[Xen-devel] [PATCH MM-PART3 v3 2/9] xen/arm: mm: Introduce _PAGE_PRESENT and _PAGE_POPULATE

[Julien Grall <julien.grall@xxxxxxx>]

At the moment, the flags are not enough to describe what kind of update
will done on the VA range. They need to be used in conjunction with the
enum xenmap_operation.

It would be more convenient to have all the information for the update
in a single place.

Two new flags are added to remove the relience on xenmap_operation:
    - _PAGE_PRESENT: Indicate whether we are adding/removing the mapping
    - _PAGE_POPULATE: Indicate whether we only populate page-tables

Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
Reviewed-by: Andrii Anisov <andrii_anisov@xxxxxxxx>

---
    Changes in v3:
        - Clarify the description of the new flags

    Changes in v2:
        - Add Andrii's reviewed-by
---
 xen/arch/arm/mm.c          | 2 +-
 xen/include/asm-arm/page.h | 9 +++++++--
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 23e9565ddc..b13d9adf40 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -1056,7 +1056,7 @@ int map_pages_to_xen(unsigned long virt,
 
 int populate_pt_range(unsigned long virt, unsigned long nr_mfns)
 {
-    return xen_pt_update(RESERVE, virt, INVALID_MFN, nr_mfns, 0);
+    return xen_pt_update(RESERVE, virt, INVALID_MFN, nr_mfns, _PAGE_POPULATE);
 }
 
 int destroy_xen_mappings(unsigned long v, unsigned long e)
diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h
index 2bcdb0f1a5..37e1d9aadb 100644
--- a/xen/include/asm-arm/page.h
+++ b/xen/include/asm-arm/page.h
@@ -76,6 +76,8 @@
  *
  * [0:2] Memory Attribute Index
  * [3:4] Permission flags
+ * [5]   Page present
+ * [6]   Only populate page tables
  */
 #define PAGE_AI_MASK(x) ((x) & 0x7U)
 
@@ -86,12 +88,15 @@
 #define PAGE_XN_MASK(x) (((x) >> _PAGE_XN_BIT) & 0x1U)
 #define PAGE_RO_MASK(x) (((x) >> _PAGE_RO_BIT) & 0x1U)
 
+#define _PAGE_PRESENT    (1U << 5)
+#define _PAGE_POPULATE   (1U << 6)
+
 /*
  * _PAGE_DEVICE and _PAGE_NORMAL are convenience defines. They are not
  * meant to be used outside of this header.
  */
-#define _PAGE_DEVICE    _PAGE_XN
-#define _PAGE_NORMAL    MT_NORMAL
+#define _PAGE_DEVICE    (_PAGE_XN|_PAGE_PRESENT)
+#define _PAGE_NORMAL    (MT_NORMAL|_PAGE_PRESENT)
 
 #define PAGE_HYPERVISOR_RO      (_PAGE_NORMAL|_PAGE_RO|_PAGE_XN)
 #define PAGE_HYPERVISOR_RX      (_PAGE_NORMAL|_PAGE_RO)
-- 
2.11.0


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