From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:48388) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TYI2f-0004e4-RN for qemu-devel@nongnu.org; Tue, 13 Nov 2012 10:04:48 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TYI2c-0001dI-Pd for qemu-devel@nongnu.org; Tue, 13 Nov 2012 10:04:45 -0500 Received: from mx1.redhat.com ([209.132.183.28]:47996) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TYI2c-0001d0-Hy for qemu-devel@nongnu.org; Tue, 13 Nov 2012 10:04:42 -0500 Message-ID: <50A26171.9090808@redhat.com> Date: Tue, 13 Nov 2012 16:04:17 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1351013211-1907-1-git-send-email-peter.maydell@linaro.org> <20121026004832.GG7222@truffula.fritz.box> <20121026035812.GK7222@truffula.fritz.box> <508A8B96.60302@redhat.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] dma: Define dma_context_memory and use in sysbus-ohci List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: Peter Crosthwaite , patches@linaro.org, qemu-devel@nongnu.org, Gerd Hoffmann , David Gibson , Avi Kivity Il 13/11/2012 12:44, Peter Maydell ha scritto: >>> >> As soon as Avi's iommu patches go in, in fact, dma->as will just be as. >>> >> Even if as == NULL were to be outlawed and you'd be forced to write >>> >> get_address_space_memory(), taking the pain to create dummy DMAContexts >>> >> now is just not worth it. >> > >> > Personally I think it's better not to permit NULL DMAContexts or >> > AddressSpaces here, because they're kind of a hack (in the same way >> > that the "system address space" is kind of a hack). In real hardware >> > you probably aren't really doing dma to that address space but to >> > some more local bus. dma_context_memory/address_space_memory are >> > nice and easy to search for, whereas NULL isn't. [And in general >> > I think NULL is too easy to use; if you have to go looking for the >> > system dma context you've been prompted to think about whether >> > that's the right one...] > Ping! Can we have a ruling on what the right fix for this is so > we can fix these segfaults before 1.3 release, please? I think this patch is already in Gerd's queue. Paolo