From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH v4 1/4] xen/arm: vgic-v2: Report the correct GICC size to the guest Date: Fri, 23 Oct 2015 14:43:16 +0100 Message-ID: <562A3974.2080601@citrix.com> References: <1444328634-32110-1-git-send-email-julien.grall@citrix.com> <1444328634-32110-2-git-send-email-julien.grall@citrix.com> <1445606932.2374.163.camel@citrix.com> <562A3783.8060703@citrix.com> <1445607584.2374.172.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1ZpceR-0005OY-1P for xen-devel@lists.xenproject.org; Fri, 23 Oct 2015 13:44:59 +0000 In-Reply-To: <1445607584.2374.172.camel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell , xen-devel@lists.xenproject.org Cc: stefano.stabellini@eu.citrix.com List-Id: xen-devel@lists.xenproject.org On 23/10/15 14:39, Ian Campbell wrote: > On Fri, 2015-10-23 at 14:34 +0100, Julien Grall wrote: >> Hi Ian, >> >> On 23/10/15 14:28, Ian Campbell wrote: >>> On Thu, 2015-10-08 at 19:23 +0100, Julien Grall wrote: >>>> The GICv2 DT node is usually used by the guest to know the >>>> address/size >>>> of the regions (GICD, GICC...) to map into their virtual memory. >>>> >>>> While the GICv2 spec requires the size of the GICC to be 8KB, we >>>> correctly do an 8KB stage-2 mapping but errornously report 256 in the >>>> device tree (based on GUEST_GICC_SIZE). >>> >>> "erroneously" >>> >>>> >>>> I bet we didn't see any issue so far because all the registers except >>>> GICC_DIR lives in the first 256 bytes of the GICC region and all the >>>> guest >>> >>> "guests" >>> >>>> I have seen so far are driving the GIC with GICC_CTLR.EIOmode = >>>> 0. >>>> >>>> Signed-off-by: Julien Grall >>> >>> Acked-by: Ian Campbell >>> >>> (typo's fixable on commit). >> >> Thank you! >> >>>> --- >>>> This patch is a good candidate to backport for Xen 4.6 - 4.4. >>>> Without it a guest relying on the DT can't use GICC_DIR. >>> >>> Noted, but just to check: This patch (and none of the other fixes in >>> this >>> series) are all which are required for a guest to be able to use >>> GICC_DIR, >>> right? >> >> Correct. BTW, I forgot to mention that this patch may not apply cleanly >> on Xen 4.4 as rearranged the guest memory address space in Xen 4.5. > > I'd be inclined not to bother with it for 4.4 at this juncture then. I'm fine with that. Regards, -- Julien Grall