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

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Date:   Tue, 28 Nov 2023 15:25:11 +0000
From:   "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
To:     "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "Yang, Weijiang" <weijiang.yang@...el.com>,
        "pbonzini@...hat.com" <pbonzini@...hat.com>,
        "seanjc@...gle.com" <seanjc@...gle.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Hansen, Dave" <dave.hansen@...el.com>
CC:     "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 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?
> 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>