From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36146) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cUVU0-0005md-8a for qemu-devel@nongnu.org; Fri, 20 Jan 2017 04:27:45 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cUVTx-0001oo-5F for qemu-devel@nongnu.org; Fri, 20 Jan 2017 04:27:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43992) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cUVTw-0001oY-Vn for qemu-devel@nongnu.org; Fri, 20 Jan 2017 04:27:41 -0500 Date: Fri, 20 Jan 2017 17:27:36 +0800 From: Peter Xu Message-ID: <20170120092736.GM4914@pxdev.xzpeter.org> References: <1484276800-26814-1-git-send-email-peterx@redhat.com> <1484276800-26814-3-git-send-email-peterx@redhat.com> <20170120090506.GJ4914@pxdev.xzpeter.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] [PATCH RFC v3 02/14] intel_iommu: simplify irq region translation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Tian, Kevin" Cc: "qemu-devel@nongnu.org" , "Lan, Tianyu" , "mst@redhat.com" , "jan.kiszka@siemens.com" , "jasowang@redhat.com" , "alex.williamson@redhat.com" , "bd.aviv@gmail.com" On Fri, Jan 20, 2017 at 09:15:27AM +0000, Tian, Kevin wrote: > > From: Peter Xu [mailto:peterx@redhat.com] > > Sent: Friday, January 20, 2017 5:05 PM > > > > On Fri, Jan 20, 2017 at 08:22:14AM +0000, Tian, Kevin wrote: > > > > From: Peter Xu [mailto:peterx@redhat.com] > > > > Sent: Friday, January 13, 2017 11:06 AM > > > > > > > > Before we have int-remap, we need to bypass interrupt write requests. > > > > That's not necessary now - we have supported int-remap, and all the irq > > > > region requests should be redirected there. Cleaning up the block with > > > > an assertion instead. > > > > > > This comment is not accurate. According to code, the reason why you > > > can do such simplification is because we have standalone memory > > > region now for interrupt addresses. There should be nothing to do > > > with int-remap, which can be disabled by guest... Maybe the standalone > > > region was added when developing int-remap, but functionally they > > > are not related. :-) > > > > IMHO the above commit message is fairly clear. :-) > > > > But sure I can add some more emphasise like: > > > > "Before we have int-remap memory region, ..." > > > > Do you think it's okay? Or any better suggestion? > > > > (Just to mention that even guest disables IR, the MSI region will > > still be there.) > > > > My option is simple - this patch has nothing to do with int-remap. > It's not necessary, not because we supported int-remap. It's because > we have a standalone memory region for interrupt addresses, as you > described in the code. :-) I really think they are the same thing... How about this: Now we have a standalone memory region for MSI, all the irq region requests should be redirected there. Cleaning up the block with an assertion instead. -- peterx