xen: add configurable max domain size

Add a config option to set the max size of a Xen domain.  This is used
to scale the size of the physical-to-machine array; it ends up using
around 1 page/GByte, so there's no reason to be very restrictive.

For a 32-bit guest, the default value of 8GB is probably sufficient;
there's not much point in giving a 32-bit machine much more memory
than that.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/asm-x86/xen/page.h b/include/asm-x86/xen/page.h
index 293344f8102e..377c04591c15 100644
--- a/include/asm-x86/xen/page.h
+++ b/include/asm-x86/xen/page.h
@@ -26,6 +26,11 @@ typedef struct xpaddr {
 #define FOREIGN_FRAME_BIT       (1UL<<31)
 #define FOREIGN_FRAME(m)        ((m) | FOREIGN_FRAME_BIT)
 
+/* Maximum amount of memory we can handle in a domain in pages */
+#define MAX_DOMAIN_PAGES                                                \
+    ((unsigned long)((u64)CONFIG_XEN_MAX_DOMAIN_MEMORY * 1024 * 1024 * 1024 / PAGE_SIZE))
+
+
 extern unsigned long get_phys_to_machine(unsigned long pfn);
 extern void set_phys_to_machine(unsigned long pfn, unsigned long mfn);