[PATCH 3/4] domain heap allocator changes - remove bit width restrictions

["Jan Beulich" <jbeulich@novell.com>]

Hide the (default or user specified) DMA width from anything outside
the heap allocator. I/O-capable guests can now request any width for
the memory they want exchanged/added.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

Index: 2007-02-07/xen/arch/x86/domain_build.c
===================================================================
--- 2007-02-07.orig/xen/arch/x86/domain_build.c	2007-02-01 17:41:08.000000000 +0100
+++ 2007-02-07/xen/arch/x86/domain_build.c	2007-02-07 17:12:45.000000000 +0100
@@ -429,11 +429,14 @@ int construct_dom0(struct domain *d,
     if ( (1UL << order) > nr_pages )
         panic("Domain 0 allocation is too small for kernel image.\n");
 
-    /*
-     * Allocate from DMA pool: on i386 this ensures that our low-memory 1:1
-     * mapping covers the allocation.
-     */
-    if ( (page = alloc_domheap_pages(d, order, MEMF_dma)) == NULL )
+#ifdef __i386__
+    /* Ensure that our low-memory 1:1 mapping covers the allocation. */
+    page = alloc_domheap_pages(d, order,
+                               MEMF_bits(30 + (v_start >> 31)));
+#else
+    page = alloc_domheap_pages(d, order, 0);
+#endif
+    if ( page == NULL )
         panic("Not enough RAM for domain 0 allocation.\n");
     alloc_spfn = page_to_mfn(page);
     alloc_epfn = alloc_spfn + d->tot_pages;
Index: 2007-02-07/xen/common/memory.c
===================================================================
--- 2007-02-07.orig/xen/common/memory.c	2007-01-30 10:23:30.000000000 +0100
+++ 2007-02-07/xen/common/memory.c	2007-02-07 16:26:50.000000000 +0100
@@ -322,12 +322,12 @@ static long memory_exchange(XEN_GUEST_HA
          (exch.out.address_bits <
           (get_order_from_pages(max_page) + PAGE_SHIFT)) )
     {
-        if ( exch.out.address_bits < dma_bitsize )
+        if ( exch.out.address_bits <= PAGE_SHIFT )
         {
             rc = -ENOMEM;
             goto fail_early;
         }
-        memflags = MEMF_dma;
+        memflags = MEMF_bits(exch.out.address_bits);
     }
 
     if ( exch.in.extent_order <= exch.out.extent_order )
@@ -535,9 +535,9 @@ long do_memory_op(unsigned long cmd, XEN
              (reservation.address_bits <
               (get_order_from_pages(max_page) + PAGE_SHIFT)) )
         {
-            if ( reservation.address_bits < dma_bitsize )
+            if ( reservation.address_bits <= PAGE_SHIFT )
                 return start_extent;
-            args.memflags = MEMF_dma;
+            args.memflags = MEMF_bits(reservation.address_bits);
         }
 
         if ( likely(reservation.domid == DOMID_SELF) )
Index: 2007-02-07/xen/common/page_alloc.c
===================================================================
--- 2007-02-07.orig/xen/common/page_alloc.c	2007-02-07 16:26:45.000000000 +0100
+++ 2007-02-07/xen/common/page_alloc.c	2007-02-07 17:12:00.000000000 +0100
@@ -48,8 +48,8 @@ string_param("badpage", opt_badpage);
 /*
  * Bit width of the DMA heap.
  */
-unsigned int  dma_bitsize = CONFIG_DMA_BITSIZE;
-unsigned long max_dma_mfn = (1UL << (CONFIG_DMA_BITSIZE - PAGE_SHIFT)) - 1;
+static unsigned int  dma_bitsize = CONFIG_DMA_BITSIZE;
+static unsigned long max_dma_mfn = (1UL << (CONFIG_DMA_BITSIZE - PAGE_SHIFT)) - 1;
 static void parse_dma_bits(char *s)
 {
     unsigned int v = simple_strtol(s, NULL, 0);
@@ -58,7 +58,7 @@ static void parse_dma_bits(char *s)
         dma_bitsize = BITS_PER_LONG + PAGE_SHIFT;
         max_dma_mfn = ~0UL;
     }
-    else if ( v > PAGE_SHIFT )
+    else if ( v > PAGE_SHIFT + 1 )
     {
         dma_bitsize = v;
         max_dma_mfn = (1UL << (dma_bitsize - PAGE_SHIFT)) - 1;
@@ -711,12 +711,22 @@ struct page_info *__alloc_domheap_pages(
     struct page_info *pg = NULL;
     cpumask_t mask;
     unsigned long i;
+    unsigned int bits = memflags >> _MEMF_bits, zone_hi;
 
     ASSERT(!in_irq());
 
-    if ( !(memflags & MEMF_dma) )
+    if ( bits && bits <= PAGE_SHIFT + 1 )
+        return NULL;
+
+    zone_hi = bits - PAGE_SHIFT - 1;
+    if ( zone_hi >= NR_ZONES )
+        zone_hi = NR_ZONES - 1;
+
+    if ( NR_ZONES + PAGE_SHIFT > dma_bitsize &&
+         (!bits || bits > dma_bitsize) )
     {
-        pg = alloc_heap_pages(dma_bitsize - PAGE_SHIFT, NR_ZONES - 1, cpu, order);
+        pg = alloc_heap_pages(dma_bitsize - PAGE_SHIFT, zone_hi, cpu, order);
+
         /* Failure? Then check if we can fall back to the DMA pool. */
         if ( unlikely(pg == NULL) &&
              ((order > MAX_ORDER) ||
@@ -729,7 +739,7 @@ struct page_info *__alloc_domheap_pages(
 
     if ( pg == NULL )
         if ( (pg = alloc_heap_pages(MEMZONE_XEN + 1,
-                                    dma_bitsize - PAGE_SHIFT - 1,
+                                    zone_hi,
                                     cpu, order)) == NULL )
             return NULL;
 
Index: 2007-02-07/xen/include/asm-ia64/config.h
===================================================================
--- 2007-02-07.orig/xen/include/asm-ia64/config.h	2007-01-22 12:26:37.000000000 +0100
+++ 2007-02-07/xen/include/asm-ia64/config.h	2007-02-07 16:26:50.000000000 +0100
@@ -42,7 +42,7 @@
 #define CONFIG_IOSAPIC
 #define supervisor_mode_kernel (0)
 
-#define CONFIG_DMA_BITSIZE 30
+#define CONFIG_DMA_BITSIZE 32
 
 /* If PERFC is used, include privop maps.  */
 #ifdef PERF_COUNTERS
Index: 2007-02-07/xen/include/asm-x86/config.h
===================================================================
--- 2007-02-07.orig/xen/include/asm-x86/config.h	2007-01-08 14:15:31.000000000 +0100
+++ 2007-02-07/xen/include/asm-x86/config.h	2007-02-07 16:26:50.000000000 +0100
@@ -82,7 +82,7 @@
 /* Debug stack is restricted to 8kB by guard pages. */
 #define DEBUG_STACK_SIZE 8192
 
-#define CONFIG_DMA_BITSIZE 30
+#define CONFIG_DMA_BITSIZE 32
 
 #if defined(__x86_64__)
 
Index: 2007-02-07/xen/include/xen/mm.h
===================================================================
--- 2007-02-07.orig/xen/include/xen/mm.h	2007-02-07 16:25:40.000000000 +0100
+++ 2007-02-07/xen/include/xen/mm.h	2007-02-07 16:26:50.000000000 +0100
@@ -71,10 +71,10 @@ int assign_pages(
     unsigned int memflags);
 
 /* memflags: */
-#define _MEMF_dma         0
-#define  MEMF_dma         (1U<<_MEMF_dma)
-#define _MEMF_no_refcount 1
+#define _MEMF_no_refcount 0
 #define  MEMF_no_refcount (1U<<_MEMF_no_refcount)
+#define _MEMF_bits        24
+#define  MEMF_bits(n)     ((n)<<_MEMF_bits)
 
 #ifdef CONFIG_PAGEALLOC_MAX_ORDER
 #define MAX_ORDER CONFIG_PAGEALLOC_MAX_ORDER
@@ -82,10 +82,6 @@ int assign_pages(
 #define MAX_ORDER 20 /* 2^20 contiguous pages */
 #endif
 
-/* DMA heap parameters. */
-extern unsigned int  dma_bitsize;
-extern unsigned long max_dma_mfn;
-
 /* Automatic page scrubbing for dead domains. */
 extern struct list_head page_scrub_list;
 #define page_scrub_schedule_work()              \