From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Zyngier Subject: Re: [PATCH] arm64: dts: Fix GIC reg sizes for APM X-Gene Date: Wed, 11 Mar 2015 18:17:29 +0000 Message-ID: <550086B9.4010001@arm.com> References: <1422342206-4750-1-git-send-email-psawargaonkar@apm.com> <550056FD.8060804@arm.com> <55007BE3.30300@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Feng Kan Cc: Pranavkumar Sawargaonkar , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "patches-qTEPVZfXA3Y@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "kvmarm-FPEHb7Xf0XXUo1n7N8X6UoWGPAHP3yOg@public.gmane.org" , "arnd-r2nGTMty4D4@public.gmane.org" , "christoffer.dall-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "jcm-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org" , Tushar Jagad List-Id: devicetree@vger.kernel.org On 11/03/15 17:57, Feng Kan wrote: > On Wed, Mar 11, 2015 at 10:31 AM, Marc Zyngier wrote: >> On 11/03/15 17:19, Feng Kan wrote: >>> On Wed, Mar 11, 2015 at 7:53 AM, Marc Zyngier wrote: >>>> On 27/01/15 07:03, Pranavkumar Sawargaonkar wrote: >>>>> In APM X-Gene, GIC register space is 64K aligned while the sizes mentioned >>>>> in the dt are 4K aligned. This breaks KVM when kernel is built with 64K page >>>>> size due to size alignment checking in vgic driver for VCPU Control and >>>>> VCPU register. >>>>> >>>>> This patch corrects the sizes to be inline with the hardware spec. >>>> >>>> This patch may be correct, but it is useless. The firmware on my APM >>>> system (some version of u-boot) repaints the DT at boot time, negating >>>> the effect of this patch. >>> We have updated u-boot to reflect this change. I can supply you with a updated >>> image if you wish. >> >> That would be useful, thanks. >> >> But more importantly, why bother upstreaming your DT into the kernel >> tree if your firmware is going to overwrite whatever we provide? > We did tried to submit a version upstream but was rejected. > >> >> Either the firmware let the user provide its own DT (and doesn't touch >> it other than to change the CPU enable method, insert a /memreserve/ or >> similar things), or the firmware always provide its own DT, and doesn't >> let the user provide its own. Corrupting the user DT is a disaster, as >> we just found. > Yes, the intent of the change is listed in the link below. It is not a > justification by any means, > just the effects of things appearing in layers. > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-September/288574.html Yeah. This is as wrong as it can possibly be. Oh well... Thanks, M. -- Jazz is not dead. It just smells funny... -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Wed, 11 Mar 2015 18:17:29 +0000 Subject: [PATCH] arm64: dts: Fix GIC reg sizes for APM X-Gene In-Reply-To: References: <1422342206-4750-1-git-send-email-psawargaonkar@apm.com> <550056FD.8060804@arm.com> <55007BE3.30300@arm.com> Message-ID: <550086B9.4010001@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 11/03/15 17:57, Feng Kan wrote: > On Wed, Mar 11, 2015 at 10:31 AM, Marc Zyngier wrote: >> On 11/03/15 17:19, Feng Kan wrote: >>> On Wed, Mar 11, 2015 at 7:53 AM, Marc Zyngier wrote: >>>> On 27/01/15 07:03, Pranavkumar Sawargaonkar wrote: >>>>> In APM X-Gene, GIC register space is 64K aligned while the sizes mentioned >>>>> in the dt are 4K aligned. This breaks KVM when kernel is built with 64K page >>>>> size due to size alignment checking in vgic driver for VCPU Control and >>>>> VCPU register. >>>>> >>>>> This patch corrects the sizes to be inline with the hardware spec. >>>> >>>> This patch may be correct, but it is useless. The firmware on my APM >>>> system (some version of u-boot) repaints the DT at boot time, negating >>>> the effect of this patch. >>> We have updated u-boot to reflect this change. I can supply you with a updated >>> image if you wish. >> >> That would be useful, thanks. >> >> But more importantly, why bother upstreaming your DT into the kernel >> tree if your firmware is going to overwrite whatever we provide? > We did tried to submit a version upstream but was rejected. > >> >> Either the firmware let the user provide its own DT (and doesn't touch >> it other than to change the CPU enable method, insert a /memreserve/ or >> similar things), or the firmware always provide its own DT, and doesn't >> let the user provide its own. Corrupting the user DT is a disaster, as >> we just found. > Yes, the intent of the change is listed in the link below. It is not a > justification by any means, > just the effects of things appearing in layers. > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-September/288574.html Yeah. This is as wrong as it can possibly be. Oh well... Thanks, M. -- Jazz is not dead. It just smells funny...