Re: [PATCH v2] hw/i386: place setup_data at fixed place in memory

From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Laszlo Ersek <lersek@redhat.com>
Cc: "Ard Biesheuvel" <ardb@kernel.org>,
	"Daniel P. Berrangé" <berrange@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"QEMU Developers" <qemu-devel@nongnu.org>,
	"Xiaoyao Li" <xiaoyao.li@intel.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Peter Maydell" <peter.maydell@linaro.org>,
	"Gerd Hoffmann" <kraxel@redhat.com>,
	linux-efi <linux-efi@vger.kernel.org>
Subject: Re: [PATCH v2] hw/i386: place setup_data at fixed place in memory
Date: Thu, 4 Aug 2022 14:11:13 +0200	[thread overview]
Message-ID: <Yuu3YeTRLE/gx6YC@zx2c4.com> (raw)
In-Reply-To: <eadc852a-63f9-a017-aef7-f046eb56e28f@redhat.com>

Hi Laszlo,

On Thu, Aug 04, 2022 at 01:31:36PM +0200, Laszlo Ersek wrote:
> None of the existing info passing methods seem early enough, generic
> enough, and secure enough (at the same time)...

Can you look at the v2 patch? It seems to work on every configuration I
throw at it. Keep in mind that setup_data is only used very, very early.
I can think of a few other places to put it too, looking at the x86
memory map, that will survive long enough.

I think this might actually be a straightforwardly solvable problem if
you think about it more basically.

Jason