linux-kernel - Re: [PATCHv5 05/12] efi/x86: Implement support for unaccepted memory

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Message-ID: <20220502134031.roylivc3icazuk5h@box.shutemov.name>
Date:   Mon, 2 May 2022 16:40:31 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Borislav Petkov <bp@...en8.de>
Cc:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Sean Christopherson <seanjc@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Joerg Roedel <jroedel@...e.de>,
        Ard Biesheuvel <ardb@...nel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        David Rientjes <rientjes@...gle.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Tom Lendacky <thomas.lendacky@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Ingo Molnar <mingo@...hat.com>,
        Varad Gautam <varad.gautam@...e.com>,
        Dario Faggioli <dfaggioli@...e.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Brijesh Singh <brijesh.singh@....com>,
        Mike Rapoport <rppt@...nel.org>,
        David Hildenbrand <david@...hat.com>, x86@...nel.org,
        linux-mm@...ck.org, linux-coco@...ts.linux.dev,
        linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv5 05/12] efi/x86: Implement support for unaccepted memory

On Fri, Apr 29, 2022 at 12:53:30PM +0200, Borislav Petkov wrote:
> > +	/*
> > +	 * If unaccepted memory is present allocate a bitmap to track what
> > +	 * memory has to be accepted before access.
> > +	 *
> > +	 * One bit in the bitmap represents 2MiB in the address space:
> > +	 * A 4k bitmap can track 64GiB of physical address space.
> > +	 *
> > +	 * In the worst case scenario -- a huge hole in the middle of the
> > +	 * address space -- It needs 256MiB to handle 4PiB of the address
> > +	 * space.
> > +	 *
> > +	 * TODO: handle situation if params->unaccepted_memory has already set.
> 
> "... is already set."
> 
> And when is that TODO taken care of? Later patch or patchset?

No, not yet. kexec is not a priority at the moment. It will come later.

-- 
 Kirill A. Shutemov