It is meaningless (and potentially dangerous - see hvmemul_virtual_to_linear())
to set mem_access_emulate_each_rep before xc_monitor_enable() (which allocates
vcpu->arch.vm_event) has been called, so return an error from the
XEN_DOMCTL_MONITOR_OP_EMULATE_EACH_REP hypercall when that is the case.
Signed-off-by: Razvan Cojocaru <rcojoc...@bitdefender.com>
---
xen/include/asm-x86/monitor.h | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/xen/include/asm-x86/monitor.h b/xen/include/asm-x86/monitor.h
index 0954b59..0544836 100644
--- a/xen/include/asm-x86/monitor.h
+++ b/xen/include/asm-x86/monitor.h
@@ -35,11 +35,22 @@ int arch_monitor_domctl_op(struct domain *d, struct
xen_domctl_monitor_op *mop)
switch ( mop->op )
{
case XEN_DOMCTL_MONITOR_OP_EMULATE_EACH_REP:
+ {
+ bool_t value = !!mop->event;
domain_pause(d);
- d->arch.mem_access_emulate_each_rep = !!mop->event;
+ /*
+ * Enabling emulate_each_rep without a vm_event subscriber
+ * is meaningless.
+ */
+ if ( !d->vcpu || !d->vcpu[0]->arch.vm_event )
+ {
+ domain_unpause(d);
+ return -EINVAL;
+ }
+ d->arch.mem_access_emulate_each_rep = value;
domain_unpause(d);
break;
-
+ }
default:
return -EOPNOTSUPP;
}
--
1.9.1
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