[Xen-devel] [PATCH 5/5] libxl/PCI: align reserved device memory boundary for HAP guests

[Jan Beulich <jbeulich@xxxxxxxx>]

As the code comment says, this will allow use of a 2Mb super page
mapping at the end of "low" memory.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -563,6 +563,13 @@ int libxl__domain_device_construct_rdm(l
         /* Just check if RDM > our memory boundary. */
         if (rdm_start > rdm_mem_boundary) {
             /*
+             * For HAP guests round down to a 2Mb boundary to allow use
+             * of large page mappings.
+             */
+            if (libxl_defbool_val(d_config->c_info.hap)
+                && rdm_start > 0x200000)
+                rdm_start &= ~0x1fffff;
+            /*
              * We will move downwards lowmem_end so we have to expand
              * highmem_end.
              */


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