From fabd7b9e36003010a63e8a8b4180c2e1bd35fb92 Mon Sep 17 00:00:00 2001
From: Igor Mammedov <imammedo@redhat.com>
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 <drjones@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>
From: Michael S. Tsirkin <mst@redhat.com>
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 <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Tested-by: Igor Mammedov <imammedo@redhat.com>
Message-id: 1446047243-3221-1-git-send-email-mst@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 572ec519ed6fe68f10ec65963527536c2322eab0)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
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