linux-kernel - [PATCH RFC 19/22] KVM: x86: hyper-v: Honor HV

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Message-Id: <20210413122630.975617-20-vkuznets@redhat.com>
Date:   Tue, 13 Apr 2021 14:26:27 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     kvm@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Siddharth Chandrasekaran <sidcha@...zon.de>,
        linux-kernel@...r.kernel.org, linux-hyperv@...r.kernel.org
Subject: [PATCH RFC 19/22] KVM: x86: hyper-v: Honor HV_DEBUGGING privilege bit

Hyper-V partition must possess 'HV_DEBUGGING' privilege to issue
HVCALL_POST_DEBUG_DATA/HVCALL_RETRIEVE_DEBUG_DATA/
HVCALL_RESET_DEBUG_SESSION hypercalls.

Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.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 b661f92d90c8..7cb1dd1a9fc1 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2211,6 +2211,12 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
 			break;
 		}
 
+		if (unlikely(!(hv_vcpu->cpuid_cache.features_ebx &
+			       HV_DEBUGGING))) {
+			ret = HV_STATUS_ACCESS_DENIED;
+			break;
+		}
+
 		if (!(syndbg->options & HV_X64_SYNDBG_OPTION_USE_HCALLS)) {
 			ret = HV_STATUS_OPERATION_DENIED;
 			break;
-- 
2.30.2