Re: [Update PATCH] x86/Hyper-V: Initialize Syn timer clock when it's

From: Vitaly Kuznetsov
Date: Mon Mar 30 2020 - 11:09:13 EST


ltykernel@xxxxxxxxx writes:

> From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
>
> Current code initializes clock event data structure for syn timer
> even when it's not available. Fix it.
>
> Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
> ---
> - Fix the wrong title.

The new one is ... weird too :-)

I think it was supposed to be something like "x86/Hyper-V: don't
allocate clockevent device when synthetic timer is unavailable"

>
> drivers/hv/hv.c | 15 +++++++++------

Which tree is this patch for? Upstream clockevent allocation has moved
to drivers/clocksource/hyperv_timer.c

> 1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
> index 632d25674e7f..2e893768fc76 100644
> --- a/drivers/hv/hv.c
> +++ b/drivers/hv/hv.c
> @@ -212,13 +212,16 @@ int hv_synic_alloc(void)
> tasklet_init(&hv_cpu->msg_dpc,
> vmbus_on_msg_dpc, (unsigned long) hv_cpu);
>
> - hv_cpu->clk_evt = kzalloc(sizeof(struct clock_event_device),
> - GFP_KERNEL);
> - if (hv_cpu->clk_evt == NULL) {
> - pr_err("Unable to allocate clock event device\n");
> - goto err;
> + if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) {
> + hv_cpu->clk_evt =
> + kzalloc(sizeof(struct clock_event_device),
> + GFP_KERNEL);
> + if (hv_cpu->clk_evt == NULL) {
> + pr_err("Unable to allocate clock event device\n");
> + goto err;
> + }
> + hv_init_clockevent_device(hv_cpu->clk_evt, cpu);
> }
> - hv_init_clockevent_device(hv_cpu->clk_evt, cpu);
>
> hv_cpu->synic_message_page =
> (void *)get_zeroed_page(GFP_ATOMIC);

--
Vitaly