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From:   Thomas Gleixner <tglx@linutronix.de>
To:     "Michael Kelley (LINUX)" <mikelley@microsoft.com>,
        LKML <linux-kernel@vger.kernel.org>
Cc:     "x86@kernel.org" <x86@kernel.org>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Andrew Cooper <andrew.cooper3@citrix.com>,
        Arjan van de Ven <arjan@linux.intel.com>,
        Huang Rui <ray.huang@amd.com>, Juergen Gross <jgross@suse.com>,
        Dimitri Sivanich <dimitri.sivanich@hpe.com>,
        Wei Liu <wei.liu@kernel.org>
Subject: RE: [patch V3 30/40] x86/cpu: Provide an AMD/HYGON specific
 topology parser
In-Reply-To: <BYAPR21MB1688C2B1723ADDA1640F956AD70BA@BYAPR21MB1688.namprd21.prod.outlook.com>
References: <20230802101635.459108805@linutronix.de>
 <20230802101934.418143974@linutronix.de>
 <BYAPR21MB1688C2B1723ADDA1640F956AD70BA@BYAPR21MB1688.namprd21.prod.outlook.com>
Date:   Wed, 02 Aug 2023 21:46:00 +0200
Message-ID: <87leetjkhz.ffs@tglx>
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On Wed, Aug 02 2023 at 19:28, Michael Kelley (LINUX) wrote:
> From: Thomas Gleixner <tglx@linutronix.de> Sent: Wednesday, August 2, 2023 3:22 AM
>> +	/*
>> +	 * If leaf 0xb is available, then SMT shift is set already. If not
>> +	 * take it from ecx.threads_per_cu and use topo_update_dom() -
>> +	 * topology_set_dom() would propagate and overwrite the already
>> +	 * propagated CORE level.
>> +	 */
>> +	if (!has_0xb) {
>> +		topology_update_dom(tscan, TOPO_SMT_DOMAIN, get_count_order(leaf.threads_per_cu),
>> +				    leaf.threads_per_cu + 1);
>
> Isn't the +1 also needed on the argument to get_count_order()?
> I haven't actually run the config, but if hyper-threading is disabled,
> presumably threads_per_cu is 0, and get_count_order returns -1.

Bah. I'm sure that I wanted to do that. No idea how I forgot about it
again.