linux-kernel - [PATCH v2 27/30] KVM: x86: hyper-v: Honor HV_X64_EX_PROCESSOR_MASKS

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Date:   Fri, 21 May 2021 11:52:01 +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
Subject: [PATCH v2 27/30] KVM: x86: hyper-v: Honor HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED bit

Hypercalls which use extended processor masks are only available when
HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED privilege bit is exposed (and
'RECOMMENDED' is rather a misnomer).

Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
---
 arch/x86/kvm/hyperv.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index ba5af4d27ccf..4ad27e7cdb05 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2046,11 +2046,19 @@ static bool hv_check_hypercall_access(struct kvm_vcpu_hv *hv_vcpu, u16 code)
 			hv_vcpu->cpuid_cache.features_ebx & HV_DEBUGGING;
 	case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX:
 	case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX:
+		if (!(hv_vcpu->cpuid_cache.enlightenments_eax &
+		      HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
+			return false;
+		fallthrough;
 	case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST:
 	case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE:
 		return hv_vcpu->cpuid_cache.enlightenments_eax &
 			HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED;
 	case HVCALL_SEND_IPI_EX:
+		if (!(hv_vcpu->cpuid_cache.enlightenments_eax &
+		      HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
+			return false;
+		fallthrough;
 	case HVCALL_SEND_IPI:
 		return hv_vcpu->cpuid_cache.enlightenments_eax &
 			HV_X64_CLUSTER_IPI_RECOMMENDED;
-- 
2.31.1