From mboxrd@z Thu Jan 1 00:00:00 1970 From: Borislav Petkov Subject: Re: [PATCH 0/2 RESEND v7] add reserved e820 ranges to the kdump kernel e820 table Date: Mon, 26 Nov 2018 19:04:55 +0100 Message-ID: <20181126180455.GI4843@zn.tnic> References: <20181124051223.19994-1-lijiang@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Dave Hansen Cc: Lianbo Jiang , linux-kernel@vger.kernel.org, kexec@lists.infradead.org, x86@kernel.org, linux-ia64@vger.kernel.org, linux-efi@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, akpm@linux-foundation.org, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, ard.biesheuvel@linaro.org, tony.luck@intel.com, fenghua.yu@intel.com, dyoung@redhat.com, bhe@redhat.com List-Id: linux-efi@vger.kernel.org On Mon, Nov 26, 2018 at 09:44:46AM -0800, Dave Hansen wrote: > On 11/23/18 9:12 PM, Lianbo Jiang wrote: > > These patches add the new I/O resource descriptor 'IORES_DESC_RESERVED' > > for the iomem resources search interfaces, and in order to make it still > > work after the new descriptor is added, these codes originally related > > to 'IORES_DESC_NONE' have been updated. > > I'm having a really hard time figuring out what problem these patches solve. > > What end-user visible behavior does this set change? Yeah, that was a long process of digging out the "why". I'd recommend reading the previous threads and, more specifically: https://lkml.kernel.org/r/CABhMZUUscS3jUZUSM5Y6EYJK6weo7Mjj5-EAKGvbw0qEe%2B38zw@mail.gmail.com in short: we need to export e820 reserved ranges to the second kernel so that it can talk to PCI devices properly. (And I'm wondering how it did work until now...) -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.