From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: acpidump crashes on some machines Date: Thu, 23 Aug 2012 11:22:29 +0100 Message-ID: <50360465.3090602@citrix.com> References: <4FE1C423.6070001@amd.com> <20120620145127.GD12787@phenom.dumpdata.com> <4FE32DDA.10204@amd.com> <20120630014825.GA7003@phenom.dumpdata.com> <20120630021936.GA27100@phenom.dumpdata.com> <50114002.2030700@amd.com> <20120817205207.GA3002@phenom.dumpdata.com> <503602A0.9040908@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <503602A0.9040908@amd.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Andre Przywara Cc: Jeremy Fitzhardinge , xen-devel , Jan Beulich , Konrad Rzeszutek Wilk List-Id: xen-devel@lists.xenproject.org On 23/08/12 11:14, Andre Przywara wrote: > On 08/17/2012 10:52 PM, Konrad Rzeszutek Wilk wrote: >> On Thu, Jul 26, 2012 at 03:02:58PM +0200, Andre Przywara wrote: >>> On 06/30/2012 04:19 AM, Konrad Rzeszutek Wilk wrote: >>> >>> Konrad, David, >>> >>> back on track for this issue. Thanks for your input, I could do some >>> more debugging (see below for a refresh): >>> >>> It seems like it affects only the first page of the 1:1 mapping. I >>> didn't have an issues with the last PFN or the page behind it (which >>> failed properly). >>> >>> David, thanks for the hint with varying dom0_mem parameter. I >>> thought I already checked this, but I did it once again and it >>> turned out that it is only an issue if dom0_mem is smaller than the >>> ACPI area, which generates a hole in the memory map. So we have >>> (simplified) >>> * 1:1 mapping to 1 MB >>> * normal mapping till dom0_mem >>> * unmapped area till ACPI E820 area >>> * ACPI E820 1:1 mapping >>> >>> As far as I could chase it down the 1:1 mapping itself looks OK, I >>> couldn't find any off-by-one bugs here. So maybe it is code that >>> later on invalidates areas between the normal guest mapping and the >>> ACPI mem? >> >> I think I found it. Can you try this pls [and if you can't find >> early_to_phys.. just use the __set_phys_to call] > > Yes, that works. At least after a quick test on my test box. Both the > test module and acpidump work as expected. If I replace the "<" in your > patch with the original "<=", I get the warning (and due to the > "continue" it also works). Note that the balloon driver could subsequently overwrite the p2m entry. I don't think it is worth redoing the patch to adjust the region passed to the balloon driver to avoid this though. > I also successfully tested the minimal fix (just replacing <= with <). > I will feed it to the testers here to cover more machines. > > Do you want to keep the warnings in (which exceed 80 characters, btw)? I think we do. David