From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Fri, 6 Feb 2015 19:07:20 +0000 Subject: [PATCH] kvmtool: don't use PCI config space IRQ line field In-Reply-To: References: <4324891.mqG6Yyfi6J@wuerfel> <1423064390-15269-1-git-send-email-andre.przywara@arm.com> <20150206185527.GC24099@arm.com> Message-ID: <20150206190719.GG24099@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Feb 06, 2015 at 07:02:25PM +0000, Peter Maydell wrote: > On 6 February 2015 at 18:55, Will Deacon wrote: > > On Wed, Feb 04, 2015 at 03:39:50PM +0000, Andre Przywara wrote: > >> In PCI config space there is an interrupt line field (offset 0x3f), > >> which is used to initially communicate the IRQ line number from > >> firmware to the OS. _Hardware_ should never use this information, > >> as the OS is free to write any information in there. > > > > Is this true even with probe-only? I appreciate that this isn't a BAR, > > but it still feels odd for Linux to write this in that case. > > The hardware (model) shouldn't be doing anything with the value > in this register anyway, so I think this change to kvmtool is > correct regardless of Linux's behaviour. Well, kvmtool is also pretending to be firmware in this case, which is why it passes things like probe-only and PSCI nodes. Will