From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51880) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZrSxP-0006RZ-Qt for qemu-devel@nongnu.org; Wed, 28 Oct 2015 11:48:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZrSxO-0008Sq-Qu for qemu-devel@nongnu.org; Wed, 28 Oct 2015 11:48:11 -0400 Date: Wed, 28 Oct 2015 17:48:02 +0200 From: "Michael S. Tsirkin" Message-ID: <1446047243-3221-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: [Qemu-devel] [PATCH 1/2] dataplane: simplify indirect descriptor read List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Igor Mammedov , qemu-block@nongnu.org, Stefan Hajnoczi Use address_space_read to make sure we handle the case of an indirect descriptor crossing DIMM boundary correctly. Signed-off-by: Michael S. Tsirkin --- Warning: compile-tested only. hw/virtio/dataplane/vring.c | 28 ++++++++++++++++++---------- 1 file changed, 18 insertions(+), 10 deletions(-) diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c index 68f1994..0b92fcf 100644 --- a/hw/virtio/dataplane/vring.c +++ b/hw/virtio/dataplane/vring.c @@ -257,6 +257,21 @@ static void copy_in_vring_desc(VirtIODevice *vdev, host->next = virtio_lduw_p(vdev, &guest->next); } +static bool read_vring_desc(VirtIODevice *vdev, + hwaddr guest, + struct vring_desc *host) +{ + if (address_space_read(&address_space_memory, guest, MEMTXATTRS_UNSPECIFIED, + (uint8_t *)host, sizeof *host)) { + return false; + } + host->addr = virtio_tswap64(vdev, host->addr); + host->len = virtio_tswap32(vdev, host->len); + host->flags = virtio_tswap16(vdev, host->flags); + host->next = virtio_tswap16(vdev, host->next); + return true; +} + /* This is stolen from linux/drivers/vhost/vhost.c. */ static int get_indirect(VirtIODevice *vdev, Vring *vring, VirtQueueElement *elem, struct vring_desc *indirect) @@ -284,23 +299,16 @@ static int get_indirect(VirtIODevice *vdev, Vring *vring, } do { - struct vring_desc *desc_ptr; - MemoryRegion *mr; - /* Translate indirect descriptor */ - desc_ptr = vring_map(&mr, - indirect->addr + found * sizeof(desc), - sizeof(desc), false); - if (!desc_ptr) { - error_report("Failed to map indirect descriptor " + if (!read_vring_desc(vdev, indirect->addr + found * sizeof(desc), + &desc)) { + error_report("Failed to read indirect descriptor " "addr %#" PRIx64 " len %zu", (uint64_t)indirect->addr + found * sizeof(desc), sizeof(desc)); vring->broken = true; return -EFAULT; } - copy_in_vring_desc(vdev, desc_ptr, &desc); - memory_region_unref(mr); /* Ensure descriptor has been loaded before accessing fields */ barrier(); /* read_barrier_depends(); */ -- MST