From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46251) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YxE2p-0005GT-TH for qemu-devel@nongnu.org; Tue, 26 May 2015 08:33:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YxE2k-0004Co-Qd for qemu-devel@nongnu.org; Tue, 26 May 2015 08:33:19 -0400 Received: from mail-pa0-f44.google.com ([209.85.220.44]:34963) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YxE2k-0004Cd-Ho for qemu-devel@nongnu.org; Tue, 26 May 2015 08:33:14 -0400 Received: by pacwv17 with SMTP id wv17so91855583pac.2 for ; Tue, 26 May 2015 05:33:13 -0700 (PDT) Message-ID: <55646803.8040007@ozlabs.ru> Date: Tue, 26 May 2015 22:33:07 +1000 From: Alexey Kardashevskiy MIME-Version: 1.0 References: <1429964684-23872-1-git-send-email-aik@ozlabs.ru> <1429964684-23872-7-git-send-email-aik@ozlabs.ru> <55633A54.8080807@ozlabs.ru> <20150526024628.GA30620@voom.redhat.com> <5564359A.2070009@redhat.com> <556447BB.9000802@ozlabs.ru> <55644819.3000003@redhat.com> In-Reply-To: <55644819.3000003@redhat.com> Content-Type: text/plain; charset=koi8-r; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH qemu v7 06/14] spapr_iommu: Introduce "enabled" state for TCE table List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , David Gibson Cc: Michael Roth , Alex Williamson , qemu-ppc@nongnu.org, qemu-devel@nongnu.org, Alexander Graf On 05/26/2015 08:16 PM, Paolo Bonzini wrote: > > > On 26/05/2015 12:15, Alexey Kardashevskiy wrote: >> There was a "[RFC PATCH 00/15] spapr: add support for PHB hotplug" >> patchset from Mike, this patch added "unrealize" for spapr_phb: >> >> [RFC PATCH 05/15] spapr_pci: add PHB unrealize >> >> I believe I am dealing with the fixed version of this patch so I'll ask >> Mike to respin it. >> >> >>> >>>> So, the sentences after that one note an exception for alias and >>>> container regions. I think iommu regions should behave similarly >>>> - in a sense they're just a procedurally generated collection of >>>> alias regions. >>> >>> The difference is that containers and aliases are resolved at the time >>> the memory region tree is flattened, while IOMMU regions are resolved >>> at run time. >> >> So they are not parts of flattened view and I should be able to >> add/remove these IOMMU subregions any time I like? > > Yes. I got lost here: >>> If it's not true now that they can be unparented at any time like >>> alias regions, we should probably try to make it true. >> >> Unfortunately it's not so easy... Uff. Tricky :) memory_region_del_subregion() is not unparenting but just a wrapped object_unref(), right? But since iommu MR are resolved dynamically, the whole conversation we are having here now has nothing to do with my&Mike concern what we can and cannot do with DMA windows here. Is this correct? -- Alexey