virtio: Add vhost-user-rtc and vhost-user-rtc-pci

Authored solely by me for Panasonic Automotive Systems Co., Ltd., but
based on existing vhost-user devices I wrote in 2025, so the copyright
is mixed.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Link: https://lore.kernel.org/qemu-devel/20260416-vhost-user-rtc-v2-1-100a53bfc6ce@linaro.org
Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>

diff --git a/MAINTAINERS b/MAINTAINERS
index 80d28e618d4eeda7da4dbb338caf8fa5aec2f9d8..eda1e84268a591404919284b8eef5d9f9eae224b 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2586,6 +2586,12 @@ S: Maintained
 F: include/hw/virtio/vhost-user-spi.h
 F: hw/virtio/vhost-user-spi*
 
+vhost-user-rtc
+M: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
+S: Supported
+F: include/hw/virtio/vhost-user-rtc.h
+F: hw/virtio/vhost-user-rtc*
+
 virtio-crypto
 M: Gonglei <arei.gonglei@huawei.com>
 S: Supported

diff --git a/docs/system/devices/virtio/vhost-user.rst b/docs/system/devices/virtio/vhost-user.rst
index 2806d81ca201551a91246a10e0d98fd36d74200b..acfbd609d0f9c87e3af684797adf156a8a61bc88 100644 (file)
--- a/docs/system/devices/virtio/vhost-user.rst
+++ b/docs/system/devices/virtio/vhost-user.rst
@@ -61,6 +61,9 @@ platform details for what sort of virtio bus to use.
   * - vhost-user-spi
     - Proxy spi devices to host
     - `vhost-device-spi <https://github.com/rust-vmm/vhost-device/tree/main/vhost-device-spi>`_
+  * - vhost-user-rtc
+    - Real time clock
+    - `vhost-device-rtc <https://github.com/rust-vmm/vhost-device/tree/main/vhost-device-rtc>`_
 
 The referenced *daemons* are not exhaustive, any conforming backend
 implementing the device and using the vhost-user protocol should work.

diff --git a/hw/virtio/Kconfig b/hw/virtio/Kconfig
index 8895682c619402eb3c9cd7269d3319f39711b4bd..2ebdac16b31aec3ec283c0285a4dcfa67f0a5157 100644 (file)
--- a/hw/virtio/Kconfig
+++ b/hw/virtio/Kconfig
@@ -136,3 +136,8 @@ config VHOST_USER_TEST
     bool
     default y
     depends on VIRTIO && VHOST_USER
+
+config VHOST_USER_RTC
+    bool
+    default y
+    depends on VIRTIO && VHOST_USER

diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
index 415e359e9fc79b6b1adbbcfc4f87a7106ef1d4a6..e0566a60de7989c4048956e268f151659467fe34 100644 (file)
--- a/hw/virtio/meson.build
+++ b/hw/virtio/meson.build
@@ -27,6 +27,7 @@ if have_vhost
     system_virtio_ss.add(when: 'CONFIG_VHOST_USER_SND', if_true: files('vhost-user-snd.c'))
     system_virtio_ss.add(when: 'CONFIG_VHOST_USER_INPUT', if_true: files('vhost-user-input.c'))
     system_virtio_ss.add(when: 'CONFIG_VHOST_USER_SPI', if_true: files('vhost-user-spi.c'))
+    system_virtio_ss.add(when: 'CONFIG_VHOST_USER_RTC', if_true: files('vhost-user-rtc.c'))
 
     # PCI Stubs
     system_virtio_ss.add(when: ['CONFIG_VIRTIO_PCI', 'CONFIG_VHOST_USER_TEST'],
@@ -43,6 +44,8 @@ if have_vhost
                          if_true: files('vhost-user-input-pci.c'))
     system_virtio_ss.add(when: ['CONFIG_VIRTIO_PCI', 'CONFIG_VHOST_USER_SPI'],
                          if_true: files('vhost-user-spi-pci.c'))
+    system_virtio_ss.add(when: ['CONFIG_VIRTIO_PCI', 'CONFIG_VHOST_USER_RTC'],
+                         if_true: files('vhost-user-rtc-pci.c'))
   endif
   if have_vhost_vdpa
     system_virtio_ss.add(files('vhost-vdpa.c'))

diff --git a/hw/virtio/vhost-user-rtc-pci.c b/hw/virtio/vhost-user-rtc-pci.c
new file mode 100644 (file)
index 0000000..449368d
--- /dev/null
+++ b/hw/virtio/vhost-user-rtc-pci.c
@@ -0,0 +1,70 @@
+/*
+ * Vhost-user RTC virtio device PCI glue
+ *
+ * Copyright (c) 2025 Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
+ * Copyright 2026 Panasonic Automotive Systems Co., Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "hw/virtio/vhost-user-rtc.h"
+#include "hw/virtio/virtio-pci.h"
+
+struct VHostUserRTCPCI {
+    VirtIOPCIProxy parent_obj;
+    VHostUserRTC vdev;
+};
+
+typedef struct VHostUserRTCPCI VHostUserRTCPCI;
+
+#define TYPE_VHOST_USER_RTC_PCI "vhost-user-rtc-pci-base"
+
+DECLARE_INSTANCE_CHECKER(VHostUserRTCPCI, VHOST_USER_RTC_PCI,
+                         TYPE_VHOST_USER_RTC_PCI)
+
+static void vhost_user_rtc_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
+{
+    VHostUserRTCPCI *dev = VHOST_USER_RTC_PCI(vpci_dev);
+    DeviceState *vdev = DEVICE(&dev->vdev);
+
+    vpci_dev->nvectors = 1;
+
+    qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
+}
+
+static void vhost_user_rtc_pci_class_init(ObjectClass *klass, const void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VirtioPCIClass *k = VIRTIO_PCI_CLASS(klass);
+    PCIDeviceClass *pcidev_k = PCI_DEVICE_CLASS(klass);
+    k->realize = vhost_user_rtc_pci_realize;
+    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+    pcidev_k->vendor_id = PCI_VENDOR_ID_REDHAT_QUMRANET;
+    pcidev_k->device_id = 0; /* Set by virtio-pci based on virtio id */
+    pcidev_k->revision = 0x00;
+    pcidev_k->class_id = PCI_CLASS_SYSTEM_RTC;
+}
+
+static void vhost_user_rtc_pci_instance_init(Object *obj)
+{
+    VHostUserRTCPCI *dev = VHOST_USER_RTC_PCI(obj);
+
+    virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
+                                TYPE_VHOST_USER_RTC);
+}
+
+static const VirtioPCIDeviceTypeInfo vhost_user_rtc_pci_info = {
+    .base_name = TYPE_VHOST_USER_RTC_PCI,
+    .non_transitional_name = "vhost-user-rtc-pci",
+    .instance_size = sizeof(VHostUserRTCPCI),
+    .instance_init = vhost_user_rtc_pci_instance_init,
+    .class_init = vhost_user_rtc_pci_class_init,
+};
+
+static void vhost_user_rtc_pci_register(void)
+{
+    virtio_pci_types_register(&vhost_user_rtc_pci_info);
+}
+
+type_init(vhost_user_rtc_pci_register);

diff --git a/hw/virtio/vhost-user-rtc.c b/hw/virtio/vhost-user-rtc.c
new file mode 100644 (file)
index 0000000..88b0c70
--- /dev/null
+++ b/hw/virtio/vhost-user-rtc.c
@@ -0,0 +1,64 @@
+/*
+ * Vhost-user RTC virtio device
+ *
+ * Copyright (c) 2025 Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
+ * Copyright 2026 Panasonic Automotive Systems Co., Ltd.
+ *
+ * Simple wrapper of the generic vhost-user-device.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "hw/virtio/vhost-user-rtc.h"
+#include "standard-headers/linux/virtio_ids.h"
+
+static const VMStateDescription vu_rtc_vmstate = {
+    .name = "vhost-user-rtc",
+    .unmigratable = 1,
+};
+
+static const Property vrtc_properties[] = {
+    DEFINE_PROP_CHR("chardev", VHostUserBase, chardev),
+};
+
+static void vu_rtc_base_realize(DeviceState *dev, Error **errp)
+{
+    VHostUserBase *vub = VHOST_USER_BASE(dev);
+    VHostUserBaseClass *vubs = VHOST_USER_BASE_GET_CLASS(dev);
+
+    vub->virtio_id = VIRTIO_ID_CLOCK;
+    vub->num_vqs = 2;
+    vub->config_size = 0;
+    vub->vq_size = 1024;
+
+    vubs->parent_realize(dev, errp);
+}
+
+static void vu_rtc_class_init(ObjectClass *klass, const void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VHostUserBaseClass *vubc = VHOST_USER_BASE_CLASS(klass);
+
+    dc->vmsd = &vu_rtc_vmstate;
+    device_class_set_props(dc, vrtc_properties);
+    device_class_set_parent_realize(dc, vu_rtc_base_realize,
+                                    &vubc->parent_realize);
+
+    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+}
+
+static const TypeInfo vu_rtc_info = {
+    .name = TYPE_VHOST_USER_RTC,
+    .parent = TYPE_VHOST_USER_BASE,
+    .instance_size = sizeof(VHostUserRTC),
+    .class_init = vu_rtc_class_init,
+};
+
+static void vu_rtc_register_types(void)
+{
+    type_register_static(&vu_rtc_info);
+}
+
+type_init(vu_rtc_register_types)

diff --git a/include/hw/virtio/vhost-user-rtc.h b/include/hw/virtio/vhost-user-rtc.h
new file mode 100644 (file)
index 0000000..6b7b53c
--- /dev/null
+++ b/include/hw/virtio/vhost-user-rtc.h
@@ -0,0 +1,22 @@
+/*
+ * Vhost-user RTC virtio device
+ *
+ * Copyright (c) 2025 Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
+ * Copyright 2026 Panasonic Automotive Systems Co., Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef QEMU_VHOST_USER_RTC_H
+#define QEMU_VHOST_USER_RTC_H
+
+#include "hw/virtio/vhost-user-base.h"
+
+#define TYPE_VHOST_USER_RTC "vhost-user-rtc"
+OBJECT_DECLARE_SIMPLE_TYPE(VHostUserRTC, VHOST_USER_RTC)
+
+struct VHostUserRTC {
+    VHostUserBase parent_obj;
+};
+
+#endif /* QEMU_VHOST_USER_RTC_H */