linux-kernel - Re: [PATCH] ACPI: processor_idle: Skip dummy wait for processors based on the Zen microarchitecture

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Message-ID: <YyrPqlo/ysCeh4qU@zn.tnic>
Date:   Wed, 21 Sep 2022 10:47:38 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     K Prateek Nayak <kprateek.nayak@....com>
Cc:     linux-kernel@...r.kernel.org, rafael@...nel.org, lenb@...nel.org,
        linux-acpi@...r.kernel.org, linux-pm@...r.kernel.org,
        dave.hansen@...ux.intel.com, tglx@...utronix.de, andi@...as.de,
        puwen@...on.cn, mario.limonciello@....com, peterz@...radead.org,
        rui.zhang@...el.com, gpiccoli@...lia.com,
        daniel.lezcano@...aro.org, ananth.narayan@....com,
        gautham.shenoy@....com, Calvin Ong <calvin.ong@....com>,
        stable@...r.kernel.org, regressions@...ts.linux.dev
Subject: Re: [PATCH] ACPI: processor_idle: Skip dummy wait for processors
 based on the Zen microarchitecture

On Wed, Sep 21, 2022 at 12:06:38PM +0530, K Prateek Nayak wrote:
> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> index 16a1663d02d4..18850aa2b79b 100644
> --- a/drivers/acpi/processor_idle.c
> +++ b/drivers/acpi/processor_idle.c
> @@ -528,8 +528,11 @@ static int acpi_idle_bm_check(void)
>  static void wait_for_freeze(void)
>  {
>  #ifdef	CONFIG_X86
> -	/* No delay is needed if we are in guest */
> -	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
> +	/*
> +	 * No delay is needed if we are in guest or on a processor
> +	 * based on the Zen microarchitecture.
> +	 */
> +	if (boot_cpu_has(X86_FEATURE_HYPERVISOR) || boot_cpu_has(X86_FEATURE_ZEN))

s/boot_cpu_has/cpu_feature_enabled/g

while at it.

-- 
Regards/Gruss,
    Boris.

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