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From:   isaku.yamahata@intel.com
To:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     isaku.yamahata@intel.com, isaku.yamahata@gmail.com,
        Paolo Bonzini <pbonzini@redhat.com>, erdemaktas@google.com,
        Sean Christopherson <seanjc@google.com>,
        Sagi Shahar <sagis@google.com>
Subject: [RFC PATCH v6 090/104] KVM: TDX: Handle TDX PV CPUID hypercall
Date:   Thu,  5 May 2022 11:15:24 -0700
Message-Id: <98939c0ec83a109c8f49045e82096d6cdd5dafa3.1651774251.git.isaku.yamahata@intel.com>
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From: Isaku Yamahata <isaku.yamahata@intel.com>

Wire up TDX PV CPUID hypercall to the KVM backend function.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
 arch/x86/kvm/vmx/tdx.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 9c712f661a7c..c7cdfee397ec 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -946,12 +946,34 @@ static int tdx_emulate_vmcall(struct kvm_vcpu *vcpu)
 	return 1;
 }
 
+static int tdx_emulate_cpuid(struct kvm_vcpu *vcpu)
+{
+	u32 eax, ebx, ecx, edx;
+
+	/* EAX and ECX for cpuid is stored in R12 and R13. */
+	eax = tdvmcall_a0_read(vcpu);
+	ecx = tdvmcall_a1_read(vcpu);
+
+	kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx, true);
+
+	tdvmcall_a0_write(vcpu, eax);
+	tdvmcall_a1_write(vcpu, ebx);
+	tdvmcall_a2_write(vcpu, ecx);
+	tdvmcall_a3_write(vcpu, edx);
+
+	tdvmcall_set_return_code(vcpu, TDG_VP_VMCALL_SUCCESS);
+
+	return 1;
+}
+
 static int handle_tdvmcall(struct kvm_vcpu *vcpu)
 {
 	if (tdvmcall_exit_type(vcpu))
 		return tdx_emulate_vmcall(vcpu);
 
 	switch (tdvmcall_leaf(vcpu)) {
+	case EXIT_REASON_CPUID:
+		return tdx_emulate_cpuid(vcpu);
 	default:
 		break;
 	}
-- 
2.25.1