[Xen-devel] [PATCH v1] Reset iomem's gfn to LIBXL_INVALID_GFN on reboot

[Oleksandr Grytsov <al1img@xxxxxxxxx>]

From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>

During domain reboot its configuration is partially reused
to re-create a new domain, but iomem's GFN field for the
iomem is only restored for those memory ranges, which are
configured in form of [IOMEM_START,NUM_PAGES[@GFN], but not for
those in form of [IOMEM_START,NUM_PAGES], e.g. without GFN.
For the latter GFN is reset to 0, but while mapping ranges
to a domain during reboot there is a check that GFN treated
as valid if it is not equal to LIBXL_INVALID_GFN, thus making
Xen to map IOMEM_START to address 0 in the guest's address space.

Workaround it by resseting GFN to LIBXL_INVALID_GFN, so xl
can set proper values for mapping on reboot.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
---
 tools/libxl/libxl_domain.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tools/libxl/libxl_domain.c b/tools/libxl/libxl_domain.c
index 9d0eb5aed1..0ae16a5b12 100644
--- a/tools/libxl/libxl_domain.c
+++ b/tools/libxl/libxl_domain.c
@@ -2120,6 +2120,15 @@ static void retrieve_domain_configuration_end(libxl__egc 
*egc,
         }
     }
 
+    /* reset IOMEM's GFN to initial value */
+    {
+        int i;
+
+        for (i = 0; i < d_config->b_info.num_iomem; i++)
+            if (d_config->b_info.iomem[i].gfn == 0)
+                d_config->b_info.iomem[i].gfn = LIBXL_INVALID_GFN;
+    }
+
     /* Devices: disk, nic, vtpm, pcidev etc. */
 
     /* The MERGE macro implements following logic:
-- 
2.17.1


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