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From: Ingo Molnar <mingo@kernel.org>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
	Leif Lindholm <leif.lindholm@linaro.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	Matt Fleming <matt.fleming@intel.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Mark Salter <msalter@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
	Denys Vlasenko <dvlasenk@redhat.com>,
	Brian Gerst <brgerst@gmail.com>
Subject: Re: [PATCH 2/2] arm64/efi: Don't pad between EFI_MEMORY_RUNTIME regions
Date: Sun, 27 Sep 2015 09:06:44 +0200	[thread overview]
Message-ID: <20150927070644.GC26125@gmail.com> (raw)
In-Reply-To: <CAKv+Gu_JRCmx5qKq7SDDq73BegVs3LKZwe+OdvTKb4YD_CURyw@mail.gmail.com>


* Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:

> > If we allocate the EFI runtime as a single virtual memory block then issues 
> > like rounding between sections does not even come up as a problem: we map the 
> > original offsets and sizes byte by byte.
> 
> Well, by that reasoning, we should not call SetVirtualAddressMap() in the first 
> place, and just use the 1:1 mapping UEFI uses natively. This is more than 
> feasible on arm64, and I actually fought hard against using 
> SetVirtualAddressMap() at all, but I was overruled by others. I think this is 
> also trivially possible on X64, since the 1:1 mapping is already active 
> alongside the VA mapping.

Could we please re-list all the arguments pro and contra of 1:1 physical mappings, 
in a post that also explains the background so that more people can chime in, not 
just people versed in EFI internals? It's very much possible that a bad decision 
was made.

Thanks,

	Ingo

  reply	other threads:[~2015-09-27  7:06 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-25 22:02 [GIT PULL 0/2] EFI urgent fixes Matt Fleming
2015-09-25 22:02 ` [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Matt Fleming
2015-09-26  5:56   ` Ingo Molnar
2015-09-26  6:44     ` Ard Biesheuvel
2015-09-26 13:43     ` Matt Fleming
2015-09-27  7:03       ` Ingo Molnar
2015-09-28  6:49         ` Ard Biesheuvel
2015-09-28  8:22           ` Ingo Molnar
2015-09-28  9:51             ` Ard Biesheuvel
2015-09-29  9:12               ` Ingo Molnar
2015-09-29 10:41                 ` Ard Biesheuvel
2015-09-29 14:18                   ` Matt Fleming
2015-09-29 13:52                 ` Matt Fleming
2015-09-26 17:01     ` Andy Lutomirski
2015-09-26 17:20       ` H. Peter Anvin
2015-09-26 18:15         ` Ard Biesheuvel
2015-09-26 19:49           ` H. Peter Anvin
2015-09-26 19:57             ` Matt Fleming
2015-09-26 20:09               ` Ard Biesheuvel
2015-09-26 20:19                 ` H. Peter Anvin
2015-09-27 16:30                   ` Andy Lutomirski
2015-09-27 18:06                     ` Matthew Garrett
2015-09-28  6:16                       ` Ingo Molnar
2015-09-28  6:41                         ` Matthew Garrett
2015-09-29 21:58                           ` Laszlo Ersek
2015-09-30  9:30                             ` Ard Biesheuvel
2015-09-30 16:43                               ` Andy Lutomirski
2015-09-30 17:24                                 ` James Bottomley
2015-09-30  0:54                         ` H. Peter Anvin
2015-09-26 19:55         ` Matt Fleming
2015-09-27  6:50       ` Ingo Molnar
2015-10-01 12:48   ` [tip:core/urgent] x86/efi: Fix boot crash by mapping EFI memmap entries bottom-up at runtime, instead of top-down tip-bot for Matt Fleming
2015-10-02  9:44     ` Matt Fleming
2015-09-25 22:02 ` [PATCH 2/2] arm64/efi: Don't pad between EFI_MEMORY_RUNTIME regions Matt Fleming
2015-09-26  6:01   ` Ingo Molnar
2015-09-26  7:08     ` Ard Biesheuvel
2015-09-27  7:06       ` Ingo Molnar [this message]
2015-09-27 10:40         ` Borislav Petkov
2015-09-28  6:20           ` Ingo Molnar
2015-09-29  9:31           ` Dave Young
2015-09-29 10:24             ` Borislav Petkov
2015-09-29 14:36           ` Matt Fleming
2015-09-30  0:56             ` H. Peter Anvin
2015-09-30  8:33               ` Borislav Petkov
2015-09-30  1:03         ` H. Peter Anvin
2015-09-30  1:16           ` Andy Lutomirski
2015-09-30  1:19             ` H. Peter Anvin
2015-09-30  4:24             ` Ard Biesheuvel
2015-10-01 10:44           ` Ingo Molnar

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