hvmloader: reduce minimum allocation alignment from 1024 bytes to 16.

1024 bytes create a lot of wastage when the majority of allocations
are of BIOS table data structures which are generally happy with much
lower alignment. I conservatively chose 16 bytes.

Most callers pass 0 for the alignment anyway, for the rombios high
code allocation I kept it 1024 byte aligned since it was the only case
that didn't seem obviously ok with a smaller alignment.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>

2 files changed, 7 insertions, 7 deletions

diff --git a/tools/firmware/hvmloader/32bitbios_support.c b/tools/firmware/hvmloader/32bitbios_support.c
index 44e89fd636..abd17754f1 100644
--- a/tools/firmware/hvmloader/32bitbios_support.c
+++ b/tools/firmware/hvmloader/32bitbios_support.c
@@ -67,7 +67,7 @@ static uint32_t relocate_32bitbios(char *elfarray, uint32_t elfarraysize)
      */
     reloc_size = reloc_off;
     printf("%d bytes of ROMBIOS high-memory extensions:\n", reloc_size);
-    highbiosarea = mem_alloc(reloc_size, 0);
+    highbiosarea = mem_alloc(reloc_size, 1024);
     BUG_ON(highbiosarea == NULL);
     printf("  Relocating to 0x%x-0x%x ... ",
            (uint32_t)&highbiosarea[0],
diff --git a/tools/firmware/hvmloader/util.c b/tools/firmware/hvmloader/util.c
index 4d80845fc7..90bd39971e 100644
--- a/tools/firmware/hvmloader/util.c
+++ b/tools/firmware/hvmloader/util.c
@@ -312,9 +312,9 @@ void *mem_alloc(uint32_t size, uint32_t align)
     xen_pfn_t mfn;
     uint32_t s, e;
 
-    /* Align to at least one kilobyte. */
-    if ( align < 1024 )
-        align = 1024;
+    /* Align to at least 16 bytes. */
+    if ( align < 16 )
+        align = 16;
 
     s = (reserve + align) & ~(align - 1);
     e = s + size - 1;
@@ -366,9 +366,9 @@ void *scratch_alloc(uint32_t size, uint32_t align)
 {
     uint32_t s, e;
 
-    /* Align to at least one kilobyte. */
-    if ( align < 1024 )
-        align = 1024;
+    /* Align to at least 16 bytes. */
+    if ( align < 16 )
+        align = 16;
 
     s = (scratch_start + align - 1) & ~(align - 1);
     e = s + size - 1;