Re: [Qemu-devel] [PATCH v5 1/3] Check if GlobalProperty exists before registering

Re: [Qemu-devel] [PATCH v5 1/3] Check if GlobalProperty exists before registering

[Anthony Liguori]

Crístian Viana <vianac@linux.vnet.ibm.com> writes:

> If a GlobalProperty has already been registered, it won't have its
> value overwritten.
>
> Signed-off-by: Crístian Viana <vianac@linux.vnet.ibm.com>
> ---
>
> Changes since v4: 
> - Only register a GlobalProperty if it hasn't already been registered. That
>   avoids the property values to be overwritten (fix previous known bug).
>
>  hw/qdev-properties.c |    8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/hw/qdev-properties.c b/hw/qdev-properties.c
> index 099a7aa..fda94dd 100644
> --- a/hw/qdev-properties.c
> +++ b/hw/qdev-properties.c
> @@ -1105,6 +1105,14 @@ static QTAILQ_HEAD(, GlobalProperty) global_props = QTAILQ_HEAD_INITIALIZER(glob
>
>  static void qdev_prop_register_global(GlobalProperty *prop)
>  {
> +    GlobalProperty *p;
> +
> +    QTAILQ_FOREACH(p, &global_props, next) {
> +        if (strcmp(prop->driver, p->driver) == 0) {
> +            return;
> +        }
> +    }
> +
>      QTAILQ_INSERT_TAIL(&global_props, prop, next);
>  }

This is relying on a very subtle characteristic: that -global properties
are registered before machine options.  We probably need to be more
explicit about who we want to win.  In the very least, you should add a
comment here that says this check is specifically to allow -global to
"win" over machine options.

Regards,

Anthony Liguori

>  
> -- 
> 1.7.9.5

Re: [Qemu-devel] [PATCH v5 2/3] Force driftfix=none on previous machines

[Anthony Liguori]

Crístian Viana <vianac@linux.vnet.ibm.com> writes:

> The current value for the -rtc driftfix option is 'none'. This patch
> makes sure that the old machines configuration will work the same way
> even after that option changes its default value.
>
> Signed-off-by: Crístian Viana <vianac@linux.vnet.ibm.com>

Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>

Regards,

Anthony Liguori

> ---
>  hw/pc_piix.c |    4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/hw/pc_piix.c b/hw/pc_piix.c
> index eae258c..2658ec2 100644
> --- a/hw/pc_piix.c
> +++ b/hw/pc_piix.c
> @@ -379,6 +379,10 @@ static QEMUMachine pc_machine_v1_1 = {
>              .driver   = TYPE_USB_DEVICE,\
>              .property = "full-path",\
>              .value    = "no",\
> +        },{\
> +            .driver   = "mc146818rtc",\
> +            .property = "lost_tick_policy",\
> +            .value    = "discard",\
>          }
>  
>  static QEMUMachine pc_machine_v1_0 = {
> -- 
> 1.7.9.5

Re: [Qemu-devel] [PATCH v5 3/3] Change driftfix default value to slew

[Anthony Liguori]

Crístian Viana <vianac@linux.vnet.ibm.com> writes:

> Windows 2008+ is very sensitive to missed ticks. The RTC is used by default as
> the time source. If driftfix is not enabled, Windows is prone to
> blue screening.
>
> Signed-off-by: Crístian Viana <vianac@linux.vnet.ibm.com>

Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>

Regards,

Anthony Liguori

> ---
>  hw/mc146818rtc.c |    2 +-
>  vl.c             |   11 ++++++++++-
>  2 files changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c
> index 3777f85..dfd7ee6 100644
> --- a/hw/mc146818rtc.c
> +++ b/hw/mc146818rtc.c
> @@ -686,7 +686,7 @@ ISADevice *rtc_init(ISABus *bus, int base_year, qemu_irq intercept_irq)
>  static Property mc146818rtc_properties[] = {
>      DEFINE_PROP_INT32("base_year", RTCState, base_year, 1980),
>      DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", RTCState,
> -                               lost_tick_policy, LOST_TICK_DISCARD),
> +                               lost_tick_policy, LOST_TICK_SLEW),
>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> diff --git a/vl.c b/vl.c
> index 1329c30..3ae43fc 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -559,7 +559,16 @@ static void configure_rtc(QemuOpts *opts)
>  
>              qdev_prop_register_global_list(slew_lost_ticks);
>          } else if (!strcmp(value, "none")) {
> -            /* discard is default */
> +            static GlobalProperty discard_lost_ticks[] = {
> +                {
> +                    .driver   = "mc146818rtc",
> +                    .property = "lost_tick_policy",
> +                    .value    = "discard",
> +                },
> +                { /* end of list */ }
> +            };
> +
> +            qdev_prop_register_global_list(discard_lost_ticks);
>          } else {
>              fprintf(stderr, "qemu: invalid option value '%s'\n", value);
>              exit(1);
> -- 
> 1.7.9.5