Index: head/sys/dev/hyperv/storvsc/hv_storvsc_drv_freebsd.c
===================================================================
--- head/sys/dev/hyperv/storvsc/hv_storvsc_drv_freebsd.c
+++ head/sys/dev/hyperv/storvsc/hv_storvsc_drv_freebsd.c
@@ -1775,13 +1775,28 @@
 	prplist->gpa_range.gpa_ofs = segs[0].ds_addr & PAGE_MASK;
 
 	for (i = 0; i < nsegs; i++) {
-		prplist->gpa_page[i] = atop(segs[i].ds_addr);
 #ifdef INVARIANTS
-		if (i != 0 && i != nsegs - 1) {
-			KASSERT((segs[i].ds_addr & PAGE_MASK) == 0 &&
-			    segs[i].ds_len == PAGE_SIZE, ("not a full page"));
+		if (nsegs > 1) {
+			if (i == 0) {
+				KASSERT((segs[i].ds_addr & PAGE_MASK) +
+				    segs[i].ds_len == PAGE_SIZE,
+				    ("invalid 1st page, ofs 0x%jx, len %zu",
+				     (uintmax_t)segs[i].ds_addr,
+				     segs[i].ds_len));
+			} else if (i == nsegs - 1) {
+				KASSERT((segs[i].ds_addr & PAGE_MASK) == 0,
+				    ("invalid last page, ofs 0x%jx",
+				     (uintmax_t)segs[i].ds_addr));
+			} else {
+				KASSERT((segs[i].ds_addr & PAGE_MASK) == 0 &&
+				    segs[i].ds_len == PAGE_SIZE,
+				    ("not a full page, ofs 0x%jx, len %zu",
+				     (uintmax_t)segs[i].ds_addr,
+				     segs[i].ds_len));
+			}
 		}
 #endif
+		prplist->gpa_page[i] = atop(segs[i].ds_addr);
 	}
 	reqp->prp_cnt = nsegs;
 }