diff --git a/hw/scsi/mptsas.c b/hw/scsi/mptsas.c
index 2e091c01564a328d2712f2ae4f32c8f19666f525..765ab53c34d1ef8f31e7c3184adc3fba8aba2065 100644
--- a/hw/scsi/mptsas.c
+++ b/hw/scsi/mptsas.c
@@ -756,7 +756,7 @@ static void mptsas_fetch_request(MPTSASState *s)
 
     /* Read the message header from the guest first. */
     addr = s->host_mfa_high_addr | MPTSAS_FIFO_GET(s, request_post);
-    pci_dma_read(pci, addr, req, sizeof(hdr));
+    pci_dma_read(pci, addr, req, sizeof(*hdr));
 
     if (hdr->Function < ARRAY_SIZE(mpi_request_sizes) &&
         mpi_request_sizes[hdr->Function]) {
@@ -766,8 +766,8 @@ static void mptsas_fetch_request(MPTSASState *s)
          */
         size = mpi_request_sizes[hdr->Function];
         assert(size <= MPTSAS_MAX_REQUEST_SIZE);
-        pci_dma_read(pci, addr + sizeof(hdr), &req[sizeof(hdr)],
-                     size - sizeof(hdr));
+        pci_dma_read(pci, addr + sizeof(*hdr), &req[sizeof(*hdr)],
+                     size - sizeof(*hdr));
     }
 
     if (hdr->Function == MPI_FUNCTION_SCSI_IO_REQUEST) {