svn commit: r361578 - head/sys/x86/xen

[Roger Pau Monné]

Author: royger
Date: Thu May 28 08:18:34 2020
New Revision: 361578
URL: https://svnweb.freebsd.org/changeset/base/361578

Log:
  xenpv: do not use low 1MB for Xen mappings on i386
  
  On amd64 we already avoid using memory below 4GB in order to prevent
  clashes with MMIO regions, but i386 was allowed to use any hole in
  the physical memory map in order to map Xen pages.
  
  Limit this to memory above the 1MB boundary on i386 in order to avoid
  clashes with the MMIO holes in that area.
  
  Sponsored by:	Citrix Systems R&D
  MFC after:	1 week

Modified:
  head/sys/x86/xen/xenpv.c

Modified: head/sys/x86/xen/xenpv.c
==============================================================================
--- head/sys/x86/xen/xenpv.c	Thu May 28 08:05:46 2020	(r361577)
+++ head/sys/x86/xen/xenpv.c	Thu May 28 08:18:34 2020	(r361578)
@@ -54,12 +54,14 @@ __FBSDID("$FreeBSD$");
  * prevent clashes with MMIO/ACPI regions.
  *
  * Since this is not possible on i386 just use any available memory
- * chunk and hope we don't clash with anything else.
+ * chunk above 1MB and hope we don't clash with anything else.
  */
 #ifdef __amd64__
 #define LOW_MEM_LIMIT	0x100000000ul
+#elif defined(__i386__)
+#define LOW_MEM_LIMIT	0x100000ul
 #else
-#define LOW_MEM_LIMIT	0
+#error "Unsupported architecture"
 #endif
 
 static devclass_t xenpv_devclass;