *s = VMCOREINFO(dev);
+
+    s->has_vmcoreinfo = false;
+    memset(&s->vmcoreinfo, 0, sizeof(s->vmcoreinfo));
+    s->vmcoreinfo.host_format = cpu_to_le16(VMCOREINFO_FORMAT_ELF);
+}
+
+static void vmcoreinfo_realize(DeviceState *dev, Error **errp)
+{
+    VMCoreInfoState *s = VMCOREINFO(dev);
+    FWCfgState *fw_cfg = fw_cfg_find();
+
+    /* Given that this function is executing, there is at least one VMCOREINFO
+     * device. Check if there are several.
+     */
+    if (!vmcoreinfo_find()) {
+        error_setg(errp, "at most one %s device is permitted",
+                   VMCOREINFO_DEVICE);
+        return;
+    }
+
+    if (!fw_cfg || !fw_cfg->dma_enabled) {
+        error_setg(errp, "%s device requires fw_cfg with DMA",
+                   VMCOREINFO_DEVICE);
+        return;
+    }
+
+    fw_cfg_add_file_callback(fw_cfg, "etc/vmcoreinfo",
+                             NULL, fw_cfg_vmci_write, s,
+                             &s->vmcoreinfo, sizeof(s->vmcoreinfo), false);
+
+    qemu_register_reset(vmcoreinfo_reset, dev);
+}
+
+static const VMStateDescription vmstate_vmcoreinfo = {
+    .name = "vmcoreinfo",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_BOOL(has_vmcoreinfo, VMCoreInfoState),
+        VMSTATE_UINT16(vmcoreinfo.host_format, VMCoreInfoState),
+        VMSTATE_UINT16(vmcoreinfo.guest_format, VMCoreInfoState),
+        VMSTATE_UINT32(vmcoreinfo.size, VMCoreInfoState),
+        VMSTATE_UINT64(vmcoreinfo.paddr, VMCoreInfoState),
+        VMSTATE_END_OF_LIST()
+    },
+};
+
+static void vmcoreinfo_device_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->vmsd = &vmstate_vmcoreinfo;
+    dc->realize = vmcoreinfo_realize;
+    dc->hotpluggable = false;
+}
+
+static const TypeInfo vmcoreinfo_device_info = {
+    .name          = VMCOREINFO_DEVICE,
+    .parent        = TYPE_DEVICE,
+    .instance_size = sizeof(VMCoreInfoState),
+    .class_init    = vmcoreinfo_device_class_init,
+};
+
+static void vmcoreinfo_register_types(void)
+{
+    type_register_static(&vmcoreinfo_device_info);
+}
+
+type_init(vmcoreinfo_register_types)