diff mbox series

[6/7] xen/arm: mm: Move domain_{,un}map_* helpers in a separate file

Message ID 20220624091146.35716-7-julien@xen.org (mailing list archive)
State Superseded
Headers show
Series xen/arm: mm: Bunch of clean-ups | expand

Commit Message

Julien Grall June 24, 2022, 9:11 a.m. UTC
From: Julien Grall <jgrall@amazon.com>

The file xen/arch/mm.c has been growing quite a lot. It now contains
various independent part of the MM subsytem.

One of them is the helpers to map/unmap a page when CONFIG_DOMAIN_PAGE
(only used by arm32). Move them in a new file xen/arch/arm/domain_page.c.

In order to be able to use CONFIG_DOMAIN_PAGE in the Makefile, a new
Kconfig option is introduced that is selected by x86 and arm32.

Signed-off-by: Julien Grall <jgrall@amazon.com>
---
 xen/arch/arm/Kconfig                |   1 +
 xen/arch/arm/Makefile               |   1 +
 xen/arch/arm/domain_page.c          | 193 +++++++++++++++++++++++++++
 xen/arch/arm/include/asm/arm32/mm.h |   6 +
 xen/arch/arm/include/asm/config.h   |   1 -
 xen/arch/arm/include/asm/lpae.h     |  17 +++
 xen/arch/arm/mm.c                   | 198 +---------------------------
 xen/arch/x86/Kconfig                |   1 +
 xen/arch/x86/include/asm/config.h   |   1 -
 xen/common/Kconfig                  |   3 +
 10 files changed, 224 insertions(+), 198 deletions(-)
 create mode 100644 xen/arch/arm/domain_page.c

Comments

Jan Beulich June 24, 2022, 9:43 a.m. UTC | #1
On 24.06.2022 11:11, Julien Grall wrote:
> From: Julien Grall <jgrall@amazon.com>
> 
> The file xen/arch/mm.c has been growing quite a lot. It now contains
> various independent part of the MM subsytem.
> 
> One of them is the helpers to map/unmap a page when CONFIG_DOMAIN_PAGE
> (only used by arm32). Move them in a new file xen/arch/arm/domain_page.c.
> 
> In order to be able to use CONFIG_DOMAIN_PAGE in the Makefile, a new
> Kconfig option is introduced that is selected by x86 and arm32.
> 
> Signed-off-by: Julien Grall <jgrall@amazon.com>

In principle
Acked-by: Jan Beulich <jbeulich@suse.com>

But ...

> --- a/xen/arch/x86/Kconfig
> +++ b/xen/arch/x86/Kconfig
> @@ -10,6 +10,7 @@ config X86
>  	select ALTERNATIVE_CALL
>  	select ARCH_SUPPORTS_INT128
>  	select CORE_PARKING
> +	select DOMAIN_PAGE
>  	select HAS_ALTERNATIVE
>  	select HAS_COMPAT
>  	select HAS_CPUFREQ
> diff --git a/xen/arch/x86/include/asm/config.h b/xen/arch/x86/include/asm/config.h
> index 07bcd158314b..fbc4bb3416bd 100644
> --- a/xen/arch/x86/include/asm/config.h
> +++ b/xen/arch/x86/include/asm/config.h
> @@ -22,7 +22,6 @@
>  #define CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 1
>  #define CONFIG_DISCONTIGMEM 1
>  #define CONFIG_NUMA_EMU 1
> -#define CONFIG_DOMAIN_PAGE 1

... while I realize it has been named this way, I wonder whether ...

> --- a/xen/common/Kconfig
> +++ b/xen/common/Kconfig
> @@ -11,6 +11,9 @@ config COMPAT
>  config CORE_PARKING
>  	bool
>  
> +config DOMAIN_PAGE
> +	bool

... this isn't a good opportunity to make the name match what it is
about - MAP_DOMAIN_PAGE. See e.g. {clear,copy}_domain_page() which
aren't under this guard, and domain pages in general is a concept we
can't get away without in the first place.

Jan
Julien Grall July 16, 2022, 3 p.m. UTC | #2
Hi Jan,

On 24/06/2022 10:43, Jan Beulich wrote:
> On 24.06.2022 11:11, Julien Grall wrote:
>> From: Julien Grall <jgrall@amazon.com>
>>
>> The file xen/arch/mm.c has been growing quite a lot. It now contains
>> various independent part of the MM subsytem.
>>
>> One of them is the helpers to map/unmap a page when CONFIG_DOMAIN_PAGE
>> (only used by arm32). Move them in a new file xen/arch/arm/domain_page.c.
>>
>> In order to be able to use CONFIG_DOMAIN_PAGE in the Makefile, a new
>> Kconfig option is introduced that is selected by x86 and arm32.
>>
>> Signed-off-by: Julien Grall <jgrall@amazon.com>
> 
> In principle
> Acked-by: Jan Beulich <jbeulich@suse.com>
> 
> But ...
> 
>> --- a/xen/arch/x86/Kconfig
>> +++ b/xen/arch/x86/Kconfig
>> @@ -10,6 +10,7 @@ config X86
>>   	select ALTERNATIVE_CALL
>>   	select ARCH_SUPPORTS_INT128
>>   	select CORE_PARKING
>> +	select DOMAIN_PAGE
>>   	select HAS_ALTERNATIVE
>>   	select HAS_COMPAT
>>   	select HAS_CPUFREQ
>> diff --git a/xen/arch/x86/include/asm/config.h b/xen/arch/x86/include/asm/config.h
>> index 07bcd158314b..fbc4bb3416bd 100644
>> --- a/xen/arch/x86/include/asm/config.h
>> +++ b/xen/arch/x86/include/asm/config.h
>> @@ -22,7 +22,6 @@
>>   #define CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 1
>>   #define CONFIG_DISCONTIGMEM 1
>>   #define CONFIG_NUMA_EMU 1
>> -#define CONFIG_DOMAIN_PAGE 1
> 
> ... while I realize it has been named this way, I wonder whether ...
> 
>> --- a/xen/common/Kconfig
>> +++ b/xen/common/Kconfig
>> @@ -11,6 +11,9 @@ config COMPAT
>>   config CORE_PARKING
>>   	bool
>>   
>> +config DOMAIN_PAGE
>> +	bool
> 
> ... this isn't a good opportunity to make the name match what it is
> about - MAP_DOMAIN_PAGE. See e.g. {clear,copy}_domain_page() which
> aren't under this guard, and domain pages in general is a concept we
> can't get away without in the first place.

Fair point. I decided to move this change in a prerequisite name the new 
Kconfig ARCH_MAP_DOMAIN_PAGE.

Cheers,
diff mbox series

Patch

diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index be9eff014120..eddec5b2e750 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -1,6 +1,7 @@ 
 config ARM_32
 	def_bool y
 	depends on "$(ARCH)" = "arm32"
+	select DOMAIN_PAGE
 
 config ARM_64
 	def_bool y
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index bb7a6151c13c..4f3a50a7bad8 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -17,6 +17,7 @@  obj-y += device.o
 obj-$(CONFIG_IOREQ_SERVER) += dm.o
 obj-y += domain.o
 obj-y += domain_build.init.o
+obj-$(CONFIG_DOMAIN_PAGE) += domain_page.o
 obj-y += domctl.o
 obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
 obj-y += efi/
diff --git a/xen/arch/arm/domain_page.c b/xen/arch/arm/domain_page.c
new file mode 100644
index 000000000000..ca7a907b8bb9
--- /dev/null
+++ b/xen/arch/arm/domain_page.c
@@ -0,0 +1,193 @@ 
+#include <xen/mm.h>
+#include <xen/pmap.h>
+#include <xen/vmap.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))
+
+/* cpu0's domheap page tables */
+static DEFINE_PAGE_TABLES(cpu0_dommap, DOMHEAP_SECOND_PAGES);
+
+/*
+ * xen_dommap == pages used by map_domain_page, these pages contain
+ * the second level pagetables which map the domheap region
+ * starting at DOMHEAP_VIRT_START in 2MB chunks.
+ */
+static DEFINE_PER_CPU(lpae_t *, xen_dommap);
+
+/*
+ * Prepare the area that will be used to map domheap pages. They are
+ * mapped in 2MB chunks, so we need to allocate the page-tables up to
+ * the 2nd level.
+ *
+ * The caller should make sure the root page-table for @cpu has been
+ * been allocated.
+ */
+bool init_domheap_mappings(unsigned int cpu)
+{
+    unsigned int order = get_order_from_pages(DOMHEAP_SECOND_PAGES);
+    lpae_t *root = per_cpu(xen_pgtable, cpu);
+    unsigned int i, first_idx;
+    lpae_t *domheap;
+    mfn_t mfn;
+
+    ASSERT(root);
+    ASSERT(!per_cpu(xen_dommap, cpu));
+
+    /*
+     * The domheap for cpu0 is before the heap is initialized. So we
+     * need to use pre-allocated pages.
+     */
+    if ( !cpu )
+        domheap = cpu0_dommap;
+    else
+        domheap = alloc_xenheap_pages(order, 0);
+
+    if ( !domheap )
+        return false;
+
+    /* Ensure the domheap has no stray mappings */
+    memset(domheap, 0, DOMHEAP_SECOND_PAGES * PAGE_SIZE);
+
+    /*
+     * Update the first level mapping to reference the local CPUs
+     * domheap mapping pages.
+     */
+    mfn = virt_to_mfn(domheap);
+    first_idx = first_table_offset(DOMHEAP_VIRT_START);
+    for ( i = 0; i < DOMHEAP_SECOND_PAGES; i++ )
+    {
+        lpae_t pte = mfn_to_xen_entry(mfn_add(mfn, i), MT_NORMAL);
+        pte.pt.table = 1;
+        write_pte(&root[first_idx + i], pte);
+    }
+
+    per_cpu(xen_dommap, cpu) = domheap;
+
+    return true;
+}
+
+void *map_domain_page_global(mfn_t mfn)
+{
+    return vmap(&mfn, 1);
+}
+
+void unmap_domain_page_global(const void *va)
+{
+    vunmap(va);
+}
+
+/* Map a page of domheap memory */
+void *map_domain_page(mfn_t mfn)
+{
+    unsigned long flags;
+    lpae_t *map = this_cpu(xen_dommap);
+    unsigned long slot_mfn = mfn_x(mfn) & ~XEN_PT_LPAE_ENTRY_MASK;
+    vaddr_t va;
+    lpae_t pte;
+    int i, slot;
+
+    local_irq_save(flags);
+
+    /* The map is laid out as an open-addressed hash table where each
+     * entry is a 2MB superpage pte.  We use the available bits of each
+     * PTE as a reference count; when the refcount is zero the slot can
+     * be reused. */
+    for ( slot = (slot_mfn >> XEN_PT_LPAE_SHIFT) % DOMHEAP_ENTRIES, i = 0;
+          i < DOMHEAP_ENTRIES;
+          slot = (slot + 1) % DOMHEAP_ENTRIES, i++ )
+    {
+        if ( map[slot].pt.avail < 0xf &&
+             map[slot].pt.base == slot_mfn &&
+             map[slot].pt.valid )
+        {
+            /* This slot already points to the right place; reuse it */
+            map[slot].pt.avail++;
+            break;
+        }
+        else if ( map[slot].pt.avail == 0 )
+        {
+            /* Commandeer this 2MB slot */
+            pte = mfn_to_xen_entry(_mfn(slot_mfn), MT_NORMAL);
+            pte.pt.avail = 1;
+            write_pte(map + slot, pte);
+            break;
+        }
+
+    }
+    /* If the map fills up, the callers have misbehaved. */
+    BUG_ON(i == DOMHEAP_ENTRIES);
+
+#ifndef NDEBUG
+    /* Searching the hash could get slow if the map starts filling up.
+     * Cross that bridge when we come to it */
+    {
+        static int max_tries = 32;
+        if ( i >= max_tries )
+        {
+            dprintk(XENLOG_WARNING, "Domheap map is filling: %i tries\n", i);
+            max_tries *= 2;
+        }
+    }
+#endif
+
+    local_irq_restore(flags);
+
+    va = (DOMHEAP_VIRT_START
+          + (slot << SECOND_SHIFT)
+          + ((mfn_x(mfn) & XEN_PT_LPAE_ENTRY_MASK) << THIRD_SHIFT));
+
+    /*
+     * We may not have flushed this specific subpage at map time,
+     * since we only flush the 4k page not the superpage
+     */
+    flush_xen_tlb_range_va_local(va, PAGE_SIZE);
+
+    return (void *)va;
+}
+
+/* Release a mapping taken with map_domain_page() */
+void unmap_domain_page(const void *va)
+{
+    unsigned long flags;
+    lpae_t *map = this_cpu(xen_dommap);
+    int slot = ((unsigned long) va - DOMHEAP_VIRT_START) >> SECOND_SHIFT;
+
+    if ( !va )
+        return;
+
+    local_irq_save(flags);
+
+    ASSERT(slot >= 0 && slot < DOMHEAP_ENTRIES);
+    ASSERT(map[slot].pt.avail != 0);
+
+    map[slot].pt.avail--;
+
+    local_irq_restore(flags);
+}
+
+mfn_t domain_page_map_to_mfn(const void *ptr)
+{
+    unsigned long va = (unsigned long)ptr;
+    lpae_t *map = this_cpu(xen_dommap);
+    int slot = (va - DOMHEAP_VIRT_START) >> SECOND_SHIFT;
+    unsigned long offset = (va>>THIRD_SHIFT) & XEN_PT_LPAE_ENTRY_MASK;
+
+    if ( (va >= VMAP_VIRT_START) && ((VMAP_VIRT_START - va) < VMAP_VIRT_SIZE) )
+        return virt_to_mfn(va);
+
+    ASSERT(slot >= 0 && slot < DOMHEAP_ENTRIES);
+    ASSERT(map[slot].pt.avail != 0);
+
+    return mfn_add(lpae_get_mfn(map[slot]), offset);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/arm/include/asm/arm32/mm.h b/xen/arch/arm/include/asm/arm32/mm.h
index 575373aeb985..8bfc906e7178 100644
--- a/xen/arch/arm/include/asm/arm32/mm.h
+++ b/xen/arch/arm/include/asm/arm32/mm.h
@@ -1,6 +1,12 @@ 
 #ifndef __ARM_ARM32_MM_H__
 #define __ARM_ARM32_MM_H__
 
+#include <xen/percpu.h>
+
+#include <asm/lpae.h>
+
+DECLARE_PER_CPU(lpae_t *, xen_pgtable);
+
 /*
  * Only a limited amount of RAM, called xenheap, is always mapped on ARM32.
  * For convenience always return false.
diff --git a/xen/arch/arm/include/asm/config.h b/xen/arch/arm/include/asm/config.h
index 66db618b34e7..2fafb9f2283c 100644
--- a/xen/arch/arm/include/asm/config.h
+++ b/xen/arch/arm/include/asm/config.h
@@ -122,7 +122,6 @@ 
 
 #ifdef CONFIG_ARM_32
 
-#define CONFIG_DOMAIN_PAGE 1
 #define CONFIG_SEPARATE_XENHEAP 1
 
 #define FRAMETABLE_VIRT_START  _AT(vaddr_t,0x02000000)
diff --git a/xen/arch/arm/include/asm/lpae.h b/xen/arch/arm/include/asm/lpae.h
index fc19cbd84772..3fdd5d0de28e 100644
--- a/xen/arch/arm/include/asm/lpae.h
+++ b/xen/arch/arm/include/asm/lpae.h
@@ -261,6 +261,23 @@  lpae_t mfn_to_xen_entry(mfn_t mfn, unsigned int attr);
 #define third_table_offset(va)  TABLE_OFFSET(third_linear_offset(va))
 #define zeroeth_table_offset(va)  TABLE_OFFSET(zeroeth_linear_offset(va))
 
+/*
+ * Macros to define page-tables:
+ *  - DEFINE_BOOT_PAGE_TABLE is used to define page-table that are used
+ *  in assembly code before BSS is zeroed.
+ *  - DEFINE_PAGE_TABLE{,S} are used to define one or multiple
+ *  page-tables to be used after BSS is zeroed (typically they are only used
+ *  in C).
+ */
+#define DEFINE_BOOT_PAGE_TABLE(name)                                          \
+lpae_t __aligned(PAGE_SIZE) __section(".data.page_aligned")                   \
+    name[XEN_PT_LPAE_ENTRIES]
+
+#define DEFINE_PAGE_TABLES(name, nr)                    \
+lpae_t __aligned(PAGE_SIZE) name[XEN_PT_LPAE_ENTRIES * (nr)]
+
+#define DEFINE_PAGE_TABLE(name) DEFINE_PAGE_TABLES(name, 1)
+
 #endif /* __ARM_LPAE_H__ */
 
 /*
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 995aa1e4480e..74666b2e720a 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -57,23 +57,6 @@  mm_printk(const char *fmt, ...) {}
     } while (0)
 #endif
 
-/*
- * Macros to define page-tables:
- *  - DEFINE_BOOT_PAGE_TABLE is used to define page-table that are used
- *  in assembly code before BSS is zeroed.
- *  - DEFINE_PAGE_TABLE{,S} are used to define one or multiple
- *  page-tables to be used after BSS is zeroed (typically they are only used
- *  in C).
- */
-#define DEFINE_BOOT_PAGE_TABLE(name)                                          \
-lpae_t __aligned(PAGE_SIZE) __section(".data.page_aligned")                   \
-    name[XEN_PT_LPAE_ENTRIES]
-
-#define DEFINE_PAGE_TABLES(name, nr)                    \
-lpae_t __aligned(PAGE_SIZE) name[XEN_PT_LPAE_ENTRIES * (nr)]
-
-#define DEFINE_PAGE_TABLE(name) DEFINE_PAGE_TABLES(name, 1)
-
 /* 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.
@@ -110,7 +93,7 @@  DEFINE_BOOT_PAGE_TABLE(boot_third);
 /* Main runtime page tables */
 
 /*
- * For arm32 xen_pgtable and xen_dommap are per-PCPU and are allocated before
+ * For arm32 xen_pgtable are per-PCPU and are allocated before
  * bringing up each CPU. For arm64 xen_pgtable is common to all PCPUs.
  *
  * xen_second, xen_fixmap and xen_xenmap are always shared between all
@@ -126,18 +109,10 @@  static DEFINE_PAGE_TABLE(xen_first);
 #define HYP_PT_ROOT_LEVEL 1
 /* Per-CPU pagetable pages */
 /* xen_pgtable == root of the trie (zeroeth level on 64-bit, first on 32-bit) */
-static DEFINE_PER_CPU(lpae_t *, xen_pgtable);
+DEFINE_PER_CPU(lpae_t *, xen_pgtable);
 #define THIS_CPU_PGTABLE this_cpu(xen_pgtable)
-/*
- * xen_dommap == pages used by map_domain_page, these pages contain
- * the second level pagetables which map the domheap region
- * starting at DOMHEAP_VIRT_START in 2MB chunks.
- */
-static DEFINE_PER_CPU(lpae_t *, xen_dommap);
 /* Root of the trie for cpu0, other CPU's PTs are dynamically allocated */
 static DEFINE_PAGE_TABLE(cpu0_pgtable);
-/* cpu0's domheap page tables */
-static DEFINE_PAGE_TABLES(cpu0_dommap, DOMHEAP_SECOND_PAGES);
 #endif
 
 /* Common pagetable leaves */
@@ -371,175 +346,6 @@  void clear_fixmap(unsigned map)
     BUG_ON(res != 0);
 }
 
-#ifdef CONFIG_DOMAIN_PAGE
-/*
- * Prepare the area that will be used to map domheap pages. They are
- * mapped in 2MB chunks, so we need to allocate the page-tables up to
- * the 2nd level.
- *
- * The caller should make sure the root page-table for @cpu has been
- * been allocated.
- */
-bool init_domheap_mappings(unsigned int cpu)
-{
-    unsigned int order = get_order_from_pages(DOMHEAP_SECOND_PAGES);
-    lpae_t *root = per_cpu(xen_pgtable, cpu);
-    unsigned int i, first_idx;
-    lpae_t *domheap;
-    mfn_t mfn;
-
-    ASSERT(root);
-    ASSERT(!per_cpu(xen_dommap, cpu));
-
-    /*
-     * The domheap for cpu0 is before the heap is initialized. So we
-     * need to use pre-allocated pages.
-     */
-    if ( !cpu )
-        domheap = cpu0_dommap;
-    else
-        domheap = alloc_xenheap_pages(order, 0);
-
-    if ( !domheap )
-        return false;
-
-    /* Ensure the domheap has no stray mappings */
-    memset(domheap, 0, DOMHEAP_SECOND_PAGES * PAGE_SIZE);
-
-    /*
-     * Update the first level mapping to reference the local CPUs
-     * domheap mapping pages.
-     */
-    mfn = virt_to_mfn(domheap);
-    first_idx = first_table_offset(DOMHEAP_VIRT_START);
-    for ( i = 0; i < DOMHEAP_SECOND_PAGES; i++ )
-    {
-        lpae_t pte = mfn_to_xen_entry(mfn_add(mfn, i), MT_NORMAL);
-        pte.pt.table = 1;
-        write_pte(&root[first_idx + i], pte);
-    }
-
-    per_cpu(xen_dommap, cpu) = domheap;
-
-    return true;
-}
-
-void *map_domain_page_global(mfn_t mfn)
-{
-    return vmap(&mfn, 1);
-}
-
-void unmap_domain_page_global(const void *va)
-{
-    vunmap(va);
-}
-
-/* Map a page of domheap memory */
-void *map_domain_page(mfn_t mfn)
-{
-    unsigned long flags;
-    lpae_t *map = this_cpu(xen_dommap);
-    unsigned long slot_mfn = mfn_x(mfn) & ~XEN_PT_LPAE_ENTRY_MASK;
-    vaddr_t va;
-    lpae_t pte;
-    int i, slot;
-
-    local_irq_save(flags);
-
-    /* The map is laid out as an open-addressed hash table where each
-     * entry is a 2MB superpage pte.  We use the available bits of each
-     * PTE as a reference count; when the refcount is zero the slot can
-     * be reused. */
-    for ( slot = (slot_mfn >> XEN_PT_LPAE_SHIFT) % DOMHEAP_ENTRIES, i = 0;
-          i < DOMHEAP_ENTRIES;
-          slot = (slot + 1) % DOMHEAP_ENTRIES, i++ )
-    {
-        if ( map[slot].pt.avail < 0xf &&
-             map[slot].pt.base == slot_mfn &&
-             map[slot].pt.valid )
-        {
-            /* This slot already points to the right place; reuse it */
-            map[slot].pt.avail++;
-            break;
-        }
-        else if ( map[slot].pt.avail == 0 )
-        {
-            /* Commandeer this 2MB slot */
-            pte = mfn_to_xen_entry(_mfn(slot_mfn), MT_NORMAL);
-            pte.pt.avail = 1;
-            write_pte(map + slot, pte);
-            break;
-        }
-
-    }
-    /* If the map fills up, the callers have misbehaved. */
-    BUG_ON(i == DOMHEAP_ENTRIES);
-
-#ifndef NDEBUG
-    /* Searching the hash could get slow if the map starts filling up.
-     * Cross that bridge when we come to it */
-    {
-        static int max_tries = 32;
-        if ( i >= max_tries )
-        {
-            dprintk(XENLOG_WARNING, "Domheap map is filling: %i tries\n", i);
-            max_tries *= 2;
-        }
-    }
-#endif
-
-    local_irq_restore(flags);
-
-    va = (DOMHEAP_VIRT_START
-          + (slot << SECOND_SHIFT)
-          + ((mfn_x(mfn) & XEN_PT_LPAE_ENTRY_MASK) << THIRD_SHIFT));
-
-    /*
-     * We may not have flushed this specific subpage at map time,
-     * since we only flush the 4k page not the superpage
-     */
-    flush_xen_tlb_range_va_local(va, PAGE_SIZE);
-
-    return (void *)va;
-}
-
-/* Release a mapping taken with map_domain_page() */
-void unmap_domain_page(const void *va)
-{
-    unsigned long flags;
-    lpae_t *map = this_cpu(xen_dommap);
-    int slot = ((unsigned long) va - DOMHEAP_VIRT_START) >> SECOND_SHIFT;
-
-    if ( !va )
-        return;
-
-    local_irq_save(flags);
-
-    ASSERT(slot >= 0 && slot < DOMHEAP_ENTRIES);
-    ASSERT(map[slot].pt.avail != 0);
-
-    map[slot].pt.avail--;
-
-    local_irq_restore(flags);
-}
-
-mfn_t domain_page_map_to_mfn(const void *ptr)
-{
-    unsigned long va = (unsigned long)ptr;
-    lpae_t *map = this_cpu(xen_dommap);
-    int slot = (va - DOMHEAP_VIRT_START) >> SECOND_SHIFT;
-    unsigned long offset = (va>>THIRD_SHIFT) & XEN_PT_LPAE_ENTRY_MASK;
-
-    if ( (va >= VMAP_VIRT_START) && ((VMAP_VIRT_START - va) < VMAP_VIRT_SIZE) )
-        return virt_to_mfn(va);
-
-    ASSERT(slot >= 0 && slot < DOMHEAP_ENTRIES);
-    ASSERT(map[slot].pt.avail != 0);
-
-    return mfn_add(lpae_get_mfn(map[slot]), offset);
-}
-#endif
-
 void flush_page_to_ram(unsigned long mfn, bool sync_icache)
 {
     void *v = map_domain_page(_mfn(mfn));
diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index 1e31edc99f9d..e440b473b677 100644
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -10,6 +10,7 @@  config X86
 	select ALTERNATIVE_CALL
 	select ARCH_SUPPORTS_INT128
 	select CORE_PARKING
+	select DOMAIN_PAGE
 	select HAS_ALTERNATIVE
 	select HAS_COMPAT
 	select HAS_CPUFREQ
diff --git a/xen/arch/x86/include/asm/config.h b/xen/arch/x86/include/asm/config.h
index 07bcd158314b..fbc4bb3416bd 100644
--- a/xen/arch/x86/include/asm/config.h
+++ b/xen/arch/x86/include/asm/config.h
@@ -22,7 +22,6 @@ 
 #define CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 1
 #define CONFIG_DISCONTIGMEM 1
 #define CONFIG_NUMA_EMU 1
-#define CONFIG_DOMAIN_PAGE 1
 
 #define CONFIG_PAGEALLOC_MAX_ORDER (2 * PAGETABLE_ORDER)
 #define CONFIG_DOMU_MAX_ORDER      PAGETABLE_ORDER
diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index 41a67891bcc8..b308f4aa0ee5 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -11,6 +11,9 @@  config COMPAT
 config CORE_PARKING
 	bool
 
+config DOMAIN_PAGE
+	bool
+
 config GRANT_TABLE
 	bool "Grant table support" if EXPERT
 	default y