xen/23897-x86-mce-offline-again.patch

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# HG changeset patch
# User Keir Fraser <keir@xen.org>
# Date 1317413803 -3600
# Node ID 2215d7d7382617adbe97831fe35752a027917d1d
# Parent d568e2313fd6f055b66a6c3cb2bca6372b77692e
X86 MCE: Prevent malicious guest access broken page again
To avoid recursive mce.
Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
Committed-by: Keir Fraser <keir@xen.org>
--- a/xen/arch/x86/cpu/mcheck/mce_intel.c
+++ b/xen/arch/x86/cpu/mcheck/mce_intel.c
@@ -639,6 +639,8 @@ static void intel_memerr_dhandler(int bn
/* This is free page */
if (status & PG_OFFLINE_OFFLINED)
result->result = MCA_RECOVERED;
+ else if (status & PG_OFFLINE_AGAIN)
+ result->result = MCA_NO_ACTION;
else if (status & PG_OFFLINE_PENDING) {
/* This page has owner */
if (status & PG_OFFLINE_OWNED) {
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -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>
@@ -704,6 +705,19 @@ 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);
--- a/xen/include/public/sysctl.h
+++ b/xen/include/public/sysctl.h
@@ -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