Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Thu, 18 Oct 2018 13:19:41 +0200
From:   Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To:     Christophe de Dinechin <christophe.de.dinechin@gmail.com>
Cc:     linux-kernel@vger.kernel.org, x86@kernel.org,
        Andy Lutomirski <luto@kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        kvm@vger.kernel.org, "Jason A. Donenfeld" <Jason@zx2c4.com>,
        Rik van Riel <riel@surriel.com>,
        Dave Hansen <dave.hansen@linux.intel.com>
Subject: Re: [PATCH 03/11] x86/fpu: make __raw_xsave_addr() use feature
 number instead of mask
Message-ID: <20181018111941.og4jg4yzg53f2nnt@linutronix.de>
References: <20181004140547.13014-1-bigeasy@linutronix.de>
 <20181004140547.13014-4-bigeasy@linutronix.de>
 <m1murk75nk.fsf@dinechin.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8BIT
In-Reply-To: <m1murk75nk.fsf@dinechin.org>
User-Agent: NeoMutt/20180716
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 2018-10-11 19:30:07 [+0200], Christophe de Dinechin wrote:
> > diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
> > index 87a57b7642d36..38d0b5ea40425 100644
> > --- a/arch/x86/kernel/fpu/xstate.c
> > +++ b/arch/x86/kernel/fpu/xstate.c
> > @@ -811,10 +811,8 @@ void fpu__resume_cpu(void)
> >   *
> >   * Note: does not work for compacted buffers.
> >   */
> > -void *__raw_xsave_addr(struct xregs_state *xsave, int xstate_feature_mask)
> > +void *__raw_xsave_addr(struct xregs_state *xsave, int feature_nr)
> 
> It might be clearer to offer both interfaces, since both are used?
> 
…
> > @@ -869,7 +868,8 @@ void *get_xsave_addr(struct xregs_state *xsave, int xstate_feature)
> >  	if (!(xsave->header.xfeatures & xstate_feature))
> >  		return NULL;
> >
> > -	return __raw_xsave_addr(xsave, xstate_feature);
> > +	feature_nr = fls64(xstate_feature) - 1;
> > +	return __raw_xsave_addr(xsave, feature_nr);
> 
> and then move that to a wrapper function that takes a mask?

made another patch this fls is gone now and everyone is using a number
instead of a mask.

Sebastian