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Message-ID: <87jzu1h5cm.ffs@tglx>
Date: Fri, 11 Aug 2023 19:11:05 +0200
From: Thomas Gleixner <tglx@...utronix.de>
To: Pu Wen <pu_wen@...mail.com>, 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 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?
Thanks,
tglx
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