[libvirt] [PATCH 3/4] PowerPC cpu : Handle only high order 16 bits for PVR

[Prerna Saxena]

>From 1bcba78ed387a876208fec1ef60b81d65c8474e5 Mon Sep 17 00:00:00 2001
From: "Pradipta Kr. Banerjee" <bpradip at in.ibm.com>
Date: Tue, 7 Oct 2014 11:12:36 +0530

IBM Power processors differ uniquely across generations (such as power6,
power7, power8). Each generation signifies a new PowerISA version
that exhibits features unique to that generation.
The higher 16 bits of PVR for IBM Power processors encode the CPU generation,
while the CPU chip (sub)version is encoded in lower 16 bits.

For all practical purposes of launching a VM, we care about the
generation which the vCPU will belong to, and not specifically the chip
version. This patch updates the libvirt PVR check to reflect this
relationship.
It also contains changes to cpu_map.xml since processor generations
as understood by QEMU compat mode go as "power6", "power7" or "power8"
[Reference : QEMU commit 8dfa3a5e85 ]

Signed-off-by: Pradipta Kr. Banerjee <bpradip at in.ibm.com>
Signed-off-by: Prerna Saxena <prerna at linux.vnet.ibm.com>
---
 src/cpu/cpu_map.xml   | 22 ++++++++--------------
 src/cpu/cpu_powerpc.c |  7 ++++++-
 2 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/src/cpu/cpu_map.xml b/src/cpu/cpu_map.xml
index 18c7b0d..f2f13fb 100644
--- a/src/cpu/cpu_map.xml
+++ b/src/cpu/cpu_map.xml
@@ -602,30 +602,24 @@
     <vendor name='IBM'/>
 
     <!-- IBM-based CPU models -->
-    <model name='POWER7'>
+    <model name='power6'>
       <vendor name='IBM'/>
-      <pvr value='0x003f0200'/>
+      <pvr value='0x003e0000'/>
     </model>
 
-    <model name='POWER7_v2.1'>
+    <model name='power7'>
       <vendor name='IBM'/>
-      <pvr value='0x003f0201'/>
+      <pvr value='0x003f0000'/>
     </model>
 
-    <model name='POWER7_v2.3'>
+    <model name='power7+'>
       <vendor name='IBM'/>
-      <pvr value='0x003f0203'/>
+      <pvr value='0x004a0000'/>
     </model>
 
-    <model name='POWER7+_v2.1'>
+    <model name='power8'>
       <vendor name='IBM'/>
-      <pvr value='0x004a0201'/>
+      <pvr value='0x004b0000'/>
     </model>
-
-    <model name='POWER8_v1.0'>
-      <vendor name='IBM'/>
-      <pvr value='0x004b0100'/>
-    </model>
-
   </arch>
 </cpus>
diff --git a/src/cpu/cpu_powerpc.c b/src/cpu/cpu_powerpc.c
index 9ab33c2..ddca0d4 100644
--- a/src/cpu/cpu_powerpc.c
+++ b/src/cpu/cpu_powerpc.c
@@ -93,7 +93,12 @@ ppcModelFindPVR(const struct ppc_map *map,
 
     model = map->models;
     while (model != NULL) {
-        if (model->data.pvr == pvr)
+    /*IBM PowerPC processors encode PVR as CPU family in higher 16 bits and
+     *a CPU version in lower 16 bits. Since there is no significant change
+     *in behavior between versions, there is no point to add every single CPU
+     *version in cpu_map.xml
+     */
+        if ((model->data.pvr & 0xFFFF0000) == (pvr & 0xFFFF0000))
             return model;
 
         model = model->next;
-- 
1.8.3.1


-- 
Prerna Saxena

Linux Technology Centre,
IBM Systems and Technology Lab,
Bangalore, India