From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olaf Hering Subject: Re: fixed location of share info page in HVM guests Date: Tue, 28 Aug 2012 14:42:55 +0200 Message-ID: <20120828124255.GA32452@aepfle.de> References: <20120828082302.GA27309@aepfle.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Keir Fraser Cc: xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On Tue, Aug 28, Keir Fraser wrote: > Okay, that was a bit too clever, trying to hide between IOAPIC and LAPIC > pages. How about a bit lower in memory -- FE700000-FE7FFFFF? > > Everything in range FC000000-FFFFFFFF should already be marked > E820_RESERVED. You can test that, and also see > tools/firmware/hvmloader/e820.c:build_e820_table() (and note that > RESERVED_MEMBASE == FC000000). Yes, FC000000-FFFFFFFF has already an E820_RESERVED entry. Within that range the kernel finds the IOAPIC, LAPIC and the HPET, perhaps because they are listed in the ACPI table or because they are found by other ways. To make the location of the of the shared pages configurable from the tools, does tools/firmware/hvmloader/acpi/dsdt.asl have a way to describe such special region? Maybe the kernel parses that table early enough, before the shared_info page gets used. Olaf