[PATCH] release kvmclock page on reset

[Glauber Costa <glommer@redhat.com>]

Up to know, we were relying on guest cooperation to turn off kvmclock.
I just realized that even though this is fine and nice, a more robust
method is to (also) turn it off on vcpu_reset on the hypervisor side.
This will protect us against reboots, and we don't expect the guest
to reset its cpu during normal operation anyway.

Signed-off-by: Glauber Costa <glommer@redhat.com>
---
 arch/x86/kvm/x86.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bcc0efc..38b55b3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5878,6 +5878,11 @@ int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu)
 	kvm_make_request(KVM_REQ_EVENT, vcpu);
 	vcpu->arch.apf.msr_val = 0;
 
+	if (vcpu->arch.time_page) {
+		kvm_release_page_dirty(vcpu->arch.time_page);
+		vcpu->arch.time_page = NULL;
+	}
+
 	kvm_clear_async_pf_completion_queue(vcpu);
 	kvm_async_pf_hash_reset(vcpu);
 	vcpu->arch.apf.halted = false;
-- 
1.7.2.3