Liu, Jinsong
2011-Sep-29 15:22 UTC
[Xen-devel] [PATCH] X86 MCE: Prevent malicious guest access broken page again
X86 MCE: Prevent malicious guest access broken page again
To avoid recursive mce.
Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
diff -r 753cbb4f4416 xen/arch/x86/cpu/mcheck/mce_intel.c
--- a/xen/arch/x86/cpu/mcheck/mce_intel.c Sat Aug 20 23:53:03 2011 +0800
+++ b/xen/arch/x86/cpu/mcheck/mce_intel.c Sun Aug 21 00:45:44 2011 +0800
@@ -665,6 +665,8 @@ static void intel_memerr_dhandler(
/* This is free page */
if (status & PG_OFFLINE_OFFLINED)
*result = MCER_RECOVERED;
+ else if (status & PG_OFFLINE_AGAIN)
+ *result = MCER_CONTINUE;
else if (status & PG_OFFLINE_PENDING) {
/* This page has owner */
if (status & PG_OFFLINE_OWNED) {
diff -r 753cbb4f4416 xen/common/page_alloc.c
--- a/xen/common/page_alloc.c Sat Aug 20 23:53:03 2011 +0800
+++ b/xen/common/page_alloc.c Sun Aug 21 00:45:44 2011 +0800
@@ -38,6 +38,7 @@
#include <xen/tmem.h>
#include <xen/tmem_xen.h>
#include <public/sysctl.h>
+#include <public/sched.h>
#include <asm/page.h>
#include <asm/numa.h>
#include <asm/flushtlb.h>
@@ -708,6 +709,19 @@ int offline_page(unsigned long mfn, int
return -EINVAL;
}
+ /*
+ * NB. When broken page belong to guest, usually hypervisor will
+ * notify the guest to handle the broken page. However, hypervisor
+ * need to prevent malicious guest access the broken page again.
+ * Under such case, hypervisor shutdown guest, preventing recursive mce.
+ */
+ if ( (pg->count_info & PGC_broken) && (owner =
page_get_owner(pg)) )
+ {
+ *status = PG_OFFLINE_AGAIN;
+ domain_shutdown(owner, SHUTDOWN_crash);
+ return 0;
+ }
+
spin_lock(&heap_lock);
old_info = mark_page_offline(pg, broken);
diff -r 753cbb4f4416 xen/include/public/sysctl.h
--- a/xen/include/public/sysctl.h Sat Aug 20 23:53:03 2011 +0800
+++ b/xen/include/public/sysctl.h Sun Aug 21 00:45:44 2011 +0800
@@ -399,6 +399,7 @@ struct xen_sysctl_page_offline_op {
#define PG_OFFLINE_OFFLINED (0x1UL << 1)
#define PG_OFFLINE_PENDING (0x1UL << 2)
#define PG_OFFLINE_FAILED (0x1UL << 3)
+#define PG_OFFLINE_AGAIN (0x1UL << 4)
#define PG_ONLINE_FAILED PG_OFFLINE_FAILED
#define PG_ONLINE_ONLINED PG_OFFLINE_OFFLINED
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