linux-kernel - Re: [PATCH] x86/efi: update e820 about reserved EFI boot services data to fix kexec breakage

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Message-ID: <20191204113140.GA3081@weiser.dinsnail.net>
Date:   Wed, 4 Dec 2019 12:31:40 +0100
From:   Michael Weiser <michael@...ser.dinsnail.net>
To:     Dave Young <dyoung@...hat.com>
Cc:     linux-efi@...r.kernel.org, x86@...nel.org,
        linux-kernel@...r.kernel.org,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        kexec@...ts.infradead.org, Ingo Molnar <mingo@...hat.com>,
        Borislav Petkov <bp@...en8.de>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] x86/efi: update e820 about reserved EFI boot services
 data to fix kexec breakage

Hello Dave,

On Wed, Dec 04, 2019 at 03:59:17PM +0800, Dave Young wrote:
> > Signed-off-by: Dave Young <dyoung@...hat.com>
> > ---
> >  arch/x86/platform/efi/quirks.c |    6 ++----
> >  1 file changed, 2 insertions(+), 4 deletions(-)
> > 
> > --- linux-x86.orig/arch/x86/platform/efi/quirks.c
> > +++ linux-x86/arch/x86/platform/efi/quirks.c
> > @@ -260,10 +260,6 @@ void __init efi_arch_mem_reserve(phys_ad
> >  		return;
> >  	}
> >  
> > -	/* No need to reserve regions that will never be freed. */
> > -	if (md.attribute & EFI_MEMORY_RUNTIME)
> > -		return;
> > -
> >  	size += addr % EFI_PAGE_SIZE;
> >  	size = round_up(size, EFI_PAGE_SIZE);
> >  	addr = round_down(addr, EFI_PAGE_SIZE);
> > @@ -293,6 +289,8 @@ void __init efi_arch_mem_reserve(phys_ad
> >  	early_memunmap(new, new_size);
> >  
> >  	efi_memmap_install(new_phys, num_entries);
> > +	e820__range_update(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
> > +	e820__update_table(e820_table);
> >  }
> >  
> >  /*
> Michael, could you a one more test and provide a tested-by if it works
> for you?

Did three successful kexecs in sequence of mainline 5.4.0 plus the patch
(had problems getting recent -next to boot on my machine). ESRT region
stayed reserved and intact so that the "Invalid version" error message   
is gone.

Tested-by: Michael Weiser <michael.weiser@....de>
--
Thanks!
Michael