KVM: x86/xen: Fix get_attr of KVM_XEN_ATTR_TYPE_SHARED_INFO

In commit 319afe6 ("KVM: xen: do not use struct gfn_to_hva_cache") we
stopped storing this in-kernel as a GPA, and started storing it as a GFN.
Which means we probably should have stopped calling gpa_to_gfn() on it
when userspace asks for it back.

Cc: [email protected]
Fixes: 319afe6 ("KVM: xen: do not use struct gfn_to_hva_cache")
Signed-off-by: David Woodhouse <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

arch/x86/kvm/xen.c

@@ -282,7 +282,7 @@ int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
 		break;
 
 	case KVM_XEN_ATTR_TYPE_SHARED_INFO:
-		data->u.shared_info.gfn = gpa_to_gfn(kvm->arch.xen.shinfo_gfn);
+		data->u.shared_info.gfn = kvm->arch.xen.shinfo_gfn;
 		r = 0;
 		break;