From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [regression, bisected] x86: efi: Pass boot services variable info to runtime code Date: Tue, 28 May 2013 10:35:05 +0200 Message-ID: <20130528083505.GA30042@gmail.com> References: <20130522162747.GA20816@sgi.com> <20130523115801.GJ14575@console-pimps.org> <20130523203234.GD20913@sgi.com> <20130524074331.GL14575@console-pimps.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20130524074331.GL14575-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Matt Fleming Cc: Russ Anderson , Matthew Garrett , 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" , Borislav Petkov List-Id: linux-efi@vger.kernel.org * Matt Fleming wrote: > What appears to be happening is that your the EFI runtime services code > is calling into the EFI boot services code, which is definitely a bug in > your firmware because we're at runtime, but we've seen other machines > that do similar things so we usually handle it just fine. However, what > makes your case different, and the reason you see the above splat, is > that it's using the physical address of the EFI boot services region, > not the virtual one we setup with SetVirtualAddressMap(). Which is a > second firmware bug. Again, we have seen other machines that access > physical addresses after SetVirtualAddressMap(), but until now we > haven't had any non-optional code that triggered them. > > The only reason I can see that the offending commit would introduce this > problem is because it calls QueryVariableInfo() at boot time. I notice > that your machine is an SGI UV one, is there any chance you could get a > firmware fix for this? If possible, it would be also good to confirm > that it's this chunk of code in setup_efi_vars(), > > status = efi_call_phys4(sys_table->runtime->query_variable_info, > EFI_VARIABLE_NON_VOLATILE | > EFI_VARIABLE_BOOTSERVICE_ACCESS | > EFI_VARIABLE_RUNTIME_ACCESS, &store_size, > &remaining_size, &var_size); > > that later makes GetNextVariable() jump to the physical address of the > EFI Boot Services region. Because if not, we need to do some more > digging. > > Borislav, how are your 1:1 mapping patches coming along? In theory, once > those are merged we can gracefully workaround these kinds of issues. Handling these gracefully without crashing boxes or expecting firmware to be sane (which is wishful thinking) would be _SO_ preferred ... I suspect 1:1 mapped is what Windows does - and we simply need to provide a Windows-EFI compatible environment (which is reality), not just an EFI-spec environment (which is a fiction). Thanks, Ingo