From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [patch 3/4] QEMU/KVM: non-virtualized ACPI PMTimer support Date: Sat, 31 May 2008 10:52:08 +0300 Message-ID: <484103A8.1020403@qumranet.com> References: <20080524234342.983197667@localhost.localdomain> <20080525000036.645310064@localhost.localdomain> <48393D06.2060406@qumranet.com> <20080529175626.GA30591@dmt> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Chris Wright , kvm-devel To: Marcelo Tosatti Return-path: Received: from bzq-179-150-194.static.bezeqint.net ([212.179.150.194]:31840 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750710AbYEaHwH (ORCPT ); Sat, 31 May 2008 03:52:07 -0400 In-Reply-To: <20080529175626.GA30591@dmt> Sender: kvm-owner@vger.kernel.org List-ID: Marcelo Tosatti wrote: > On Sun, May 25, 2008 at 01:18:46PM +0300, Avi Kivity wrote: > >>> pm_io_base = PM_IO_BASE; >>> + pmtmr_base = cmos_readb(0x60); >>> + pmtmr_base |= cmos_readb(0x61) << 8; >>> + pmtmr_base |= cmos_readb(0x62) << 16; >>> + pmtmr_base |= cmos_readb(0x63) << 24; >>> + if (!pmtmr_base) >>> + pmtmr_base = pm_io_base + 0x08; >>> >>> >> You're splitting the ACPI ioport range into two. I think the correct >> fix here is to have qemu supply a PMBA hint to the BIOS. If the hint is >> present, the bios should locate pm_io_base there, and should also avoid >> placing other pio resources there. >> > > PBLK_BASE (processor block) is statically defined in acpi-dsdt.dsl, and > I don't see any easy way to change that dynamically. > > In practice I don't see any problem with not having the PMBA registers > in a contiguous range, since I doubt any ACPI implementation will assume > PIIX4 specific details (ACPI driver looks for the register addresses in > FADT, so does not matter if they're contiguous or not). > Right, it's a cleanliness issue, not correctness. The only guest I can think of that will care about the actual layout is linuxbios/coreboot. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.