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Re: [Xen-devel] [PATCH v3 1/2] amd/passthrough: Do not leak domain mappings from do_invalidate_dte()



On 12/4/2013 11:59 AM, Andrew Cooper wrote:
Coverity ID: 1135379

As the code stands, the domain mapping will be leaked on each error path.

The mapping can be for a much shorter period of time, and all the relevent
information can be pulled out at once.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CC: Keir Fraser <keir@xxxxxxx>
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>

---

Changes in v3:
  * Dont break the pointer arithmatic on gdte
---
  xen/drivers/passthrough/amd/iommu_guest.c |    9 ++++-----
  1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/xen/drivers/passthrough/amd/iommu_guest.c 
b/xen/drivers/passthrough/amd/iommu_guest.c
index 952600a..c1fa0ff 100644
--- a/xen/drivers/passthrough/amd/iommu_guest.c
+++ b/xen/drivers/passthrough/amd/iommu_guest.c
@@ -430,6 +430,10 @@ static int do_invalidate_dte(struct domain *d, cmd_entry_t 
*cmd)
gdom_id = get_domid_from_dte(gdte);
      gcr3_gfn = get_guest_cr3_from_dte(gdte);
+    glx      = get_glx_from_dte(gdte);
+    gv       = get_gv_from_dte(gdte);
+
+    unmap_domain_page(gdte);
Shouldn't this be "unmap_domain_page (dte_base)" instead?

/* Do not update host dte before gcr3 has been set */
      if ( gcr3_gfn == 0 )
@@ -449,11 +453,6 @@ static int do_invalidate_dte(struct domain *d, cmd_entry_t 
*cmd)
          return -ENODEV;
      }
- glx = get_glx_from_dte(gdte);
-    gv = get_gv_from_dte(gdte);
-
-    unmap_domain_page(dte_base);
-
      /* Setup host device entry */
      hdom_id = host_domid(d, gdom_id);
      req_id = get_dma_requestor_id(iommu->seg, mbdf);
Also, the comment saying "/* Read guest dte information */ " should probably be moved as well.

Suravee


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