linux-kernel - Re: [PATCH 8/8] x86/intel_rdt: rmdir,umount and hotcpu updates for MBA

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Date:   Mon, 16 Jan 2017 17:13:41 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Vikas Shivappa <vikas.shivappa@...ux.intel.com>
cc:     vikas.shivappa@...el.com, linux-kernel@...r.kernel.org,
        x86@...nel.org, hpa@...or.com, mingo@...nel.org,
        peterz@...radead.org, ravi.v.shankar@...el.com,
        tony.luck@...el.com, fenghua.yu@...el.com, h.peter.anvin@...el.com
Subject: Re: [PATCH 8/8] x86/intel_rdt: rmdir,umount and hotcpu updates for
 MBA

On Tue, 10 Jan 2017, Vikas Shivappa wrote:

> During rmdir only reset the ctrl values for the rdtgroup's closid. This
> is done so that that next time when the closid is reused they dont
> reflect old values.

How on earth is that related to MBA?

> Remove the closid update during cpuonline in cqm as its
> already in the CAT code. Since both cqm and CAT want the rmid and closid
> to be zero when cpu is online, remove the PQR MSR write to zero during
> cpuonline because the MSRs are at zero after cpu reset and also during

Are you sure that the MSRs are zero when the cpu goes offline and then
online again? That's not a reset.

Thanks,

	tglx