linux-kernel - Re: [PATCHv12 4/9] x86/boot/compressed: Handle unaccepted memory

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Date:   Mon, 22 May 2023 13:08:28 +0200
From:   Ard Biesheuvel <ardb@...nel.org>
To:     "Kirill A. Shutemov" <kirill@...temov.name>
Cc:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Borislav Petkov <bp@...en8.de>,
        Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...el.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Joerg Roedel <jroedel@...e.de>,
        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>,
        Dario Faggioli <dfaggioli@...e.com>,
        Mike Rapoport <rppt@...nel.org>,
        David Hildenbrand <david@...hat.com>,
        Mel Gorman <mgorman@...hsingularity.net>,
        marcelo.cerri@...onical.com, tim.gardner@...onical.com,
        khalid.elmously@...onical.com, philip.cox@...onical.com,
        aarcange@...hat.com, peterx@...hat.com, x86@...nel.org,
        linux-mm@...ck.org, linux-coco@...ts.linux.dev,
        linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org,
        Liam Merwick <liam.merwick@...cle.com>
Subject: Re: [PATCHv12 4/9] x86/boot/compressed: Handle unaccepted memory

On Mon, 22 May 2023 at 13:01, Kirill A. Shutemov <kirill@...temov.name> wrote:
>
> On Fri, May 19, 2023 at 01:16:41PM +0300, Kirill A. Shutemov wrote:
> > On Fri, May 19, 2023 at 02:14:29AM +0300, Kirill A. Shutemov wrote:
> > > diff --git a/arch/x86/boot/compressed/mem.c b/arch/x86/boot/compressed/mem.c
> > > index 67594fcb11d9..87372b96d613 100644
> > > --- a/arch/x86/boot/compressed/mem.c
> > > +++ b/arch/x86/boot/compressed/mem.c
> > > @@ -1,9 +1,32 @@
> > >  // SPDX-License-Identifier: GPL-2.0-only
> > >
> > >  #include "error.h"
> > > +#include "misc.h"
> > >
> > >  void arch_accept_memory(phys_addr_t start, phys_addr_t end)
> > >  {
> > >     /* Platform-specific memory-acceptance call goes here */
> > >     error("Cannot accept memory");
> > >  }
> > > +
> > > +void init_unaccepted_memory(void)
> > > +{
> > > +   guid_t guid =  LINUX_EFI_UNACCEPTED_MEM_TABLE_GUID;
> > > +   struct efi_unaccepted_memory *unaccepted_table;
> > > +   unsigned long cfg_table_pa;
> > > +   unsigned int cfg_table_len;
> > > +   int ret;
> > > +
> > > +   ret = efi_get_conf_table(boot_params, &cfg_table_pa, &cfg_table_len);
> > > +   if (ret)
> > > +           error("EFI config table not found.");
> > > +
> > > +   unaccepted_table = (void *)efi_find_vendor_table(boot_params,
> > > +                                                    cfg_table_pa,
> > > +                                                    cfg_table_len,
> > > +                                                    guid);
> > > +   if (unaccepted_table->version != 1)
> > > +           error("Unknown version of unaccepted memory table\n");
> > > +
> > > +   set_unaccepted_table(unaccepted_table);
> > > +}
> >
> > 0-day reported boot failure outdise TDX guest with CONFIG_INTEL_TDX_GUEST=y.
>
> 0-day folks reported one more issue: booting on non-EFI system fail.
>
> Updated fixup:
>
> diff --git a/arch/x86/boot/compressed/mem.c b/arch/x86/boot/compressed/mem.c
> index 0108c97399a5..e7f7ef31e581 100644
> --- a/arch/x86/boot/compressed/mem.c
> +++ b/arch/x86/boot/compressed/mem.c
> @@ -46,8 +46,13 @@ void init_unaccepted_memory(void)
>         struct efi_unaccepted_memory *unaccepted_table;
>         unsigned long cfg_table_pa;
>         unsigned int cfg_table_len;
> +       enum efi_type et;
>         int ret;
>
> +       et = efi_get_type(boot_params);
> +       if (et == EFI_TYPE_NONE)
> +               return;
> +
>         ret = efi_get_conf_table(boot_params, &cfg_table_pa, &cfg_table_len);
>         if (ret)
>                 error("EFI config table not found.");
> @@ -56,6 +61,9 @@ void init_unaccepted_memory(void)
>                                                          cfg_table_pa,
>                                                          cfg_table_len,
>                                                          guid);
> +       if (!unaccepted_table)
> +               return;
> +
>         if (unaccepted_table->version != 1)
>                 error("Unknown version of unaccepted memory table\n");
>

With these changes applied,

Reviewed-by: Ard Biesheuvel <ardb@...nel.org>