From patchwork Wed Sep 26 02:59:31 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gibson X-Patchwork-Id: 186928 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 97D0C2C008F for ; Wed, 26 Sep 2012 12:59:07 +1000 (EST) Received: from localhost ([::1]:48486 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TGhq5-0002Pi-AZ for incoming@patchwork.ozlabs.org; Tue, 25 Sep 2012 22:59:05 -0400 Received: from eggs.gnu.org ([208.118.235.92]:60387) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TGhpy-0002Pb-Iz for qemu-devel@nongnu.org; Tue, 25 Sep 2012 22:58:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TGhpx-0006QW-4B for qemu-devel@nongnu.org; Tue, 25 Sep 2012 22:58:58 -0400 Received: from ozlabs.org ([203.10.76.45]:38432) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TGhpw-0006QG-PP; Tue, 25 Sep 2012 22:58:57 -0400 Received: by ozlabs.org (Postfix, from userid 1007) id A88B42C0090; Wed, 26 Sep 2012 12:58:53 +1000 (EST) From: David Gibson To: kraxel@redhat.com Date: Wed, 26 Sep 2012 12:59:31 +1000 Message-Id: <1348628371-6828-1-git-send-email-david@gibson.dropbear.id.au> X-Mailer: git-send-email 1.7.10.4 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 203.10.76.45 Cc: David Gibson , qemu-devel@nongnu.org, qemu-stable@nongnu.org Subject: [Qemu-devel] [PATCH] usb: Fix usb_packet_map() in the presence of IOMMUs X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org With the IOMMU infrastructure introduced before 1.2, we need to use dma_memory_map() to obtain a qemu pointer to memory from an IO bus address. However, dma_memory_map() alters the given length to reflect the length over which the used DMA translation is valid - which could be either more or less than the requested length. usb_packet_map() does not correctly handle these cases, simply failing if dma_memory_map() alters the requested length. If dma_memory_map() increased the length, we just need to use the requested length for the qemu_iovec_add(). However, if it decreased the length, it means that a single DMA translation is not valid for the whole sglist element, and so we need to loop, splitting it up into multiple iovec entries for each piece with a DMA translation (in practice >2 pieces is unlikely). This patch implements the correct behaviour Signed-off-by: David Gibson --- hw/usb/libhw.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/hw/usb/libhw.c b/hw/usb/libhw.c index c0de30e..703e2d2 100644 --- a/hw/usb/libhw.c +++ b/hw/usb/libhw.c @@ -28,19 +28,25 @@ int usb_packet_map(USBPacket *p, QEMUSGList *sgl) { DMADirection dir = (p->pid == USB_TOKEN_IN) ? DMA_DIRECTION_FROM_DEVICE : DMA_DIRECTION_TO_DEVICE; - dma_addr_t len; void *mem; int i; for (i = 0; i < sgl->nsg; i++) { - len = sgl->sg[i].len; - mem = dma_memory_map(sgl->dma, sgl->sg[i].base, &len, dir); - if (!mem) { - goto err; - } - qemu_iovec_add(&p->iov, mem, len); - if (len != sgl->sg[i].len) { - goto err; + dma_addr_t base = sgl->sg[i].base; + dma_addr_t len = sgl->sg[i].len; + + while (len) { + dma_addr_t xlen = len; + mem = dma_memory_map(sgl->dma, sgl->sg[i].base, &xlen, dir); + if (!mem) { + goto err; + } + if (xlen > len) { + xlen = len; + } + qemu_iovec_add(&p->iov, mem, xlen); + len -= xlen; + base += xlen; } } return 0;