Re: [PATCH v5 10/18] vfio-user: instantiate vfio-user context

From: Stefan Hajnoczi <stefanha@redhat.com>
To: Jagannathan Raman <jag.raman@oracle.com>
Cc: eduardo@habkost.net, elena.ufimtseva@oracle.com,
	john.g.johnson@oracle.com, berrange@redhat.com, bleal@redhat.com,
	john.levon@nutanix.com, mst@redhat.com, armbru@redhat.com,
	quintela@redhat.com, qemu-devel@nongnu.org, f4bug@amsat.org,
	marcandre.lureau@gmail.com, thanos.makatos@nutanix.com,
	pbonzini@redhat.com, eblake@redhat.com, dgilbert@redhat.com
Subject: Re: [PATCH v5 10/18] vfio-user: instantiate vfio-user context
Date: Tue, 25 Jan 2022 14:44:13 +0000	[thread overview]
Message-ID: <YfAMvTOdrdFpU700@stefanha-x1.localdomain> (raw)
In-Reply-To: <66bb8c18bb5372f72aaa66d62f09258ec7775100.1642626515.git.jag.raman@oracle.com>

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On Wed, Jan 19, 2022 at 04:41:59PM -0500, Jagannathan Raman wrote:
> create a context with the vfio-user library to run a PCI device
> 
> Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
> Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
> Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
> ---
>  hw/remote/vfio-user-obj.c | 78 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 78 insertions(+)
> 
> diff --git a/hw/remote/vfio-user-obj.c b/hw/remote/vfio-user-obj.c
> index 80757b0029..810a7c3943 100644
> --- a/hw/remote/vfio-user-obj.c
> +++ b/hw/remote/vfio-user-obj.c
> @@ -41,6 +41,9 @@
>  #include "hw/remote/machine.h"
>  #include "qapi/error.h"
>  #include "qapi/qapi-visit-sockets.h"
> +#include "qemu/notify.h"
> +#include "sysemu/sysemu.h"
> +#include "libvfio-user.h"
>  
>  #define TYPE_VFU_OBJECT "x-vfio-user-server"
>  OBJECT_DECLARE_TYPE(VfuObject, VfuObjectClass, VFU_OBJECT)
> @@ -82,13 +85,23 @@ struct VfuObject {
>      char *device;
>  
>      Error *err;
> +
> +    Notifier machine_done;
> +
> +    vfu_ctx_t *vfu_ctx;
>  };
>  
> +static void vfu_object_init_ctx(VfuObject *o, Error **errp);
> +
>  static void vfu_object_set_socket(Object *obj, Visitor *v, const char *name,
>                                    void *opaque, Error **errp)
>  {
>      VfuObject *o = VFU_OBJECT(obj);
>  
> +    if (o->vfu_ctx) {
> +        return;
> +    }

No error?

> +
>      qapi_free_SocketAddress(o->socket);
>  
>      o->socket = NULL;
> @@ -104,17 +117,68 @@ static void vfu_object_set_socket(Object *obj, Visitor *v, const char *name,
>      }
>  
>      trace_vfu_prop("socket", o->socket->u.q_unix.path);
> +
> +    vfu_object_init_ctx(o, errp);
>  }
>  
>  static void vfu_object_set_device(Object *obj, const char *str, Error **errp)
>  {
>      VfuObject *o = VFU_OBJECT(obj);
>  
> +    if (o->vfu_ctx) {
> +        return;
> +    }

No error?

> +
>      g_free(o->device);
>  
>      o->device = g_strdup(str);
>  
>      trace_vfu_prop("device", str);
> +
> +    vfu_object_init_ctx(o, errp);
> +}
> +
> +/*
> + * TYPE_VFU_OBJECT depends on the availability of the 'socket' and 'device'
> + * properties. It also depends on devices instantiated in QEMU. These
> + * dependencies are not available during the instance_init phase of this
> + * object's life-cycle. As such, the server is initialized after the
> + * machine is setup. machine_init_done_notifier notifies TYPE_VFU_OBJECT
> + * when the machine is setup, and the dependencies are available.
> + */
> +static void vfu_object_machine_done(Notifier *notifier, void *data)
> +{
> +    VfuObject *o = container_of(notifier, VfuObject, machine_done);
> +    Error *err = NULL;
> +
> +    vfu_object_init_ctx(o, &err);
> +
> +    if (err) {
> +        error_propagate(&error_abort, err);
> +    }
> +}
> +
> +static void vfu_object_init_ctx(VfuObject *o, Error **errp)
> +{
> +    ERRP_GUARD();
> +
> +    if (o->vfu_ctx || !o->socket || !o->device ||
> +            !phase_check(PHASE_MACHINE_READY)) {
> +        return;
> +    }
> +
> +    if (o->err) {
> +        error_propagate(errp, o->err);
> +        o->err = NULL;
> +        return;
> +    }
> +
> +    o->vfu_ctx = vfu_create_ctx(VFU_TRANS_SOCK, o->socket->u.q_unix.path, 0,
> +                                o, VFU_DEV_TYPE_PCI);
> +    if (o->vfu_ctx == NULL) {
> +        error_setg(errp, "vfu: Failed to create context - %s", strerror(errno));
> +        return;
> +    }
>  }
>  
>  static void vfu_object_init(Object *obj)
> @@ -124,6 +188,11 @@ static void vfu_object_init(Object *obj)
>  
>      k->nr_devs++;
>  
> +    if (!phase_check(PHASE_MACHINE_READY)) {
> +        o->machine_done.notify = vfu_object_machine_done;
> +        qemu_add_machine_init_done_notifier(&o->machine_done);
> +    }
> +
>      if (!object_dynamic_cast(OBJECT(current_machine), TYPE_REMOTE_MACHINE)) {
>          error_setg(&o->err, "vfu: %s only compatible with %s machine",
>                     TYPE_VFU_OBJECT, TYPE_REMOTE_MACHINE);
> @@ -142,6 +211,10 @@ static void vfu_object_finalize(Object *obj)
>  
>      o->socket = NULL;
>  
> +    if (o->vfu_ctx) {
> +        vfu_destroy_ctx(o->vfu_ctx);
> +    }
> +
>      g_free(o->device);
>  
>      o->device = NULL;
> @@ -149,6 +222,11 @@ static void vfu_object_finalize(Object *obj)
>      if (!k->nr_devs && k->auto_shutdown) {
>          qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
>      }
> +
> +    if (o->machine_done.notify) {
> +        qemu_remove_machine_init_done_notifier(&o->machine_done);
> +        o->machine_done.notify = NULL;
> +    }
>  }
>  
>  static void vfu_object_class_init(ObjectClass *klass, void *data)
> -- 
> 2.20.1
> 

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