linux-kernel - Re: [patch V3a 30/40] x86/cpu: Provide an AMD/HYGON specific topology parser

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <tencent_594804A808BD93A4EBF50A994F228E3A7F07@qq.com>
Date:   Sat, 12 Aug 2023 11:58:59 +0800
From:   Pu Wen <pu_wen@...mail.com>
To:     Thomas Gleixner <tglx@...utronix.de>, Pu Wen <puwen@...on.cn>,
        LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, Tom Lendacky <thomas.lendacky@....com>,
        Andrew Cooper <andrew.cooper3@...rix.com>,
        Arjan van de Ven <arjan@...ux.intel.com>,
        Huang Rui <ray.huang@....com>, Juergen Gross <jgross@...e.com>,
        Dimitri Sivanich <dimitri.sivanich@....com>,
        Michael Kelley <mikelley@...rosoft.com>,
        Wei Liu <wei.liu@...nel.org>
Subject: Re: [patch V3a 30/40] x86/cpu: Provide an AMD/HYGON specific topology
 parser

On 2023/8/12 1:11, Thomas Gleixner wrote:
> On Fri, Aug 11 2023 at 20:58, Pu Wen wrote:
>> On 2023/8/3 3:51, Thomas Gleixner wrote:
>>> +	if (tscan->c->x86_vendor == X86_VENDOR_AMD) {
>>> +		if (tscan->c->x86 == 0x15)
>>> +			tscan->c->topo.cu_id = leaf.cuid;
>>> +
>>> +		cacheinfo_amd_init_llc_id(tscan->c, leaf.nodeid);
>>> +	} else {
>>> +		/*
>>> +		 * Package ID is ApicId[6..] on Hygon CPUs. See commit
>>> +		 * e0ceeae708ce for explanation. The topology info is
>>> +		 * screwed up: The package shift is always 6 and the node
>>> +		 * ID is bit [4:5]. Don't touch the latter without
>>> +		 * confirmation from the Hygon developers.
>>> +		 */
>>> +		topology_set_dom(tscan, TOPO_CORE_DOMAIN, 6, tscan->dom_ncpus[TOPO_CORE_DOMAIN]);
>>
>> Hygon updated CPUs will not always shift 6, and shift 6 is not good for
>> running guests.
>> So suggest to modify like this:
>>       if (!boot_cpu_has(X86_FEATURE_HYPERVISOR) && tscan->c->x86_model <=
>> 0x3)
>>           topology_set_dom(tscan, TOPO_CORE_DOMAIN, 6,
>> tscan->dom_ncpus[TOPO_CORE_DOMAIN]);
> 
> This is exactly what the existing code does today. Can you please send a
> delta patch on top of this with a proper explanation?

Will.

And I think it's better to send a prerequisite patch(is attached) after
patch 02 of this series. Since it can be individually back-ported to the
stable releases.

-- 
Regards,
Pu Wen



View attachment "x86-cpu-Refine-the-CPU-topology-deriving-method-for-Hygon.patch" of type "text/plain" (1472 bytes)