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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 17/22] KVM: x86: hyper-v: Honor HV_POST_MESSAGES privilege bit
Date: Tue, 13 Apr 2021 14:26:25 +0200
Message-ID: <20210413122630.975617-18-vkuznets@redhat.com> (raw)
In-Reply-To: <20210413122630.975617-1-vkuznets@redhat.com>

Hyper-V partition must possess 'HV_POST_MESSAGES' privilege to issue
HVCALL_POST_MESSAGE hypercalls.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 arch/x86/kvm/hyperv.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 0df18187d908..6e4bf1da9dcf 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2073,12 +2073,16 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
 	u64 param, ingpa, outgpa, ret = HV_STATUS_SUCCESS;
 	uint16_t code, rep_idx, rep_cnt;
 	bool fast, rep;
+	struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
 
 	/*
 	 * hypercall generates UD from non zero cpl and real mode
-	 * per HYPER-V spec
+	 * per HYPER-V spec. Fail the call when 'hv_vcpu' context
+	 * was not allocated (e.g. per-vCPU Hyper-V CPUID entries
+	 * are unset) as well.
 	 */
-	if (static_call(kvm_x86_get_cpl)(vcpu) != 0 || !is_protmode(vcpu)) {
+	if (static_call(kvm_x86_get_cpl)(vcpu) != 0 || !is_protmode(vcpu) ||
+	    !hv_vcpu) {
 		kvm_queue_exception(vcpu, UD_VECTOR);
 		return 1;
 	}
@@ -2125,6 +2129,12 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
 			break;
 		fallthrough;	/* maybe userspace knows this conn_id */
 	case HVCALL_POST_MESSAGE:
+		if (unlikely(!(hv_vcpu->cpuid_cache.features_ebx &
+			       HV_POST_MESSAGES))) {
+			ret = HV_STATUS_ACCESS_DENIED;
+			break;
+		}
+
 		/* don't bother userspace if it has no way to handle it */
 		if (unlikely(rep || !to_hv_synic(vcpu)->active)) {
 			ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
-- 
2.30.2


  parent reply index

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-13 12:26 [PATCH RFC 00/22] KVM: x86: hyper-v: Fine-grained access check to Hyper-V hypercalls and MSRs Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 01/22] asm-generic/hyperv: add HV_STATUS_ACCESS_DENIED definition Vitaly Kuznetsov
2021-04-15 14:14   ` Wei Liu
2021-04-15 15:33     ` Vitaly Kuznetsov
2021-04-16 10:31       ` Wei Liu
2021-04-13 12:26 ` [PATCH RFC 02/22] KVM: x86: hyper-v: Cache guest CPUID leaves determining features availability Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 03/22] KVM: x86: hyper-v: Honor HV_MSR_VP_RUNTIME_AVAILABLE privilege bit Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 04/22] KVM: x86: hyper-v: Honor HV_MSR_TIME_REF_COUNT_AVAILABLE " Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 05/22] KVM: x86: hyper-v: Honor HV_MSR_HYPERCALL_AVAILABLE " Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 06/22] KVM: x86: hyper-v: Honor HV_MSR_VP_INDEX_AVAILABLE " Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 07/22] KVM: x86: hyper-v: Honor HV_MSR_RESET_AVAILABLE " Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 08/22] KVM: x86: hyper-v: Honor HV_MSR_REFERENCE_TSC_AVAILABLE " Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 09/22] KVM: x86: hyper-v: Honor HV_MSR_SYNIC_AVAILABLE " Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 10/22] KVM: x86: hyper-v: Honor HV_MSR_SYNTIMER_AVAILABLE " Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 11/22] KVM: x86: hyper-v: Honor HV_MSR_APIC_ACCESS_AVAILABLE " Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 12/22] KVM: x86: hyper-v: Honor HV_ACCESS_FREQUENCY_MSRS " Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 13/22] KVM: x86: hyper-v: Honor HV_ACCESS_REENLIGHTENMENT " Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 14/22] KVM: x86: hyper-v: Honor HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE " Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 15/22] " Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 16/22] KVM: x86: hyper-v: Honor HV_STIMER_DIRECT_MODE_AVAILABLE " Vitaly Kuznetsov
2021-04-13 12:26 ` Vitaly Kuznetsov [this message]
2021-04-13 12:26 ` [PATCH RFC 18/22] KVM: x86: hyper-v: Honor HV_SIGNAL_EVENTS " Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 19/22] KVM: x86: hyper-v: Honor HV_DEBUGGING " Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 20/22] KVM: x86: hyper-v: Honor HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED bit Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 21/22] KVM: x86: hyper-v: Honor HV_X64_CLUSTER_IPI_RECOMMENDED bit Vitaly Kuznetsov
2021-04-13 12:26 ` [PATCH RFC 22/22] KVM: x86: hyper-v: Check access to HVCALL_NOTIFY_LONG_SPIN_WAIT hypercall Vitaly Kuznetsov

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