From 95cced34fbd37b40b9dd57e1a5538bccd57544e2 Mon Sep 17 00:00:00 2001
From: Igor Mammedov <imammedo@redhat.com>
Date: Sun, 25 Feb 2018 20:31:35 -0500
Subject: [PATCH] pc: Add x86_topo_ids_from_apicid()

It's reverse of apicid_from_topo_ids() and will be used in follow up
patches to fill in data structures for query-hotpluggable-cpus and
for user friendly error reporting.

Backports commit 9f3aab58539b4cc716e42e772be8116dc2e7d159 from qemu
---
 qemu/target-i386/topology.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/qemu/target-i386/topology.h b/qemu/target-i386/topology.h
index f8b0ca4e..6c7ef3a1 100644
--- a/qemu/target-i386/topology.h
+++ b/qemu/target-i386/topology.h
@@ -92,6 +92,21 @@ static inline unsigned apicid_pkg_offset(unsigned nr_cores, unsigned nr_threads)
            apicid_core_width(nr_cores, nr_threads);
 }
 
+/* Calculate thread/core/package IDs for a specific topology,
+ * based on APIC ID
+ */
+static inline void x86_topo_ids_from_apicid(apic_id_t apicid,
+                                            unsigned nr_cores,
+                                            unsigned nr_threads,
+                                            X86CPUTopoInfo *topo)
+{
+    topo->smt_id = apicid &
+                   ~(0xFFFFFFFFUL << apicid_smt_width(nr_cores, nr_threads));
+    topo->core_id = (apicid >> apicid_core_offset(nr_cores, nr_threads)) &
+                   ~(0xFFFFFFFFUL << apicid_core_width(nr_cores, nr_threads));
+    topo->pkg_id = apicid >> apicid_pkg_offset(nr_cores, nr_threads);
+}
+
 /* Make APIC ID for the CPU based on Pkg_ID, Core_ID, SMT_ID
  *
  * The caller must make sure core_id < nr_cores and smt_id < nr_threads.