[Xen-devel] [for-4.11][PATCH v7 04/16] xen/arm: mm: Remove unused M2P code

[Julien Grall <julien.grall@xxxxxxx>]

Arm does not have an M2P and very unlikely to get one in the future,
therefore don't keep defines that are not necessary in the common code.

At the same time move the remaining M2P define just above
set_gpfn_from_mfn to keep all the dummy helpers for M2P together.

Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxx>

---

Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>

    Changes in v6:
        - Add a comment to explain why we implement dummy version of M2P
        for Arm.
        - Add George's reviewed-by
        - Fix typo in the commit message

    Changes in v4:
        - Patch added.
---
 xen/include/asm-arm/mm.h | 29 ++++++++---------------------
 1 file changed, 8 insertions(+), 21 deletions(-)

diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h
index a0e922f360..cabb1daf30 100644
--- a/xen/include/asm-arm/mm.h
+++ b/xen/include/asm-arm/mm.h
@@ -313,33 +313,20 @@ static inline void *page_to_virt(const struct page_info 
*pg)
 struct page_info *get_page_from_gva(struct vcpu *v, vaddr_t va,
                                     unsigned long flags);
 
-/*
- * The MPT (machine->physical mapping table) is an array of word-sized
- * values, indexed on machine frame number. It is expected that guest OSes
- * will use it to store a "physical" frame number to give the appearance of
- * contiguous (or near contiguous) physical memory.
- */
-#undef  machine_to_phys_mapping
-#define machine_to_phys_mapping  ((unsigned long *)RDWR_MPT_VIRT_START)
-#define INVALID_M2P_ENTRY        (~0UL)
-#define VALID_M2P(_e)            (!((_e) & (1UL<<(BITS_PER_LONG-1))))
-#define SHARED_M2P_ENTRY         (~0UL - 1UL)
-#define SHARED_M2P(_e)           ((_e) == SHARED_M2P_ENTRY)
-
-#define _set_gpfn_from_mfn(mfn, pfn) ({                        \
-    struct domain *d = page_get_owner(__mfn_to_page(mfn));     \
-    if(d && (d == dom_cow))                                    \
-        machine_to_phys_mapping[(mfn)] = SHARED_M2P_ENTRY;     \
-    else                                                       \
-        machine_to_phys_mapping[(mfn)] = (pfn);                \
-    })
-
 static inline void put_gfn(struct domain *d, unsigned long gfn) {}
 static inline int relinquish_shared_pages(struct domain *d)
 {
     return 0;
 }
 
+/*
+ * Arm does not have an M2P, but common code expects a handful of
+ * M2P-related defines and functions. Provide dummy versions of these.
+ */
+#define INVALID_M2P_ENTRY        (~0UL)
+#define SHARED_M2P_ENTRY         (~0UL - 1UL)
+#define SHARED_M2P(_e)           ((_e) == SHARED_M2P_ENTRY)
+
 /* Xen always owns P2M on ARM */
 #define set_gpfn_from_mfn(mfn, pfn) do { (void) (mfn), (void)(pfn); } while (0)
 #define mfn_to_gmfn(_d, mfn)  (mfn)
-- 
2.11.0


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