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From:   Vitaly Kuznetsov <vkuznets@redhat.com>
To:     kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Cc:     Sean Christopherson <seanjc@google.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Siddharth Chandrasekaran <sidcha@amazon.de>,
        linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org
Subject: [PATCH RFC 18/22] KVM: x86: hyper-v: Honor HV_SIGNAL_EVENTS privilege bit
Date:   Tue, 13 Apr 2021 14:26:26 +0200
Message-Id: <20210413122630.975617-19-vkuznets@redhat.com>
In-Reply-To: <20210413122630.975617-1-vkuznets@redhat.com>
References: <20210413122630.975617-1-vkuznets@redhat.com>
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Hyper-V partition must possess 'HV_SIGNAL_EVENTS' privilege to issue
HVCALL_SIGNAL_EVENT hypercalls.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 arch/x86/kvm/hyperv.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 6e4bf1da9dcf..b661f92d90c8 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2120,6 +2120,12 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
 		kvm_vcpu_on_spin(vcpu, true);
 		break;
 	case HVCALL_SIGNAL_EVENT:
+		if (unlikely(!(hv_vcpu->cpuid_cache.features_ebx &
+			       HV_SIGNAL_EVENTS))) {
+			ret = HV_STATUS_ACCESS_DENIED;
+			break;
+		}
+
 		if (unlikely(rep)) {
 			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
 			break;
-- 
2.30.2