Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Chao Gao <chao.gao@intel.com>
To:     kvm@vger.kernel.org
Cc:     Chao Gao <chao.gao@intel.com>, linux-kernel@vger.kernel.org,
        x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        Ingo Molnar <mingo@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar@redhat.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Liran Alon <liran.alon@oracle.com>
Subject: [PATCH v3] KVM: VMX: Don't halt vcpu when L1 is injecting events to L2
Date:   Sun, 11 Feb 2018 10:06:30 +0800
Message-Id: <1518314790-31774-1-git-send-email-chao.gao@intel.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Although L2 is in halt state, it will be in the active state after
VM entry if the VM entry is vectoring according to SDM 26.6.2 Activity
State. Halting the vcpu here means the event won't be injected to L2
and this decision isn't reported to L1. Thus L0 drops an event that
should be injected to L2.

Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Chao Gao <chao.gao@intel.com>
---
changes in v3:
 - s/VECTORING_INFO_VALID_MASK/INTR_INFO_VALID_MASK
 - Changes of subject, comments.

Changes in v2:
 - Remove VID stuff. Only handle event injection in this patch.

Signed-off-by: Chao Gao <chao.gao@intel.com>
---
 arch/x86/kvm/vmx.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index bb5b488..cf7c2fc 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10985,7 +10985,12 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 	if (ret)
 		return ret;
 
-	if (vmcs12->guest_activity_state == GUEST_ACTIVITY_HLT)
+	/*
+	 * If we're entering a halted L2 vcpu and the L2 vcpu won't be woken
+	 * by event injection, halt vcpu.
+	 */
+	if ((vmcs12->guest_activity_state == GUEST_ACTIVITY_HLT) &&
+	    !(vmcs12->vm_entry_intr_info_field & INTR_INFO_VALID_MASK))
 		return kvm_vcpu_halt(vcpu);
 
 	vmx->nested.nested_run_pending = 1;
-- 
1.9.1