linux-kernel - Re: [PATCH v4 2/8] x86/fpu: Drop @perm from guest pseudo FPU container

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Message-ID: <Z+yZRSxgj6iwdVTe@intel.com>
Date: Wed, 2 Apr 2025 09:56:21 +0800
From: Chao Gao <chao.gao@...el.com>
To: "Chang S. Bae" <chang.seok.bae@...el.com>
CC: <x86@...nel.org>, <linux-kernel@...r.kernel.org>, <kvm@...r.kernel.org>,
	<tglx@...utronix.de>, <dave.hansen@...el.com>, <seanjc@...gle.com>,
	<pbonzini@...hat.com>, <peterz@...radead.org>, <rick.p.edgecombe@...el.com>,
	<weijiang.yang@...el.com>, <john.allen@....com>, <bp@...en8.de>,
	<xin3.li@...el.com>, Maxim Levitsky <mlevitsk@...hat.com>, Ingo Molnar
	<mingo@...hat.com>, Dave Hansen <dave.hansen@...ux.intel.com>, "H. Peter
 Anvin" <hpa@...or.com>, Samuel Holland <samuel.holland@...ive.com>, "Mitchell
 Levy" <levymitchell0@...il.com>, Stanislav Spassov <stanspas@...zon.de>,
	"Eric Biggers" <ebiggers@...gle.com>, Uros Bizjak <ubizjak@...il.com>
Subject: Re: [PATCH v4 2/8] x86/fpu: Drop @perm from guest pseudo FPU
 container

On Tue, Apr 01, 2025 at 10:16:47AM -0700, Chang S. Bae wrote:
>On 3/18/2025 8:31 AM, Chao Gao wrote:
>> -static void fpu_init_guest_permissions(struct fpu_guest *gfpu)
>> +static void fpu_lock_guest_permissions(struct fpu_guest *gfpu)
>>   {
>>   	struct fpu_state_perm *fpuperm;
>>   	u64 perm;
>> @@ -218,8 +218,6 @@ static void fpu_init_guest_permissions(struct fpu_guest *gfpu)
>>   	WRITE_ONCE(fpuperm->__state_perm, perm | FPU_GUEST_PERM_LOCKED);
>>   	spin_unlock_irq(&current->sighand->siglock);
>> -
>> -	gfpu->perm = perm & ~FPU_GUEST_PERM_LOCKED;
>>   }
>
>With the removal, the function no longer requires a struct fpu_guest argument
>as it now operates solely on the group leader's FPU state.

Good catch! I will drop the fpu_guest argument.

>
>Thanks,
>Chang