linux-kernel - Re: [PATCH v5 04/19] KVM:x86: Refresh CPUID on write to guest MSR_IA32

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Message-ID: <f5c7b43e-80cf-53b6-730b-ff9e1c023f13@intel.com>
Date:   Wed, 9 Aug 2023 11:11:01 +0800
From:   "Yang, Weijiang" <weijiang.yang@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>
CC:     <peterz@...radead.org>, <john.allen@....com>,
        <kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <rick.p.edgecombe@...el.com>, <chao.gao@...el.com>,
        <binbin.wu@...ux.intel.com>
Subject: Re: [PATCH v5 04/19] KVM:x86: Refresh CPUID on write to guest
 MSR_IA32_XSS

On 8/5/2023 5:43 AM, Paolo Bonzini wrote:
> On 8/4/23 18:02, Sean Christopherson wrote:
>>> Update CPUID(EAX=0DH,ECX=1) when the guest's XSS is modified.
>>> CPUID(EAX=0DH,ECX=1).EBX reports required storage size of
>>> all enabled xstate features in XCR0 | XSS. Guest can allocate
>>> sufficient xsave buffer based on the info.
>>
>> Please wrap changelogs closer to ~75 chars.  I'm pretty sure this isn't the first
>> time I've made this request...
>
> I suspect this is because of the long "word" CPUID(EAX=0DH,ECX=1).EBX. It would make the lengths less homogeneous if lines 1 stayed the same but lines 2-4 became longer.
Yes, more or less, but I need to learn some "techniques" to make the wording looks trimmed and tidy. Thanks!
> Paolo
>