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From: Thomas Gleixner <tglx@linutronix.de>
To: Usama Arif <usama.arif@bytedance.com>,
	dwmw2@infradead.org, kim.phillips@amd.com
Cc: arjan@linux.intel.com, mingo@redhat.com, bp@alien8.de,
	dave.hansen@linux.intel.com, hpa@zytor.com, x86@kernel.org,
	pbonzini@redhat.com, paulmck@kernel.org,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	rcu@vger.kernel.org, mimoja@mimoja.de, hewenliang4@huawei.com,
	thomas.lendacky@amd.com, seanjc@google.com,
	pmenzel@molgen.mpg.de, fam.zheng@bytedance.com,
	punit.agrawal@bytedance.com, simon.evans@bytedance.com,
	liangma@liangbit.com, David Woodhouse <dwmw@amazon.co.uk>,
	Usama Arif <usama.arif@bytedance.com>
Subject: Re: [PATCH v8 8/9] x86/mtrr: Avoid repeated save of MTRRs on boot-time CPU bringup
Date: Thu, 09 Feb 2023 19:31:16 +0100	[thread overview]
Message-ID: <87mt5m1yiz.ffs@tglx> (raw)
In-Reply-To: <20230209154156.266385-9-usama.arif@bytedance.com>

On Thu, Feb 09 2023 at 15:41, Usama Arif wrote:
>  void mtrr_save_state(void)
>  {
> +	static bool mtrr_saved;
>  	int first_cpu;
>  
>  	if (!mtrr_enabled())
>  		return;
>  
> +	if (system_state < SYSTEM_RUNNING) {
> +		if (!mtrr_saved) {
> +			mtrr_save_fixed_ranges(NULL);
> +			mtrr_saved = true;
> +		}
> +		return;
> +	}
> +
>  	first_cpu = cpumask_first(cpu_online_mask);
>  	smp_call_function_single(first_cpu, mtrr_save_fixed_ranges, NULL, 1);

So why is this relevant after the initial bringup? The BP MTRRs have
been saved already above, no?

Thanks,

        tglx

  reply	other threads:[~2023-02-09 18:31 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-09 15:41 [PATCH v8 0/9] Parallel CPU bringup for x86_64 Usama Arif
2023-02-09 15:41 ` [PATCH v8 1/9] x86/apic/x2apic: Allow CPU cluster_mask to be populated in parallel Usama Arif
2023-02-09 15:41 ` [PATCH v8 2/9] cpu/hotplug: Move idle_thread_get() to <linux/smpboot.h> Usama Arif
2023-02-09 15:41 ` [PATCH v8 3/9] cpu/hotplug: Add dynamic parallel bringup states before CPUHP_BRINGUP_CPU Usama Arif
2023-02-09 15:41 ` [PATCH v8 4/9] x86/smpboot: Reference count on smpboot_setup_warm_reset_vector() Usama Arif
2023-02-09 15:41 ` [PATCH v8 5/9] x86/smpboot: Split up native_cpu_up into separate phases and document them Usama Arif
2023-02-09 15:41 ` [PATCH v8 6/9] x86/smpboot: Support parallel startup of secondary CPUs Usama Arif
2023-02-09 18:25   ` Thomas Gleixner
2023-02-09 20:37     ` [External] " Usama Arif
2023-02-09 15:41 ` [PATCH v8 7/9] x86/smpboot: Send INIT/SIPI/SIPI to secondary CPUs in parallel Usama Arif
2023-02-09 15:41 ` [PATCH v8 8/9] x86/mtrr: Avoid repeated save of MTRRs on boot-time CPU bringup Usama Arif
2023-02-09 18:31   ` Thomas Gleixner [this message]
2023-02-09 20:32     ` [External] " Usama Arif
2023-02-09 20:37       ` David Woodhouse
2023-02-09 23:50       ` Thomas Gleixner
2023-02-10  8:55         ` David Woodhouse
2023-02-13 15:19           ` Usama Arif
2023-02-13 20:42             ` Thomas Gleixner
2023-02-09 15:41 ` [PATCH v8 9/9] x86/smpboot: Serialize topology updates for secondary bringup Usama Arif
2023-02-13 20:43   ` Thomas Gleixner
2023-02-13 20:53     ` David Woodhouse
2023-02-13 22:30       ` [External] " Usama Arif
2023-02-14  6:57         ` David Woodhouse
2023-02-10  4:11 ` [PATCH v8 0/9] Parallel CPU bringup for x86_64 Paul E. McKenney
2023-02-10  9:02   ` David Woodhouse

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