xen/debug: WARN_ON when identity PFN has no _PAGE_IOMAP flag set.
Only enabled if XEN_DEBUG is enabled. We print a warning
when:
pfn_to_mfn(pfn) == pfn, but no VM_IO (_PAGE_IOMAP) flag set
(and pfn is an identity mapped pfn)
pfn_to_mfn(pfn) != pfn, and VM_IO flag is set.
(ditto, pfn is an identity mapped pfn)
[v2: Make it dependent on CONFIG_XEN_DEBUG instead of ..DEBUG_FS]
[v3: Fix compiler warning]
Reviewed-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index 5b54892..e4343fe 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -48,3 +48,11 @@
help
Enable statistics output and various tuning options in debugfs.
Enabling this option may incur a significant performance overhead.
+
+config XEN_DEBUG
+ bool "Enable Xen debug checks"
+ depends on XEN
+ default n
+ help
+ Enable various WARN_ON checks in the Xen MMU code.
+ Enabling this option WILL incur a significant performance overhead.