Re: [Qemu-devel] [PATCH v13 05/24] tcg: add options for enabling MTTCG

[Pranith Kumar]

Hi Alex,

On Wed, Feb 22, 2017 at 12:13 PM, Alex Bennée <address@hidden> wrote:
> From: KONRAD Frederic <address@hidden>
>
> We know there will be cases where MTTCG won't work until additional work
> is done in the front/back ends to support. It will however be useful to
> be able to turn it on.
>
> As a result MTTCG will default to off unless the combination is
> supported. However the user can turn it on for the sake of testing.
>
> Signed-off-by: KONRAD Frederic <address@hidden>
> [AJB: move to -accel tcg,thread=multi|single, defaults]
> Signed-off-by: Alex Bennée <address@hidden>
> Reviewed-by: Richard Henderson <address@hidden>
> ---
> v1:
>   - merge with add mttcg option.
>   - update commit message
> v2:
>   - machine_init->opts_init
> v3:
>   - moved from -tcg to -accel tcg,thread=single|multi
>   - fix checkpatch warnings
> v4:
>   - make mttcg_enabled extern, qemu_tcg_mttcg_enabled() now just macro
>   - qemu_tcg_configure now propagates Error instead of exiting
>   - better error checking of thread=foo
>   - use CONFIG flags for default_mttcg_enabled()
>   - disable mttcg with icount, error if both forced on
> v7
>   - explicitly disable MTTCG for TCG_OVERSIZED_GUEST
>   - use check_tcg_memory_orders_compatible() instead of CONFIG_MTTCG_HOST
>   - change CONFIG_MTTCG_TARGET to TARGET_SUPPORTS_MTTCG
> v8
>   - fix missing include tcg.h
>   - change mismatched MOs to a warning instead of error
> v10
>   - TCG_DEFAULT_MO -> TCG_GUEST_DEFAULT_MO
> v11
>   - tweak warning message
> ---
>  cpus.c                | 73 
> +++++++++++++++++++++++++++++++++++++++++++++++++++
>  include/qom/cpu.h     |  9 +++++++
>  include/sysemu/cpus.h |  2 ++
>  qemu-options.hx       | 20 ++++++++++++++
>  tcg/tcg.h             |  9 +++++++
>  vl.c                  | 49 +++++++++++++++++++++++++++++++++-
>  6 files changed, 161 insertions(+), 1 deletion(-)
>
> diff --git a/cpus.c b/cpus.c
> index 0bcb5b50b6..c296ec715f 100644
> --- a/cpus.c
> +++ b/cpus.c
<...>
> +void qemu_tcg_configure(QemuOpts *opts, Error **errp)
> +{
> +    const char *t = qemu_opt_get(opts, "thread");
> +    if (t) {
> +        if (strcmp(t, "multi") == 0) {
> +            if (TCG_OVERSIZED_GUEST) {
> +                error_setg(errp, "No MTTCG when guest word size > hosts");
> +            } else {
> +                if (!check_tcg_memory_orders_compatible()) {
> +                    error_report("Guest expects a stronger memory ordering 
> than"
> +                                 "the host provides");
> +                    error_printf("This may cause strange/hard to debug 
> errors");
> +                }

This prints it as:

Guest expects a stronger memory ordering thanthe host provides

Please add a space between 'than' and 'the'. Also why are you using
error_report() for the first line and error_printf() for the second?

Thanks,
-- 
Pranith