[PATCH v4 15/16] KVM: SVM: call avic_vcpu_load/avic_vcpu_put when enabling/disabling AVIC

Maxim Levitsky
2021-08-10T20:54:34Z

Currently it is possible to have the following scenario:

1. AVIC is disabled by svm_refresh_apicv_exec_ctrl
2. svm_vcpu_blocking calls avic_vcpu_put which does nothing
3. svm_vcpu_unblocking enables the AVIC (due to KVM_REQ_APICV_UPDATE)
and then calls avic_vcpu_load
4. warning is triggered in avic_vcpu_load since
AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK was never cleared

While it is possible to just remove the warning, it seems to be more robust
to fully disable/enable AVIC in svm_refresh_apicv_exec_ctrl by calling the
avic_vcpu_load/avic_vcpu_put

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
arch/x86/kvm/svm/avic.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index e7728b16a46f..01c0e83e1b71 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -651,6 +651,11 @@ void svm_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu)
}
vmcb_mark_dirty(vmcb, VMCB_AVIC);

+ if (activated)
+ avic_vcpu_load(vcpu, vcpu->cpu);
+ else
+ avic_vcpu_put(vcpu);
+
svm_set_pi_irte_mode(vcpu, activated);
}

--
2.26.3