From: Jan Beulich Date: Wed, 20 Dec 2017 15:19:12 +0000 (+0100) Subject: sync CPU state upon final domain destruction X-Git-Tag: RELEASE-4.7.5~102 X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=664433a1a04fa3618ca5bab530d68cf100107f41;p=xen.git sync CPU state upon final domain destruction See the code comment being added for why we need this. This is being placed here to balance between the desire to prevent future similar issues (the risk of which would grow if it was put further down the call stack, e.g. in vmx_vcpu_destroy()) and the intention to limit the performance impact (otherwise it could also go into rcu_do_batch(), paralleling the use in do_tasklet_work()). Reported-by: Igor Druzhinin Signed-off-by: Jan Beulich Acked-by: Andrew Cooper master commit: 24246e1fb7496b830aca8a6a1fd3064ca1e3ebf9 master date: 2017-11-23 11:38:22 +0100 --- diff --git a/xen/common/domain.c b/xen/common/domain.c index c5c78b9b3c..047a489647 100644 --- a/xen/common/domain.c +++ b/xen/common/domain.c @@ -798,6 +798,14 @@ static void complete_domain_destroy(struct rcu_head *head) struct vcpu *v; int i; + /* + * Flush all state for the vCPU previously having run on the current CPU. + * This is in particular relevant for x86 HVM ones on VMX, so that this + * flushing of state won't happen from the TLB flush IPI handler behind + * the back of a vmx_vmcs_enter() / vmx_vmcs_exit() section. + */ + sync_local_execstate(); + for ( i = d->max_vcpus - 1; i >= 0; i-- ) { if ( (v = d->vcpu[i]) == NULL )