Author: mav
Date: Thu Feb  1 16:24:03 2018
New Revision: 328675
URL: https://svnweb.freebsd.org/changeset/base/328675

Log:
  MFC r313113 (by imp):
  Ensure that the passthrough request will fit in MAXPHYS bytes after it
  has been rounded to full pages. This avoids a panic in
  vm_fault_quick_hold_pages due to this off-by-one error passing one
  page too many into vmapbuf.

Modified:
  stable/11/sys/dev/nvme/nvme_ctrlr.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/dev/nvme/nvme_ctrlr.c
==============================================================================
--- stable/11/sys/dev/nvme/nvme_ctrlr.c Thu Feb  1 16:22:28 2018        
(r328674)
+++ stable/11/sys/dev/nvme/nvme_ctrlr.c Thu Feb  1 16:24:03 2018        
(r328675)
@@ -874,8 +874,20 @@ nvme_ctrlr_passthrough_cmd(struct nvme_controller *ctr
        struct mtx              *mtx;
        struct buf              *buf = NULL;
        int                     ret = 0;
+       vm_offset_t             addr, end;
 
        if (pt->len > 0) {
+               /*
+                * vmapbuf calls vm_fault_quick_hold_pages which only maps full
+                * pages. Ensure this request has fewer than MAXPHYS bytes when
+                * extended to full pages.
+                */
+               addr = (vm_offset_t)pt->buf;
+               end = round_page(addr + pt->len);
+               addr = trunc_page(addr);
+               if (end - addr > MAXPHYS)
+                       return EIO;
+
                if (pt->len > ctrlr->max_xfer_size) {
                        nvme_printf(ctrlr, "pt->len (%d) "
                            "exceeds max_xfer_size (%d)\n", pt->len,
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