From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: IOAPIC doesn't handle byte writes Date: Sun, 4 Dec 2011 11:53:05 +0200 Message-ID: <20111204095305.GA12507@redhat.com> References: <1321967582.16507.10.camel@tabernacle.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, "udo@hypervisor.org" To: Julian Stecklina Return-path: Received: from mx1.redhat.com ([209.132.183.28]:63119 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752642Ab1LDJxL (ORCPT ); Sun, 4 Dec 2011 04:53:11 -0500 Content-Disposition: inline In-Reply-To: <1321967582.16507.10.camel@tabernacle.lan> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, Nov 22, 2011 at 02:13:02PM +0100, Julian Stecklina wrote: > Hello, > > KVM emulates an IOAPIC that doesn't handle byte writes to its > IOAPIC_REG_SELECT register, although for example the ICH10 spec[1] > clearly states that this is an 8-bit register. See > http://www.intel.com/content/dam/doc/datasheet/io-controller-hub-10-family-datasheet.pdf > Table 13-4 on page 433. > The same spec also says that access to data register has to be dword, but new code as of 1b8cf174cf2c0f0c66030fe81af818e9abf4f302 does not enforce this. Old code never enforced it for read too :( -- Gleb.