[Xen-changelog] [xen staging] libxl/PCI: align reserved device memory boundary for HAP guests

[patchbot@xxxxxxx]

commit 5f29f349818be5b4e06caae57727405a7ea1a978
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Feb 27 15:45:31 2020 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Feb 27 15:45:31 2020 +0100

    libxl/PCI: align reserved device memory boundary for HAP guests
    
    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>
    Acked-by: Wei Liu <wl@xxxxxxx>
---
 tools/libxl/libxl_dm.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index e0c3aa4998..f4007bbe50 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -563,6 +563,13 @@ int libxl__domain_device_construct_rdm(libxl__gc *gc,
         /* 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 > MB(2))
+                rdm_start &= ~(MB(2) - 1);
+            /*
              * We will move downwards lowmem_end so we have to expand
              * highmem_end.
              */
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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