From cf03a152c5d749fd0083bfe540df9524f1d2ff1d Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 20 Dec 2023 08:47:54 -0500 Subject: [PATCH] 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 Message-ID: <20231220134755.814917-4-stefanha@redhat.com> Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- hw/core/qdev-properties-system.c | 46 +++++++++++++++++++++++++++++++++++++ include/hw/qdev-properties-system.h | 5 ++++ qapi/virtio.json | 29 +++++++++++++++++++++++ 3 files changed, 80 insertions(+) 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\":\"\", " + "\"vqs\":[1,2,3,...]},...]", + .get = get_iothread_vq_mapping_list, + .set = set_iothread_vq_mapping_list, + .release = release_iothread_vq_mapping_list, +}; diff --git a/include/hw/qdev-properties-system.h b/include/hw/qdev-properties-system.h index 91f7a2452d..06c359c190 100644 --- a/include/hw/qdev-properties-system.h +++ b/include/hw/qdev-properties-system.h @@ -24,6 +24,7 @@ extern const PropertyInfo qdev_prop_off_auto_pcibar; extern const PropertyInfo qdev_prop_pcie_link_speed; extern const PropertyInfo qdev_prop_pcie_link_width; extern const PropertyInfo qdev_prop_cpus390entitlement; +extern const PropertyInfo qdev_prop_iothread_vq_mapping_list; #define DEFINE_PROP_PCI_DEVFN(_n, _s, _f, _d) \ DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_pci_devfn, int32_t) @@ -82,4 +83,8 @@ extern const PropertyInfo qdev_prop_cpus390entitlement; DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_cpus390entitlement, \ CpuS390Entitlement) +#define DEFINE_PROP_IOTHREAD_VQ_MAPPING_LIST(_name, _state, _field) \ + DEFINE_PROP(_name, _state, _field, qdev_prop_iothread_vq_mapping_list, \ + IOThreadVirtQueueMappingList *) + #endif diff --git a/qapi/virtio.json b/qapi/virtio.json index e6dcee7b83..19c7c36e36 100644 --- a/qapi/virtio.json +++ b/qapi/virtio.json @@ -928,3 +928,32 @@ 'data': { 'path': 'str', 'queue': 'uint16', '*index': 'uint16' }, 'returns': 'VirtioQueueElement', 'features': [ 'unstable' ] } + +## +# @IOThreadVirtQueueMapping: +# +# Describes the subset of virtqueues assigned to an IOThread. +# +# @iothread: the id of IOThread object +# +# @vqs: an optional array of virtqueue indices that will be handled by this +# IOThread. When absent, virtqueues are assigned round-robin across all +# IOThreadVirtQueueMappings provided. Either all IOThreadVirtQueueMappings +# must have @vqs or none of them must have it. +# +# Since: 9.0 +## + +{ 'struct': 'IOThreadVirtQueueMapping', + 'data': { 'iothread': 'str', '*vqs': ['uint16'] } } + +## +# @DummyVirtioForceArrays: +# +# Not used by QMP; hack to let us use IOThreadVirtQueueMappingList internally +# +# Since: 9.0 +## + +{ 'struct': 'DummyVirtioForceArrays', + 'data': { 'unused-iothread-vq-mapping': ['IOThreadVirtQueueMapping'] } } -- 2.11.4.GIT