From: Borislav Petkov <bp@alien8.de>
To: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Andi Kleen <ak@linux.intel.com>, Tony Luck <tony.luck@intel.com>,
linux-kernel@vger.kernel.org,
antonio.gomez.iglesias@linux.intel.com,
neelima.krishnan@intel.com, stable@vger.kernel.org
Subject: Re: [PATCH] x86/tsx: Use MSR_TSX_CTRL to clear CPUID bits
Date: Tue, 15 Feb 2022 11:24:01 +0100 [thread overview]
Message-ID: <Ygt/QSTSMlUJnzFS@zn.tnic> (raw)
In-Reply-To: <20220215002014.mb7g4y3hfefmyozx@guptapa-mobl1.amr.corp.intel.com>
On Mon, Feb 14, 2022 at 04:20:14PM -0800, Pawan Gupta wrote:
> ... we are calling tsx_clear_cpuid() unconditionally.
I know, that's why I asked...
> > If those CPUs which support only disabling TSX through MSR_IA32_TSX_CTRL
> > but don't have MSR_TSX_FORCE_ABORT - if those CPUs set
> > X86_FEATURE_RTM_ALWAYS_ABORT too, then this should work.
... this^^.
IOW, what are you fixing here exactly?
Let's look at the two callsites of tsx_clear_cpuid():
1. tsx_init: that will do something on X86_FEATURE_RTM_ALWAYS_ABORT CPUs.
2. init_intel: that will get called when
tsx_ctrl_state == TSX_CTRL_RTM_ALWAYS_ABORT
But TSX_CTRL_RTM_ALWAYS_ABORT gets set only when
X86_FEATURE_RTM_ALWAYS_ABORT is set. I.e., the first case, in
tsx_init().
So, IIUC, you wanna fix the case where CPUs which set
X86_FEATURE_RTM_ALWAYS_ABORT but *don't* have MSR_TSX_FORCE_ABORT, those
CPUs should still disable TSX through MSR_IA32_TSX_CTRL.
Correct?
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2022-02-15 10:24 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <5bd785a1d6ea0b572250add0c6617b4504bc24d1.1644440311.git.pawan.kumar.gupta@linux.intel.com>
[not found] ` <YgqToxbGQluNHABF@zn.tnic>
2022-02-14 22:41 ` [PATCH] x86/tsx: Use MSR_TSX_CTRL to clear CPUID bits Pawan Gupta
2022-02-14 23:28 ` Borislav Petkov
2022-02-15 0:20 ` Pawan Gupta
2022-02-15 10:24 ` Borislav Petkov [this message]
2022-02-15 12:11 ` Pawan Gupta
2022-02-15 16:31 ` Borislav Petkov
2022-02-15 18:19 ` Pawan Gupta
2022-02-15 19:33 ` Borislav Petkov
2022-02-16 0:39 ` Pawan Gupta
2022-02-16 0:49 ` Andrew Cooper
2022-02-16 1:28 ` Pawan Gupta
2022-02-16 6:08 ` Pawan Gupta
2022-02-16 10:30 ` Borislav Petkov
2022-02-16 19:03 ` Pawan Gupta
2022-02-16 11:46 ` Andrew Cooper
2022-02-16 18:59 ` Pawan Gupta
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