From fabd7b9e36003010a63e8a8b4180c2e1bd35fb92 Mon Sep 17 00:00:00 2001 From: Igor Mammedov Date: Fri, 20 Nov 2015 10:44:40 +0100 Subject: [PATCH 7/9] dataplane: simplify indirect descriptor read Message-id: <1448016282-257478-8-git-send-email-imammedo@redhat.com> Patchwork-id: 68412 O-Subject: [RHEV-7.2.z qemu-kvm-rhev PATCH 7/9] dataplane: simplify indirect descriptor read Bugzilla: 1288096 RH-Acked-by: Andrew Jones RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Michael S. Tsirkin From: Michael S. Tsirkin 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 Reviewed-by: Stefan Hajnoczi Tested-by: Igor Mammedov Message-id: 1446047243-3221-1-git-send-email-mst@redhat.com Signed-off-by: Stefan Hajnoczi (cherry picked from commit 572ec519ed6fe68f10ec65963527536c2322eab0) Signed-off-by: Miroslav Rezanina --- 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 2a6bf22..e27a834 100644 --- a/hw/virtio/dataplane/vring.c +++ b/hw/virtio/dataplane/vring.c @@ -216,6 +216,21 @@ 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) @@ -243,23 +258,16 @@ 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(); */ -- 1.8.3.1