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From: Ingo Molnar <mingo2.kernel.org@gmail.com>
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Date: Wed, 6 May 2015 06:54:43 +0200
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, Andy Lutomirski <luto@amacapital.net>,
        Borislav Petkov <bp@alien8.de>, Fenghua Yu <fenghua.yu@intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Oleg Nesterov <oleg@redhat.com>, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 201/208] x86/fpu: Clean up xstate feature reservation
Message-ID: <20150506045443.GB12393@gmail.com>
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* Dave Hansen <dave.hansen@linux.intel.com> wrote:

> On 05/05/2015 10:58 AM, Ingo Molnar wrote:
> >  struct xregs_state {
> >  	struct fxregs_state		i387;
> >  	struct xstate_header		header;
> > -	struct ymmh_struct		ymmh;
> > -	struct lwp_struct		lwp;
> > -	struct bndreg			bndreg[4];
> > -	struct bndcsr			bndcsr;
> > -	/* New processor state extensions will go here. */
> > +	u8				__reserved[XSTATE_RESERVE];
> >  } __attribute__ ((packed, aligned (64)));
> 
> Just to reiterate.  The size of 'XSTATE_RESERVE' is completely 
> unknown at compile time.  [...]

Yes, see my previous mail.

> [...] It's wrong in the existing kernel, but we should fix it up 
> instead of mucking with it like this.

I'm not mucking with it, I'm slowly migrating it towards a dynamic 
model that doesn't suck - see my other mails.

Thanks,

	Ingo