[lunar:linux-kvm][PATCH] Revert "UBUNTU: SAUCE: [kvm] tsc: make no_timer_check default to 1"

[Colin King (gmail)]

Looks good to me. Thanks Dimitri.

Acked-by: Colin Ian King <colin.i.king at gmail.com>

On 07/02/2023 18:27, Dimitri John Ledkov wrote:
> This reverts commit 4ecbc83125d8bab884d6f5790498f910f1cb8e84.
> 
> This patch probably did nothing since introduction. Paravirtualized
> platforms Hyper-V, VMWare and KVM in their cpu init functions set
> no_timer_check = 1, thus setting no_timer_check by default to 1 is
> redundant.
> 
> Please drop this patch in a rebase.
> 
> This patch was dropped in jammy:linux-aws, but was present in earlier
> editions of the aws kernel. I am not sure if this patch was
> intentionally dropped there, as I don't see anything similar done on
> x86 Xen virtualization. Maybe these checks are now desired on AWS
> since it is effectively becoming bare-metal.
> 
> Signed-off-by: Dimitri John Ledkov <dimitri.ledkov at canonical.com>
> ---
>   Documentation/admin-guide/kernel-parameters.txt |  3 +--
>   arch/x86/kernel/apic/io_apic.c                  | 14 ++++----------
>   2 files changed, 5 insertions(+), 12 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index af7c3bf3e0..d82ca5185c 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -3736,8 +3736,7 @@
>   			disable unhandled interrupt sources.
>   
>   	no_timer_check	[X86,APIC] Disables the code which tests for
> -			broken timer IRQ sources. For AWS, this is defaulted
> -			to disabled, can be re-enabled using no_timer_check=0.
> +			broken timer IRQ sources.
>   
>   	noisapnp	[ISAPNP] Disables ISA PnP code.
>   
> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
> index 0172706b05..a868b76cd3 100644
> --- a/arch/x86/kernel/apic/io_apic.c
> +++ b/arch/x86/kernel/apic/io_apic.c
> @@ -1574,20 +1574,14 @@ void __init setup_ioapic_ids_from_mpc(void)
>   }
>   #endif
>   
> -int no_timer_check __initdata = 1;
> +int no_timer_check __initdata;
>   
>   static int __init notimercheck(char *s)
>   {
> -	int ret = 0;
> -
> -	if (s)
> -		ret = kstrtoint(s, 0, &no_timer_check);
> -	else
> -		no_timer_check = 1;
> -
> -	return ret;
> +	no_timer_check = 1;
> +	return 1;
>   }
> -early_param("no_timer_check", notimercheck);
> +__setup("no_timer_check", notimercheck);
>   
>   static void __init delay_with_tsc(void)
>   {