linux-kernel - Re: [PATCH v7 07/26] x86/fpu/xstate: Warn if kernel dynamic xfeatures detected in normal fpstate

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Date:   Wed, 29 Nov 2023 22:18:53 +0800
From:   "Yang, Weijiang" <weijiang.yang@...el.com>
To:     "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
CC:     "Hansen, Dave" <dave.hansen@...el.com>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "seanjc@...gle.com" <seanjc@...gle.com>,
        "pbonzini@...hat.com" <pbonzini@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "john.allen@....com" <john.allen@....com>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "Gao, Chao" <chao.gao@...el.com>,
        "mlevitsk@...hat.com" <mlevitsk@...hat.com>
Subject: Re: [PATCH v7 07/26] x86/fpu/xstate: Warn if kernel dynamic xfeatures
 detected in normal fpstate

On 11/28/2023 11:25 PM, Edgecombe, Rick P wrote:
> On Fri, 2023-11-24 at 00:53 -0500, Yang Weijiang wrote:
>> Kernel dynamic xfeatures now are __ONLY__ enabled for guest fpstate,
>> i.e.,
>> none for normal kernel fpstate. The bits are added when guest FPU
>    ^never?

Sure, will change it, thank you!

>> config
>> is initialized. Guest fpstate is allocated with fpstate->is_guest set
>> to
>> %true.
>>
>> For normal fpstate, the bits should have been removed when
>> initializes
>> kernel FPU config settings, WARN_ONCE() if kernel detects normal
>> fpstate
>> xfeatures contains kernel dynamic xfeatures before executes xsaves.
>>
>> Signed-off-by: Yang Weijiang <weijiang.yang@...el.com>
> Otherwise...
>
> Reviewed-by: Rick Edgecombe <rick.p.edgecombe@...el.com>