[Xen-devel] [PATCH] x86 vm_event: reset monitor in vm_event_cleanup_domain()

[Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>]

It is currently possible to leave a monitor flag enabled even
after vm_event_cleanup_domain() has been called, potentially
leading to a crash in hvm_msr_write_intercept() and hvm_set_crX()
(when v->arch.vm_event has become NULL, but the corresponding
corresponding v->domain->arch.monitor flag is non-zero).
This patch zeroes out arch.monitor in vm_event_cleanup_domain().

Signed-off-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
---
 xen/arch/x86/vm_event.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/xen/arch/x86/vm_event.c b/xen/arch/x86/vm_event.c
index 9677ecc..08d678a 100644
--- a/xen/arch/x86/vm_event.c
+++ b/xen/arch/x86/vm_event.c
@@ -56,6 +56,7 @@ void vm_event_cleanup_domain(struct domain *d)
     }
 
     d->arch.mem_access_emulate_each_rep = 0;
+    memset(&d->arch.monitor, 0, sizeof(d->arch.monitor));
 }
 
 void vm_event_toggle_singlestep(struct domain *d, struct vcpu *v)
-- 
2.7.0


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