xen/tmem: Convert the file common/tmem_xen.c to use typesafe MFN

The file common/tmem_xen.c is now converted to use typesafe. This is
requiring to override the macro page_to_mfn to make it work with mfn_t.

Note that all variables converted to mfn_t havem there initial value,
when set, switch from 0 to INVALID_MFN. This is fine because the initial
values was always overriden before used.

Also add a couple of missing newlines suggested by Andrew in the code.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/common/tmem_xen.c

@@ -14,6 +14,10 @@
 #include <xen/cpu.h>
 #include <xen/init.h>
 
+/* Override macros from asm/page.h to make them work with mfn_t */
+#undef page_to_mfn
+#define page_to_mfn(pg) _mfn(__page_to_mfn(pg))
+
 bool __read_mostly opt_tmem;
 boolean_param("tmem", opt_tmem);
 
@@ -31,7 +35,7 @@ static DEFINE_PER_CPU_READ_MOSTLY(unsigned char *, dstmem);
 static DEFINE_PER_CPU_READ_MOSTLY(void *, scratch_page);
 
 #if defined(CONFIG_ARM)
-static inline void *cli_get_page(xen_pfn_t cmfn, unsigned long *pcli_mfn,
+static inline void *cli_get_page(xen_pfn_t cmfn, mfn_t *pcli_mfn,
                                  struct page_info **pcli_pfp, bool cli_write)
 {
     ASSERT_UNREACHABLE();
@@ -39,14 +43,14 @@ static inline void *cli_get_page(xen_pfn_t cmfn, unsigned long *pcli_mfn,
 }
 
 static inline void cli_put_page(void *cli_va, struct page_info *cli_pfp,
-                                unsigned long cli_mfn, bool mark_dirty)
+                                mfn_t cli_mfn, bool mark_dirty)
 {
     ASSERT_UNREACHABLE();
 }
 #else
 #include <asm/p2m.h>
 
-static inline void *cli_get_page(xen_pfn_t cmfn, unsigned long *pcli_mfn,
+static inline void *cli_get_page(xen_pfn_t cmfn, mfn_t *pcli_mfn,
                                  struct page_info **pcli_pfp, bool cli_write)
 {
     p2m_type_t t;
@@ -68,16 +72,17 @@ static inline void *cli_get_page(xen_pfn_t cmfn, unsigned long *pcli_mfn,
 
     *pcli_mfn = page_to_mfn(page);
     *pcli_pfp = page;
-    return map_domain_page(_mfn(*pcli_mfn));
+
+    return map_domain_page(*pcli_mfn);
 }
 
 static inline void cli_put_page(void *cli_va, struct page_info *cli_pfp,
-                                unsigned long cli_mfn, bool mark_dirty)
+                                mfn_t cli_mfn, bool mark_dirty)
 {
     if ( mark_dirty )
     {
         put_page_and_type(cli_pfp);
-        paging_mark_dirty(current->domain, _mfn(cli_mfn));
+        paging_mark_dirty(current->domain, cli_mfn);
     }
     else
         put_page(cli_pfp);
@@ -88,14 +93,14 @@ static inline void cli_put_page(void *cli_va, struct page_info *cli_pfp,
 int tmem_copy_from_client(struct page_info *pfp,
     xen_pfn_t cmfn, tmem_cli_va_param_t clibuf)
 {
-    unsigned long tmem_mfn, cli_mfn = 0;
+    mfn_t tmem_mfn, cli_mfn = INVALID_MFN;
     char *tmem_va, *cli_va = NULL;
     struct page_info *cli_pfp = NULL;
     int rc = 1;
 
     ASSERT(pfp != NULL);
     tmem_mfn = page_to_mfn(pfp);
-    tmem_va = map_domain_page(_mfn(tmem_mfn));
+    tmem_va = map_domain_page(tmem_mfn);
     if ( guest_handle_is_null(clibuf) )
     {
         cli_va = cli_get_page(cmfn, &cli_mfn, &cli_pfp, 0);
@@ -125,7 +130,7 @@ int tmem_compress_from_client(xen_pfn_t cmfn,
     unsigned char *wmem = this_cpu(workmem);
     char *scratch = this_cpu(scratch_page);
     struct page_info *cli_pfp = NULL;
-    unsigned long cli_mfn = 0;
+    mfn_t cli_mfn = INVALID_MFN;
     void *cli_va = NULL;
 
     if ( dmem == NULL || wmem == NULL )
@@ -152,7 +157,7 @@ int tmem_compress_from_client(xen_pfn_t cmfn,
 int tmem_copy_to_client(xen_pfn_t cmfn, struct page_info *pfp,
     tmem_cli_va_param_t clibuf)
 {
-    unsigned long tmem_mfn, cli_mfn = 0;
+    mfn_t tmem_mfn, cli_mfn = INVALID_MFN;
     char *tmem_va, *cli_va = NULL;
     struct page_info *cli_pfp = NULL;
     int rc = 1;
@@ -165,7 +170,8 @@ int tmem_copy_to_client(xen_pfn_t cmfn, struct page_info *pfp,
             return -EFAULT;
     }
     tmem_mfn = page_to_mfn(pfp);
-    tmem_va = map_domain_page(_mfn(tmem_mfn));
+    tmem_va = map_domain_page(tmem_mfn);
+
     if ( cli_va )
     {
         memcpy(cli_va, tmem_va, PAGE_SIZE);
@@ -181,7 +187,7 @@ int tmem_copy_to_client(xen_pfn_t cmfn, struct page_info *pfp,
 int tmem_decompress_to_client(xen_pfn_t cmfn, void *tmem_va,
                                     size_t size, tmem_cli_va_param_t clibuf)
 {
-    unsigned long cli_mfn = 0;
+    mfn_t cli_mfn = INVALID_MFN;
     struct page_info *cli_pfp = NULL;
     void *cli_va = NULL;
     char *scratch = this_cpu(scratch_page);