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From: Ingo Molnar <mingo@kernel.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, Mario Limonciello <mario_limonciello@dell.com>,
	Matthew Garrett <mjg59@srcf.ucam.org>,
	Borislav Petkov <bp@alien8.de>, Matt Fleming <mfleming@suse.de>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 0/5] Allow the trampoline to use EFI boot services RAM
Date: Wed, 10 Aug 2016 14:30:58 +0200	[thread overview]
Message-ID: <20160810123058.GB3204@gmail.com> (raw)
In-Reply-To: <cover.1470821230.git.luto@kernel.org>


One side note:

* Andy Lutomirski <luto@kernel.org> wrote:

> This series fixes it the other way: it allow the trampoline to live
> in boot services memory.  It achieves this by deferring the panic
> due to failure to reserve a trampoline until early_initcall time
> and then adjusting the EFI boot services quirk to reserve space
> for the trampoline if we haven't already found it a home.

>   x86/efi: Allocate a trampoline if needed in efi_free_boot_services()

Btw., this means that we first try to allocate the trampoline the old fashioned 
way, and in the rare cases this fails we allocate it from the EFI data area, 
right?

This is problematic from the probability management POV: we are creating a rare 
piece of code that will run only on a select few systems.

I think it would be much better to allocate the trampoline from the EFI area on 
all EFI systems by default. Is there any reason why that would not work?

Thanks,

	Ingo

  parent reply	other threads:[~2016-08-10 19:07 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-10  9:29 [PATCH v2 0/5] Allow the trampoline to use EFI boot services RAM Andy Lutomirski
2016-08-10  9:29 ` [PATCH v2 1/5] x86/boot: Run reserve_bios_regions() after we initialize the memory map Andy Lutomirski
2016-08-11 11:57   ` [tip:x86/urgent] " tip-bot for Andy Lutomirski
2016-08-10  9:29 ` [PATCH v2 2/5] x86/boot: Synchronize trampoline_cr4_features and mmu_cr4_features directly Andy Lutomirski
2016-08-11 11:58   ` [tip:x86/urgent] " tip-bot for Andy Lutomirski
2016-08-10  9:29 ` [PATCH v2 3/5] x86/boot: Defer setup_real_mode() to early_initcall time Andy Lutomirski
2016-08-11 11:58   ` [tip:x86/urgent] " tip-bot for Andy Lutomirski
2016-08-10  9:29 ` [PATCH v2 4/5] x86/boot: Rework reserve_real_mode() to allow multiple tries Andy Lutomirski
2016-08-11 11:59   ` [tip:x86/urgent] " tip-bot for Andy Lutomirski
2016-08-10  9:29 ` [PATCH v2 5/5] x86/efi: Allocate a trampoline if needed in efi_free_boot_services() Andy Lutomirski
2016-08-11 16:19   ` [tip:x86/urgent] " tip-bot for Andy Lutomirski
2016-08-10 12:28 ` [PATCH v2 0/5] Allow the trampoline to use EFI boot services RAM Ingo Molnar
2016-08-10 13:21   ` Andy Lutomirski
2016-08-10 16:08     ` Mario_Limonciello
2016-08-10 12:30 ` Ingo Molnar [this message]
2016-08-10 13:18   ` Andy Lutomirski
2016-08-11  8:52     ` Ingo Molnar
2016-08-11 10:36       ` Matt Fleming

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