[PATCH v2 00/16] xen/arm: Clean-up memory subsystems

[PATCH v2 00/16] xen/arm: Clean-up memory subsystems

[Julien Grall]

Hi all,

This is a merged of the remainder of 2 series + new clean-up patches:
    - xen/arm: Extend the usage of typesafe MFN [1]
    - xen/arm: Move LPAE definition in a separate header. [2]

Cheers,

[1] <20170613161323.25196-1-julien.grall@arm.com>
[2] <20170615203057.755-1-julien.grall@arm.com>

Julien Grall (16):
  xen/mm: Don't use _{g,m}fn for defining INVALID_{G,M}FN
  xen/arm: setup: Remove bogus xenheap_mfn_end in setup_mm for arm64
  xen/arm: mm: Use typesafe mfn for xenheap_mfn_*
  xen/arm: p2m: Redefine mfn_to_page and page_to_mfn to use typesafe
  xen/arm: mm: Redefine virt_to_mfn to support typesafe
  xen/arm: domain_build: Redefine virt_to_mfn to support typesafe
  xen/arm: alternative: Redefine virt_to_mfn to support typesafe
  xen/arm: livepatch: Redefine virt_to_mfn to support typesafe
  xen/arm: create_xen_entries: Use typesafe MFN
  xen/arm: Move LPAE definition in a separate header
  xen/arm: lpae: Fix comments coding style
  xen/arm: p2m: Rename p2m_valid, p2m_table, p2m_mapping and
    p2m_is_superpage
  xen/arm: p2m: Move lpae_* helpers in lpae.h
  xen/arm: mm: Use lpae_valid and lpae_table in create_xen_entries
  xen/arm: mm: Introduce temporary variable in create_xen_entries
  xen/arm: mm: Use __func__ rather than plain name in format string

 xen/arch/arm/alternative.c  |   6 +-
 xen/arch/arm/domain_build.c |   6 +-
 xen/arch/arm/livepatch.c    |   6 +-
 xen/arch/arm/mm.c           |  84 +++++++++---------
 xen/arch/arm/p2m.c          |  72 ++++++---------
 xen/arch/arm/setup.c        |  20 ++---
 xen/include/asm-arm/lpae.h  | 209 ++++++++++++++++++++++++++++++++++++++++++++
 xen/include/asm-arm/mm.h    |  14 +--
 xen/include/asm-arm/page.h  | 152 +-------------------------------
 xen/include/xen/mm.h        |   4 +-
 10 files changed, 317 insertions(+), 256 deletions(-)
 create mode 100644 xen/include/asm-arm/lpae.h

-- 
2.11.0


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[PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Julien Grall]

INVALID_{G,M}FN are defined using static inline helpers _{g,m}fn.
This means, they cannot be used to initialize a build time static variable:

In file included from mm.c:24:0:
xen/xen/include/xen/mm.h:59:26: error: initializer element is not constant
 #define INVALID_MFN      _mfn(~0UL)

Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Tim Deegan <tim@xen.org>
---
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Tim Deegan <tim@xen.org>
Cc: Wei Liu <wei.liu2@citrix.com>

    Changes in v2:
        - Add Tim's acked
        - The solution suggested in v1 is also working for non-debug
        build. So keep the code as it is.
---
 xen/include/xen/mm.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/include/xen/mm.h b/xen/include/xen/mm.h
index c9198232e2..e61b6e991c 100644
--- a/xen/include/xen/mm.h
+++ b/xen/include/xen/mm.h
@@ -56,7 +56,7 @@
 
 TYPE_SAFE(unsigned long, mfn);
 #define PRI_mfn          "05lx"
-#define INVALID_MFN      _mfn(~0UL)
+#define INVALID_MFN      (mfn_t){ ~0UL }
 
 #ifndef mfn_t
 #define mfn_t /* Grep fodder: mfn_t, _mfn() and mfn_x() are defined above */
@@ -89,7 +89,7 @@ static inline bool_t mfn_eq(mfn_t x, mfn_t y)
 
 TYPE_SAFE(unsigned long, gfn);
 #define PRI_gfn          "05lx"
-#define INVALID_GFN      _gfn(~0UL)
+#define INVALID_GFN      (gfn_t){ ~0UL }
 
 #ifndef gfn_t
 #define gfn_t /* Grep fodder: gfn_t, _gfn() and gfn_x() are defined above */
-- 
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[PATCH v2 02/16] xen/arm: setup: Remove bogus xenheap_mfn_end in setup_mm for arm64

[Julien Grall]

xenheap_mfn_end is storing an MFN and not a physical address. Xen is not
currently using xenheap_mfn_end and the value will be reset after the
loop. So drop this bogus xenheap_mfn_end.

Signed-off-by: Julien Grall <julien.grall@arm.com>
---
    Changes in v2:
        - Update commit message
---
 xen/arch/arm/setup.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index f00f29a45b..ab4d8e4218 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -654,8 +654,6 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
             if ( e > bank_end )
                 e = bank_end;
 
-            xenheap_mfn_end = e;
-
             dt_unreserved_regions(s, e, init_boot_pages, 0);
             s = n;
         }
-- 
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[PATCH v2 03/16] xen/arm: mm: Use typesafe mfn for xenheap_mfn_*

[Julien Grall]

Add more safety when using xenheap_mfn_*.

Signed-off-by: Julien Grall <julien.grall@arm.com>
---

    I haven't introduced mfn_less_than() and mfn_greather_than() as
    there would be only a couple of usage. We would be able to introduce
    them and replace the open-coding easily in the future grepping
    mfn_x().
---
 xen/arch/arm/mm.c        | 16 ++++++++--------
 xen/arch/arm/setup.c     | 18 +++++++++---------
 xen/include/asm-arm/mm.h | 11 ++++++-----
 3 files changed, 23 insertions(+), 22 deletions(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 7b313ca123..452c1e26c3 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -138,8 +138,8 @@ uint64_t init_ttbr;
 static paddr_t phys_offset;
 
 /* Limits of the Xen heap */
-unsigned long xenheap_mfn_start __read_mostly = ~0UL;
-unsigned long xenheap_mfn_end __read_mostly;
+mfn_t xenheap_mfn_start __read_mostly = INVALID_MFN;
+mfn_t xenheap_mfn_end __read_mostly;
 vaddr_t xenheap_virt_end __read_mostly;
 #ifdef CONFIG_ARM_64
 vaddr_t xenheap_virt_start __read_mostly;
@@ -801,8 +801,8 @@ void __init setup_xenheap_mappings(unsigned long base_mfn,
 
     /* Record where the xenheap is, for translation routines. */
     xenheap_virt_end = XENHEAP_VIRT_START + nr_mfns * PAGE_SIZE;
-    xenheap_mfn_start = base_mfn;
-    xenheap_mfn_end = base_mfn + nr_mfns;
+    xenheap_mfn_start = _mfn(base_mfn);
+    xenheap_mfn_end = _mfn(base_mfn + nr_mfns);
 }
 #else /* CONFIG_ARM_64 */
 void __init setup_xenheap_mappings(unsigned long base_mfn,
@@ -816,16 +816,16 @@ void __init setup_xenheap_mappings(unsigned long base_mfn,
     mfn = base_mfn & ~((FIRST_SIZE>>PAGE_SHIFT)-1);
 
     /* First call sets the xenheap physical and virtual offset. */
-    if ( xenheap_mfn_start == ~0UL )
+    if ( mfn_eq(xenheap_mfn_start, INVALID_MFN) )
     {
-        xenheap_mfn_start = base_mfn;
+        xenheap_mfn_start = _mfn(base_mfn);
         xenheap_virt_start = DIRECTMAP_VIRT_START +
             (base_mfn - mfn) * PAGE_SIZE;
     }
 
-    if ( base_mfn < xenheap_mfn_start )
+    if ( base_mfn < mfn_x(xenheap_mfn_start) )
         panic("cannot add xenheap mapping at %lx below heap start %lx",
-              base_mfn, xenheap_mfn_start);
+              base_mfn, mfn_x(xenheap_mfn_start));
 
     end_mfn = base_mfn + nr_mfns;
 
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index ab4d8e4218..3b34855668 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -555,8 +555,8 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
      * and enough mapped pages for copying the DTB.
      */
     dtb_pages = (dtb_size + PAGE_SIZE-1) >> PAGE_SHIFT;
-    boot_mfn_start = xenheap_mfn_end - dtb_pages - 1;
-    boot_mfn_end = xenheap_mfn_end;
+    boot_mfn_start = mfn_x(xenheap_mfn_end) - dtb_pages - 1;
+    boot_mfn_end = mfn_x(xenheap_mfn_end);
 
     init_boot_pages(pfn_to_paddr(boot_mfn_start), pfn_to_paddr(boot_mfn_end));
 
@@ -591,11 +591,11 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
                 e = bank_end;
 
             /* Avoid the xenheap */
-            if ( s < pfn_to_paddr(xenheap_mfn_start+xenheap_pages)
-                 && pfn_to_paddr(xenheap_mfn_start) < e )
+            if ( s < mfn_to_maddr(mfn_add(xenheap_mfn_start, xenheap_pages))
+                 && mfn_to_maddr(xenheap_mfn_start) < e )
             {
-                e = pfn_to_paddr(xenheap_mfn_start);
-                n = pfn_to_paddr(xenheap_mfn_start+xenheap_pages);
+                e = mfn_to_maddr(xenheap_mfn_start);
+                n = mfn_to_maddr(mfn_add(xenheap_mfn_start, xenheap_pages));
             }
 
             dt_unreserved_regions(s, e, init_boot_pages, 0);
@@ -610,7 +610,7 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
 
     /* Add xenheap memory that was not already added to the boot
        allocator. */
-    init_xenheap_pages(pfn_to_paddr(xenheap_mfn_start),
+    init_xenheap_pages(mfn_to_maddr(xenheap_mfn_start),
                        pfn_to_paddr(boot_mfn_start));
 }
 #else /* CONFIG_ARM_64 */
@@ -662,8 +662,8 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
     total_pages += ram_size >> PAGE_SHIFT;
 
     xenheap_virt_end = XENHEAP_VIRT_START + ram_end - ram_start;
-    xenheap_mfn_start = ram_start >> PAGE_SHIFT;
-    xenheap_mfn_end = ram_end >> PAGE_SHIFT;
+    xenheap_mfn_start = maddr_to_mfn(ram_start);
+    xenheap_mfn_end = maddr_to_mfn(ram_end);
 
     /*
      * Need enough mapped pages for copying the DTB.
diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h
index 274b1752b3..b2e7ea7761 100644
--- a/xen/include/asm-arm/mm.h
+++ b/xen/include/asm-arm/mm.h
@@ -115,7 +115,7 @@ struct page_info
 #define PGC_count_width   PG_shift(9)
 #define PGC_count_mask    ((1UL<<PGC_count_width)-1)
 
-extern unsigned long xenheap_mfn_start, xenheap_mfn_end;
+extern mfn_t xenheap_mfn_start, xenheap_mfn_end;
 extern vaddr_t xenheap_virt_end;
 #ifdef CONFIG_ARM_64
 extern vaddr_t xenheap_virt_start;
@@ -125,7 +125,8 @@ extern vaddr_t xenheap_virt_start;
 #define is_xen_heap_page(page) is_xen_heap_mfn(page_to_mfn(page))
 #define is_xen_heap_mfn(mfn) ({                                 \
     unsigned long _mfn = (mfn);                                 \
-    (_mfn >= xenheap_mfn_start && _mfn < xenheap_mfn_end);      \
+    (_mfn >= mfn_x(xenheap_mfn_start) &&                        \
+     _mfn < mfn_x(xenheap_mfn_end));                            \
 })
 #else
 #define is_xen_heap_page(page) ((page)->count_info & PGC_xen_heap)
@@ -235,7 +236,7 @@ static inline paddr_t __virt_to_maddr(vaddr_t va)
 static inline void *maddr_to_virt(paddr_t ma)
 {
     ASSERT(is_xen_heap_mfn(ma >> PAGE_SHIFT));
-    ma -= pfn_to_paddr(xenheap_mfn_start);
+    ma -= mfn_to_maddr(xenheap_mfn_start);
     return (void *)(unsigned long) ma + XENHEAP_VIRT_START;
 }
 #else
@@ -243,7 +244,7 @@ static inline void *maddr_to_virt(paddr_t ma)
 {
     ASSERT(pfn_to_pdx(ma >> PAGE_SHIFT) < (DIRECTMAP_SIZE >> PAGE_SHIFT));
     return (void *)(XENHEAP_VIRT_START -
-                    pfn_to_paddr(xenheap_mfn_start) +
+                    mfn_to_maddr(xenheap_mfn_start) +
                     ((ma & ma_va_bottom_mask) |
                      ((ma & ma_top_mask) >> pfn_pdx_hole_shift)));
 }
@@ -284,7 +285,7 @@ static inline struct page_info *virt_to_page(const void *v)
     ASSERT(va < xenheap_virt_end);
 
     pdx = (va - XENHEAP_VIRT_START) >> PAGE_SHIFT;
-    pdx += pfn_to_pdx(xenheap_mfn_start);
+    pdx += pfn_to_pdx(mfn_x(xenheap_mfn_start));
     return frame_table + pdx - frametable_base_pdx;
 }
 
-- 
2.11.0


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[PATCH v2 04/16] xen/arm: p2m: Redefine mfn_to_page and page_to_mfn to use typesafe

[Julien Grall]

The file xen/arch/arm/p2m.c is using typesafe MFN in most of the place.
This requires caller to mfn_to_page and page_to_mfn to use _mfn/mfn_x.

To avoid extra _mfn/mfn_x, re-define mfn_to_page and page_to_mfn within
xen/arch/arm/p2m.c to handle typesafe MFN.

Signed-off-by: Julien Grall <julien.grall@arm.com>
---
    The idea behind redefining locally mfn_to_page and page_to_mfn is
    splitting the introduction of typesafe MFN in smaller series and
    between multiple people. We know the file is typesafe ready and if
    we decide to make the main helper typesafe, we would just need to
    drop the definition at the top of the file.
---
 xen/arch/arm/p2m.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 266d1c3bd6..6c1ac70044 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -38,6 +38,12 @@ static unsigned int __read_mostly max_vmid = MAX_VMID_8_BIT;
 
 #define P2M_ROOT_PAGES    (1<<P2M_ROOT_ORDER)
 
+/* Override macros from asm/mm.h to make them work with mfn_t */
+#undef mfn_to_page
+#define mfn_to_page(mfn) __mfn_to_page(mfn_x(mfn))
+#undef page_to_mfn
+#define page_to_mfn(pg) _mfn(__page_to_mfn(pg))
+
 unsigned int __read_mostly p2m_ipa_bits;
 
 /* Helpers to lookup the properties of each level */
@@ -115,7 +121,7 @@ void dump_p2m_lookup(struct domain *d, paddr_t addr)
     printk("dom%d IPA 0x%"PRIpaddr"\n", d->domain_id, addr);
 
     printk("P2M @ %p mfn:0x%lx\n",
-           p2m->root, page_to_mfn(p2m->root));
+           p2m->root, mfn_x(page_to_mfn(p2m->root)));
 
     dump_pt_walk(page_to_maddr(p2m->root), addr,
                  P2M_ROOT_LEVEL, P2M_ROOT_PAGES);
@@ -591,7 +597,7 @@ static int p2m_create_table(struct p2m_domain *p2m, lpae_t *entry)
      * The access value does not matter because the hardware will ignore
      * the permission fields for table entry.
      */
-    pte = mfn_to_p2m_entry(_mfn(page_to_mfn(page)), p2m_invalid,
+    pte = mfn_to_p2m_entry(page_to_mfn(page), p2m_invalid,
                            p2m->default_access);
 
     p2m_write_pte(entry, pte, p2m->clean_pte);
@@ -650,9 +656,9 @@ static void p2m_put_l3_page(const lpae_t pte)
      */
     if ( p2m_is_foreign(pte.p2m.type) )
     {
-        unsigned long mfn = pte.p2m.base;
+        mfn_t mfn = _mfn(pte.p2m.base);
 
-        ASSERT(mfn_valid(_mfn(mfn)));
+        ASSERT(mfn_valid(mfn));
         put_page(mfn_to_page(mfn));
     }
 }
@@ -702,7 +708,7 @@ static void p2m_free_entry(struct p2m_domain *p2m,
     mfn = _mfn(entry.p2m.base);
     ASSERT(mfn_valid(mfn));
 
-    pg = mfn_to_page(mfn_x(mfn));
+    pg = mfn_to_page(mfn);
 
     page_list_del(pg, &p2m->pages);
     free_domheap_page(pg);
@@ -780,7 +786,7 @@ static bool p2m_split_superpage(struct p2m_domain *p2m, lpae_t *entry,
 
     unmap_domain_page(table);
 
-    pte = mfn_to_p2m_entry(_mfn(page_to_mfn(page)), p2m_invalid,
+    pte = mfn_to_p2m_entry(page_to_mfn(page), p2m_invalid,
                            p2m->default_access);
 
     /*
@@ -1443,7 +1449,7 @@ struct page_info *get_page_from_gva(struct vcpu *v, vaddr_t va,
     if ( !mfn_valid(maddr_to_mfn(maddr)) )
         goto err;
 
-    page = mfn_to_page(mfn_x(maddr_to_mfn(maddr)));
+    page = mfn_to_page(maddr_to_mfn(maddr));
     ASSERT(page);
 
     if ( unlikely(!get_page(page, d)) )
-- 
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[PATCH v2 05/16] xen/arm: mm: Redefine virt_to_mfn to support typesafe

[Julien Grall]

The file xen/arch/arm/mm.c is using the typesafe MFN in most of the
place. This requires all caller of virt_to_mfn to prefixed by _mfn(...).

To avoid the extra _mfn(...), re-defined virt_to_mfn within arch/arm/mm.c
to handle typesafe MFN.

This patch also introduce __virt_to_mfn, so virt_to_mfn can be
re-defined easily.

Signed-off-by: Julien Grall <julien.grall@arm.com>
---
    Changes in v2:
        - Use __virt_to_mfn rather than mfn_x(virt_to_mfn()).
---
 xen/arch/arm/mm.c        | 16 ++++++++++------
 xen/include/asm-arm/mm.h |  3 ++-
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 452c1e26c3..5612834dfc 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -44,6 +44,10 @@
 
 struct domain *dom_xen, *dom_io, *dom_cow;
 
+/* Override macros from asm/page.h to make them work with mfn_t */
+#undef virt_to_mfn
+#define virt_to_mfn(va) _mfn(__virt_to_mfn(va))
+
 /* Static start-of-day pagetables that we use before the allocators
  * are up. These are used by all CPUs during bringup before switching
  * to the CPUs own pagetables.
@@ -479,7 +483,7 @@ unsigned long domain_page_map_to_mfn(const void *ptr)
     unsigned long offset = (va>>THIRD_SHIFT) & LPAE_ENTRY_MASK;
 
     if ( va >= VMAP_VIRT_START && va < VMAP_VIRT_END )
-        return virt_to_mfn(va);
+        return __virt_to_mfn(va);
 
     ASSERT(slot >= 0 && slot < DOMHEAP_ENTRIES);
     ASSERT(map[slot].pt.avail != 0);
@@ -764,7 +768,7 @@ int init_secondary_pagetables(int cpu)
      * domheap mapping pages. */
     for ( i = 0; i < DOMHEAP_SECOND_PAGES; i++ )
     {
-        pte = mfn_to_xen_entry(_mfn(virt_to_mfn(domheap+i*LPAE_ENTRIES)),
+        pte = mfn_to_xen_entry(virt_to_mfn(domheap+i*LPAE_ENTRIES),
                                WRITEALLOC);
         pte.pt.table = 1;
         write_pte(&first[first_table_offset(DOMHEAP_VIRT_START+i*FIRST_SIZE)], pte);
@@ -961,7 +965,7 @@ static int create_xen_table(lpae_t *entry)
     if ( p == NULL )
         return -ENOMEM;
     clear_page(p);
-    pte = mfn_to_xen_entry(_mfn(virt_to_mfn(p)), WRITEALLOC);
+    pte = mfn_to_xen_entry(virt_to_mfn(p), WRITEALLOC);
     pte.pt.table = 1;
     write_pte(entry, pte);
     return 0;
@@ -1216,7 +1220,7 @@ int xenmem_add_to_physmap_one(
     unsigned long idx,
     gfn_t gfn)
 {
-    unsigned long mfn = 0;
+    mfn_t mfn = INVALID_MFN;
     int rc;
     p2m_type_t t;
     struct page_info *page = NULL;
@@ -1302,7 +1306,7 @@ int xenmem_add_to_physmap_one(
             return -EINVAL;
         }
 
-        mfn = page_to_mfn(page);
+        mfn = _mfn(page_to_mfn(page));
         t = p2m_map_foreign;
 
         rcu_unlock_domain(od);
@@ -1321,7 +1325,7 @@ int xenmem_add_to_physmap_one(
     }
 
     /* Map at new location. */
-    rc = guest_physmap_add_entry(d, gfn, _mfn(mfn), 0, t);
+    rc = guest_physmap_add_entry(d, gfn, mfn, 0, t);
 
     /* If we fail to add the mapping, we need to drop the reference we
      * took earlier on foreign pages */
diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h
index b2e7ea7761..6e2b3c7f2b 100644
--- a/xen/include/asm-arm/mm.h
+++ b/xen/include/asm-arm/mm.h
@@ -264,7 +264,7 @@ static inline int gvirt_to_maddr(vaddr_t va, paddr_t *pa, unsigned int flags)
 #define __va(x)             (maddr_to_virt(x))
 
 /* Convert between Xen-heap virtual addresses and machine frame numbers. */
-#define virt_to_mfn(va)   (virt_to_maddr(va) >> PAGE_SHIFT)
+#define __virt_to_mfn(va) (virt_to_maddr(va) >> PAGE_SHIFT)
 #define mfn_to_virt(mfn)  (maddr_to_virt((paddr_t)(mfn) << PAGE_SHIFT))
 
 /*
@@ -274,6 +274,7 @@ static inline int gvirt_to_maddr(vaddr_t va, paddr_t *pa, unsigned int flags)
  */
 #define mfn_to_page(mfn)    __mfn_to_page(mfn)
 #define page_to_mfn(pg)     __page_to_mfn(pg)
+#define virt_to_mfn(va)     __virt_to_mfn(va)
 
 /* Convert between Xen-heap virtual addresses and page-info structures. */
 static inline struct page_info *virt_to_page(const void *v)
-- 
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[PATCH v2 06/16] xen/arm: domain_build: Redefine virt_to_mfn to support typesafe

[Julien Grall]

The file xen/arch/arm/domain_build.c is using typesafe MFN in most of
the place. The only caller to virt_to_mfn is using prefixed with
_mfn(...).

To avoid extra _mfn(...), re-define virt_to_mfn within
arch/arm/domain_build.c to handle typesafe MFN.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
---
    Changes in v2:
        - Add Stefano's reviewed-by
---
 xen/arch/arm/domain_build.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index c6776d76fc..1bec4fa23d 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -45,6 +45,10 @@ struct map_range_data
     p2m_type_t p2mt;
 };
 
+/* Override macros from asm/page.h to make them work with mfn_t */
+#undef virt_to_mfn
+#define virt_to_mfn(va) _mfn(__virt_to_mfn(va))
+
 //#define DEBUG_11_ALLOCATION
 #ifdef DEBUG_11_ALLOCATION
 # define D11PRINT(fmt, args...) printk(XENLOG_DEBUG fmt, ##args)
@@ -1903,7 +1907,7 @@ static int prepare_acpi(struct domain *d, struct kernel_info *kinfo)
     rc = map_regions_p2mt(d,
                           gaddr_to_gfn(d->arch.efi_acpi_gpa),
                           PFN_UP(d->arch.efi_acpi_len),
-                          _mfn(virt_to_mfn(d->arch.efi_acpi_table)),
+                          virt_to_mfn(d->arch.efi_acpi_table),
                           p2m_mmio_direct_c);
     if ( rc != 0 )
     {
-- 
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[PATCH v2 07/16] xen/arm: alternative: Redefine virt_to_mfn to support typesafe

[Julien Grall]

The file xen/arch/arm/alternative.c is using typesafe MFN in most of
the place. The only caller to virt_to_mfn is using with _mfn(...).

To avoid extra _mfn(...), re-define virt_to_mfn within
xen/arch/arm/alternative.c to handle typesafe MFN.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabelllini <sstabellini@kernel.org>
---
    Changes in v2:
        - Add Stefano's reviewed-by
---
 xen/arch/arm/alternative.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/alternative.c b/xen/arch/arm/alternative.c
index 4d7e5b6155..a3bcda3117 100644
--- a/xen/arch/arm/alternative.c
+++ b/xen/arch/arm/alternative.c
@@ -32,6 +32,10 @@
 #include <asm/insn.h>
 #include <asm/page.h>
 
+/* Override macros from asm/page.h to make them work with mfn_t */
+#undef virt_to_mfn
+#define virt_to_mfn(va) _mfn(__virt_to_mfn(va))
+
 extern const struct alt_instr __alt_instructions[], __alt_instructions_end[];
 
 struct alt_region {
@@ -154,7 +158,7 @@ static int __apply_alternatives_multi_stop(void *unused)
     {
         int ret;
         struct alt_region region;
-        mfn_t xen_mfn = _mfn(virt_to_mfn(_start));
+        mfn_t xen_mfn = virt_to_mfn(_start);
         paddr_t xen_size = _end - _start;
         unsigned int xen_order = get_order_from_bytes(xen_size);
         void *xenmap;
-- 
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[PATCH v2 08/16] xen/arm: livepatch: Redefine virt_to_mfn to support typesafe

[Julien Grall]

The file xen/arch/arm/livepatch.c is using typesafe MFN in most of
the place. The only caller to virt_to_mfn is using with _mfn(...).

To avoid extra _mfn(...), re-define virt_to_mfn within
xen/arch/arm/livepatch.c to handle typesafe MFN.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
---

Cc: Ross Lagerwall <ross.lagerwall@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

    Changes in v2:
        - Add Stefano's reviewed-by
        - Still missing an ack from Konrad and/or Ross.
---
 xen/arch/arm/livepatch.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/livepatch.c b/xen/arch/arm/livepatch.c
index de95e54744..3e53524365 100644
--- a/xen/arch/arm/livepatch.c
+++ b/xen/arch/arm/livepatch.c
@@ -12,6 +12,10 @@
 #include <asm/livepatch.h>
 #include <asm/mm.h>
 
+/* Override macros from asm/page.h to make them work with mfn_t */
+#undef virt_to_mfn
+#define virt_to_mfn(va) _mfn(__virt_to_mfn(va))
+
 void *vmap_of_xen_text;
 
 int arch_livepatch_quiesce(void)
@@ -22,7 +26,7 @@ int arch_livepatch_quiesce(void)
     if ( vmap_of_xen_text )
         return -EINVAL;
 
-    text_mfn = _mfn(virt_to_mfn(_start));
+    text_mfn = virt_to_mfn(_start);
     text_order = get_order_from_bytes(_end - _start);
 
     /*
-- 
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[PATCH v2 09/16] xen/arm: create_xen_entries: Use typesafe MFN

[Julien Grall]

Add a bit more safety when using create_xen_entries.

Also when destroying/modifying mapping, the MFN is currently not used.
Rather than passing _mfn(0) use INVALID_MFN to stay consistent with the
other usage.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

---
    Changes in v2:
        - Add Stefano's reviewed-by
---
 xen/arch/arm/mm.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 5612834dfc..8d34ae7279 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -980,7 +980,7 @@ enum xenmap_operation {
 
 static int create_xen_entries(enum xenmap_operation op,
                               unsigned long virt,
-                              unsigned long mfn,
+                              mfn_t mfn,
                               unsigned long nr_mfns,
                               unsigned int ai)
 {
@@ -989,7 +989,7 @@ static int create_xen_entries(enum xenmap_operation op,
     lpae_t pte;
     lpae_t *third = NULL;
 
-    for(; addr < addr_end; addr += PAGE_SIZE, mfn++)
+    for(; addr < addr_end; addr += PAGE_SIZE, mfn = mfn_add(mfn, 1))
     {
         if ( !xen_second[second_linear_offset(addr)].pt.valid ||
              !xen_second[second_linear_offset(addr)].pt.table )
@@ -1010,13 +1010,13 @@ static int create_xen_entries(enum xenmap_operation op,
             case RESERVE:
                 if ( third[third_table_offset(addr)].pt.valid )
                 {
-                    printk("create_xen_entries: trying to replace an existing mapping addr=%lx mfn=%lx\n",
-                           addr, mfn);
+                    printk("create_xen_entries: trying to replace an existing mapping addr=%lx mfn=%"PRI_mfn"\n",
+                           addr, mfn_x(mfn));
                     return -EINVAL;
                 }
                 if ( op == RESERVE )
                     break;
-                pte = mfn_to_xen_entry(_mfn(mfn), ai);
+                pte = mfn_to_xen_entry(mfn, ai);
                 pte.pt.table = 1;
                 write_pte(&third[third_table_offset(addr)], pte);
                 break;
@@ -1061,24 +1061,25 @@ int map_pages_to_xen(unsigned long virt,
                      unsigned long nr_mfns,
                      unsigned int flags)
 {
-    return create_xen_entries(INSERT, virt, mfn, nr_mfns, flags);
+    return create_xen_entries(INSERT, virt, _mfn(mfn), nr_mfns, flags);
 }
 
 int populate_pt_range(unsigned long virt, unsigned long mfn,
                       unsigned long nr_mfns)
 {
-    return create_xen_entries(RESERVE, virt, mfn, nr_mfns, 0);
+    return create_xen_entries(RESERVE, virt, _mfn(mfn), nr_mfns, 0);
 }
 
 int destroy_xen_mappings(unsigned long v, unsigned long e)
 {
-    return create_xen_entries(REMOVE, v, 0, (e - v) >> PAGE_SHIFT, 0);
+    return create_xen_entries(REMOVE, v, INVALID_MFN, (e - v) >> PAGE_SHIFT, 0);
 }
 
 int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int flags)
 {
     ASSERT((flags & (PTE_NX | PTE_RO)) == flags);
-    return create_xen_entries(MODIFY, s, 0, (e - s) >> PAGE_SHIFT, flags);
+    return create_xen_entries(MODIFY, s, INVALID_MFN, (e - s) >> PAGE_SHIFT,
+                              flags);
 }
 
 enum mg { mg_clear, mg_ro, mg_rw, mg_rx };
-- 
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[PATCH v2 10/16] xen/arm: Move LPAE definition in a separate header

[Julien Grall]

page.h is getting bigger. Move out every LPAE definitions in a separate
header. There is no functional changes.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

---

Cc: proskurin@sec.in.tum.de

    Changes in v2:
        - Move comment after the #endif rather than before
        - Add Stefano's reviewed-by
---
 xen/include/asm-arm/lpae.h | 169 +++++++++++++++++++++++++++++++++++++++++++++
 xen/include/asm-arm/page.h | 152 +---------------------------------------
 2 files changed, 170 insertions(+), 151 deletions(-)
 create mode 100644 xen/include/asm-arm/lpae.h

diff --git a/xen/include/asm-arm/lpae.h b/xen/include/asm-arm/lpae.h
new file mode 100644
index 0000000000..ad8c571ea5
--- /dev/null
+++ b/xen/include/asm-arm/lpae.h
@@ -0,0 +1,169 @@
+#ifndef __ARM_LPAE_H__
+#define __ARM_LPAE_H__
+
+#ifndef __ASSEMBLY__
+
+/* WARNING!  Unlike the Intel pagetable code, where l1 is the lowest
+ * level and l4 is the root of the trie, the ARM pagetables follow ARM's
+ * documentation: the levels are called first, second &c in the order
+ * that the MMU walks them (i.e. "first" is the root of the trie). */
+
+/******************************************************************************
+ * ARMv7-A LPAE pagetables: 3-level trie, mapping 40-bit input to
+ * 40-bit output addresses.  Tables at all levels have 512 64-bit entries
+ * (i.e. are 4Kb long).
+ *
+ * The bit-shuffling that has the permission bits in branch nodes in a
+ * different place from those in leaf nodes seems to be to allow linear
+ * pagetable tricks.  If we're not doing that then the set of permission
+ * bits that's not in use in a given node type can be used as
+ * extra software-defined bits. */
+
+typedef struct __packed {
+    /* These are used in all kinds of entry. */
+    unsigned long valid:1;      /* Valid mapping */
+    unsigned long table:1;      /* == 1 in 4k map entries too */
+
+    /* These ten bits are only used in Block entries and are ignored
+     * in Table entries. */
+    unsigned long ai:3;         /* Attribute Index */
+    unsigned long ns:1;         /* Not-Secure */
+    unsigned long user:1;       /* User-visible */
+    unsigned long ro:1;         /* Read-Only */
+    unsigned long sh:2;         /* Shareability */
+    unsigned long af:1;         /* Access Flag */
+    unsigned long ng:1;         /* Not-Global */
+
+    /* The base address must be appropriately aligned for Block entries */
+    unsigned long long base:36; /* Base address of block or next table */
+    unsigned long sbz:4;        /* Must be zero */
+
+    /* These seven bits are only used in Block entries and are ignored
+     * in Table entries. */
+    unsigned long contig:1;     /* In a block of 16 contiguous entries */
+    unsigned long pxn:1;        /* Privileged-XN */
+    unsigned long xn:1;         /* eXecute-Never */
+    unsigned long avail:4;      /* Ignored by hardware */
+
+    /* These 5 bits are only used in Table entries and are ignored in
+     * Block entries */
+    unsigned long pxnt:1;       /* Privileged-XN */
+    unsigned long xnt:1;        /* eXecute-Never */
+    unsigned long apt:2;        /* Access Permissions */
+    unsigned long nst:1;        /* Not-Secure */
+} lpae_pt_t;
+
+/* The p2m tables have almost the same layout, but some of the permission
+ * and cache-control bits are laid out differently (or missing) */
+typedef struct __packed {
+    /* These are used in all kinds of entry. */
+    unsigned long valid:1;      /* Valid mapping */
+    unsigned long table:1;      /* == 1 in 4k map entries too */
+
+    /* These ten bits are only used in Block entries and are ignored
+     * in Table entries. */
+    unsigned long mattr:4;      /* Memory Attributes */
+    unsigned long read:1;       /* Read access */
+    unsigned long write:1;      /* Write access */
+    unsigned long sh:2;         /* Shareability */
+    unsigned long af:1;         /* Access Flag */
+    unsigned long sbz4:1;
+
+    /* The base address must be appropriately aligned for Block entries */
+    unsigned long long base:36; /* Base address of block or next table */
+    unsigned long sbz3:4;
+
+    /* These seven bits are only used in Block entries and are ignored
+     * in Table entries. */
+    unsigned long contig:1;     /* In a block of 16 contiguous entries */
+    unsigned long sbz2:1;
+    unsigned long xn:1;         /* eXecute-Never */
+    unsigned long type:4;       /* Ignore by hardware. Used to store p2m types */
+
+    unsigned long sbz1:5;
+} lpae_p2m_t;
+
+/* Permission mask: xn, write, read */
+#define P2M_PERM_MASK (0x00400000000000C0ULL)
+#define P2M_CLEAR_PERM(pte) ((pte).bits & ~P2M_PERM_MASK)
+
+/*
+ * Walk is the common bits of p2m and pt entries which are needed to
+ * simply walk the table (e.g. for debug).
+ */
+typedef struct __packed {
+    /* These are used in all kinds of entry. */
+    unsigned long valid:1;      /* Valid mapping */
+    unsigned long table:1;      /* == 1 in 4k map entries too */
+
+    unsigned long pad2:10;
+
+    /* The base address must be appropriately aligned for Block entries */
+    unsigned long long base:36; /* Base address of block or next table */
+
+    unsigned long pad1:16;
+} lpae_walk_t;
+
+typedef union {
+    uint64_t bits;
+    lpae_pt_t pt;
+    lpae_p2m_t p2m;
+    lpae_walk_t walk;
+} lpae_t;
+
+#endif /* __ASSEMBLY__ */
+
+/*
+ * These numbers add up to a 48-bit input address space.
+ *
+ * On 32-bit the zeroeth level does not exist, therefore the total is
+ * 39-bits. The ARMv7-A architecture actually specifies a 40-bit input
+ * address space for the p2m, with an 8K (1024-entry) top-level table.
+ * However Xen only supports 16GB of RAM on 32-bit ARM systems and
+ * therefore 39-bits are sufficient.
+ */
+
+#define LPAE_SHIFT      9
+#define LPAE_ENTRIES    (_AC(1,U) << LPAE_SHIFT)
+#define LPAE_ENTRY_MASK (LPAE_ENTRIES - 1)
+
+#define THIRD_SHIFT    (PAGE_SHIFT)
+#define THIRD_ORDER    (THIRD_SHIFT - PAGE_SHIFT)
+#define THIRD_SIZE     ((paddr_t)1 << THIRD_SHIFT)
+#define THIRD_MASK     (~(THIRD_SIZE - 1))
+#define SECOND_SHIFT   (THIRD_SHIFT + LPAE_SHIFT)
+#define SECOND_ORDER   (SECOND_SHIFT - PAGE_SHIFT)
+#define SECOND_SIZE    ((paddr_t)1 << SECOND_SHIFT)
+#define SECOND_MASK    (~(SECOND_SIZE - 1))
+#define FIRST_SHIFT    (SECOND_SHIFT + LPAE_SHIFT)
+#define FIRST_ORDER    (FIRST_SHIFT - PAGE_SHIFT)
+#define FIRST_SIZE     ((paddr_t)1 << FIRST_SHIFT)
+#define FIRST_MASK     (~(FIRST_SIZE - 1))
+#define ZEROETH_SHIFT  (FIRST_SHIFT + LPAE_SHIFT)
+#define ZEROETH_ORDER  (ZEROETH_SHIFT - PAGE_SHIFT)
+#define ZEROETH_SIZE   ((paddr_t)1 << ZEROETH_SHIFT)
+#define ZEROETH_MASK   (~(ZEROETH_SIZE - 1))
+
+/* Calculate the offsets into the pagetables for a given VA */
+#define zeroeth_linear_offset(va) ((va) >> ZEROETH_SHIFT)
+#define first_linear_offset(va) ((va) >> FIRST_SHIFT)
+#define second_linear_offset(va) ((va) >> SECOND_SHIFT)
+#define third_linear_offset(va) ((va) >> THIRD_SHIFT)
+
+#define TABLE_OFFSET(offs) ((unsigned int)(offs) & LPAE_ENTRY_MASK)
+#define first_table_offset(va)  TABLE_OFFSET(first_linear_offset(va))
+#define second_table_offset(va) TABLE_OFFSET(second_linear_offset(va))
+#define third_table_offset(va)  TABLE_OFFSET(third_linear_offset(va))
+#define zeroeth_table_offset(va)  TABLE_OFFSET(zeroeth_linear_offset(va))
+
+#endif /* __ARM_LPAE_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h
index 3670ab665d..cef2f28914 100644
--- a/xen/include/asm-arm/page.h
+++ b/xen/include/asm-arm/page.h
@@ -3,6 +3,7 @@
 
 #include <public/xen.h>
 #include <asm/processor.h>
+#include <asm/lpae.h>
 
 #ifdef CONFIG_ARM_64
 #define PADDR_BITS              48
@@ -97,114 +98,6 @@
 #include <xen/lib.h>
 #include <asm/system.h>
 
-/* WARNING!  Unlike the Intel pagetable code, where l1 is the lowest
- * level and l4 is the root of the trie, the ARM pagetables follow ARM's
- * documentation: the levels are called first, second &c in the order
- * that the MMU walks them (i.e. "first" is the root of the trie). */
-
-/******************************************************************************
- * ARMv7-A LPAE pagetables: 3-level trie, mapping 40-bit input to
- * 40-bit output addresses.  Tables at all levels have 512 64-bit entries
- * (i.e. are 4Kb long).
- *
- * The bit-shuffling that has the permission bits in branch nodes in a
- * different place from those in leaf nodes seems to be to allow linear
- * pagetable tricks.  If we're not doing that then the set of permission
- * bits that's not in use in a given node type can be used as
- * extra software-defined bits. */
-
-typedef struct __packed {
-    /* These are used in all kinds of entry. */
-    unsigned long valid:1;      /* Valid mapping */
-    unsigned long table:1;      /* == 1 in 4k map entries too */
-
-    /* These ten bits are only used in Block entries and are ignored
-     * in Table entries. */
-    unsigned long ai:3;         /* Attribute Index */
-    unsigned long ns:1;         /* Not-Secure */
-    unsigned long user:1;       /* User-visible */
-    unsigned long ro:1;         /* Read-Only */
-    unsigned long sh:2;         /* Shareability */
-    unsigned long af:1;         /* Access Flag */
-    unsigned long ng:1;         /* Not-Global */
-
-    /* The base address must be appropriately aligned for Block entries */
-    unsigned long long base:36; /* Base address of block or next table */
-    unsigned long sbz:4;        /* Must be zero */
-
-    /* These seven bits are only used in Block entries and are ignored
-     * in Table entries. */
-    unsigned long contig:1;     /* In a block of 16 contiguous entries */
-    unsigned long pxn:1;        /* Privileged-XN */
-    unsigned long xn:1;         /* eXecute-Never */
-    unsigned long avail:4;      /* Ignored by hardware */
-
-    /* These 5 bits are only used in Table entries and are ignored in
-     * Block entries */
-    unsigned long pxnt:1;       /* Privileged-XN */
-    unsigned long xnt:1;        /* eXecute-Never */
-    unsigned long apt:2;        /* Access Permissions */
-    unsigned long nst:1;        /* Not-Secure */
-} lpae_pt_t;
-
-/* The p2m tables have almost the same layout, but some of the permission
- * and cache-control bits are laid out differently (or missing) */
-typedef struct __packed {
-    /* These are used in all kinds of entry. */
-    unsigned long valid:1;      /* Valid mapping */
-    unsigned long table:1;      /* == 1 in 4k map entries too */
-
-    /* These ten bits are only used in Block entries and are ignored
-     * in Table entries. */
-    unsigned long mattr:4;      /* Memory Attributes */
-    unsigned long read:1;       /* Read access */
-    unsigned long write:1;      /* Write access */
-    unsigned long sh:2;         /* Shareability */
-    unsigned long af:1;         /* Access Flag */
-    unsigned long sbz4:1;
-
-    /* The base address must be appropriately aligned for Block entries */
-    unsigned long long base:36; /* Base address of block or next table */
-    unsigned long sbz3:4;
-
-    /* These seven bits are only used in Block entries and are ignored
-     * in Table entries. */
-    unsigned long contig:1;     /* In a block of 16 contiguous entries */
-    unsigned long sbz2:1;
-    unsigned long xn:1;         /* eXecute-Never */
-    unsigned long type:4;       /* Ignore by hardware. Used to store p2m types */
-
-    unsigned long sbz1:5;
-} lpae_p2m_t;
-
-/* Permission mask: xn, write, read */
-#define P2M_PERM_MASK (0x00400000000000C0ULL)
-#define P2M_CLEAR_PERM(pte) ((pte).bits & ~P2M_PERM_MASK)
-
-/*
- * Walk is the common bits of p2m and pt entries which are needed to
- * simply walk the table (e.g. for debug).
- */
-typedef struct __packed {
-    /* These are used in all kinds of entry. */
-    unsigned long valid:1;      /* Valid mapping */
-    unsigned long table:1;      /* == 1 in 4k map entries too */
-
-    unsigned long pad2:10;
-
-    /* The base address must be appropriately aligned for Block entries */
-    unsigned long long base:36; /* Base address of block or next table */
-
-    unsigned long pad1:16;
-} lpae_walk_t;
-
-typedef union {
-    uint64_t bits;
-    lpae_pt_t pt;
-    lpae_p2m_t p2m;
-    lpae_walk_t walk;
-} lpae_t;
-
 #if defined(CONFIG_ARM_32)
 # include <asm/arm32/page.h>
 #elif defined(CONFIG_ARM_64)
@@ -390,49 +283,6 @@ static inline int gva_to_ipa(vaddr_t va, paddr_t *paddr, unsigned int flags)
 
 #endif /* __ASSEMBLY__ */
 
-/*
- * These numbers add up to a 48-bit input address space.
- *
- * On 32-bit the zeroeth level does not exist, therefore the total is
- * 39-bits. The ARMv7-A architecture actually specifies a 40-bit input
- * address space for the p2m, with an 8K (1024-entry) top-level table.
- * However Xen only supports 16GB of RAM on 32-bit ARM systems and
- * therefore 39-bits are sufficient.
- */
-
-#define LPAE_SHIFT      9
-#define LPAE_ENTRIES    (_AC(1,U) << LPAE_SHIFT)
-#define LPAE_ENTRY_MASK (LPAE_ENTRIES - 1)
-
-#define THIRD_SHIFT    (PAGE_SHIFT)
-#define THIRD_ORDER    (THIRD_SHIFT - PAGE_SHIFT)
-#define THIRD_SIZE     ((paddr_t)1 << THIRD_SHIFT)
-#define THIRD_MASK     (~(THIRD_SIZE - 1))
-#define SECOND_SHIFT   (THIRD_SHIFT + LPAE_SHIFT)
-#define SECOND_ORDER   (SECOND_SHIFT - PAGE_SHIFT)
-#define SECOND_SIZE    ((paddr_t)1 << SECOND_SHIFT)
-#define SECOND_MASK    (~(SECOND_SIZE - 1))
-#define FIRST_SHIFT    (SECOND_SHIFT + LPAE_SHIFT)
-#define FIRST_ORDER    (FIRST_SHIFT - PAGE_SHIFT)
-#define FIRST_SIZE     ((paddr_t)1 << FIRST_SHIFT)
-#define FIRST_MASK     (~(FIRST_SIZE - 1))
-#define ZEROETH_SHIFT  (FIRST_SHIFT + LPAE_SHIFT)
-#define ZEROETH_ORDER  (ZEROETH_SHIFT - PAGE_SHIFT)
-#define ZEROETH_SIZE   ((paddr_t)1 << ZEROETH_SHIFT)
-#define ZEROETH_MASK   (~(ZEROETH_SIZE - 1))
-
-/* Calculate the offsets into the pagetables for a given VA */
-#define zeroeth_linear_offset(va) ((va) >> ZEROETH_SHIFT)
-#define first_linear_offset(va) ((va) >> FIRST_SHIFT)
-#define second_linear_offset(va) ((va) >> SECOND_SHIFT)
-#define third_linear_offset(va) ((va) >> THIRD_SHIFT)
-
-#define TABLE_OFFSET(offs) ((unsigned int)(offs) & LPAE_ENTRY_MASK)
-#define first_table_offset(va)  TABLE_OFFSET(first_linear_offset(va))
-#define second_table_offset(va) TABLE_OFFSET(second_linear_offset(va))
-#define third_table_offset(va)  TABLE_OFFSET(third_linear_offset(va))
-#define zeroeth_table_offset(va)  TABLE_OFFSET(zeroeth_linear_offset(va))
-
 #define PAGE_ALIGN(x) (((x) + PAGE_SIZE - 1) & PAGE_MASK)
 
 #endif /* __ARM_PAGE_H__ */
-- 
2.11.0


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[PATCH v2 11/16] xen/arm: lpae: Fix comments coding style

[Julien Grall]

Also adding one missing full stop + fix description

Signed-off-by: Julien Grall <julien.grall@arm.com>
---

Cc: proskurin@sec.in.tum.de

    I haven't retained Stefano's reviewed-by because of the description
    update.

   Changes in v2:
        - Fix description regarding x86 page-table
---
 xen/include/asm-arm/lpae.h | 49 ++++++++++++++++++++++++++++++----------------
 1 file changed, 32 insertions(+), 17 deletions(-)

diff --git a/xen/include/asm-arm/lpae.h b/xen/include/asm-arm/lpae.h
index ad8c571ea5..aa85cb8112 100644
--- a/xen/include/asm-arm/lpae.h
+++ b/xen/include/asm-arm/lpae.h
@@ -3,10 +3,12 @@
 
 #ifndef __ASSEMBLY__
 
-/* WARNING!  Unlike the Intel pagetable code, where l1 is the lowest
- * level and l4 is the root of the trie, the ARM pagetables follow ARM's
- * documentation: the levels are called first, second &c in the order
- * that the MMU walks them (i.e. "first" is the root of the trie). */
+/*
+ * WARNING!  Unlike the x86 pagetable code, where l1 is the lowest level and
+ * l4 is the root of the trie, the ARM pagetables follow ARM's documentation:
+ * the levels are called first, second &c in the order that the MMU walks them
+ * (i.e. "first" is the root of the trie).
+ */
 
 /******************************************************************************
  * ARMv7-A LPAE pagetables: 3-level trie, mapping 40-bit input to
@@ -17,15 +19,18 @@
  * different place from those in leaf nodes seems to be to allow linear
  * pagetable tricks.  If we're not doing that then the set of permission
  * bits that's not in use in a given node type can be used as
- * extra software-defined bits. */
+ * extra software-defined bits.
+ */
 
 typedef struct __packed {
     /* These are used in all kinds of entry. */
     unsigned long valid:1;      /* Valid mapping */
     unsigned long table:1;      /* == 1 in 4k map entries too */
 
-    /* These ten bits are only used in Block entries and are ignored
-     * in Table entries. */
+    /*
+     * These ten bits are only used in Block entries and are ignored
+     * in Table entries.
+     */
     unsigned long ai:3;         /* Attribute Index */
     unsigned long ns:1;         /* Not-Secure */
     unsigned long user:1;       /* User-visible */
@@ -38,30 +43,38 @@ typedef struct __packed {
     unsigned long long base:36; /* Base address of block or next table */
     unsigned long sbz:4;        /* Must be zero */
 
-    /* These seven bits are only used in Block entries and are ignored
-     * in Table entries. */
+    /*
+     * These seven bits are only used in Block entries and are ignored
+     * in Table entries.
+     */
     unsigned long contig:1;     /* In a block of 16 contiguous entries */
     unsigned long pxn:1;        /* Privileged-XN */
     unsigned long xn:1;         /* eXecute-Never */
     unsigned long avail:4;      /* Ignored by hardware */
 
-    /* These 5 bits are only used in Table entries and are ignored in
-     * Block entries */
+    /*
+     * These 5 bits are only used in Table entries and are ignored in
+     * Block entries.
+     */
     unsigned long pxnt:1;       /* Privileged-XN */
     unsigned long xnt:1;        /* eXecute-Never */
     unsigned long apt:2;        /* Access Permissions */
     unsigned long nst:1;        /* Not-Secure */
 } lpae_pt_t;
 
-/* The p2m tables have almost the same layout, but some of the permission
- * and cache-control bits are laid out differently (or missing) */
+/*
+ * The p2m tables have almost the same layout, but some of the permission
+ * and cache-control bits are laid out differently (or missing).
+ */
 typedef struct __packed {
     /* These are used in all kinds of entry. */
     unsigned long valid:1;      /* Valid mapping */
     unsigned long table:1;      /* == 1 in 4k map entries too */
 
-    /* These ten bits are only used in Block entries and are ignored
-     * in Table entries. */
+    /*
+     * These ten bits are only used in Block entries and are ignored
+     * in Table entries.
+     */
     unsigned long mattr:4;      /* Memory Attributes */
     unsigned long read:1;       /* Read access */
     unsigned long write:1;      /* Write access */
@@ -73,8 +86,10 @@ typedef struct __packed {
     unsigned long long base:36; /* Base address of block or next table */
     unsigned long sbz3:4;
 
-    /* These seven bits are only used in Block entries and are ignored
-     * in Table entries. */
+    /*
+     * These seven bits are only used in Block entries and are ignored
+     * in Table entries.
+     */
     unsigned long contig:1;     /* In a block of 16 contiguous entries */
     unsigned long sbz2:1;
     unsigned long xn:1;         /* eXecute-Never */
-- 
2.11.0


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[PATCH v2 12/16] xen/arm: p2m: Rename p2m_valid, p2m_table, p2m_mapping and p2m_is_superpage

[Julien Grall]

The helpers p2m_valid, p2m_table, p2m_mapping and p2m_is_superpage are
not specific to the stage-2 translation tables. They can also work on
any LPAE translation tables. So rename then to lpae_* and use pte.walk
to look for the value of the field.

Signed-off-by: Julien Grall <julien.grall@arm.com>
---

Cc: proskurin@sec.in.tum.de

    Changes in v2:
        - Patch added
---
 xen/arch/arm/p2m.c | 45 +++++++++++++++++++++++----------------------
 1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 6c1ac70044..1136d837fb 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -52,27 +52,27 @@ static const paddr_t level_masks[] =
 static const uint8_t level_orders[] =
     { ZEROETH_ORDER, FIRST_ORDER, SECOND_ORDER, THIRD_ORDER };
 
-static inline bool_t p2m_valid(lpae_t pte)
+static inline bool_t lpae_valid(lpae_t pte)
 {
-    return pte.p2m.valid;
+    return pte.walk.valid;
 }
 /*
  * These two can only be used on L0..L2 ptes because L3 mappings set
  * the table bit and therefore these would return the opposite to what
  * you would expect.
  */
-static inline bool_t p2m_table(lpae_t pte)
+static inline bool_t lpae_table(lpae_t pte)
 {
-    return p2m_valid(pte) && pte.p2m.table;
+    return lpae_valid(pte) && pte.walk.table;
 }
-static inline bool_t p2m_mapping(lpae_t pte)
+static inline bool_t lpae_mapping(lpae_t pte)
 {
-    return p2m_valid(pte) && !pte.p2m.table;
+    return lpae_valid(pte) && !pte.walk.table;
 }
 
-static inline bool p2m_is_superpage(lpae_t pte, unsigned int level)
+static inline bool lpae_is_superpage(lpae_t pte, unsigned int level)
 {
-    return (level < 3) && p2m_mapping(pte);
+    return (level < 3) && lpae_mapping(pte);
 }
 
 static void p2m_flush_tlb(struct p2m_domain *p2m);
@@ -281,7 +281,7 @@ static int p2m_next_level(struct p2m_domain *p2m, bool read_only,
 
     entry = *table + offset;
 
-    if ( !p2m_valid(*entry) )
+    if ( !lpae_valid(*entry) )
     {
         if ( read_only )
             return GUEST_TABLE_MAP_FAILED;
@@ -292,7 +292,7 @@ static int p2m_next_level(struct p2m_domain *p2m, bool read_only,
     }
 
     /* The function p2m_next_level is never called at the 3rd level */
-    if ( p2m_mapping(*entry) )
+    if ( lpae_mapping(*entry) )
         return GUEST_TABLE_SUPER_PAGE;
 
     mfn = _mfn(entry->p2m.base);
@@ -372,7 +372,7 @@ mfn_t p2m_get_entry(struct p2m_domain *p2m, gfn_t gfn,
 
     entry = table[offsets[level]];
 
-    if ( p2m_valid(entry) )
+    if ( lpae_valid(entry) )
     {
         *t = entry.p2m.type;
 
@@ -577,7 +577,7 @@ static int p2m_create_table(struct p2m_domain *p2m, lpae_t *entry)
     lpae_t *p;
     lpae_t pte;
 
-    ASSERT(!p2m_valid(*entry));
+    ASSERT(!lpae_valid(*entry));
 
     page = alloc_domheap_page(NULL, 0);
     if ( page == NULL )
@@ -645,7 +645,7 @@ enum p2m_operation {
  */
 static void p2m_put_l3_page(const lpae_t pte)
 {
-    ASSERT(p2m_valid(pte));
+    ASSERT(lpae_valid(pte));
 
     /*
      * TODO: Handle other p2m types
@@ -673,11 +673,11 @@ static void p2m_free_entry(struct p2m_domain *p2m,
     struct page_info *pg;
 
     /* Nothing to do if the entry is invalid. */
-    if ( !p2m_valid(entry) )
+    if ( !lpae_valid(entry) )
         return;
 
     /* Nothing to do but updating the stats if the entry is a super-page. */
-    if ( p2m_is_superpage(entry, level) )
+    if ( lpae_is_superpage(entry, level) )
     {
         p2m->stats.mappings[level]--;
         return;
@@ -733,7 +733,7 @@ static bool p2m_split_superpage(struct p2m_domain *p2m, lpae_t *entry,
      * a superpage.
      */
     ASSERT(level < target);
-    ASSERT(p2m_is_superpage(*entry, level));
+    ASSERT(lpae_is_superpage(*entry, level));
 
     page = alloc_domheap_page(NULL, 0);
     if ( !page )
@@ -870,7 +870,7 @@ static int __p2m_set_entry(struct p2m_domain *p2m,
         /* We need to split the original page. */
         lpae_t split_pte = *entry;
 
-        ASSERT(p2m_is_superpage(*entry, level));
+        ASSERT(lpae_is_superpage(*entry, level));
 
         if ( !p2m_split_superpage(p2m, &split_pte, level, target, offsets) )
         {
@@ -944,12 +944,12 @@ static int __p2m_set_entry(struct p2m_domain *p2m,
      * sequence when updating the translation table (D4.7.1 in ARM DDI
      * 0487A.j).
      */
-    if ( p2m_valid(orig_pte) )
+    if ( lpae_valid(orig_pte) )
         p2m_remove_pte(entry, p2m->clean_pte);
 
     if ( mfn_eq(smfn, INVALID_MFN) )
         /* Flush can be deferred if the entry is removed */
-        p2m->need_flush |= !!p2m_valid(orig_pte);
+        p2m->need_flush |= !!lpae_valid(orig_pte);
     else
     {
         lpae_t pte = mfn_to_p2m_entry(smfn, t, a);
@@ -964,7 +964,7 @@ static int __p2m_set_entry(struct p2m_domain *p2m,
          * Although, it could be defered when only the permissions are
          * changed (e.g in case of memaccess).
          */
-        if ( p2m_valid(orig_pte) )
+        if ( lpae_valid(orig_pte) )
         {
             if ( likely(!p2m->mem_access_enabled) ||
                  P2M_CLEAR_PERM(pte) != P2M_CLEAR_PERM(orig_pte) )
@@ -986,10 +986,11 @@ static int __p2m_set_entry(struct p2m_domain *p2m,
      * Free the entry only if the original pte was valid and the base
      * is different (to avoid freeing when permission is changed).
      */
-    if ( p2m_valid(orig_pte) && entry->p2m.base != orig_pte.p2m.base )
+    if ( lpae_valid(orig_pte) && entry->p2m.base != orig_pte.p2m.base )
         p2m_free_entry(p2m, orig_pte, level);
 
-    if ( need_iommu(p2m->domain) && (p2m_valid(orig_pte) || p2m_valid(*entry)) )
+    if ( need_iommu(p2m->domain) &&
+         (lpae_valid(orig_pte) || lpae_valid(*entry)) )
         rc = iommu_iotlb_flush(p2m->domain, gfn_x(sgfn), 1UL << page_order);
     else
         rc = 0;
-- 
2.11.0


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[PATCH v2 13/16] xen/arm: p2m: Move lpae_* helpers in lpae.h

[Julien Grall]

lpae_* helpers can work on any LPAE translation tables. Move them in
lpae.h to allow other part of Xen to use them.

Signed-off-by: Julien Grall <julien.grall@arm.com>
---

Cc: proskurin@sec.in.tum.de

    Changes in v2:
        - Patch added
---
 xen/arch/arm/p2m.c         | 23 -----------------------
 xen/include/asm-arm/lpae.h | 25 +++++++++++++++++++++++++
 2 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 1136d837fb..f9145f052f 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -52,29 +52,6 @@ static const paddr_t level_masks[] =
 static const uint8_t level_orders[] =
     { ZEROETH_ORDER, FIRST_ORDER, SECOND_ORDER, THIRD_ORDER };
 
-static inline bool_t lpae_valid(lpae_t pte)
-{
-    return pte.walk.valid;
-}
-/*
- * These two can only be used on L0..L2 ptes because L3 mappings set
- * the table bit and therefore these would return the opposite to what
- * you would expect.
- */
-static inline bool_t lpae_table(lpae_t pte)
-{
-    return lpae_valid(pte) && pte.walk.table;
-}
-static inline bool_t lpae_mapping(lpae_t pte)
-{
-    return lpae_valid(pte) && !pte.walk.table;
-}
-
-static inline bool lpae_is_superpage(lpae_t pte, unsigned int level)
-{
-    return (level < 3) && lpae_mapping(pte);
-}
-
 static void p2m_flush_tlb(struct p2m_domain *p2m);
 
 /* Unlock the flush and do a P2M TLB flush if necessary */
diff --git a/xen/include/asm-arm/lpae.h b/xen/include/asm-arm/lpae.h
index aa85cb8112..6fbf7c606c 100644
--- a/xen/include/asm-arm/lpae.h
+++ b/xen/include/asm-arm/lpae.h
@@ -126,6 +126,31 @@ typedef union {
     lpae_walk_t walk;
 } lpae_t;
 
+static inline bool_t lpae_valid(lpae_t pte)
+{
+    return pte.walk.valid;
+}
+
+/*
+ * These two can only be used on L0..L2 ptes because L3 mappings set
+ * the table bit and therefore these would return the opposite to what
+ * you would expect.
+ */
+static inline bool_t lpae_table(lpae_t pte)
+{
+    return lpae_valid(pte) && pte.walk.table;
+}
+
+static inline bool_t lpae_mapping(lpae_t pte)
+{
+    return lpae_valid(pte) && !pte.walk.table;
+}
+
+static inline bool lpae_is_superpage(lpae_t pte, unsigned int level)
+{
+    return (level < 3) && lpae_mapping(pte);
+}
+
 #endif /* __ASSEMBLY__ */
 
 /*
-- 
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[PATCH v2 14/16] xen/arm: mm: Use lpae_valid and lpae_table in create_xen_entries

[Julien Grall]

This newly introduced lpae_valid and lpae_table helpers will recude the
code and make more readable.

Signed-off-by: Julien Grall <julien.grall@arm.com>
---

    Changes in v2:
        - Patch added
---
 xen/arch/arm/mm.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 8d34ae7279..6241c53821 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -991,8 +991,7 @@ static int create_xen_entries(enum xenmap_operation op,
 
     for(; addr < addr_end; addr += PAGE_SIZE, mfn = mfn_add(mfn, 1))
     {
-        if ( !xen_second[second_linear_offset(addr)].pt.valid ||
-             !xen_second[second_linear_offset(addr)].pt.table )
+        if ( !lpae_table(xen_second[second_linear_offset(addr)]) )
         {
             rc = create_xen_table(&xen_second[second_linear_offset(addr)]);
             if ( rc < 0 ) {
@@ -1001,14 +1000,14 @@ static int create_xen_entries(enum xenmap_operation op,
             }
         }
 
-        BUG_ON(!xen_second[second_linear_offset(addr)].pt.valid);
+        BUG_ON(!lpae_valid(xen_second[second_linear_offset(addr)]));
 
         third = mfn_to_virt(xen_second[second_linear_offset(addr)].pt.base);
 
         switch ( op ) {
             case INSERT:
             case RESERVE:
-                if ( third[third_table_offset(addr)].pt.valid )
+                if ( lpae_valid(third[third_table_offset(addr)]) )
                 {
                     printk("create_xen_entries: trying to replace an existing mapping addr=%lx mfn=%"PRI_mfn"\n",
                            addr, mfn_x(mfn));
@@ -1022,7 +1021,7 @@ static int create_xen_entries(enum xenmap_operation op,
                 break;
             case MODIFY:
             case REMOVE:
-                if ( !third[third_table_offset(addr)].pt.valid )
+                if ( !lpae_valid(third[third_table_offset(addr)]) )
                 {
                     printk("create_xen_entries: trying to %s a non-existing mapping addr=%lx\n",
                            op == REMOVE ? "remove" : "modify", addr);
-- 
2.11.0


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[PATCH v2 15/16] xen/arm: mm: Introduce temporary variable in create_xen_entries

[Julien Grall]

This is improving the code readability and avoid to dereference the
table every single time we need to access the entry.

Signed-off-by: Julien Grall <julien.grall@arm.com>
---

    Changes in v2:
        - Patch added
---
 xen/arch/arm/mm.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 6241c53821..657fee0b17 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -986,28 +986,30 @@ static int create_xen_entries(enum xenmap_operation op,
 {
     int rc;
     unsigned long addr = virt, addr_end = addr + nr_mfns * PAGE_SIZE;
-    lpae_t pte;
+    lpae_t pte, *entry;
     lpae_t *third = NULL;
 
     for(; addr < addr_end; addr += PAGE_SIZE, mfn = mfn_add(mfn, 1))
     {
-        if ( !lpae_table(xen_second[second_linear_offset(addr)]) )
+        entry = &xen_second[second_linear_offset(addr)];
+        if ( !lpae_table(*entry) )
         {
-            rc = create_xen_table(&xen_second[second_linear_offset(addr)]);
+            rc = create_xen_table(entry);
             if ( rc < 0 ) {
                 printk("create_xen_entries: L2 failed\n");
                 goto out;
             }
         }
 
-        BUG_ON(!lpae_valid(xen_second[second_linear_offset(addr)]));
+        BUG_ON(!lpae_valid(*entry));
 
-        third = mfn_to_virt(xen_second[second_linear_offset(addr)].pt.base);
+        third = mfn_to_virt(entry->pt.base);
+        entry = &third[third_table_offset(addr)];
 
         switch ( op ) {
             case INSERT:
             case RESERVE:
-                if ( lpae_valid(third[third_table_offset(addr)]) )
+                if ( lpae_valid(*entry) )
                 {
                     printk("create_xen_entries: trying to replace an existing mapping addr=%lx mfn=%"PRI_mfn"\n",
                            addr, mfn_x(mfn));
@@ -1017,11 +1019,11 @@ static int create_xen_entries(enum xenmap_operation op,
                     break;
                 pte = mfn_to_xen_entry(mfn, ai);
                 pte.pt.table = 1;
-                write_pte(&third[third_table_offset(addr)], pte);
+                write_pte(entry, pte);
                 break;
             case MODIFY:
             case REMOVE:
-                if ( !lpae_valid(third[third_table_offset(addr)]) )
+                if ( !lpae_valid(*entry) )
                 {
                     printk("create_xen_entries: trying to %s a non-existing mapping addr=%lx\n",
                            op == REMOVE ? "remove" : "modify", addr);
@@ -1031,7 +1033,7 @@ static int create_xen_entries(enum xenmap_operation op,
                     pte.bits = 0;
                 else
                 {
-                    pte = third[third_table_offset(addr)];
+                    pte = *entry;
                     pte.pt.ro = PTE_RO_MASK(ai);
                     pte.pt.xn = PTE_NX_MASK(ai);
                     if ( !pte.pt.ro && !pte.pt.xn )
@@ -1041,7 +1043,7 @@ static int create_xen_entries(enum xenmap_operation op,
                         return -EINVAL;
                     }
                 }
-                write_pte(&third[third_table_offset(addr)], pte);
+                write_pte(entry, pte);
                 break;
             default:
                 BUG();
-- 
2.11.0


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[PATCH v2 16/16] xen/arm: mm: Use __func__ rather than plain name in format string

[Julien Grall]

Signed-off-by: Julien Grall <julien.grall@arm.com>
---

    Changes in v2:
        - Patch added
---
 xen/arch/arm/mm.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 657fee0b17..91af4c8743 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -996,7 +996,7 @@ static int create_xen_entries(enum xenmap_operation op,
         {
             rc = create_xen_table(entry);
             if ( rc < 0 ) {
-                printk("create_xen_entries: L2 failed\n");
+                printk("%s: L2 failed\n", __func__);
                 goto out;
             }
         }
@@ -1011,8 +1011,8 @@ static int create_xen_entries(enum xenmap_operation op,
             case RESERVE:
                 if ( lpae_valid(*entry) )
                 {
-                    printk("create_xen_entries: trying to replace an existing mapping addr=%lx mfn=%"PRI_mfn"\n",
-                           addr, mfn_x(mfn));
+                    printk("%s: trying to replace an existing mapping addr=%lx mfn=%"PRI_mfn"\n",
+                           __func__, addr, mfn_x(mfn));
                     return -EINVAL;
                 }
                 if ( op == RESERVE )
@@ -1025,8 +1025,8 @@ static int create_xen_entries(enum xenmap_operation op,
             case REMOVE:
                 if ( !lpae_valid(*entry) )
                 {
-                    printk("create_xen_entries: trying to %s a non-existing mapping addr=%lx\n",
-                           op == REMOVE ? "remove" : "modify", addr);
+                    printk("%s: trying to %s a non-existing mapping addr=%lx\n",
+                           __func__, op == REMOVE ? "remove" : "modify", addr);
                     return -EINVAL;
                 }
                 if ( op == REMOVE )
@@ -1038,8 +1038,8 @@ static int create_xen_entries(enum xenmap_operation op,
                     pte.pt.xn = PTE_NX_MASK(ai);
                     if ( !pte.pt.ro && !pte.pt.xn )
                     {
-                        printk("create_xen_entries: Incorrect combination for addr=%lx\n",
-                               addr);
+                        printk("%s: Incorrect combination for addr=%lx\n",
+                               __func__, addr);
                         return -EINVAL;
                     }
                 }
-- 
2.11.0


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Re: [PATCH v2 08/16] xen/arm: livepatch: Redefine virt_to_mfn to support typesafe

[Konrad Rzeszutek Wilk]

On Mon, Jun 19, 2017 at 05:57:45PM +0100, Julien Grall wrote:
> The file xen/arch/arm/livepatch.c is using typesafe MFN in most of
> the place. The only caller to virt_to_mfn is using with _mfn(...).
> 
> To avoid extra _mfn(...), re-define virt_to_mfn within
> xen/arch/arm/livepatch.c to handle typesafe MFN.
> 
> Signed-off-by: Julien Grall <julien.grall@arm.com>
> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

> ---
> 
> Cc: Ross Lagerwall <ross.lagerwall@citrix.com>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> 
>     Changes in v2:
>         - Add Stefano's reviewed-by
>         - Still missing an ack from Konrad and/or Ross.
> ---
>  xen/arch/arm/livepatch.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/xen/arch/arm/livepatch.c b/xen/arch/arm/livepatch.c
> index de95e54744..3e53524365 100644
> --- a/xen/arch/arm/livepatch.c
> +++ b/xen/arch/arm/livepatch.c
> @@ -12,6 +12,10 @@
>  #include <asm/livepatch.h>
>  #include <asm/mm.h>
>  
> +/* Override macros from asm/page.h to make them work with mfn_t */
> +#undef virt_to_mfn
> +#define virt_to_mfn(va) _mfn(__virt_to_mfn(va))
> +
>  void *vmap_of_xen_text;
>  
>  int arch_livepatch_quiesce(void)
> @@ -22,7 +26,7 @@ int arch_livepatch_quiesce(void)
>      if ( vmap_of_xen_text )
>          return -EINVAL;
>  
> -    text_mfn = _mfn(virt_to_mfn(_start));
> +    text_mfn = virt_to_mfn(_start);
>      text_order = get_order_from_bytes(_end - _start);
>  
>      /*
> -- 
> 2.11.0
> 

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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Jan Beulich]

>>> On 19.06.17 at 18:57, <julien.grall@arm.com> wrote:
> --- a/xen/include/xen/mm.h
> +++ b/xen/include/xen/mm.h
> @@ -56,7 +56,7 @@
>  
>  TYPE_SAFE(unsigned long, mfn);
>  #define PRI_mfn          "05lx"
> -#define INVALID_MFN      _mfn(~0UL)
> +#define INVALID_MFN      (mfn_t){ ~0UL }

While I don't expect anyone to wish to use a suffix expression on
this constant, for maximum compatibility this should still be fully
parenthesized, I think. Of course this should be easy enough to
do while committing.

Are you able to assure us that clang supports this gcc extension
(compound literal for non-compound types), or are we going to
have to see whether clang complains after having committed the
change (which in turn would likely only be found later, once
someone tries a non-debug build with clang)?

Jan


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Re: [PATCH v2 12/16] xen/arm: p2m: Rename p2m_valid, p2m_table, p2m_mapping and p2m_is_superpage

[Andrew Cooper]

On 19/06/2017 17:57, Julien Grall wrote:
> The helpers p2m_valid, p2m_table, p2m_mapping and p2m_is_superpage are
> not specific to the stage-2 translation tables. They can also work on
> any LPAE translation tables. So rename then to lpae_* and use pte.walk
> to look for the value of the field.
>
> Signed-off-by: Julien Grall <julien.grall@arm.com>

s/bool_t/bool/ as you go?

~Andrew

> ---
>
> Cc: proskurin@sec.in.tum.de
>
>     Changes in v2:
>         - Patch added
> ---
>  xen/arch/arm/p2m.c | 45 +++++++++++++++++++++++----------------------
>  1 file changed, 23 insertions(+), 22 deletions(-)
>
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 6c1ac70044..1136d837fb 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -52,27 +52,27 @@ static const paddr_t level_masks[] =
>  static const uint8_t level_orders[] =
>      { ZEROETH_ORDER, FIRST_ORDER, SECOND_ORDER, THIRD_ORDER };
>  
> -static inline bool_t p2m_valid(lpae_t pte)
> +static inline bool_t lpae_valid(lpae_t pte)
>  {
> -    return pte.p2m.valid;
> +    return pte.walk.valid;
>  }
>  /*
>   * These two can only be used on L0..L2 ptes because L3 mappings set
>   * the table bit and therefore these would return the opposite to what
>   * you would expect.
>   */
> -static inline bool_t p2m_table(lpae_t pte)
> +static inline bool_t lpae_table(lpae_t pte)
>  {
> -    return p2m_valid(pte) && pte.p2m.table;
> +    return lpae_valid(pte) && pte.walk.table;
>  }
> -static inline bool_t p2m_mapping(lpae_t pte)
> +static inline bool_t lpae_mapping(lpae_t pte)
>  {
> -    return p2m_valid(pte) && !pte.p2m.table;
> +    return lpae_valid(pte) && !pte.walk.table;
>  }
>  
> -static inline bool p2m_is_superpage(lpae_t pte, unsigned int level)
> +static inline bool lpae_is_superpage(lpae_t pte, unsigned int level)
>  {
> -    return (level < 3) && p2m_mapping(pte);
> +    return (level < 3) && lpae_mapping(pte);
>  }
>  
>  static void p2m_flush_tlb(struct p2m_domain *p2m);
>


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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Tim Deegan]

At 01:32 -0600 on 20 Jun (1497922345), Jan Beulich wrote:
> >>> On 19.06.17 at 18:57, <julien.grall@arm.com> wrote:
> > --- a/xen/include/xen/mm.h
> > +++ b/xen/include/xen/mm.h
> > @@ -56,7 +56,7 @@
> >  
> >  TYPE_SAFE(unsigned long, mfn);
> >  #define PRI_mfn          "05lx"
> > -#define INVALID_MFN      _mfn(~0UL)
> > +#define INVALID_MFN      (mfn_t){ ~0UL }
> 
> While I don't expect anyone to wish to use a suffix expression on
> this constant, for maximum compatibility this should still be fully
> parenthesized, I think. Of course this should be easy enough to
> do while committing.
> 
> Are you able to assure us that clang supports this gcc extension
> (compound literal for non-compound types)

AIUI this is a C99 feature, not a GCCism.  Clang supports it as far
back as 3.0: https://godbolt.org/g/YY97uj

Tim.


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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Jan Beulich]

>>> On 20.06.17 at 11:14, <tim@xen.org> wrote:
> At 01:32 -0600 on 20 Jun (1497922345), Jan Beulich wrote:
>> >>> On 19.06.17 at 18:57, <julien.grall@arm.com> wrote:
>> > --- a/xen/include/xen/mm.h
>> > +++ b/xen/include/xen/mm.h
>> > @@ -56,7 +56,7 @@
>> >  
>> >  TYPE_SAFE(unsigned long, mfn);
>> >  #define PRI_mfn          "05lx"
>> > -#define INVALID_MFN      _mfn(~0UL)
>> > +#define INVALID_MFN      (mfn_t){ ~0UL }
>> 
>> While I don't expect anyone to wish to use a suffix expression on
>> this constant, for maximum compatibility this should still be fully
>> parenthesized, I think. Of course this should be easy enough to
>> do while committing.
>> 
>> Are you able to assure us that clang supports this gcc extension
>> (compound literal for non-compound types)
> 
> AIUI this is a C99 feature, not a GCCism.

Most parts of it yes (it is a gcc extension in C89 mode only), but the
specific use here isn't afaict: Compound literals outside of functions
are static objects, and hence couldn't be used as initializers of other
objects.

>  Clang supports it as far back as 3.0: https://godbolt.org/g/YY97uj 

Good.

Jan


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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Tim Deegan]

At 03:36 -0600 on 20 Jun (1497929778), Jan Beulich wrote:
> >>> On 20.06.17 at 11:14, <tim@xen.org> wrote:
> > At 01:32 -0600 on 20 Jun (1497922345), Jan Beulich wrote:
> >> >>> On 19.06.17 at 18:57, <julien.grall@arm.com> wrote:
> >> > --- a/xen/include/xen/mm.h
> >> > +++ b/xen/include/xen/mm.h
> >> > @@ -56,7 +56,7 @@
> >> >  
> >> >  TYPE_SAFE(unsigned long, mfn);
> >> >  #define PRI_mfn          "05lx"
> >> > -#define INVALID_MFN      _mfn(~0UL)
> >> > +#define INVALID_MFN      (mfn_t){ ~0UL }
> >> 
> >> While I don't expect anyone to wish to use a suffix expression on
> >> this constant, for maximum compatibility this should still be fully
> >> parenthesized, I think. Of course this should be easy enough to
> >> do while committing.
> >> 
> >> Are you able to assure us that clang supports this gcc extension
> >> (compound literal for non-compound types)
> > 
> > AIUI this is a C99 feature, not a GCCism.
> 
> Most parts of it yes (it is a gcc extension in C89 mode only), but the
> specific use here isn't afaict: Compound literals outside of functions
> are static objects, and hence couldn't be used as initializers of other
> objects.

Ah, I see.  So would it be better to use

  #define INVALID_MFN ((const mfn_t) { ~0UL })

?

Tim.

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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Jan Beulich]

>>> On 20.06.17 at 12:06, <tim@xen.org> wrote:
> At 03:36 -0600 on 20 Jun (1497929778), Jan Beulich wrote:
>> >>> On 20.06.17 at 11:14, <tim@xen.org> wrote:
>> > At 01:32 -0600 on 20 Jun (1497922345), Jan Beulich wrote:
>> >> >>> On 19.06.17 at 18:57, <julien.grall@arm.com> wrote:
>> >> > --- a/xen/include/xen/mm.h
>> >> > +++ b/xen/include/xen/mm.h
>> >> > @@ -56,7 +56,7 @@
>> >> >  
>> >> >  TYPE_SAFE(unsigned long, mfn);
>> >> >  #define PRI_mfn          "05lx"
>> >> > -#define INVALID_MFN      _mfn(~0UL)
>> >> > +#define INVALID_MFN      (mfn_t){ ~0UL }
>> >> 
>> >> While I don't expect anyone to wish to use a suffix expression on
>> >> this constant, for maximum compatibility this should still be fully
>> >> parenthesized, I think. Of course this should be easy enough to
>> >> do while committing.
>> >> 
>> >> Are you able to assure us that clang supports this gcc extension
>> >> (compound literal for non-compound types)
>> > 
>> > AIUI this is a C99 feature, not a GCCism.
>> 
>> Most parts of it yes (it is a gcc extension in C89 mode only), but the
>> specific use here isn't afaict: Compound literals outside of functions
>> are static objects, and hence couldn't be used as initializers of other
>> objects.
> 
> Ah, I see.  So would it be better to use
> 
>   #define INVALID_MFN ((const mfn_t) { ~0UL })
> 
> ?

While I think we should indeed consider adding the const, the above
still is a static object, and hence still not suitable as an initializer as
per C99 or C11. But as long as gcc and clang permit it, we're fine.

Jan


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Re: [PATCH v2 12/16] xen/arm: p2m: Rename p2m_valid, p2m_table, p2m_mapping and p2m_is_superpage

[Julien Grall]

Hi Andrew,

On 20/06/17 09:14, Andrew Cooper wrote:
> On 19/06/2017 17:57, Julien Grall wrote:
>> The helpers p2m_valid, p2m_table, p2m_mapping and p2m_is_superpage are
>> not specific to the stage-2 translation tables. They can also work on
>> any LPAE translation tables. So rename then to lpae_* and use pte.walk
>> to look for the value of the field.
>>
>> Signed-off-by: Julien Grall <julien.grall@arm.com>
>
> s/bool_t/bool/ as you go?

AFAICT, this is the only change required on this series so far (patch #1 
was modified and pushed by Jan). So, I would suggest to send a follow-up 
for the s/bool_t/bool/ if that's fine by Stefano?

Cheers,

-- 
Julien Grall

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Re: [PATCH v2 03/16] xen/arm: mm: Use typesafe mfn for xenheap_mfn_*

[Stefano Stabellini]

On Mon, 19 Jun 2017, Julien Grall wrote:
> Add more safety when using xenheap_mfn_*.
> 
> Signed-off-by: Julien Grall <julien.grall@arm.com>

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>


> ---
> 
>     I haven't introduced mfn_less_than() and mfn_greather_than() as
>     there would be only a couple of usage. We would be able to introduce
>     them and replace the open-coding easily in the future grepping
>     mfn_x().
> ---
>  xen/arch/arm/mm.c        | 16 ++++++++--------
>  xen/arch/arm/setup.c     | 18 +++++++++---------
>  xen/include/asm-arm/mm.h | 11 ++++++-----
>  3 files changed, 23 insertions(+), 22 deletions(-)
> 
> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> index 7b313ca123..452c1e26c3 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -138,8 +138,8 @@ uint64_t init_ttbr;
>  static paddr_t phys_offset;
>  
>  /* Limits of the Xen heap */
> -unsigned long xenheap_mfn_start __read_mostly = ~0UL;
> -unsigned long xenheap_mfn_end __read_mostly;
> +mfn_t xenheap_mfn_start __read_mostly = INVALID_MFN;
> +mfn_t xenheap_mfn_end __read_mostly;
>  vaddr_t xenheap_virt_end __read_mostly;
>  #ifdef CONFIG_ARM_64
>  vaddr_t xenheap_virt_start __read_mostly;
> @@ -801,8 +801,8 @@ void __init setup_xenheap_mappings(unsigned long base_mfn,
>  
>      /* Record where the xenheap is, for translation routines. */
>      xenheap_virt_end = XENHEAP_VIRT_START + nr_mfns * PAGE_SIZE;
> -    xenheap_mfn_start = base_mfn;
> -    xenheap_mfn_end = base_mfn + nr_mfns;
> +    xenheap_mfn_start = _mfn(base_mfn);
> +    xenheap_mfn_end = _mfn(base_mfn + nr_mfns);
>  }
>  #else /* CONFIG_ARM_64 */
>  void __init setup_xenheap_mappings(unsigned long base_mfn,
> @@ -816,16 +816,16 @@ void __init setup_xenheap_mappings(unsigned long base_mfn,
>      mfn = base_mfn & ~((FIRST_SIZE>>PAGE_SHIFT)-1);
>  
>      /* First call sets the xenheap physical and virtual offset. */
> -    if ( xenheap_mfn_start == ~0UL )
> +    if ( mfn_eq(xenheap_mfn_start, INVALID_MFN) )
>      {
> -        xenheap_mfn_start = base_mfn;
> +        xenheap_mfn_start = _mfn(base_mfn);
>          xenheap_virt_start = DIRECTMAP_VIRT_START +
>              (base_mfn - mfn) * PAGE_SIZE;
>      }
>  
> -    if ( base_mfn < xenheap_mfn_start )
> +    if ( base_mfn < mfn_x(xenheap_mfn_start) )
>          panic("cannot add xenheap mapping at %lx below heap start %lx",
> -              base_mfn, xenheap_mfn_start);
> +              base_mfn, mfn_x(xenheap_mfn_start));
>  
>      end_mfn = base_mfn + nr_mfns;
>  
> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
> index ab4d8e4218..3b34855668 100644
> --- a/xen/arch/arm/setup.c
> +++ b/xen/arch/arm/setup.c
> @@ -555,8 +555,8 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
>       * and enough mapped pages for copying the DTB.
>       */
>      dtb_pages = (dtb_size + PAGE_SIZE-1) >> PAGE_SHIFT;
> -    boot_mfn_start = xenheap_mfn_end - dtb_pages - 1;
> -    boot_mfn_end = xenheap_mfn_end;
> +    boot_mfn_start = mfn_x(xenheap_mfn_end) - dtb_pages - 1;
> +    boot_mfn_end = mfn_x(xenheap_mfn_end);
>  
>      init_boot_pages(pfn_to_paddr(boot_mfn_start), pfn_to_paddr(boot_mfn_end));
>  
> @@ -591,11 +591,11 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
>                  e = bank_end;
>  
>              /* Avoid the xenheap */
> -            if ( s < pfn_to_paddr(xenheap_mfn_start+xenheap_pages)
> -                 && pfn_to_paddr(xenheap_mfn_start) < e )
> +            if ( s < mfn_to_maddr(mfn_add(xenheap_mfn_start, xenheap_pages))
> +                 && mfn_to_maddr(xenheap_mfn_start) < e )
>              {
> -                e = pfn_to_paddr(xenheap_mfn_start);
> -                n = pfn_to_paddr(xenheap_mfn_start+xenheap_pages);
> +                e = mfn_to_maddr(xenheap_mfn_start);
> +                n = mfn_to_maddr(mfn_add(xenheap_mfn_start, xenheap_pages));
>              }
>  
>              dt_unreserved_regions(s, e, init_boot_pages, 0);
> @@ -610,7 +610,7 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
>  
>      /* Add xenheap memory that was not already added to the boot
>         allocator. */
> -    init_xenheap_pages(pfn_to_paddr(xenheap_mfn_start),
> +    init_xenheap_pages(mfn_to_maddr(xenheap_mfn_start),
>                         pfn_to_paddr(boot_mfn_start));
>  }
>  #else /* CONFIG_ARM_64 */
> @@ -662,8 +662,8 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
>      total_pages += ram_size >> PAGE_SHIFT;
>  
>      xenheap_virt_end = XENHEAP_VIRT_START + ram_end - ram_start;
> -    xenheap_mfn_start = ram_start >> PAGE_SHIFT;
> -    xenheap_mfn_end = ram_end >> PAGE_SHIFT;
> +    xenheap_mfn_start = maddr_to_mfn(ram_start);
> +    xenheap_mfn_end = maddr_to_mfn(ram_end);
>  
>      /*
>       * Need enough mapped pages for copying the DTB.
> diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h
> index 274b1752b3..b2e7ea7761 100644
> --- a/xen/include/asm-arm/mm.h
> +++ b/xen/include/asm-arm/mm.h
> @@ -115,7 +115,7 @@ struct page_info
>  #define PGC_count_width   PG_shift(9)
>  #define PGC_count_mask    ((1UL<<PGC_count_width)-1)
>  
> -extern unsigned long xenheap_mfn_start, xenheap_mfn_end;
> +extern mfn_t xenheap_mfn_start, xenheap_mfn_end;
>  extern vaddr_t xenheap_virt_end;
>  #ifdef CONFIG_ARM_64
>  extern vaddr_t xenheap_virt_start;
> @@ -125,7 +125,8 @@ extern vaddr_t xenheap_virt_start;
>  #define is_xen_heap_page(page) is_xen_heap_mfn(page_to_mfn(page))
>  #define is_xen_heap_mfn(mfn) ({                                 \
>      unsigned long _mfn = (mfn);                                 \
> -    (_mfn >= xenheap_mfn_start && _mfn < xenheap_mfn_end);      \
> +    (_mfn >= mfn_x(xenheap_mfn_start) &&                        \
> +     _mfn < mfn_x(xenheap_mfn_end));                            \
>  })
>  #else
>  #define is_xen_heap_page(page) ((page)->count_info & PGC_xen_heap)
> @@ -235,7 +236,7 @@ static inline paddr_t __virt_to_maddr(vaddr_t va)
>  static inline void *maddr_to_virt(paddr_t ma)
>  {
>      ASSERT(is_xen_heap_mfn(ma >> PAGE_SHIFT));
> -    ma -= pfn_to_paddr(xenheap_mfn_start);
> +    ma -= mfn_to_maddr(xenheap_mfn_start);
>      return (void *)(unsigned long) ma + XENHEAP_VIRT_START;
>  }
>  #else
> @@ -243,7 +244,7 @@ static inline void *maddr_to_virt(paddr_t ma)
>  {
>      ASSERT(pfn_to_pdx(ma >> PAGE_SHIFT) < (DIRECTMAP_SIZE >> PAGE_SHIFT));
>      return (void *)(XENHEAP_VIRT_START -
> -                    pfn_to_paddr(xenheap_mfn_start) +
> +                    mfn_to_maddr(xenheap_mfn_start) +
>                      ((ma & ma_va_bottom_mask) |
>                       ((ma & ma_top_mask) >> pfn_pdx_hole_shift)));
>  }
> @@ -284,7 +285,7 @@ static inline struct page_info *virt_to_page(const void *v)
>      ASSERT(va < xenheap_virt_end);
>  
>      pdx = (va - XENHEAP_VIRT_START) >> PAGE_SHIFT;
> -    pdx += pfn_to_pdx(xenheap_mfn_start);
> +    pdx += pfn_to_pdx(mfn_x(xenheap_mfn_start));
>      return frame_table + pdx - frametable_base_pdx;
>  }
>  
> -- 
> 2.11.0
> 

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Re: [PATCH v2 04/16] xen/arm: p2m: Redefine mfn_to_page and page_to_mfn to use typesafe

[Stefano Stabellini]

On Mon, 19 Jun 2017, Julien Grall wrote:
> The file xen/arch/arm/p2m.c is using typesafe MFN in most of the place.
> This requires caller to mfn_to_page and page_to_mfn to use _mfn/mfn_x.
> 
> To avoid extra _mfn/mfn_x, re-define mfn_to_page and page_to_mfn within
> xen/arch/arm/p2m.c to handle typesafe MFN.
> 
> Signed-off-by: Julien Grall <julien.grall@arm.com>
> ---
>     The idea behind redefining locally mfn_to_page and page_to_mfn is
>     splitting the introduction of typesafe MFN in smaller series and
>     between multiple people. We know the file is typesafe ready and if
>     we decide to make the main helper typesafe, we would just need to
>     drop the definition at the top of the file.
> ---
>  xen/arch/arm/p2m.c | 20 +++++++++++++-------
>  1 file changed, 13 insertions(+), 7 deletions(-)
> 
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 266d1c3bd6..6c1ac70044 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -38,6 +38,12 @@ static unsigned int __read_mostly max_vmid = MAX_VMID_8_BIT;
>  
>  #define P2M_ROOT_PAGES    (1<<P2M_ROOT_ORDER)
>  
> +/* Override macros from asm/mm.h to make them work with mfn_t */
> +#undef mfn_to_page
> +#define mfn_to_page(mfn) __mfn_to_page(mfn_x(mfn))
> +#undef page_to_mfn
> +#define page_to_mfn(pg) _mfn(__page_to_mfn(pg))
> +
>  unsigned int __read_mostly p2m_ipa_bits;
>  
>  /* Helpers to lookup the properties of each level */
> @@ -115,7 +121,7 @@ void dump_p2m_lookup(struct domain *d, paddr_t addr)
>      printk("dom%d IPA 0x%"PRIpaddr"\n", d->domain_id, addr);
>  
>      printk("P2M @ %p mfn:0x%lx\n",
> -           p2m->root, page_to_mfn(p2m->root));
> +           p2m->root, mfn_x(page_to_mfn(p2m->root)));

__page_to_mfn


>      dump_pt_walk(page_to_maddr(p2m->root), addr,
>                   P2M_ROOT_LEVEL, P2M_ROOT_PAGES);
> @@ -591,7 +597,7 @@ static int p2m_create_table(struct p2m_domain *p2m, lpae_t *entry)
>       * The access value does not matter because the hardware will ignore
>       * the permission fields for table entry.
>       */
> -    pte = mfn_to_p2m_entry(_mfn(page_to_mfn(page)), p2m_invalid,
> +    pte = mfn_to_p2m_entry(page_to_mfn(page), p2m_invalid,
>                             p2m->default_access);
>  
>      p2m_write_pte(entry, pte, p2m->clean_pte);
> @@ -650,9 +656,9 @@ static void p2m_put_l3_page(const lpae_t pte)
>       */
>      if ( p2m_is_foreign(pte.p2m.type) )
>      {
> -        unsigned long mfn = pte.p2m.base;
> +        mfn_t mfn = _mfn(pte.p2m.base);
>  
> -        ASSERT(mfn_valid(_mfn(mfn)));
> +        ASSERT(mfn_valid(mfn));
>          put_page(mfn_to_page(mfn));
>      }
>  }
> @@ -702,7 +708,7 @@ static void p2m_free_entry(struct p2m_domain *p2m,
>      mfn = _mfn(entry.p2m.base);
>      ASSERT(mfn_valid(mfn));
>  
> -    pg = mfn_to_page(mfn_x(mfn));
> +    pg = mfn_to_page(mfn);
>  
>      page_list_del(pg, &p2m->pages);
>      free_domheap_page(pg);
> @@ -780,7 +786,7 @@ static bool p2m_split_superpage(struct p2m_domain *p2m, lpae_t *entry,
>  
>      unmap_domain_page(table);
>  
> -    pte = mfn_to_p2m_entry(_mfn(page_to_mfn(page)), p2m_invalid,
> +    pte = mfn_to_p2m_entry(page_to_mfn(page), p2m_invalid,
>                             p2m->default_access);
>  
>      /*
> @@ -1443,7 +1449,7 @@ struct page_info *get_page_from_gva(struct vcpu *v, vaddr_t va,
>      if ( !mfn_valid(maddr_to_mfn(maddr)) )
>          goto err;
>  
> -    page = mfn_to_page(mfn_x(maddr_to_mfn(maddr)));
> +    page = mfn_to_page(maddr_to_mfn(maddr));
>      ASSERT(page);
>  
>      if ( unlikely(!get_page(page, d)) )
> -- 
> 2.11.0
> 

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Re: [PATCH v2 05/16] xen/arm: mm: Redefine virt_to_mfn to support typesafe

[Stefano Stabellini]

On Mon, 19 Jun 2017, Julien Grall wrote:
> The file xen/arch/arm/mm.c is using the typesafe MFN in most of the
> place. This requires all caller of virt_to_mfn to prefixed by _mfn(...).
> 
> To avoid the extra _mfn(...), re-defined virt_to_mfn within arch/arm/mm.c
> to handle typesafe MFN.
> 
> This patch also introduce __virt_to_mfn, so virt_to_mfn can be
> re-defined easily.
> 
> Signed-off-by: Julien Grall <julien.grall@arm.com>

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>



>     Changes in v2:
>         - Use __virt_to_mfn rather than mfn_x(virt_to_mfn()).
> ---
>  xen/arch/arm/mm.c        | 16 ++++++++++------
>  xen/include/asm-arm/mm.h |  3 ++-
>  2 files changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> index 452c1e26c3..5612834dfc 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -44,6 +44,10 @@
>  
>  struct domain *dom_xen, *dom_io, *dom_cow;
>  
> +/* Override macros from asm/page.h to make them work with mfn_t */
> +#undef virt_to_mfn
> +#define virt_to_mfn(va) _mfn(__virt_to_mfn(va))
> +
>  /* Static start-of-day pagetables that we use before the allocators
>   * are up. These are used by all CPUs during bringup before switching
>   * to the CPUs own pagetables.
> @@ -479,7 +483,7 @@ unsigned long domain_page_map_to_mfn(const void *ptr)
>      unsigned long offset = (va>>THIRD_SHIFT) & LPAE_ENTRY_MASK;
>  
>      if ( va >= VMAP_VIRT_START && va < VMAP_VIRT_END )
> -        return virt_to_mfn(va);
> +        return __virt_to_mfn(va);
>  
>      ASSERT(slot >= 0 && slot < DOMHEAP_ENTRIES);
>      ASSERT(map[slot].pt.avail != 0);
> @@ -764,7 +768,7 @@ int init_secondary_pagetables(int cpu)
>       * domheap mapping pages. */
>      for ( i = 0; i < DOMHEAP_SECOND_PAGES; i++ )
>      {
> -        pte = mfn_to_xen_entry(_mfn(virt_to_mfn(domheap+i*LPAE_ENTRIES)),
> +        pte = mfn_to_xen_entry(virt_to_mfn(domheap+i*LPAE_ENTRIES),
>                                 WRITEALLOC);
>          pte.pt.table = 1;
>          write_pte(&first[first_table_offset(DOMHEAP_VIRT_START+i*FIRST_SIZE)], pte);
> @@ -961,7 +965,7 @@ static int create_xen_table(lpae_t *entry)
>      if ( p == NULL )
>          return -ENOMEM;
>      clear_page(p);
> -    pte = mfn_to_xen_entry(_mfn(virt_to_mfn(p)), WRITEALLOC);
> +    pte = mfn_to_xen_entry(virt_to_mfn(p), WRITEALLOC);
>      pte.pt.table = 1;
>      write_pte(entry, pte);
>      return 0;
> @@ -1216,7 +1220,7 @@ int xenmem_add_to_physmap_one(
>      unsigned long idx,
>      gfn_t gfn)
>  {
> -    unsigned long mfn = 0;
> +    mfn_t mfn = INVALID_MFN;
>      int rc;
>      p2m_type_t t;
>      struct page_info *page = NULL;
> @@ -1302,7 +1306,7 @@ int xenmem_add_to_physmap_one(
>              return -EINVAL;
>          }
>  
> -        mfn = page_to_mfn(page);
> +        mfn = _mfn(page_to_mfn(page));
>          t = p2m_map_foreign;
>  
>          rcu_unlock_domain(od);
> @@ -1321,7 +1325,7 @@ int xenmem_add_to_physmap_one(
>      }
>  
>      /* Map at new location. */
> -    rc = guest_physmap_add_entry(d, gfn, _mfn(mfn), 0, t);
> +    rc = guest_physmap_add_entry(d, gfn, mfn, 0, t);
>  
>      /* If we fail to add the mapping, we need to drop the reference we
>       * took earlier on foreign pages */
> diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h
> index b2e7ea7761..6e2b3c7f2b 100644
> --- a/xen/include/asm-arm/mm.h
> +++ b/xen/include/asm-arm/mm.h
> @@ -264,7 +264,7 @@ static inline int gvirt_to_maddr(vaddr_t va, paddr_t *pa, unsigned int flags)
>  #define __va(x)             (maddr_to_virt(x))
>  
>  /* Convert between Xen-heap virtual addresses and machine frame numbers. */
> -#define virt_to_mfn(va)   (virt_to_maddr(va) >> PAGE_SHIFT)
> +#define __virt_to_mfn(va) (virt_to_maddr(va) >> PAGE_SHIFT)
>  #define mfn_to_virt(mfn)  (maddr_to_virt((paddr_t)(mfn) << PAGE_SHIFT))
>  
>  /*
> @@ -274,6 +274,7 @@ static inline int gvirt_to_maddr(vaddr_t va, paddr_t *pa, unsigned int flags)
>   */
>  #define mfn_to_page(mfn)    __mfn_to_page(mfn)
>  #define page_to_mfn(pg)     __page_to_mfn(pg)
> +#define virt_to_mfn(va)     __virt_to_mfn(va)
>  
>  /* Convert between Xen-heap virtual addresses and page-info structures. */
>  static inline struct page_info *virt_to_page(const void *v)
> -- 
> 2.11.0
> 

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Re: [PATCH v2 02/16] xen/arm: setup: Remove bogus xenheap_mfn_end in setup_mm for arm64

[Stefano Stabellini]

On Mon, 19 Jun 2017, Julien Grall wrote:
> xenheap_mfn_end is storing an MFN and not a physical address. Xen is not
> currently using xenheap_mfn_end and the value will be reset after the
> loop. So drop this bogus xenheap_mfn_end.
> 
> Signed-off-by: Julien Grall <julien.grall@arm.com>

I would drop the mention of the fact that Xen is not currently using
xenheap_mfn_end entirely. I might do that as I commit.

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>


> ---
>     Changes in v2:
>         - Update commit message
> ---
>  xen/arch/arm/setup.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
> index f00f29a45b..ab4d8e4218 100644
> --- a/xen/arch/arm/setup.c
> +++ b/xen/arch/arm/setup.c
> @@ -654,8 +654,6 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
>              if ( e > bank_end )
>                  e = bank_end;
>  
> -            xenheap_mfn_end = e;
> -
>              dt_unreserved_regions(s, e, init_boot_pages, 0);
>              s = n;
>          }
> -- 
> 2.11.0
> 

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Re: [PATCH v2 11/16] xen/arm: lpae: Fix comments coding style

[Stefano Stabellini]

On Mon, 19 Jun 2017, Julien Grall wrote:
> Also adding one missing full stop + fix description
> 
> Signed-off-by: Julien Grall <julien.grall@arm.com>

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

> ---
> 
> Cc: proskurin@sec.in.tum.de
> 
>     I haven't retained Stefano's reviewed-by because of the description
>     update.
> 
>    Changes in v2:
>         - Fix description regarding x86 page-table
> ---
>  xen/include/asm-arm/lpae.h | 49 ++++++++++++++++++++++++++++++----------------
>  1 file changed, 32 insertions(+), 17 deletions(-)
> 
> diff --git a/xen/include/asm-arm/lpae.h b/xen/include/asm-arm/lpae.h
> index ad8c571ea5..aa85cb8112 100644
> --- a/xen/include/asm-arm/lpae.h
> +++ b/xen/include/asm-arm/lpae.h
> @@ -3,10 +3,12 @@
>  
>  #ifndef __ASSEMBLY__
>  
> -/* WARNING!  Unlike the Intel pagetable code, where l1 is the lowest
> - * level and l4 is the root of the trie, the ARM pagetables follow ARM's
> - * documentation: the levels are called first, second &c in the order
> - * that the MMU walks them (i.e. "first" is the root of the trie). */
> +/*
> + * WARNING!  Unlike the x86 pagetable code, where l1 is the lowest level and
> + * l4 is the root of the trie, the ARM pagetables follow ARM's documentation:
> + * the levels are called first, second &c in the order that the MMU walks them
> + * (i.e. "first" is the root of the trie).
> + */
>  
>  /******************************************************************************
>   * ARMv7-A LPAE pagetables: 3-level trie, mapping 40-bit input to
> @@ -17,15 +19,18 @@
>   * different place from those in leaf nodes seems to be to allow linear
>   * pagetable tricks.  If we're not doing that then the set of permission
>   * bits that's not in use in a given node type can be used as
> - * extra software-defined bits. */
> + * extra software-defined bits.
> + */
>  
>  typedef struct __packed {
>      /* These are used in all kinds of entry. */
>      unsigned long valid:1;      /* Valid mapping */
>      unsigned long table:1;      /* == 1 in 4k map entries too */
>  
> -    /* These ten bits are only used in Block entries and are ignored
> -     * in Table entries. */
> +    /*
> +     * These ten bits are only used in Block entries and are ignored
> +     * in Table entries.
> +     */
>      unsigned long ai:3;         /* Attribute Index */
>      unsigned long ns:1;         /* Not-Secure */
>      unsigned long user:1;       /* User-visible */
> @@ -38,30 +43,38 @@ typedef struct __packed {
>      unsigned long long base:36; /* Base address of block or next table */
>      unsigned long sbz:4;        /* Must be zero */
>  
> -    /* These seven bits are only used in Block entries and are ignored
> -     * in Table entries. */
> +    /*
> +     * These seven bits are only used in Block entries and are ignored
> +     * in Table entries.
> +     */
>      unsigned long contig:1;     /* In a block of 16 contiguous entries */
>      unsigned long pxn:1;        /* Privileged-XN */
>      unsigned long xn:1;         /* eXecute-Never */
>      unsigned long avail:4;      /* Ignored by hardware */
>  
> -    /* These 5 bits are only used in Table entries and are ignored in
> -     * Block entries */
> +    /*
> +     * These 5 bits are only used in Table entries and are ignored in
> +     * Block entries.
> +     */
>      unsigned long pxnt:1;       /* Privileged-XN */
>      unsigned long xnt:1;        /* eXecute-Never */
>      unsigned long apt:2;        /* Access Permissions */
>      unsigned long nst:1;        /* Not-Secure */
>  } lpae_pt_t;
>  
> -/* The p2m tables have almost the same layout, but some of the permission
> - * and cache-control bits are laid out differently (or missing) */
> +/*
> + * The p2m tables have almost the same layout, but some of the permission
> + * and cache-control bits are laid out differently (or missing).
> + */
>  typedef struct __packed {
>      /* These are used in all kinds of entry. */
>      unsigned long valid:1;      /* Valid mapping */
>      unsigned long table:1;      /* == 1 in 4k map entries too */
>  
> -    /* These ten bits are only used in Block entries and are ignored
> -     * in Table entries. */
> +    /*
> +     * These ten bits are only used in Block entries and are ignored
> +     * in Table entries.
> +     */
>      unsigned long mattr:4;      /* Memory Attributes */
>      unsigned long read:1;       /* Read access */
>      unsigned long write:1;      /* Write access */
> @@ -73,8 +86,10 @@ typedef struct __packed {
>      unsigned long long base:36; /* Base address of block or next table */
>      unsigned long sbz3:4;
>  
> -    /* These seven bits are only used in Block entries and are ignored
> -     * in Table entries. */
> +    /*
> +     * These seven bits are only used in Block entries and are ignored
> +     * in Table entries.
> +     */
>      unsigned long contig:1;     /* In a block of 16 contiguous entries */
>      unsigned long sbz2:1;
>      unsigned long xn:1;         /* eXecute-Never */
> -- 
> 2.11.0
> 

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Re: [PATCH v2 12/16] xen/arm: p2m: Rename p2m_valid, p2m_table, p2m_mapping and p2m_is_superpage

[Stefano Stabellini]

On Wed, 21 Jun 2017, Julien Grall wrote:
> Hi Andrew,
> 
> On 20/06/17 09:14, Andrew Cooper wrote:
> > On 19/06/2017 17:57, Julien Grall wrote:
> > > The helpers p2m_valid, p2m_table, p2m_mapping and p2m_is_superpage are
> > > not specific to the stage-2 translation tables. They can also work on
> > > any LPAE translation tables. So rename then to lpae_* and use pte.walk
> > > to look for the value of the field.
> > > 
> > > Signed-off-by: Julien Grall <julien.grall@arm.com>
> > 
> > s/bool_t/bool/ as you go?
> 
> AFAICT, this is the only change required on this series so far (patch #1 was
> modified and pushed by Jan). So, I would suggest to send a follow-up for the
> s/bool_t/bool/ if that's fine by Stefano?

Sure

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Re: [PATCH v2 12/16] xen/arm: p2m: Rename p2m_valid, p2m_table, p2m_mapping and p2m_is_superpage

[Stefano Stabellini]

On Mon, 19 Jun 2017, Julien Grall wrote:
> The helpers p2m_valid, p2m_table, p2m_mapping and p2m_is_superpage are
> not specific to the stage-2 translation tables. They can also work on
> any LPAE translation tables. So rename then to lpae_* and use pte.walk
> to look for the value of the field.
> 
> Signed-off-by: Julien Grall <julien.grall@arm.com>

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>


> ---
> 
> Cc: proskurin@sec.in.tum.de
> 
>     Changes in v2:
>         - Patch added
> ---
>  xen/arch/arm/p2m.c | 45 +++++++++++++++++++++++----------------------
>  1 file changed, 23 insertions(+), 22 deletions(-)
> 
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 6c1ac70044..1136d837fb 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -52,27 +52,27 @@ static const paddr_t level_masks[] =
>  static const uint8_t level_orders[] =
>      { ZEROETH_ORDER, FIRST_ORDER, SECOND_ORDER, THIRD_ORDER };
>  
> -static inline bool_t p2m_valid(lpae_t pte)
> +static inline bool_t lpae_valid(lpae_t pte)
>  {
> -    return pte.p2m.valid;
> +    return pte.walk.valid;
>  }
>  /*
>   * These two can only be used on L0..L2 ptes because L3 mappings set
>   * the table bit and therefore these would return the opposite to what
>   * you would expect.
>   */
> -static inline bool_t p2m_table(lpae_t pte)
> +static inline bool_t lpae_table(lpae_t pte)
>  {
> -    return p2m_valid(pte) && pte.p2m.table;
> +    return lpae_valid(pte) && pte.walk.table;
>  }
> -static inline bool_t p2m_mapping(lpae_t pte)
> +static inline bool_t lpae_mapping(lpae_t pte)
>  {
> -    return p2m_valid(pte) && !pte.p2m.table;
> +    return lpae_valid(pte) && !pte.walk.table;
>  }
>  
> -static inline bool p2m_is_superpage(lpae_t pte, unsigned int level)
> +static inline bool lpae_is_superpage(lpae_t pte, unsigned int level)
>  {
> -    return (level < 3) && p2m_mapping(pte);
> +    return (level < 3) && lpae_mapping(pte);
>  }
>  
>  static void p2m_flush_tlb(struct p2m_domain *p2m);
> @@ -281,7 +281,7 @@ static int p2m_next_level(struct p2m_domain *p2m, bool read_only,
>  
>      entry = *table + offset;
>  
> -    if ( !p2m_valid(*entry) )
> +    if ( !lpae_valid(*entry) )
>      {
>          if ( read_only )
>              return GUEST_TABLE_MAP_FAILED;
> @@ -292,7 +292,7 @@ static int p2m_next_level(struct p2m_domain *p2m, bool read_only,
>      }
>  
>      /* The function p2m_next_level is never called at the 3rd level */
> -    if ( p2m_mapping(*entry) )
> +    if ( lpae_mapping(*entry) )
>          return GUEST_TABLE_SUPER_PAGE;
>  
>      mfn = _mfn(entry->p2m.base);
> @@ -372,7 +372,7 @@ mfn_t p2m_get_entry(struct p2m_domain *p2m, gfn_t gfn,
>  
>      entry = table[offsets[level]];
>  
> -    if ( p2m_valid(entry) )
> +    if ( lpae_valid(entry) )
>      {
>          *t = entry.p2m.type;
>  
> @@ -577,7 +577,7 @@ static int p2m_create_table(struct p2m_domain *p2m, lpae_t *entry)
>      lpae_t *p;
>      lpae_t pte;
>  
> -    ASSERT(!p2m_valid(*entry));
> +    ASSERT(!lpae_valid(*entry));
>  
>      page = alloc_domheap_page(NULL, 0);
>      if ( page == NULL )
> @@ -645,7 +645,7 @@ enum p2m_operation {
>   */
>  static void p2m_put_l3_page(const lpae_t pte)
>  {
> -    ASSERT(p2m_valid(pte));
> +    ASSERT(lpae_valid(pte));
>  
>      /*
>       * TODO: Handle other p2m types
> @@ -673,11 +673,11 @@ static void p2m_free_entry(struct p2m_domain *p2m,
>      struct page_info *pg;
>  
>      /* Nothing to do if the entry is invalid. */
> -    if ( !p2m_valid(entry) )
> +    if ( !lpae_valid(entry) )
>          return;
>  
>      /* Nothing to do but updating the stats if the entry is a super-page. */
> -    if ( p2m_is_superpage(entry, level) )
> +    if ( lpae_is_superpage(entry, level) )
>      {
>          p2m->stats.mappings[level]--;
>          return;
> @@ -733,7 +733,7 @@ static bool p2m_split_superpage(struct p2m_domain *p2m, lpae_t *entry,
>       * a superpage.
>       */
>      ASSERT(level < target);
> -    ASSERT(p2m_is_superpage(*entry, level));
> +    ASSERT(lpae_is_superpage(*entry, level));
>  
>      page = alloc_domheap_page(NULL, 0);
>      if ( !page )
> @@ -870,7 +870,7 @@ static int __p2m_set_entry(struct p2m_domain *p2m,
>          /* We need to split the original page. */
>          lpae_t split_pte = *entry;
>  
> -        ASSERT(p2m_is_superpage(*entry, level));
> +        ASSERT(lpae_is_superpage(*entry, level));
>  
>          if ( !p2m_split_superpage(p2m, &split_pte, level, target, offsets) )
>          {
> @@ -944,12 +944,12 @@ static int __p2m_set_entry(struct p2m_domain *p2m,
>       * sequence when updating the translation table (D4.7.1 in ARM DDI
>       * 0487A.j).
>       */
> -    if ( p2m_valid(orig_pte) )
> +    if ( lpae_valid(orig_pte) )
>          p2m_remove_pte(entry, p2m->clean_pte);
>  
>      if ( mfn_eq(smfn, INVALID_MFN) )
>          /* Flush can be deferred if the entry is removed */
> -        p2m->need_flush |= !!p2m_valid(orig_pte);
> +        p2m->need_flush |= !!lpae_valid(orig_pte);
>      else
>      {
>          lpae_t pte = mfn_to_p2m_entry(smfn, t, a);
> @@ -964,7 +964,7 @@ static int __p2m_set_entry(struct p2m_domain *p2m,
>           * Although, it could be defered when only the permissions are
>           * changed (e.g in case of memaccess).
>           */
> -        if ( p2m_valid(orig_pte) )
> +        if ( lpae_valid(orig_pte) )
>          {
>              if ( likely(!p2m->mem_access_enabled) ||
>                   P2M_CLEAR_PERM(pte) != P2M_CLEAR_PERM(orig_pte) )
> @@ -986,10 +986,11 @@ static int __p2m_set_entry(struct p2m_domain *p2m,
>       * Free the entry only if the original pte was valid and the base
>       * is different (to avoid freeing when permission is changed).
>       */
> -    if ( p2m_valid(orig_pte) && entry->p2m.base != orig_pte.p2m.base )
> +    if ( lpae_valid(orig_pte) && entry->p2m.base != orig_pte.p2m.base )
>          p2m_free_entry(p2m, orig_pte, level);
>  
> -    if ( need_iommu(p2m->domain) && (p2m_valid(orig_pte) || p2m_valid(*entry)) )
> +    if ( need_iommu(p2m->domain) &&
> +         (lpae_valid(orig_pte) || lpae_valid(*entry)) )
>          rc = iommu_iotlb_flush(p2m->domain, gfn_x(sgfn), 1UL << page_order);
>      else
>          rc = 0;
> -- 
> 2.11.0
> 

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Re: [PATCH v2 13/16] xen/arm: p2m: Move lpae_* helpers in lpae.h

[Stefano Stabellini]

On Mon, 19 Jun 2017, Julien Grall wrote:
> lpae_* helpers can work on any LPAE translation tables. Move them in
> lpae.h to allow other part of Xen to use them.
> 
> Signed-off-by: Julien Grall <julien.grall@arm.com>

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>


> ---
> 
> Cc: proskurin@sec.in.tum.de
> 
>     Changes in v2:
>         - Patch added
> ---
>  xen/arch/arm/p2m.c         | 23 -----------------------
>  xen/include/asm-arm/lpae.h | 25 +++++++++++++++++++++++++
>  2 files changed, 25 insertions(+), 23 deletions(-)
> 
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 1136d837fb..f9145f052f 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -52,29 +52,6 @@ static const paddr_t level_masks[] =
>  static const uint8_t level_orders[] =
>      { ZEROETH_ORDER, FIRST_ORDER, SECOND_ORDER, THIRD_ORDER };
>  
> -static inline bool_t lpae_valid(lpae_t pte)
> -{
> -    return pte.walk.valid;
> -}
> -/*
> - * These two can only be used on L0..L2 ptes because L3 mappings set
> - * the table bit and therefore these would return the opposite to what
> - * you would expect.
> - */
> -static inline bool_t lpae_table(lpae_t pte)
> -{
> -    return lpae_valid(pte) && pte.walk.table;
> -}
> -static inline bool_t lpae_mapping(lpae_t pte)
> -{
> -    return lpae_valid(pte) && !pte.walk.table;
> -}
> -
> -static inline bool lpae_is_superpage(lpae_t pte, unsigned int level)
> -{
> -    return (level < 3) && lpae_mapping(pte);
> -}
> -
>  static void p2m_flush_tlb(struct p2m_domain *p2m);
>  
>  /* Unlock the flush and do a P2M TLB flush if necessary */
> diff --git a/xen/include/asm-arm/lpae.h b/xen/include/asm-arm/lpae.h
> index aa85cb8112..6fbf7c606c 100644
> --- a/xen/include/asm-arm/lpae.h
> +++ b/xen/include/asm-arm/lpae.h
> @@ -126,6 +126,31 @@ typedef union {
>      lpae_walk_t walk;
>  } lpae_t;
>  
> +static inline bool_t lpae_valid(lpae_t pte)
> +{
> +    return pte.walk.valid;
> +}
> +
> +/*
> + * These two can only be used on L0..L2 ptes because L3 mappings set
> + * the table bit and therefore these would return the opposite to what
> + * you would expect.
> + */
> +static inline bool_t lpae_table(lpae_t pte)
> +{
> +    return lpae_valid(pte) && pte.walk.table;
> +}
> +
> +static inline bool_t lpae_mapping(lpae_t pte)
> +{
> +    return lpae_valid(pte) && !pte.walk.table;
> +}
> +
> +static inline bool lpae_is_superpage(lpae_t pte, unsigned int level)
> +{
> +    return (level < 3) && lpae_mapping(pte);
> +}
> +
>  #endif /* __ASSEMBLY__ */
>  
>  /*
> -- 
> 2.11.0
> 

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Re: [PATCH v2 14/16] xen/arm: mm: Use lpae_valid and lpae_table in create_xen_entries

[Stefano Stabellini]

On Mon, 19 Jun 2017, Julien Grall wrote:
> This newly introduced lpae_valid and lpae_table helpers will recude the
> code and make more readable.
> 
> Signed-off-by: Julien Grall <julien.grall@arm.com>

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

> ---
> 
>     Changes in v2:
>         - Patch added
> ---
>  xen/arch/arm/mm.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> index 8d34ae7279..6241c53821 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -991,8 +991,7 @@ static int create_xen_entries(enum xenmap_operation op,
>  
>      for(; addr < addr_end; addr += PAGE_SIZE, mfn = mfn_add(mfn, 1))
>      {
> -        if ( !xen_second[second_linear_offset(addr)].pt.valid ||
> -             !xen_second[second_linear_offset(addr)].pt.table )
> +        if ( !lpae_table(xen_second[second_linear_offset(addr)]) )
>          {
>              rc = create_xen_table(&xen_second[second_linear_offset(addr)]);
>              if ( rc < 0 ) {
> @@ -1001,14 +1000,14 @@ static int create_xen_entries(enum xenmap_operation op,
>              }
>          }
>  
> -        BUG_ON(!xen_second[second_linear_offset(addr)].pt.valid);
> +        BUG_ON(!lpae_valid(xen_second[second_linear_offset(addr)]));
>  
>          third = mfn_to_virt(xen_second[second_linear_offset(addr)].pt.base);
>  
>          switch ( op ) {
>              case INSERT:
>              case RESERVE:
> -                if ( third[third_table_offset(addr)].pt.valid )
> +                if ( lpae_valid(third[third_table_offset(addr)]) )
>                  {
>                      printk("create_xen_entries: trying to replace an existing mapping addr=%lx mfn=%"PRI_mfn"\n",
>                             addr, mfn_x(mfn));
> @@ -1022,7 +1021,7 @@ static int create_xen_entries(enum xenmap_operation op,
>                  break;
>              case MODIFY:
>              case REMOVE:
> -                if ( !third[third_table_offset(addr)].pt.valid )
> +                if ( !lpae_valid(third[third_table_offset(addr)]) )
>                  {
>                      printk("create_xen_entries: trying to %s a non-existing mapping addr=%lx\n",
>                             op == REMOVE ? "remove" : "modify", addr);
> -- 
> 2.11.0
> 

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Re: [PATCH v2 15/16] xen/arm: mm: Introduce temporary variable in create_xen_entries

[Stefano Stabellini]

On Mon, 19 Jun 2017, Julien Grall wrote:
> This is improving the code readability and avoid to dereference the
> table every single time we need to access the entry.
> 
> Signed-off-by: Julien Grall <julien.grall@arm.com>

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>


> ---
> 
>     Changes in v2:
>         - Patch added
> ---
>  xen/arch/arm/mm.c | 22 ++++++++++++----------
>  1 file changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> index 6241c53821..657fee0b17 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -986,28 +986,30 @@ static int create_xen_entries(enum xenmap_operation op,
>  {
>      int rc;
>      unsigned long addr = virt, addr_end = addr + nr_mfns * PAGE_SIZE;
> -    lpae_t pte;
> +    lpae_t pte, *entry;
>      lpae_t *third = NULL;
>  
>      for(; addr < addr_end; addr += PAGE_SIZE, mfn = mfn_add(mfn, 1))
>      {
> -        if ( !lpae_table(xen_second[second_linear_offset(addr)]) )
> +        entry = &xen_second[second_linear_offset(addr)];
> +        if ( !lpae_table(*entry) )
>          {
> -            rc = create_xen_table(&xen_second[second_linear_offset(addr)]);
> +            rc = create_xen_table(entry);
>              if ( rc < 0 ) {
>                  printk("create_xen_entries: L2 failed\n");
>                  goto out;
>              }
>          }
>  
> -        BUG_ON(!lpae_valid(xen_second[second_linear_offset(addr)]));
> +        BUG_ON(!lpae_valid(*entry));
>  
> -        third = mfn_to_virt(xen_second[second_linear_offset(addr)].pt.base);
> +        third = mfn_to_virt(entry->pt.base);
> +        entry = &third[third_table_offset(addr)];
>  
>          switch ( op ) {
>              case INSERT:
>              case RESERVE:
> -                if ( lpae_valid(third[third_table_offset(addr)]) )
> +                if ( lpae_valid(*entry) )
>                  {
>                      printk("create_xen_entries: trying to replace an existing mapping addr=%lx mfn=%"PRI_mfn"\n",
>                             addr, mfn_x(mfn));
> @@ -1017,11 +1019,11 @@ static int create_xen_entries(enum xenmap_operation op,
>                      break;
>                  pte = mfn_to_xen_entry(mfn, ai);
>                  pte.pt.table = 1;
> -                write_pte(&third[third_table_offset(addr)], pte);
> +                write_pte(entry, pte);
>                  break;
>              case MODIFY:
>              case REMOVE:
> -                if ( !lpae_valid(third[third_table_offset(addr)]) )
> +                if ( !lpae_valid(*entry) )
>                  {
>                      printk("create_xen_entries: trying to %s a non-existing mapping addr=%lx\n",
>                             op == REMOVE ? "remove" : "modify", addr);
> @@ -1031,7 +1033,7 @@ static int create_xen_entries(enum xenmap_operation op,
>                      pte.bits = 0;
>                  else
>                  {
> -                    pte = third[third_table_offset(addr)];
> +                    pte = *entry;
>                      pte.pt.ro = PTE_RO_MASK(ai);
>                      pte.pt.xn = PTE_NX_MASK(ai);
>                      if ( !pte.pt.ro && !pte.pt.xn )
> @@ -1041,7 +1043,7 @@ static int create_xen_entries(enum xenmap_operation op,
>                          return -EINVAL;
>                      }
>                  }
> -                write_pte(&third[third_table_offset(addr)], pte);
> +                write_pte(entry, pte);
>                  break;
>              default:
>                  BUG();
> -- 
> 2.11.0
> 

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Re: [PATCH v2 16/16] xen/arm: mm: Use __func__ rather than plain name in format string

[Stefano Stabellini]

On Mon, 19 Jun 2017, Julien Grall wrote:
> Signed-off-by: Julien Grall <julien.grall@arm.com>

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>


> ---
> 
>     Changes in v2:
>         - Patch added
> ---
>  xen/arch/arm/mm.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> index 657fee0b17..91af4c8743 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -996,7 +996,7 @@ static int create_xen_entries(enum xenmap_operation op,
>          {
>              rc = create_xen_table(entry);
>              if ( rc < 0 ) {
> -                printk("create_xen_entries: L2 failed\n");
> +                printk("%s: L2 failed\n", __func__);
>                  goto out;
>              }
>          }
> @@ -1011,8 +1011,8 @@ static int create_xen_entries(enum xenmap_operation op,
>              case RESERVE:
>                  if ( lpae_valid(*entry) )
>                  {
> -                    printk("create_xen_entries: trying to replace an existing mapping addr=%lx mfn=%"PRI_mfn"\n",
> -                           addr, mfn_x(mfn));
> +                    printk("%s: trying to replace an existing mapping addr=%lx mfn=%"PRI_mfn"\n",
> +                           __func__, addr, mfn_x(mfn));
>                      return -EINVAL;
>                  }
>                  if ( op == RESERVE )
> @@ -1025,8 +1025,8 @@ static int create_xen_entries(enum xenmap_operation op,
>              case REMOVE:
>                  if ( !lpae_valid(*entry) )
>                  {
> -                    printk("create_xen_entries: trying to %s a non-existing mapping addr=%lx\n",
> -                           op == REMOVE ? "remove" : "modify", addr);
> +                    printk("%s: trying to %s a non-existing mapping addr=%lx\n",
> +                           __func__, op == REMOVE ? "remove" : "modify", addr);
>                      return -EINVAL;
>                  }
>                  if ( op == REMOVE )
> @@ -1038,8 +1038,8 @@ static int create_xen_entries(enum xenmap_operation op,
>                      pte.pt.xn = PTE_NX_MASK(ai);
>                      if ( !pte.pt.ro && !pte.pt.xn )
>                      {
> -                        printk("create_xen_entries: Incorrect combination for addr=%lx\n",
> -                               addr);
> +                        printk("%s: Incorrect combination for addr=%lx\n",
> +                               __func__, addr);
>                          return -EINVAL;
>                      }
>                  }
> -- 
> 2.11.0
> 

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Re: [PATCH v2 03/16] xen/arm: mm: Use typesafe mfn for xenheap_mfn_*

[Stefano Stabellini]

On Wed, 21 Jun 2017, Stefano Stabellini wrote:
> On Mon, 19 Jun 2017, Julien Grall wrote:
> > Add more safety when using xenheap_mfn_*.
> > 
> > Signed-off-by: Julien Grall <julien.grall@arm.com>
> 
> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
> 
> 
> > ---
> > 
> >     I haven't introduced mfn_less_than() and mfn_greather_than() as
> >     there would be only a couple of usage. We would be able to introduce
> >     them and replace the open-coding easily in the future grepping
> >     mfn_x().
> > ---
> >  xen/arch/arm/mm.c        | 16 ++++++++--------
> >  xen/arch/arm/setup.c     | 18 +++++++++---------
> >  xen/include/asm-arm/mm.h | 11 ++++++-----
> >  3 files changed, 23 insertions(+), 22 deletions(-)
> > 
> > diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> > index 7b313ca123..452c1e26c3 100644
> > --- a/xen/arch/arm/mm.c
> > +++ b/xen/arch/arm/mm.c
> > @@ -138,8 +138,8 @@ uint64_t init_ttbr;
> >  static paddr_t phys_offset;
> >  
> >  /* Limits of the Xen heap */
> > -unsigned long xenheap_mfn_start __read_mostly = ~0UL;
> > -unsigned long xenheap_mfn_end __read_mostly;
> > +mfn_t xenheap_mfn_start __read_mostly = INVALID_MFN;
> > +mfn_t xenheap_mfn_end __read_mostly;

Actually I get the following build error with
gcc-linaro-4.9-2014.05-aarch64-linux-gnu-x86_64-linux-gnu:

mm.c:141:1: error: initializer element is not constant
 mfn_t xenheap_mfn_start __read_mostly = INVALID_MFN;
 ^
make[4]: *** [mm.o] Error 1

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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Julien Grall]

Hi,

On 20/06/17 11:32, Jan Beulich wrote:
>>>> On 20.06.17 at 12:06, <tim@xen.org> wrote:
>> At 03:36 -0600 on 20 Jun (1497929778), Jan Beulich wrote:
>>>>>> On 20.06.17 at 11:14, <tim@xen.org> wrote:
>>>> At 01:32 -0600 on 20 Jun (1497922345), Jan Beulich wrote:
>>>>>>>> On 19.06.17 at 18:57, <julien.grall@arm.com> wrote:
>>>>>> --- a/xen/include/xen/mm.h
>>>>>> +++ b/xen/include/xen/mm.h
>>>>>> @@ -56,7 +56,7 @@
>>>>>>
>>>>>>  TYPE_SAFE(unsigned long, mfn);
>>>>>>  #define PRI_mfn          "05lx"
>>>>>> -#define INVALID_MFN      _mfn(~0UL)
>>>>>> +#define INVALID_MFN      (mfn_t){ ~0UL }
>>>>>
>>>>> While I don't expect anyone to wish to use a suffix expression on
>>>>> this constant, for maximum compatibility this should still be fully
>>>>> parenthesized, I think. Of course this should be easy enough to
>>>>> do while committing.
>>>>>
>>>>> Are you able to assure us that clang supports this gcc extension
>>>>> (compound literal for non-compound types)
>>>>
>>>> AIUI this is a C99 feature, not a GCCism.
>>>
>>> Most parts of it yes (it is a gcc extension in C89 mode only), but the
>>> specific use here isn't afaict: Compound literals outside of functions
>>> are static objects, and hence couldn't be used as initializers of other
>>> objects.
>>
>> Ah, I see.  So would it be better to use
>>
>>   #define INVALID_MFN ((const mfn_t) { ~0UL })
>>
>> ?
>
> While I think we should indeed consider adding the const, the above
> still is a static object, and hence still not suitable as an initializer as
> per C99 or C11. But as long as gcc and clang permit it, we're fine.

Actually this solutions breaks on GCC 4.9 provided by Linaro ([1] 
4.9-2016-02 and 4.9-2017.01).

This small reproducer does not compile with -std=gnu99 (used by Xen) but 
compile with this option. Jan, have you tried 4.9 with this patch?

typedef struct
{
     unsigned long i;
} mfn_t;

mfn_t v = (const mfn_t){~0UL};

Cheers,

[1] https://releases.linaro.org/components/toolchain/binaries/

>
> Jan
>

-- 
Julien Grall

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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Jan Beulich]

>>> On 22.06.17 at 20:31, <julien.grall@arm.com> wrote:
> Hi,
> 
> On 20/06/17 11:32, Jan Beulich wrote:
>>>>> On 20.06.17 at 12:06, <tim@xen.org> wrote:
>>> At 03:36 -0600 on 20 Jun (1497929778), Jan Beulich wrote:
>>>>>>> On 20.06.17 at 11:14, <tim@xen.org> wrote:
>>>>> At 01:32 -0600 on 20 Jun (1497922345), Jan Beulich wrote:
>>>>>>>>> On 19.06.17 at 18:57, <julien.grall@arm.com> wrote:
>>>>>>> --- a/xen/include/xen/mm.h
>>>>>>> +++ b/xen/include/xen/mm.h
>>>>>>> @@ -56,7 +56,7 @@
>>>>>>>
>>>>>>>  TYPE_SAFE(unsigned long, mfn);
>>>>>>>  #define PRI_mfn          "05lx"
>>>>>>> -#define INVALID_MFN      _mfn(~0UL)
>>>>>>> +#define INVALID_MFN      (mfn_t){ ~0UL }
>>>>>>
>>>>>> While I don't expect anyone to wish to use a suffix expression on
>>>>>> this constant, for maximum compatibility this should still be fully
>>>>>> parenthesized, I think. Of course this should be easy enough to
>>>>>> do while committing.
>>>>>>
>>>>>> Are you able to assure us that clang supports this gcc extension
>>>>>> (compound literal for non-compound types)
>>>>>
>>>>> AIUI this is a C99 feature, not a GCCism.
>>>>
>>>> Most parts of it yes (it is a gcc extension in C89 mode only), but the
>>>> specific use here isn't afaict: Compound literals outside of functions
>>>> are static objects, and hence couldn't be used as initializers of other
>>>> objects.
>>>
>>> Ah, I see.  So would it be better to use
>>>
>>>   #define INVALID_MFN ((const mfn_t) { ~0UL })
>>>
>>> ?
>>
>> While I think we should indeed consider adding the const, the above
>> still is a static object, and hence still not suitable as an initializer as
>> per C99 or C11. But as long as gcc and clang permit it, we're fine.
> 
> Actually this solutions breaks on GCC 4.9 provided by Linaro ([1] 
> 4.9-2016-02 and 4.9-2017.01).
> 
> This small reproducer does not compile with -std=gnu99 (used by Xen) but 
> compile with this option. Jan, have you tried 4.9 with this patch?

That's sort of an odd question - you've sent the patch, so I would
have expected you to have made sure it doesn't break (and
while it was me to add the const, this was discussed, and you don't
make clear whether that's the issue). In any event, I've tried ...

> typedef struct
> {
>      unsigned long i;
> } mfn_t;
> 
> mfn_t v = (const mfn_t){~0UL};

... this now with 7.1.0, 6.3.0, 5.4.0, 5.2.0, and 4.9.3, and all
of them compile this without errors or warnings (at -Wall -W).
For 4.9.3 I've also specifically taken care to try not only the
x86 compiler, but also the arm32 and arm64 ones. So I'm afraid
I lack enough detail to understand what the issue is and what a
solution may look like.

Jan


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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Julien Grall]

Hi Jan,

On 23/06/17 09:30, Jan Beulich wrote:
>>>> On 22.06.17 at 20:31, <julien.grall@arm.com> wrote:
>> Hi,
>>
>> On 20/06/17 11:32, Jan Beulich wrote:
>>>>>> On 20.06.17 at 12:06, <tim@xen.org> wrote:
>>>> At 03:36 -0600 on 20 Jun (1497929778), Jan Beulich wrote:
>>>>>>>> On 20.06.17 at 11:14, <tim@xen.org> wrote:
>>>>>> At 01:32 -0600 on 20 Jun (1497922345), Jan Beulich wrote:
>>>>>>>>>> On 19.06.17 at 18:57, <julien.grall@arm.com> wrote:
>>>>>>>> --- a/xen/include/xen/mm.h
>>>>>>>> +++ b/xen/include/xen/mm.h
>>>>>>>> @@ -56,7 +56,7 @@
>>>>>>>>
>>>>>>>>  TYPE_SAFE(unsigned long, mfn);
>>>>>>>>  #define PRI_mfn          "05lx"
>>>>>>>> -#define INVALID_MFN      _mfn(~0UL)
>>>>>>>> +#define INVALID_MFN      (mfn_t){ ~0UL }
>>>>>>>
>>>>>>> While I don't expect anyone to wish to use a suffix expression on
>>>>>>> this constant, for maximum compatibility this should still be fully
>>>>>>> parenthesized, I think. Of course this should be easy enough to
>>>>>>> do while committing.
>>>>>>>
>>>>>>> Are you able to assure us that clang supports this gcc extension
>>>>>>> (compound literal for non-compound types)
>>>>>>
>>>>>> AIUI this is a C99 feature, not a GCCism.
>>>>>
>>>>> Most parts of it yes (it is a gcc extension in C89 mode only), but the
>>>>> specific use here isn't afaict: Compound literals outside of functions
>>>>> are static objects, and hence couldn't be used as initializers of other
>>>>> objects.
>>>>
>>>> Ah, I see.  So would it be better to use
>>>>
>>>>   #define INVALID_MFN ((const mfn_t) { ~0UL })
>>>>
>>>> ?
>>>
>>> While I think we should indeed consider adding the const, the above
>>> still is a static object, and hence still not suitable as an initializer as
>>> per C99 or C11. But as long as gcc and clang permit it, we're fine.
>>
>> Actually this solutions breaks on GCC 4.9 provided by Linaro ([1]
>> 4.9-2016-02 and 4.9-2017.01).
>>
>> This small reproducer does not compile with -std=gnu99 (used by Xen) but
>> compile with this option. Jan, have you tried 4.9 with this patch?
>
> That's sort of an odd question - you've sent the patch, so I would
> have expected you to have made sure it doesn't break (and
> while it was me to add the const, this was discussed, and you don't
> make clear whether that's the issue). In any event, I've tried ...

I don't personally try every single compiler every time I am writing a 
patch... This is too complex given that different stakeholders (Linaro, 
Debian, Ubuntu,...) provide various binaries with their own patches on top.

I asked you because I was wondering what is happening on x86 (I don't 
have 4.9 x86 in hand) and to rule out a bug in the compiler provided by 
Linaro.

>
>> typedef struct
>> {
>>      unsigned long i;
>> } mfn_t;
>>
>> mfn_t v = (const mfn_t){~0UL};
>
> ... this now with 7.1.0, 6.3.0, 5.4.0, 5.2.0, and 4.9.3, and all
> of them compile this without errors or warnings (at -Wall -W).
> For 4.9.3 I've also specifically taken care to try not only the
> x86 compiler, but also the arm32 and arm64 ones. So I'm afraid
> I lack enough detail to understand what the issue is and what a
> solution may look like.

I don't have much except the following error:

/tmp/test.c:6:1: error: initializer element is not constant
  mfn_t v = (const mfn_t){~0UL};
  ^

If it works for you on 4.9, then it might be a bug in the GCC provided 
by Linaro and will report it.

Cheers,

-- 
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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Julien Grall]

On 23/06/17 09:30, Jan Beulich wrote:
>>>> On 22.06.17 at 20:31, <julien.grall@arm.com> wrote:
>> Hi,
>>
>> On 20/06/17 11:32, Jan Beulich wrote:
>>>>>> On 20.06.17 at 12:06, <tim@xen.org> wrote:
>>>> At 03:36 -0600 on 20 Jun (1497929778), Jan Beulich wrote:
>>>>>>>> On 20.06.17 at 11:14, <tim@xen.org> wrote:
>>>>>> At 01:32 -0600 on 20 Jun (1497922345), Jan Beulich wrote:
>>>>>>>>>> On 19.06.17 at 18:57, <julien.grall@arm.com> wrote:
>>>>>>>> --- a/xen/include/xen/mm.h
>>>>>>>> +++ b/xen/include/xen/mm.h
>>>>>>>> @@ -56,7 +56,7 @@
>>>>>>>>
>>>>>>>>  TYPE_SAFE(unsigned long, mfn);
>>>>>>>>  #define PRI_mfn          "05lx"
>>>>>>>> -#define INVALID_MFN      _mfn(~0UL)
>>>>>>>> +#define INVALID_MFN      (mfn_t){ ~0UL }
>>>>>>>
>>>>>>> While I don't expect anyone to wish to use a suffix expression on
>>>>>>> this constant, for maximum compatibility this should still be fully
>>>>>>> parenthesized, I think. Of course this should be easy enough to
>>>>>>> do while committing.
>>>>>>>
>>>>>>> Are you able to assure us that clang supports this gcc extension
>>>>>>> (compound literal for non-compound types)
>>>>>>
>>>>>> AIUI this is a C99 feature, not a GCCism.
>>>>>
>>>>> Most parts of it yes (it is a gcc extension in C89 mode only), but the
>>>>> specific use here isn't afaict: Compound literals outside of functions
>>>>> are static objects, and hence couldn't be used as initializers of other
>>>>> objects.
>>>>
>>>> Ah, I see.  So would it be better to use
>>>>
>>>>   #define INVALID_MFN ((const mfn_t) { ~0UL })
>>>>
>>>> ?
>>>
>>> While I think we should indeed consider adding the const, the above
>>> still is a static object, and hence still not suitable as an initializer as
>>> per C99 or C11. But as long as gcc and clang permit it, we're fine.
>>
>> Actually this solutions breaks on GCC 4.9 provided by Linaro ([1]
>> 4.9-2016-02 and 4.9-2017.01).
>>
>> This small reproducer does not compile with -std=gnu99 (used by Xen) but
>> compile with this option. Jan, have you tried 4.9 with this patch?
>
> That's sort of an odd question - you've sent the patch, so I would
> have expected you to have made sure it doesn't break (and
> while it was me to add the const, this was discussed, and you don't
> make clear whether that's the issue). In any event, I've tried ...
>
>> typedef struct
>> {
>>      unsigned long i;
>> } mfn_t;
>>
>> mfn_t v = (const mfn_t){~0UL};
>
> ... this now with 7.1.0, 6.3.0, 5.4.0, 5.2.0, and 4.9.3, and all
> of them compile this without errors or warnings (at -Wall -W).

Actually did you build with -std=gnu99? I just tried 4.9.3 for x86 and
also 4.8 for ARM64 on Ubuntu Trusty. Both are broken.

Cheers,

-- 
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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Tim Deegan]

At 09:41 +0100 on 23 Jun (1498210893), Julien Grall wrote:
> Hi Jan,
> 
> On 23/06/17 09:30, Jan Beulich wrote:
> >>>> On 22.06.17 at 20:31, <julien.grall@arm.com> wrote:
> >> Hi,
> >>
> >> On 20/06/17 11:32, Jan Beulich wrote:
> >>>>>> On 20.06.17 at 12:06, <tim@xen.org> wrote:
> >>>> At 03:36 -0600 on 20 Jun (1497929778), Jan Beulich wrote:
> >>>>>>>> On 20.06.17 at 11:14, <tim@xen.org> wrote:
> >>>>>> At 01:32 -0600 on 20 Jun (1497922345), Jan Beulich wrote:
> >>>>>>>>>> On 19.06.17 at 18:57, <julien.grall@arm.com> wrote:
> >>>>>>>> --- a/xen/include/xen/mm.h
> >>>>>>>> +++ b/xen/include/xen/mm.h
> >>>>>>>> @@ -56,7 +56,7 @@
> >>>>>>>>
> >>>>>>>>  TYPE_SAFE(unsigned long, mfn);
> >>>>>>>>  #define PRI_mfn          "05lx"
> >>>>>>>> -#define INVALID_MFN      _mfn(~0UL)
> >>>>>>>> +#define INVALID_MFN      (mfn_t){ ~0UL }
> >>>>>>>
> >>>>>>> While I don't expect anyone to wish to use a suffix expression on
> >>>>>>> this constant, for maximum compatibility this should still be fully
> >>>>>>> parenthesized, I think. Of course this should be easy enough to
> >>>>>>> do while committing.
> >>>>>>>
> >>>>>>> Are you able to assure us that clang supports this gcc extension
> >>>>>>> (compound literal for non-compound types)
> >>>>>>
> >>>>>> AIUI this is a C99 feature, not a GCCism.
> >>>>>
> >>>>> Most parts of it yes (it is a gcc extension in C89 mode only), but the
> >>>>> specific use here isn't afaict: Compound literals outside of functions
> >>>>> are static objects, and hence couldn't be used as initializers of other
> >>>>> objects.
> >>>>
> >>>> Ah, I see.  So would it be better to use
> >>>>
> >>>>   #define INVALID_MFN ((const mfn_t) { ~0UL })
> >>>>
> >>>> ?
> >>>
> >>> While I think we should indeed consider adding the const, the above
> >>> still is a static object, and hence still not suitable as an initializer as
> >>> per C99 or C11. But as long as gcc and clang permit it, we're fine.
> >>
> >> Actually this solutions breaks on GCC 4.9 provided by Linaro ([1]
> >> 4.9-2016-02 and 4.9-2017.01).
> >>
> >> This small reproducer does not compile with -std=gnu99 (used by Xen) but
> >> compile with this option. Jan, have you tried 4.9 with this patch?
> >
> > That's sort of an odd question - you've sent the patch, so I would
> > have expected you to have made sure it doesn't break (and
> > while it was me to add the const, this was discussed, and you don't
> > make clear whether that's the issue). In any event, I've tried ...
> 
> I don't personally try every single compiler every time I am writing a 
> patch... This is too complex given that different stakeholders (Linaro, 
> Debian, Ubuntu,...) provide various binaries with their own patches on top.
> 
> I asked you because I was wondering what is happening on x86 (I don't 
> have 4.9 x86 in hand) and to rule out a bug in the compiler provided by 
> Linaro.
> 
> >
> >> typedef struct
> >> {
> >>      unsigned long i;
> >> } mfn_t;
> >>
> >> mfn_t v = (const mfn_t){~0UL};
> >
> > ... this now with 7.1.0, 6.3.0, 5.4.0, 5.2.0, and 4.9.3, and all
> > of them compile this without errors or warnings (at -Wall -W).
> > For 4.9.3 I've also specifically taken care to try not only the
> > x86 compiler, but also the arm32 and arm64 ones. So I'm afraid
> > I lack enough detail to understand what the issue is and what a
> > solution may look like.
> 
> I don't have much except the following error:
> 
> /tmp/test.c:6:1: error: initializer element is not constant
>   mfn_t v = (const mfn_t){~0UL};
>   ^
> 
> If it works for you on 4.9, then it might be a bug in the GCC provided 
> by Linaro and will report it.

This fails for me on x86 gcc 4.9.4, using -xc -std=gnu99.  The
complaint is valid, as Jan pointed out: the literal is a static object
and so not a valid initializer.  GCC also complains about the
'debug' version for the same reason. :(

Using a plain initializer works OK for both debug and non-debug:

  mfn_t v = {~0UL};

but I haven't checked whether other compilers like that as well.

Tim.



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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Julien Grall]

On 23/06/17 09:58, Tim Deegan wrote:
> At 09:41 +0100 on 23 Jun (1498210893), Julien Grall wrote:
>> Hi Jan,
>>
>> On 23/06/17 09:30, Jan Beulich wrote:
>>>>>> On 22.06.17 at 20:31, <julien.grall@arm.com> wrote:
>>>> Hi,
>>>>
>>>> On 20/06/17 11:32, Jan Beulich wrote:
>>>>>>>> On 20.06.17 at 12:06, <tim@xen.org> wrote:
>>>>>> At 03:36 -0600 on 20 Jun (1497929778), Jan Beulich wrote:
>>>>>>>>>> On 20.06.17 at 11:14, <tim@xen.org> wrote:
>>>>>>>> At 01:32 -0600 on 20 Jun (1497922345), Jan Beulich wrote:
>>>>>>>>>>>> On 19.06.17 at 18:57, <julien.grall@arm.com> wrote:
>>>>>>>>>> --- a/xen/include/xen/mm.h
>>>>>>>>>> +++ b/xen/include/xen/mm.h
>>>>>>>>>> @@ -56,7 +56,7 @@
>>>>>>>>>>
>>>>>>>>>>  TYPE_SAFE(unsigned long, mfn);
>>>>>>>>>>  #define PRI_mfn          "05lx"
>>>>>>>>>> -#define INVALID_MFN      _mfn(~0UL)
>>>>>>>>>> +#define INVALID_MFN      (mfn_t){ ~0UL }
>>>>>>>>>
>>>>>>>>> While I don't expect anyone to wish to use a suffix expression on
>>>>>>>>> this constant, for maximum compatibility this should still be fully
>>>>>>>>> parenthesized, I think. Of course this should be easy enough to
>>>>>>>>> do while committing.
>>>>>>>>>
>>>>>>>>> Are you able to assure us that clang supports this gcc extension
>>>>>>>>> (compound literal for non-compound types)
>>>>>>>>
>>>>>>>> AIUI this is a C99 feature, not a GCCism.
>>>>>>>
>>>>>>> Most parts of it yes (it is a gcc extension in C89 mode only), but the
>>>>>>> specific use here isn't afaict: Compound literals outside of functions
>>>>>>> are static objects, and hence couldn't be used as initializers of other
>>>>>>> objects.
>>>>>>
>>>>>> Ah, I see.  So would it be better to use
>>>>>>
>>>>>>   #define INVALID_MFN ((const mfn_t) { ~0UL })
>>>>>>
>>>>>> ?
>>>>>
>>>>> While I think we should indeed consider adding the const, the above
>>>>> still is a static object, and hence still not suitable as an initializer as
>>>>> per C99 or C11. But as long as gcc and clang permit it, we're fine.
>>>>
>>>> Actually this solutions breaks on GCC 4.9 provided by Linaro ([1]
>>>> 4.9-2016-02 and 4.9-2017.01).
>>>>
>>>> This small reproducer does not compile with -std=gnu99 (used by Xen) but
>>>> compile with this option. Jan, have you tried 4.9 with this patch?
>>>
>>> That's sort of an odd question - you've sent the patch, so I would
>>> have expected you to have made sure it doesn't break (and
>>> while it was me to add the const, this was discussed, and you don't
>>> make clear whether that's the issue). In any event, I've tried ...
>>
>> I don't personally try every single compiler every time I am writing a
>> patch... This is too complex given that different stakeholders (Linaro,
>> Debian, Ubuntu,...) provide various binaries with their own patches on top.
>>
>> I asked you because I was wondering what is happening on x86 (I don't
>> have 4.9 x86 in hand) and to rule out a bug in the compiler provided by
>> Linaro.
>>
>>>
>>>> typedef struct
>>>> {
>>>>      unsigned long i;
>>>> } mfn_t;
>>>>
>>>> mfn_t v = (const mfn_t){~0UL};
>>>
>>> ... this now with 7.1.0, 6.3.0, 5.4.0, 5.2.0, and 4.9.3, and all
>>> of them compile this without errors or warnings (at -Wall -W).
>>> For 4.9.3 I've also specifically taken care to try not only the
>>> x86 compiler, but also the arm32 and arm64 ones. So I'm afraid
>>> I lack enough detail to understand what the issue is and what a
>>> solution may look like.
>>
>> I don't have much except the following error:
>>
>> /tmp/test.c:6:1: error: initializer element is not constant
>>   mfn_t v = (const mfn_t){~0UL};
>>   ^
>>
>> If it works for you on 4.9, then it might be a bug in the GCC provided
>> by Linaro and will report it.
>
> This fails for me on x86 gcc 4.9.4, using -xc -std=gnu99.  The
> complaint is valid, as Jan pointed out: the literal is a static object
> and so not a valid initializer.  GCC also complains about the
> 'debug' version for the same reason. :(
>
> Using a plain initializer works OK for both debug and non-debug:
>
>   mfn_t v = {~0UL};
>
> but I haven't checked whether other compilers like that as well.

This seems to be a bug in GCC up to 5.0:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64856

Cheers,

-- 
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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Tim Deegan]

At 09:58 +0100 on 23 Jun (1498211910), Tim Deegan wrote:
> At 09:41 +0100 on 23 Jun (1498210893), Julien Grall wrote:
> > On 23/06/17 09:30, Jan Beulich wrote:
> > >
> > >> typedef struct
> > >> {
> > >>      unsigned long i;
> > >> } mfn_t;
> > >>
> > >> mfn_t v = (const mfn_t){~0UL};
> > >
> > > ... this now with 7.1.0, 6.3.0, 5.4.0, 5.2.0, and 4.9.3, and all
> > > of them compile this without errors or warnings (at -Wall -W).
> > > For 4.9.3 I've also specifically taken care to try not only the
> > > x86 compiler, but also the arm32 and arm64 ones. So I'm afraid
> > > I lack enough detail to understand what the issue is and what a
> > > solution may look like.
> > 
> > I don't have much except the following error:
> > 
> > /tmp/test.c:6:1: error: initializer element is not constant
> >   mfn_t v = (const mfn_t){~0UL};
> >   ^
> > 
> > If it works for you on 4.9, then it might be a bug in the GCC provided 
> > by Linaro and will report it.
> 
> This fails for me on x86 gcc 4.9.4, using -xc -std=gnu99.  The
> complaint is valid, as Jan pointed out: the literal is a static object
> and so not a valid initializer.  GCC also complains about the
> 'debug' version for the same reason. :(
> 
> Using a plain initializer works OK for both debug and non-debug:
> 
>   mfn_t v = {~0UL};
> 
> but I haven't checked whether other compilers like that as well.

And that wouldn't work for things like f(INVALID_MFN) -- sometimes we
actually do want the literal.

Tim.

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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Jan Beulich]

>>> On 23.06.17 at 10:41, <julien.grall@arm.com> wrote:
> On 23/06/17 09:30, Jan Beulich wrote:
>>>>> On 22.06.17 at 20:31, <julien.grall@arm.com> wrote:
>>> On 20/06/17 11:32, Jan Beulich wrote:
>>>>>>> On 20.06.17 at 12:06, <tim@xen.org> wrote:
>>>>> At 03:36 -0600 on 20 Jun (1497929778), Jan Beulich wrote:
>>>>>>>>> On 20.06.17 at 11:14, <tim@xen.org> wrote:
>>>>>>> At 01:32 -0600 on 20 Jun (1497922345), Jan Beulich wrote:
>>>>>>>>>>> On 19.06.17 at 18:57, <julien.grall@arm.com> wrote:
>>>>>>>>> --- a/xen/include/xen/mm.h
>>>>>>>>> +++ b/xen/include/xen/mm.h
>>>>>>>>> @@ -56,7 +56,7 @@
>>>>>>>>>
>>>>>>>>>  TYPE_SAFE(unsigned long, mfn);
>>>>>>>>>  #define PRI_mfn          "05lx"
>>>>>>>>> -#define INVALID_MFN      _mfn(~0UL)
>>>>>>>>> +#define INVALID_MFN      (mfn_t){ ~0UL }
>>>>>>>>
>>>>>>>> While I don't expect anyone to wish to use a suffix expression on
>>>>>>>> this constant, for maximum compatibility this should still be fully
>>>>>>>> parenthesized, I think. Of course this should be easy enough to
>>>>>>>> do while committing.
>>>>>>>>
>>>>>>>> Are you able to assure us that clang supports this gcc extension
>>>>>>>> (compound literal for non-compound types)
>>>>>>>
>>>>>>> AIUI this is a C99 feature, not a GCCism.
>>>>>>
>>>>>> Most parts of it yes (it is a gcc extension in C89 mode only), but the
>>>>>> specific use here isn't afaict: Compound literals outside of functions
>>>>>> are static objects, and hence couldn't be used as initializers of other
>>>>>> objects.
>>>>>
>>>>> Ah, I see.  So would it be better to use
>>>>>
>>>>>   #define INVALID_MFN ((const mfn_t) { ~0UL })
>>>>>
>>>>> ?
>>>>
>>>> While I think we should indeed consider adding the const, the above
>>>> still is a static object, and hence still not suitable as an initializer as
>>>> per C99 or C11. But as long as gcc and clang permit it, we're fine.
>>>
>>> Actually this solutions breaks on GCC 4.9 provided by Linaro ([1]
>>> 4.9-2016-02 and 4.9-2017.01).
>>>
>>> This small reproducer does not compile with -std=gnu99 (used by Xen) but
>>> compile with this option. Jan, have you tried 4.9 with this patch?
>>
>> That's sort of an odd question - you've sent the patch, so I would
>> have expected you to have made sure it doesn't break (and
>> while it was me to add the const, this was discussed, and you don't
>> make clear whether that's the issue). In any event, I've tried ...
> 
> I don't personally try every single compiler every time I am writing a 
> patch... This is too complex given that different stakeholders (Linaro, 
> Debian, Ubuntu,...) provide various binaries with their own patches on top.

Which I can understand. I've asked back the way I did just because
you appeared to imply I would do such checking routinely, which
(for the very reasons you name) I don't. I just happen to test with
differing compiler versions every once in a while.

Jan


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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Jan Beulich]

>>> On 23.06.17 at 10:55, <julien.grall@arm.com> wrote:

> 
> On 23/06/17 09:30, Jan Beulich wrote:
>>>>> On 22.06.17 at 20:31, <julien.grall@arm.com> wrote:
>>> Hi,
>>>
>>> On 20/06/17 11:32, Jan Beulich wrote:
>>>>>>> On 20.06.17 at 12:06, <tim@xen.org> wrote:
>>>>> At 03:36 -0600 on 20 Jun (1497929778), Jan Beulich wrote:
>>>>>>>>> On 20.06.17 at 11:14, <tim@xen.org> wrote:
>>>>>>> At 01:32 -0600 on 20 Jun (1497922345), Jan Beulich wrote:
>>>>>>>>>>> On 19.06.17 at 18:57, <julien.grall@arm.com> wrote:
>>>>>>>>> --- a/xen/include/xen/mm.h
>>>>>>>>> +++ b/xen/include/xen/mm.h
>>>>>>>>> @@ -56,7 +56,7 @@
>>>>>>>>>
>>>>>>>>>  TYPE_SAFE(unsigned long, mfn);
>>>>>>>>>  #define PRI_mfn          "05lx"
>>>>>>>>> -#define INVALID_MFN      _mfn(~0UL)
>>>>>>>>> +#define INVALID_MFN      (mfn_t){ ~0UL }
>>>>>>>>
>>>>>>>> While I don't expect anyone to wish to use a suffix expression on
>>>>>>>> this constant, for maximum compatibility this should still be fully
>>>>>>>> parenthesized, I think. Of course this should be easy enough to
>>>>>>>> do while committing.
>>>>>>>>
>>>>>>>> Are you able to assure us that clang supports this gcc extension
>>>>>>>> (compound literal for non-compound types)
>>>>>>>
>>>>>>> AIUI this is a C99 feature, not a GCCism.
>>>>>>
>>>>>> Most parts of it yes (it is a gcc extension in C89 mode only), but the
>>>>>> specific use here isn't afaict: Compound literals outside of functions
>>>>>> are static objects, and hence couldn't be used as initializers of other
>>>>>> objects.
>>>>>
>>>>> Ah, I see.  So would it be better to use
>>>>>
>>>>>   #define INVALID_MFN ((const mfn_t) { ~0UL })
>>>>>
>>>>> ?
>>>>
>>>> While I think we should indeed consider adding the const, the above
>>>> still is a static object, and hence still not suitable as an initializer as
>>>> per C99 or C11. But as long as gcc and clang permit it, we're fine.
>>>
>>> Actually this solutions breaks on GCC 4.9 provided by Linaro ([1]
>>> 4.9-2016-02 and 4.9-2017.01).
>>>
>>> This small reproducer does not compile with -std=gnu99 (used by Xen) but
>>> compile with this option. Jan, have you tried 4.9 with this patch?
>>
>> That's sort of an odd question - you've sent the patch, so I would
>> have expected you to have made sure it doesn't break (and
>> while it was me to add the const, this was discussed, and you don't
>> make clear whether that's the issue). In any event, I've tried ...
>>
>>> typedef struct
>>> {
>>>      unsigned long i;
>>> } mfn_t;
>>>
>>> mfn_t v = (const mfn_t){~0UL};
>>
>> ... this now with 7.1.0, 6.3.0, 5.4.0, 5.2.0, and 4.9.3, and all
>> of them compile this without errors or warnings (at -Wall -W).
> 
> Actually did you build with -std=gnu99? I just tried 4.9.3 for x86 and
> also 4.8 for ARM64 on Ubuntu Trusty. Both are broken.

Ah, indeed - that fails with 4.9.3 but succeeds with 5.2.0. And
it's not the const getting in the way here. I notice this difference
in their documentation (4.9.3 first, then 7.1.0):

Compound literals for scalar types and union types are also allowed,
but then the compound literal is equivalent to a cast.

Compound literals for scalar types and union types are also allowed.
In the following example the variable i is initialized to the value 2,
the result of incrementing the unnamed object created by the
compound literal.

	int i = ++(int) { 1 };

It is especially this example clarifying that newer compilers don't
treat this like a cast anymore (albeit a casted expression alone is
fine as initializer in 4.9.3, so there must be more to the failure).

While I still view this as a compiler bug (as it accepts the code in
default mode), as a workaround  I guess we'll need to accept a
gcc < 5 conditional in the header, which we would really have
wanted to avoid.

Jan


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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Tim Deegan]

At 03:18 -0600 on 23 Jun (1498187924), Jan Beulich wrote:
> >>> On 23.06.17 at 10:55, <julien.grall@arm.com> wrote:
> 
> > 
> > On 23/06/17 09:30, Jan Beulich wrote:
> >>>>> On 22.06.17 at 20:31, <julien.grall@arm.com> wrote:
> >>> Hi,
> >>>
> >>> On 20/06/17 11:32, Jan Beulich wrote:
> >>>>>>> On 20.06.17 at 12:06, <tim@xen.org> wrote:
> >>>>> At 03:36 -0600 on 20 Jun (1497929778), Jan Beulich wrote:
> >>>>>>>>> On 20.06.17 at 11:14, <tim@xen.org> wrote:
> >>>>>>> At 01:32 -0600 on 20 Jun (1497922345), Jan Beulich wrote:
> >>>>>>>>>>> On 19.06.17 at 18:57, <julien.grall@arm.com> wrote:
> >>>>>>>>> --- a/xen/include/xen/mm.h
> >>>>>>>>> +++ b/xen/include/xen/mm.h
> >>>>>>>>> @@ -56,7 +56,7 @@
> >>>>>>>>>
> >>>>>>>>>  TYPE_SAFE(unsigned long, mfn);
> >>>>>>>>>  #define PRI_mfn          "05lx"
> >>>>>>>>> -#define INVALID_MFN      _mfn(~0UL)
> >>>>>>>>> +#define INVALID_MFN      (mfn_t){ ~0UL }
> >>>>>>>>
> >>>>>>>> While I don't expect anyone to wish to use a suffix expression on
> >>>>>>>> this constant, for maximum compatibility this should still be fully
> >>>>>>>> parenthesized, I think. Of course this should be easy enough to
> >>>>>>>> do while committing.
> >>>>>>>>
> >>>>>>>> Are you able to assure us that clang supports this gcc extension
> >>>>>>>> (compound literal for non-compound types)
> >>>>>>>
> >>>>>>> AIUI this is a C99 feature, not a GCCism.
> >>>>>>
> >>>>>> Most parts of it yes (it is a gcc extension in C89 mode only), but the
> >>>>>> specific use here isn't afaict: Compound literals outside of functions
> >>>>>> are static objects, and hence couldn't be used as initializers of other
> >>>>>> objects.
> >>>>>
> >>>>> Ah, I see.  So would it be better to use
> >>>>>
> >>>>>   #define INVALID_MFN ((const mfn_t) { ~0UL })
> >>>>>
> >>>>> ?
> >>>>
> >>>> While I think we should indeed consider adding the const, the above
> >>>> still is a static object, and hence still not suitable as an initializer as
> >>>> per C99 or C11. But as long as gcc and clang permit it, we're fine.
> >>>
> >>> Actually this solutions breaks on GCC 4.9 provided by Linaro ([1]
> >>> 4.9-2016-02 and 4.9-2017.01).
> >>>
> >>> This small reproducer does not compile with -std=gnu99 (used by Xen) but
> >>> compile with this option. Jan, have you tried 4.9 with this patch?
> >>
> >> That's sort of an odd question - you've sent the patch, so I would
> >> have expected you to have made sure it doesn't break (and
> >> while it was me to add the const, this was discussed, and you don't
> >> make clear whether that's the issue). In any event, I've tried ...
> >>
> >>> typedef struct
> >>> {
> >>>      unsigned long i;
> >>> } mfn_t;
> >>>
> >>> mfn_t v = (const mfn_t){~0UL};
> >>
> >> ... this now with 7.1.0, 6.3.0, 5.4.0, 5.2.0, and 4.9.3, and all
> >> of them compile this without errors or warnings (at -Wall -W).
> > 
> > Actually did you build with -std=gnu99? I just tried 4.9.3 for x86 and
> > also 4.8 for ARM64 on Ubuntu Trusty. Both are broken.
> 
> Ah, indeed - that fails with 4.9.3 but succeeds with 5.2.0. And
> it's not the const getting in the way here. I notice this difference
> in their documentation (4.9.3 first, then 7.1.0):
> 
> Compound literals for scalar types and union types are also allowed,
> but then the compound literal is equivalent to a cast.
> 
> Compound literals for scalar types and union types are also allowed.
> In the following example the variable i is initialized to the value 2,
> the result of incrementing the unnamed object created by the
> compound literal.
> 
> 	int i = ++(int) { 1 };
> 
> It is especially this example clarifying that newer compilers don't
> treat this like a cast anymore (albeit a casted expression alone is
> fine as initializer in 4.9.3, so there must be more to the failure).
> 
> While I still view this as a compiler bug (as it accepts the code in
> default mode), as a workaround  I guess we'll need to accept a
> gcc < 5 conditional in the header, which we would really have
> wanted to avoid.

Since we'll have to make some scheme that works for 4.9, I think we
should just use that for all versions.

How about:
 - keep INVALID_MFN as an inline function call for most uses;
 - #define INVALID_MFN_INITIALIZER { ~0UL } for when we need a
   real constant initializer aat file scope.

Tim.

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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Jan Beulich]

>>> On 23.06.17 at 11:24, <tim@xen.org> wrote:
> At 03:18 -0600 on 23 Jun (1498187924), Jan Beulich wrote:
>> >>> On 23.06.17 at 10:55, <julien.grall@arm.com> wrote:
>> 
>> > 
>> > On 23/06/17 09:30, Jan Beulich wrote:
>> >>>>> On 22.06.17 at 20:31, <julien.grall@arm.com> wrote:
>> >>> Hi,
>> >>>
>> >>> On 20/06/17 11:32, Jan Beulich wrote:
>> >>>>>>> On 20.06.17 at 12:06, <tim@xen.org> wrote:
>> >>>>> At 03:36 -0600 on 20 Jun (1497929778), Jan Beulich wrote:
>> >>>>>>>>> On 20.06.17 at 11:14, <tim@xen.org> wrote:
>> >>>>>>> At 01:32 -0600 on 20 Jun (1497922345), Jan Beulich wrote:
>> >>>>>>>>>>> On 19.06.17 at 18:57, <julien.grall@arm.com> wrote:
>> >>>>>>>>> --- a/xen/include/xen/mm.h
>> >>>>>>>>> +++ b/xen/include/xen/mm.h
>> >>>>>>>>> @@ -56,7 +56,7 @@
>> >>>>>>>>>
>> >>>>>>>>>  TYPE_SAFE(unsigned long, mfn);
>> >>>>>>>>>  #define PRI_mfn          "05lx"
>> >>>>>>>>> -#define INVALID_MFN      _mfn(~0UL)
>> >>>>>>>>> +#define INVALID_MFN      (mfn_t){ ~0UL }
>> >>>>>>>>
>> >>>>>>>> While I don't expect anyone to wish to use a suffix expression on
>> >>>>>>>> this constant, for maximum compatibility this should still be fully
>> >>>>>>>> parenthesized, I think. Of course this should be easy enough to
>> >>>>>>>> do while committing.
>> >>>>>>>>
>> >>>>>>>> Are you able to assure us that clang supports this gcc extension
>> >>>>>>>> (compound literal for non-compound types)
>> >>>>>>>
>> >>>>>>> AIUI this is a C99 feature, not a GCCism.
>> >>>>>>
>> >>>>>> Most parts of it yes (it is a gcc extension in C89 mode only), but the
>> >>>>>> specific use here isn't afaict: Compound literals outside of functions
>> >>>>>> are static objects, and hence couldn't be used as initializers of other
>> >>>>>> objects.
>> >>>>>
>> >>>>> Ah, I see.  So would it be better to use
>> >>>>>
>> >>>>>   #define INVALID_MFN ((const mfn_t) { ~0UL })
>> >>>>>
>> >>>>> ?
>> >>>>
>> >>>> While I think we should indeed consider adding the const, the above
>> >>>> still is a static object, and hence still not suitable as an initializer as
>> >>>> per C99 or C11. But as long as gcc and clang permit it, we're fine.
>> >>>
>> >>> Actually this solutions breaks on GCC 4.9 provided by Linaro ([1]
>> >>> 4.9-2016-02 and 4.9-2017.01).
>> >>>
>> >>> This small reproducer does not compile with -std=gnu99 (used by Xen) but
>> >>> compile with this option. Jan, have you tried 4.9 with this patch?
>> >>
>> >> That's sort of an odd question - you've sent the patch, so I would
>> >> have expected you to have made sure it doesn't break (and
>> >> while it was me to add the const, this was discussed, and you don't
>> >> make clear whether that's the issue). In any event, I've tried ...
>> >>
>> >>> typedef struct
>> >>> {
>> >>>      unsigned long i;
>> >>> } mfn_t;
>> >>>
>> >>> mfn_t v = (const mfn_t){~0UL};
>> >>
>> >> ... this now with 7.1.0, 6.3.0, 5.4.0, 5.2.0, and 4.9.3, and all
>> >> of them compile this without errors or warnings (at -Wall -W).
>> > 
>> > Actually did you build with -std=gnu99? I just tried 4.9.3 for x86 and
>> > also 4.8 for ARM64 on Ubuntu Trusty. Both are broken.
>> 
>> Ah, indeed - that fails with 4.9.3 but succeeds with 5.2.0. And
>> it's not the const getting in the way here. I notice this difference
>> in their documentation (4.9.3 first, then 7.1.0):
>> 
>> Compound literals for scalar types and union types are also allowed,
>> but then the compound literal is equivalent to a cast.
>> 
>> Compound literals for scalar types and union types are also allowed.
>> In the following example the variable i is initialized to the value 2,
>> the result of incrementing the unnamed object created by the
>> compound literal.
>> 
>> 	int i = ++(int) { 1 };
>> 
>> It is especially this example clarifying that newer compilers don't
>> treat this like a cast anymore (albeit a casted expression alone is
>> fine as initializer in 4.9.3, so there must be more to the failure).
>> 
>> While I still view this as a compiler bug (as it accepts the code in
>> default mode), as a workaround  I guess we'll need to accept a
>> gcc < 5 conditional in the header, which we would really have
>> wanted to avoid.
> 
> Since we'll have to make some scheme that works for 4.9, I think we
> should just use that for all versions.
> 
> How about:
>  - keep INVALID_MFN as an inline function call for most uses;
>  - #define INVALID_MFN_INITIALIZER { ~0UL } for when we need a
>    real constant initializer aat file scope.

I'd be fine with that as much as with the other model.

Jan

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Re: [PATCH v2 01/16] xen/mm: Don't use _{g, m}fn for defining INVALID_{G, M}FN

[Julien Grall]

Hi,

On 23/06/17 10:31, Jan Beulich wrote:
>>>> On 23.06.17 at 11:24, <tim@xen.org> wrote:
>> At 03:18 -0600 on 23 Jun (1498187924), Jan Beulich wrote:
>> How about:
>>  - keep INVALID_MFN as an inline function call for most uses;
>>  - #define INVALID_MFN_INITIALIZER { ~0UL } for when we need a
>>    real constant initializer aat file scope.
>
> I'd be fine with that as much as with the other model.

I will send a patch to revert 725039d39e "mm: don't use _{g,m}fn for 
defining INVALID_{G,M}FN" and one to add INVALID_MFN_INITIALIZER.

Cheers,

-- 
Julien Grall

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