[xen staging] xen/arm: set up shared memory foreign mapping for borrower domain

[patchbot@xxxxxxx]

commit b7133c10a3fd3b66b8d6a657a55855ab78f0a75b
Author:     Penny Zheng <Penny.Zheng@xxxxxxx>
AuthorDate: Thu Sep 8 21:55:10 2022 +0800
Commit:     Stefano Stabellini <stefano.stabellini@xxxxxxx>
CommitDate: Fri Sep 9 12:58:00 2022 -0700

    xen/arm: set up shared memory foreign mapping for borrower domain
    
    This commit sets up shared memory foreign mapping for borrower domain.
    
    If owner domain is the default dom_io, all shared domain are treated as
    borrower domain.
    
    Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
    Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
 xen/arch/arm/domain_build.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 417a0e82ba..dfcda604b3 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -992,6 +992,15 @@ static int __init process_shm(struct domain *d,
             if ( ret )
                 return ret;
         }
+
+        if ( owner_dom_io || (strcmp(role_str, "borrower") == 0) )
+        {
+            /* Set up P2M foreign mapping for borrower domain. */
+            ret = map_regions_p2mt(d, _gfn(PFN_UP(gbase)), PFN_DOWN(psize),
+                                   _mfn(PFN_UP(pbase)), p2m_map_foreign_rw);
+            if ( ret )
+                return ret;
+        }
     }
 
     return 0;
--
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