[RFC PATCH 11/15] KVM: TDX: Factor out userspace return path from tdx_get_quote()

[Xu Yilun]

From: Peter Fang <peter.fang@xxxxxxxxx>

Separate the logic that returns GetQuote to userspace so that
tdx_get_quote() can be extended to support in-kernel quote generation.

No functional change intended.

Signed-off-by: Peter Fang <peter.fang@xxxxxxxxx>
Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxxxxxxxx>
---
 arch/x86/kvm/vmx/tdx.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index ed12805bbb44..9f7c39e0d4b5 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1524,6 +1524,20 @@ static int tdx_complete_simple(struct kvm_vcpu *vcpu)
 	return 1;
 }
 
+static int tdx_get_quote_user(struct kvm_vcpu *vcpu, u64 gpa, u64 size)
+{
+	vcpu->run->exit_reason = KVM_EXIT_TDX;
+	vcpu->run->tdx.flags = 0;
+	vcpu->run->tdx.nr = TDVMCALL_GET_QUOTE;
+	vcpu->run->tdx.get_quote.ret = TDVMCALL_STATUS_SUBFUNC_UNSUPPORTED;
+	vcpu->run->tdx.get_quote.gpa = gpa;
+	vcpu->run->tdx.get_quote.size = size;
+
+	vcpu->arch.complete_userspace_io = tdx_complete_simple;
+
+	return 0;
+}
+
 static int tdx_get_quote(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_tdx *tdx = to_tdx(vcpu);
@@ -1536,16 +1550,9 @@ static int tdx_get_quote(struct kvm_vcpu *vcpu)
 		return 1;
 	}
 
-	vcpu->run->exit_reason = KVM_EXIT_TDX;
-	vcpu->run->tdx.flags = 0;
-	vcpu->run->tdx.nr = TDVMCALL_GET_QUOTE;
-	vcpu->run->tdx.get_quote.ret = TDVMCALL_STATUS_SUBFUNC_UNSUPPORTED;
-	vcpu->run->tdx.get_quote.gpa = gpa & ~gfn_to_gpa(kvm_gfn_direct_bits(tdx->vcpu.kvm));
-	vcpu->run->tdx.get_quote.size = size;
-
-	vcpu->arch.complete_userspace_io = tdx_complete_simple;
+	gpa &= ~gfn_to_gpa(kvm_gfn_direct_bits(vcpu->kvm));
 
-	return 0;
+	return tdx_get_quote_user(vcpu, gpa, size);
 }
 
 static int tdx_setup_event_notify_interrupt(struct kvm_vcpu *vcpu)
-- 
2.25.1