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[PATCH 10/12] hw/virtio: add config support to vhost-user-device
From: |
Alex Bennée |
Subject: |
[PATCH 10/12] hw/virtio: add config support to vhost-user-device |
Date: |
Fri, 14 Apr 2023 17:04:31 +0100 |
To use the generic device the user will need to provide the config
region size via the command line. We also add a notifier so the guest
can be pinged if the remote daemon updates the config.
With these changes:
-device vhost-user-device-pci,virtio-id=41,num_vqs=2,config_size=8
is equivalent to:
-device vhost-user-gpio-pci
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
include/hw/virtio/vhost-user-device.h | 1 +
hw/virtio/vhost-user-device.c | 58 ++++++++++++++++++++++++++-
2 files changed, 58 insertions(+), 1 deletion(-)
diff --git a/include/hw/virtio/vhost-user-device.h
b/include/hw/virtio/vhost-user-device.h
index 8d77f06721..cb98e0dcaa 100644
--- a/include/hw/virtio/vhost-user-device.h
+++ b/include/hw/virtio/vhost-user-device.h
@@ -21,6 +21,7 @@ struct VHostUserDevice {
CharBackend chardev;
uint16_t virtio_id;
uint32_t num_vqs;
+ uint32_t config_size;
/* State tracking */
VhostUserState vhost_user;
struct vhost_virtqueue *vhost_vq;
diff --git a/hw/virtio/vhost-user-device.c b/hw/virtio/vhost-user-device.c
index bfbf3b29cb..977cfed247 100644
--- a/hw/virtio/vhost-user-device.c
+++ b/hw/virtio/vhost-user-device.c
@@ -117,6 +117,42 @@ static uint64_t vud_get_features(VirtIODevice *vdev,
return vud->vhost_dev.features & ~(1ULL << VHOST_USER_F_PROTOCOL_FEATURES);
}
+/*
+ * To handle VirtIO config we need to know the size of the config
+ * space. We don't cache the config but re-fetch it from the guest
+ * every time in case something has changed.
+ */
+static void vud_get_config(VirtIODevice *vdev, uint8_t *config)
+{
+ VHostUserDevice *vud = VHOST_USER_DEVICE(vdev);
+ Error *local_err = NULL;
+
+ /*
+ * There will have been a warning during vhost_dev_init, but lets
+ * assert here as nothing will go right now.
+ */
+ g_assert(vud->config_size && vud->vhost_user.supports_config == true);
+
+ if (vhost_dev_get_config(&vud->vhost_dev, config,
+ vud->config_size, &local_err)) {
+ error_report_err(local_err);
+ }
+}
+
+/*
+ * When the daemon signals an update to the config we just need to
+ * signal the guest as we re-read the config on demand above.
+ */
+static int vud_config_notifier(struct vhost_dev *dev)
+{
+ virtio_notify_config(dev->vdev);
+ return 0;
+}
+
+const VhostDevConfigOps vud_config_ops = {
+ .vhost_dev_config_notifier = vud_config_notifier,
+};
+
static void vud_handle_output(VirtIODevice *vdev, VirtQueue *vq)
{
/*
@@ -141,12 +177,21 @@ static int vud_connect(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserDevice *vud = VHOST_USER_DEVICE(vdev);
+ struct vhost_dev *vhost_dev = &vud->vhost_dev;
if (vud->connected) {
return 0;
}
vud->connected = true;
+ /*
+ * If we support VHOST_USER_GET_CONFIG we must enable the notifier
+ * so we can ping the guest when it updates.
+ */
+ if (vud->vhost_user.supports_config) {
+ vhost_dev_set_config_notifier(vhost_dev, &vud_config_ops);
+ }
+
/* restore vhost state */
if (virtio_device_started(vdev, vdev->status)) {
vud_start(vdev);
@@ -214,11 +259,20 @@ static void vud_device_realize(DeviceState *dev, Error
**errp)
vud->num_vqs = 1; /* reasonable default? */
}
+ /*
+ * We can't handle config requests unless we know the size of the
+ * config region, specialisations of the vhost-user-device will be
+ * able to set this.
+ */
+ if (vud->config_size) {
+ vud->vhost_user.supports_config = true;
+ }
+
if (!vhost_user_init(&vud->vhost_user, &vud->chardev, errp)) {
return;
}
- virtio_init(vdev, vud->virtio_id, 0);
+ virtio_init(vdev, vud->virtio_id, vud->config_size);
/*
* Disable guest notifiers, by default all notifications will be via the
@@ -271,6 +325,7 @@ static Property vud_properties[] = {
DEFINE_PROP_CHR("chardev", VHostUserDevice, chardev),
DEFINE_PROP_UINT16("virtio-id", VHostUserDevice, virtio_id, 0),
DEFINE_PROP_UINT32("num_vqs", VHostUserDevice, num_vqs, 1),
+ DEFINE_PROP_UINT32("config_size", VHostUserDevice, config_size, 0),
DEFINE_PROP_END_OF_LIST(),
};
@@ -285,6 +340,7 @@ static void vud_class_init(ObjectClass *klass, void *data)
vdc->realize = vud_device_realize;
vdc->unrealize = vud_device_unrealize;
vdc->get_features = vud_get_features;
+ vdc->get_config = vud_get_config;
vdc->set_status = vud_set_status;
}
--
2.39.2
- [PATCH 03/12] include/hw/virtio: add kerneldoc for virtio_init, (continued)
- [PATCH 03/12] include/hw/virtio: add kerneldoc for virtio_init, Alex Bennée, 2023/04/14
- [PATCH 02/12] include/hw/virtio: document virtio_notify_config, Alex Bennée, 2023/04/14
- [PATCH 06/12] virtio: add PCI stub for vhost-user-device, Alex Bennée, 2023/04/14
- [PATCH 01/12] hw/virtio: fix typo in VIRTIO_CONFIG_IRQ_IDX comments, Alex Bennée, 2023/04/14
- [PATCH 12/12] docs/system: add a basic enumeration of vhost-user devices, Alex Bennée, 2023/04/14
- [PATCH 11/12] hw/virtio: derive vhost-user-gpio from vhost-user-device (!BROKEN), Alex Bennée, 2023/04/14
- [PATCH 05/12] virtio: add generic vhost-user-device, Alex Bennée, 2023/04/14
- [PATCH 09/12] hw/virtio: derive vhost-user-rng from vhost-user-device, Alex Bennée, 2023/04/14
- [PATCH 04/12] include/hw/virtio: document some more usage of notifiers, Alex Bennée, 2023/04/14
- [PATCH 10/12] hw/virtio: add config support to vhost-user-device,
Alex Bennée <=
- [PATCH 08/12] qom: allow for properties to become "fixed", Alex Bennée, 2023/04/14
- [PATCH 07/12] include: attempt to document device_class_set_props, Alex Bennée, 2023/04/14
- Re: [PATCH 00/12] virtio: add vhost-user-generic and reduce copy and paste, Viresh Kumar, 2023/04/17
- Re: [PATCH 00/12] virtio: add vhost-user-generic and reduce copy and paste, Stefan Hajnoczi, 2023/04/17