Re: [PATCH v2 13/18] tcg: convert "-accel threads" to a QOM property

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 12/9/19 4:01 PM, Paolo Bonzini wrote:
> Replace the ad-hoc qemu_tcg_configure with generic code invoking QOM
> property getters and setters.  More properties (and thus more valid
> -accel suboptions) will be added in the next patches, which will move
> accelerator-related "-machine" options to accelerators.
> 
> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> ---
>   accel/tcg/tcg-all.c   | 50 ++++++++++++++++++++++++++++++++++++--------------
>   include/sysemu/cpus.h |  2 --
>   vl.c                  | 32 +++++++++++++++++---------------
>   3 files changed, 53 insertions(+), 31 deletions(-)
> 
> diff --git a/accel/tcg/tcg-all.c b/accel/tcg/tcg-all.c
> index 78a0ab5..7829f02 100644
> --- a/accel/tcg/tcg-all.c
> +++ b/accel/tcg/tcg-all.c
> @@ -34,7 +34,17 @@
>   #include "include/qapi/error.h"
>   #include "include/qemu/error-report.h"
>   #include "include/hw/boards.h"
> -#include "qemu/option.h"
> +
> +typedef struct TCGState {
> +    AccelState parent_obj;
> +
> +    bool mttcg_enabled;
> +} TCGState;
> +
> +#define TYPE_TCG_ACCEL ACCEL_CLASS_NAME("tcg")
> +
> +#define TCG_STATE(obj) \
> +        OBJECT_CHECK(TCGState, (obj), TYPE_TCG_ACCEL)
>   
>   unsigned long tcg_tb_size;
>   
> @@ -109,23 +119,31 @@ static void tcg_accel_instance_init(Object *obj)
>   {
>       TCGState *s = TCG_STATE(obj);
>   
> -    mttcg_enabled = default_mttcg_enabled();
> +    s->mttcg_enabled = default_mttcg_enabled();
>   }
>   
>   static int tcg_init(MachineState *ms)
>   {
> +    TCGState *s = TCG_STATE(current_machine->accelerator);
> +
>       tcg_exec_init(tcg_tb_size * 1024 * 1024);
>       cpu_interrupt_handler = tcg_handle_interrupt;
> +    mttcg_enabled = s->mttcg_enabled;
>       return 0;
>   }
>   
> -void qemu_tcg_configure(QemuOpts *opts, Error **errp)
> +static char *tcg_get_thread(Object *obj, Error **errp)
>   {
> -    const char *t = qemu_opt_get(opts, "thread");
> -    if (!t) {
> -        return;
> -    }
> -    if (strcmp(t, "multi") == 0) {
> +    TCGState *s = TCG_STATE(obj);
> +
> +    return g_strdup(s->mttcg_enabled ? "multi" : "single");
> +}
> +
> +static void tcg_set_thread(Object *obj, const char *value, Error **errp)
> +{
> +    TCGState *s = TCG_STATE(obj);
> +
> +    if (strcmp(value, "multi") == 0) {
>           if (TCG_OVERSIZED_GUEST) {
>               error_setg(errp, "No MTTCG when guest word size > hosts");
>           } else if (use_icount) {
> @@ -140,12 +158,12 @@ void qemu_tcg_configure(QemuOpts *opts, Error **errp)
>                               "than the host provides");
>                   error_printf("This may cause strange/hard to debug errors\n");
>               }
> -            mttcg_enabled = true;
> +            s->mttcg_enabled = true;
>           }
> -    } else if (strcmp(t, "single") == 0) {
> -        mttcg_enabled = false;
> +    } else if (strcmp(value, "single") == 0) {
> +        s->mttcg_enabled = false;
>       } else {
> -        error_setg(errp, "Invalid 'thread' setting %s", t);
> +        error_setg(errp, "Invalid 'thread' setting %s", value);
>       }
>   }
>   
> @@ -155,15 +173,19 @@ static void tcg_accel_class_init(ObjectClass *oc, void *data)
>       ac->name = "tcg";
>       ac->init_machine = tcg_init;
>       ac->allowed = &tcg_allowed;
> -}
>   
> -#define TYPE_TCG_ACCEL ACCEL_CLASS_NAME("tcg")
> +    object_class_property_add_str(oc, "thread",
> +                                  tcg_get_thread,
> +                                  tcg_set_thread,
> +                                  NULL);
> +}
>   
>   static const TypeInfo tcg_accel_type = {
>       .name = TYPE_TCG_ACCEL,
>       .parent = TYPE_ACCEL,
>       .instance_init = tcg_accel_instance_init,
>       .class_init = tcg_accel_class_init,
> +    .instance_size = sizeof(TCGState),
>   };
>   
>   static void register_accel_types(void)
> diff --git a/include/sysemu/cpus.h b/include/sysemu/cpus.h
> index 32c05f2..3c1da6a 100644
> --- a/include/sysemu/cpus.h
> +++ b/include/sysemu/cpus.h
> @@ -40,6 +40,4 @@ extern int smp_threads;
>   
>   void list_cpus(const char *optarg);
>   
> -void qemu_tcg_configure(QemuOpts *opts, Error **errp);
> -
>   #endif
> diff --git a/vl.c b/vl.c
> index 078ab7a..b6c23d1 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -295,17 +295,12 @@ static QemuOptsList qemu_accel_opts = {
>       .implied_opt_name = "accel",
>       .head = QTAILQ_HEAD_INITIALIZER(qemu_accel_opts.head),
>       .desc = {
> -        {
> -            .name = "accel",
> -            .type = QEMU_OPT_STRING,
> -            .help = "Select the type of accelerator",
> -        },
> -        {
> -            .name = "thread",
> -            .type = QEMU_OPT_STRING,
> -            .help = "Enable/disable multi-threaded TCG",
> -        },
> -        { /* end of list */ }
> +        /*
> +         * no elements => accept any
> +         * sanity checking will happen later
> +         * when setting accelerator properties
> +         */
> +        { }
>       },
>   };
>   
> @@ -2836,6 +2831,13 @@ static int do_configure_icount(void *opaque, QemuOpts *opts, Error **errp)
>       return 0;
>   }
>   
> +static int accelerator_set_property(void *opaque,
> +                                const char *name, const char *value,
> +                                Error **errp)
> +{
> +    return object_parse_property_opt(opaque, name, value, "accel", errp);
> +}
> +
>   static int do_configure_accelerator(void *opaque, QemuOpts *opts, Error **errp)
>   {
>       bool *p_init_failed = opaque;
> @@ -2850,6 +2852,10 @@ static int do_configure_accelerator(void *opaque, QemuOpts *opts, Error **errp)
>           return 0;
>       }
>       accel = ACCEL(object_new_with_class(OBJECT_CLASS(ac)));
> +    qemu_opt_foreach(opts, accelerator_set_property,
> +                     accel,
> +                     &error_fatal);
> +
>       ret = accel_init_machine(accel, current_machine);
>       if (ret < 0) {
>           *p_init_failed = true;
> @@ -2857,10 +2863,6 @@ static int do_configure_accelerator(void *opaque, QemuOpts *opts, Error **errp)
>                        acc, strerror(-ret));
>           return 0;
>       }
> -
> -    if (tcg_enabled()) {
> -        qemu_tcg_configure(opts, &error_fatal);
> -    }
>       return 1;
>   }
>   
>