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SubjectRe: [PATCH 6/7] xen: Enable PV clocksource for HVM
On 03/04/2010 01:36 AM, Sheng Yang wrote:
> And enable it by default in PV extended HVM guest.
>
> Signed-off-by: Sheng Yang<sheng@linux.intel.com>
> ---
> arch/x86/xen/hvmpv.c | 20 ++++++++++++++++++++
> arch/x86/xen/time.c | 4 +++-
> 2 files changed, 23 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86/xen/hvmpv.c b/arch/x86/xen/hvmpv.c
> index 7a741ed..284e021 100644
> --- a/arch/x86/xen/hvmpv.c
> +++ b/arch/x86/xen/hvmpv.c
> @@ -43,6 +43,7 @@ static void __init xen_hvm_pv_banner(void)
> pv_info.name);
> printk(KERN_INFO "Xen version: %d.%d%s\n",
> version>> 16, version& 0xffff, extra.extraversion);
> + printk(KERN_INFO "PV feature: PV clocksource enabled\n");
> }
>
> static int __init xen_para_available(void)
> @@ -117,6 +118,22 @@ static void __init init_shared_info(void)
> per_cpu(xen_vcpu, 0) =&HYPERVISOR_shared_info->vcpu_info[0];
> }
>
> +extern struct clocksource xen_clocksource;
>

No externs in .c files. But aside from that, I'd prefer you export a
function from xen/time.c to do the clocksource registration and call it
from both places (even if its a one-liner).

> +
> +static void __init init_pv_clocksource(void)
> +{
> + if (enable_hvm_pv(HVM_PV_CLOCK))
> + BUG();
>

BUG is a bit severe. Will it really never, ever fail? And if it does,
the consequence is hardly serious; we just fall back to emulated devices.

> +
> + pv_time_ops.sched_clock = xen_sched_clock;
> +
> + x86_platform.calibrate_tsc = xen_tsc_khz;
> + x86_platform.get_wallclock = xen_get_wallclock;
> + x86_platform.set_wallclock = xen_set_wallclock;
> +
> + clocksource_register(&xen_clocksource);
> +}
> +
> void __init xen_guest_init(void)
> {
> int r;
> @@ -130,4 +147,7 @@ void __init xen_guest_init(void)
> return;
>
> init_shared_info();
> +
> + /* PV clocksource would be enabled by default */
> + init_pv_clocksource();
> }
> diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
> index 0d3f07c..c80eacb 100644
> --- a/arch/x86/xen/time.c
> +++ b/arch/x86/xen/time.c
> @@ -13,6 +13,7 @@
> #include<linux/clockchips.h>
> #include<linux/kernel_stat.h>
> #include<linux/math64.h>
> +#include<linux/module.h>
>
> #include<asm/pvclock.h>
> #include<asm/xen/hypervisor.h>
> @@ -243,7 +244,7 @@ int xen_set_wallclock(unsigned long now)
> return -1;
> }
>
> -static struct clocksource xen_clocksource __read_mostly = {
> +struct clocksource xen_clocksource __read_mostly = {
> .name = "xen",
> .rating = 400,
> .read = xen_clocksource_get_cycles,
> @@ -252,6 +253,7 @@ static struct clocksource xen_clocksource __read_mostly = {
> .shift = XEN_SHIFT,
> .flags = CLOCK_SOURCE_IS_CONTINUOUS,
> };
> +EXPORT_SYMBOL_GPL(xen_clocksource);
>
> /*
> Xen clockevent implementation
>



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