From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: [regression, bisected] x86: efi: Pass boot services variable info to runtime code Date: Fri, 31 May 2013 15:48:26 +0100 Message-ID: <20130531144826.GB5850@srcf.ucam.org> References: <1369880172.17397.11.camel@linux-s257.site> <20130530221737.GA11105@sgi.com> <20130531101250.GD30394@gmail.com> <20130531123015.GC17843@nazgul.tnic> <20130531124356.GA8212@gmail.com> <20130531143425.GA5850@srcf.ucam.org> <1370011357.1913.15.camel@dabdike.int.hansenpartnership.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1370011357.1913.15.camel-sFMDBYUN5F8GjUHQrlYNx2Wm91YjaHnnhRte9Li2A+AAvxtiuMwx3w@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: James Bottomley Cc: Ingo Molnar , Borislav Petkov , Jiri Kosina , Russ Anderson , joeyli , Matt Fleming , matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Thomas Gleixner , "H. Peter Anvin" , Linus Torvalds , Andrew Morton List-Id: linux-efi@vger.kernel.org On Fri, May 31, 2013 at 07:42:37AM -0700, James Bottomley wrote: > On Fri, 2013-05-31 at 15:34 +0100, Matthew Garrett wrote: > > I agree that a revert is probably the right thing to do here, but the > > original patch was there to permit a more accurate calculation of the > > amount of nvram in use, not to provide additional debug information. > > Reverting it is going to differently break a different set of systems > > The only ones that are broken are the Samsung ones. Samsung claims to > have fixed their UEFI firmware, so we could refer any problems to them. No, reverting this gets us back to the old state of refusing any writes if more than 50% of the variable store *appears* to be used, regardless of whether it's actually used. Which, unfortunately, makes it impossible to install Linux on most UEFI machines. In any case, Samsung clearly haven't fixed this problem on a pile of machines that have already shipped. > Could we hedge the QueryVariableInfo checks with a test for Samsung in > the UEFI identity strings? We could, but apparently some Lenovos also have a similar problem. We just don't have the information we need to implement a comprehensive blacklist, and if we get it wrong we're back to destroying people's hardware. -- Matthew Garrett | mjg59-1xO5oi07KQx4cg9Nei1l7Q@public.gmane.org