From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: EFI runtime and kexec Date: Fri, 01 Mar 2013 17:11:30 -0800 Message-ID: <513151C2.60907@zytor.com> References: <20130301213903.GI30938@pd.tnic> <51312C8F.8000503@zytor.com> <20130301225303.GK30938@pd.tnic> <513132B0.3050308@zytor.com> <20130301230733.GL30938@pd.tnic> <1362180625.29011.4.camel@shinybook.infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1362180625.29011.4.camel-Fexsq3y4057IgHVZqg5X0TlWvGAXklZc@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: David Woodhouse Cc: Borislav Petkov , Matt Fleming , linux-efi , Matthew Garrett List-Id: linux-efi@vger.kernel.org On 03/01/2013 03:30 PM, David Woodhouse wrote: > On Sat, 2013-03-02 at 00:07 +0100, Borislav Petkov wrote: >> Hmm, yeah, that's nasty. This also means option #2 can go too because >> of the fixed addresses. Option #1 is also kinda polluting user address >> space > > User address space is there to be polluted. Create a "kernel thread" for > invoking EFI, except that this kernel thread actually has userspace page > tables. Set up those page tables however the hell you like, and then > just make sure you always invoke EFI runtime services from that thread. > Just FYI: as far as I know we already have such a "thread". -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.