[PATCH 1/2] mm, Make __get_user_pages return -EHWPOISON for HWPOISON page

[Huang Ying <ying.huang@intel.com>]

With this patch, the caller of __get_user_pages can distinguish
HWPOISON page from general FAULT page. This is needed by KVM, where
UCR MCE should be relayed to guest for HWPOISON page, while
instruction emulation and MMIO will be tried for general FAULT page.

Signed-off-by: Huang Ying <ying.huang@intel.com>
---
 include/asm-generic/errno.h |    2 ++
 mm/memory.c                 |    5 +++--
 2 files changed, 5 insertions(+), 2 deletions(-)

--- a/include/asm-generic/errno.h
+++ b/include/asm-generic/errno.h
@@ -108,4 +108,6 @@
 
 #define ERFKILL		132	/* Operation not possible due to RF-kill */
 
+#define EHWPOISON	133	/* Memory page has hardware error */
+
 #endif
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1432,9 +1432,10 @@ int __get_user_pages(struct task_struct
 				if (ret & VM_FAULT_ERROR) {
 					if (ret & VM_FAULT_OOM)
 						return i ? i : -ENOMEM;
-					if (ret &
-					    (VM_FAULT_HWPOISON|VM_FAULT_SIGBUS))
+					if (ret & VM_FAULT_SIGBUS)
 						return i ? i : -EFAULT;
+					if (ret & VM_FAULT_HWPOISON)
+						return i ? i : -EHWPOISON;
 					BUG();
 				}
 				if (ret & VM_FAULT_MAJOR)