1 files changed, 23 insertions, 0 deletions

diff --git a/drivers/misc/sgi-xp/xp_uv.c b/drivers/misc/sgi-xp/xp_uv.c
index 1e61f8a61a30..a0d093274dc0 100644
--- a/drivers/misc/sgi-xp/xp_uv.c
+++ b/drivers/misc/sgi-xp/xp_uv.c
@@ -42,11 +42,34 @@ xp_socket_pa_uv(unsigned long gpa)
 }
 
 static enum xp_retval
+xp_remote_mmr_read(unsigned long dst_gpa, const unsigned long src_gpa,
+                   size_t len)
+{
+        int ret;
+        unsigned long *dst_va = __va(uv_gpa_to_soc_phys_ram(dst_gpa));
+
+        BUG_ON(!uv_gpa_in_mmr_space(src_gpa));
+        BUG_ON(len != 8);
+
+        ret = gru_read_gpa(dst_va, src_gpa);
+        if (ret == 0)
+                return xpSuccess;
+
+        dev_err(xp, "gru_read_gpa() failed, dst_gpa=0x%016lx src_gpa=0x%016lx "
+                "len=%ld\n", dst_gpa, src_gpa, len);
+        return xpGruCopyError;
+}
+
+
+static enum xp_retval
 xp_remote_memcpy_uv(unsigned long dst_gpa, const unsigned long src_gpa,
                     size_t len)
 {
         int ret;
 
+        if (uv_gpa_in_mmr_space(src_gpa))
+                return xp_remote_mmr_read(dst_gpa, src_gpa, len);
+
         ret = gru_copy_gpa(dst_gpa, src_gpa, len);
         if (ret == 0)
                 return xpSuccess;