From cf03a152c5d749fd0083bfe540df9524f1d2ff1d Mon Sep 17 00:00:00 2001
From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Wed, 20 Dec 2023 08:47:54 -0500
Subject: qdev: add IOThreadVirtQueueMappingList property type
virtio-blk and virtio-scsi devices will need a way to specify the
mapping between IOThreads and virtqueues. At the moment all virtqueues
are assigned to a single IOThread or the main loop. This single thread
can be a CPU bottleneck, so it is necessary to allow finer-grained
assignment to spread the load.
Introduce DEFINE_PROP_IOTHREAD_VQ_MAPPING_LIST() so devices can take a
parameter that maps virtqueues to IOThreads. The command-line syntax for
this new property is as follows:
--device '{"driver":"foo","iothread-vq-mapping":[{"iothread":"iothread0","vqs":[0,1,2]},...]}'
IOThreads are specified by name and virtqueues are specified by 0-based
index.
It will be common to simply assign virtqueues round-robin across a set
of IOThreads. A convenient syntax that does not require specifying
individual virtqueue indices is available:
--device '{"driver":"foo","iothread-vq-mapping":[{"iothread":"iothread0"},{"iothread":"iothread1"},...]}'
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20231220134755.814917-4-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
hw/core/qdev-properties-system.c | 46 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
(limited to 'hw')
diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c
index 73cced4626..1a396521d5 100644
--- a/hw/core/qdev-properties-system.c
+++ b/hw/core/qdev-properties-system.c
@@ -18,6 +18,7 @@
#include "qapi/qapi-types-block.h"
#include "qapi/qapi-types-machine.h"
#include "qapi/qapi-types-migration.h"
+#include "qapi/qapi-visit-virtio.h"
#include "qapi/qmp/qerror.h"
#include "qemu/ctype.h"
#include "qemu/cutils.h"
@@ -1160,3 +1161,48 @@ const PropertyInfo qdev_prop_cpus390entitlement = {
.set = qdev_propinfo_set_enum,
.set_default_value = qdev_propinfo_set_default_value_enum,
};
+
+/* --- IOThreadVirtQueueMappingList --- */
+
+static void get_iothread_vq_mapping_list(Object *obj, Visitor *v,
+ const char *name, void *opaque, Error **errp)
+{
+ IOThreadVirtQueueMappingList **prop_ptr =
+ object_field_prop_ptr(obj, opaque);
+
+ visit_type_IOThreadVirtQueueMappingList(v, name, prop_ptr, errp);
+}
+
+static void set_iothread_vq_mapping_list(Object *obj, Visitor *v,
+ const char *name, void *opaque, Error **errp)
+{
+ IOThreadVirtQueueMappingList **prop_ptr =
+ object_field_prop_ptr(obj, opaque);
+ IOThreadVirtQueueMappingList *list;
+
+ if (!visit_type_IOThreadVirtQueueMappingList(v, name, &list, errp)) {
+ return;
+ }
+
+ qapi_free_IOThreadVirtQueueMappingList(*prop_ptr);
+ *prop_ptr = list;
+}
+
+static void release_iothread_vq_mapping_list(Object *obj,
+ const char *name, void *opaque)
+{
+ IOThreadVirtQueueMappingList **prop_ptr =
+ object_field_prop_ptr(obj, opaque);
+
+ qapi_free_IOThreadVirtQueueMappingList(*prop_ptr);
+ *prop_ptr = NULL;
+}
+
+const PropertyInfo qdev_prop_iothread_vq_mapping_list = {
+ .name = "IOThreadVirtQueueMappingList",
+ .description = "IOThread virtqueue mapping list [{\"iothread\":\"<id>\", "
+ "\"vqs\":[1,2,3,...]},...]",
+ .get = get_iothread_vq_mapping_list,
+ .set = set_iothread_vq_mapping_list,
+ .release = release_iothread_vq_mapping_list,
+};
--
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