[PATCH v3] virtio-iommu: Fix the partial copy of probe request

[Zhenzhong Duan <zhenzhong.duan@intel.com>]

The structure of probe request doesn't include the tail, this leads
to a few field missed to be copied. Currently this isn't an issue as
those missed field belong to reserved field, just in case reserved
field will be used in the future.

Changed 4th parameter of virtio_iommu_iov_to_req() to receive size
of device-readable part.

Fixes: 1733eebb9e75b ("virtio-iommu: Implement RESV_MEM probe request")
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
 v3: moved "- sizeof(struct virtio_iommu_req_tail)" to virtio_iommu_handle_req() per Jean
 v2: keep bugfix change and drop cleanup change

 hw/virtio/virtio-iommu.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index 7c122ab95780..08b227e828f8 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -675,11 +675,10 @@ static int virtio_iommu_probe(VirtIOIOMMU *s,
 
 static int virtio_iommu_iov_to_req(struct iovec *iov,
                                    unsigned int iov_cnt,
-                                   void *req, size_t req_sz)
+                                   void *req, size_t payload_sz)
 {
-    size_t sz, payload_sz = req_sz - sizeof(struct virtio_iommu_req_tail);
+    size_t sz = iov_to_buf(iov, iov_cnt, 0, req, payload_sz);
 
-    sz = iov_to_buf(iov, iov_cnt, 0, req, payload_sz);
     if (unlikely(sz != payload_sz)) {
         return VIRTIO_IOMMU_S_INVAL;
     }
@@ -692,7 +691,8 @@ static int virtio_iommu_handle_ ## __req(VirtIOIOMMU *s,                \
                                          unsigned int iov_cnt)          \
 {                                                                       \
     struct virtio_iommu_req_ ## __req req;                              \
-    int ret = virtio_iommu_iov_to_req(iov, iov_cnt, &req, sizeof(req)); \
+    int ret = virtio_iommu_iov_to_req(iov, iov_cnt, &req,               \
+                    sizeof(req) - sizeof(struct virtio_iommu_req_tail));\
                                                                         \
     return ret ? ret : virtio_iommu_ ## __req(s, &req);                 \
 }
-- 
2.25.1