From 7d5a7d6926805c069903bef845d43912cf718410 Mon Sep 17 00:00:00 2001

From: Eduardo Habkost <ehabkost@redhat.com>

Date: Tue, 3 Jul 2018 17:23:54 +0200

Subject: [PATCH 09/89] i386: Fix up the Node id for CPUID_8000_001E

RH-Author: Eduardo Habkost <ehabkost@redhat.com>

Message-id: <20180703172356.21038-9-ehabkost@redhat.com>

Patchwork-id: 81218

O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH v3 08/10] i386: Fix up the Node id for CPUID_8000_001E

Bugzilla: 1481253

RH-Acked-by: Laurent Vivier <lvivier@redhat.com>

RH-Acked-by: Igor Mammedov <imammedo@redhat.com>

RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

From: Babu Moger <babu.moger@amd.com>

This is part of topoext support. To keep the compatibility, it is better

we support all the combination of nr_cores and nr_threads currently

supported. By allowing more nr_cores and nr_threads, we might end up with

more nodes than we can actually support with the real hardware. We need to

fix up the node id to make this work. We can achieve this by shifting the

socket_id bits left to address more nodes.

Signed-off-by: Babu Moger <babu.moger@amd.com>

Message-Id: <1529443919-67509-2-git-send-email-babu.moger@amd.com>

Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

(cherry picked from commit 631be32155dbafa1fe886f2488127956c9120ba6)

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 target/i386/cpu.c | 26 +++++++++++++++++++++++++-

 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c

index 643d3b1..ef43ea0 100644

--- a/target/i386/cpu.c

+++ b/target/i386/cpu.c

@@ -19,6 +19,7 @@

 #include "qemu/osdep.h"

 #include "qemu/cutils.h"

+#include "qemu/bitops.h"

 #include "cpu.h"

 #include "exec/exec-all.h"

@@ -474,6 +475,8 @@ static void encode_topo_cpuid8000001e(CPUState *cs, X86CPU *cpu,

                                        uint32_t *ecx, uint32_t *edx)

 {

     struct core_topology topo = {0};

+    unsigned long nodes;

+    int shift;

     build_core_topology(cs->nr_cores, cpu->core_id, &topo;;

     *eax = cpu->apic_id;

@@ -506,7 +509,28 @@ static void encode_topo_cpuid8000001e(CPUState *cs, X86CPU *cpu,

      *         2  Socket id

      *       1:0  Node id

      */

-    *ecx = ((topo.num_nodes - 1) << 8) | (cpu->socket_id << 2) | topo.node_id;

+    if (topo.num_nodes <= 4) {

+        *ecx = ((topo.num_nodes - 1) << 8) | (cpu->socket_id << 2) |

+                topo.node_id;

+    } else {

+        /*

+         * Node id fix up. Actual hardware supports up to 4 nodes. But with

+         * more than 32 cores, we may end up with more than 4 nodes.

+         * Node id is a combination of socket id and node id. Only requirement

+         * here is that this number should be unique accross the system.

+         * Shift the socket id to accommodate more nodes. We dont expect both

+         * socket id and node id to be big number at the same time. This is not

+         * an ideal config but we need to to support it. Max nodes we can have

+         * is 32 (255/8) with 8 cores per node and 255 max cores. We only need

+         * 5 bits for nodes. Find the left most set bit to represent the total

+         * number of nodes. find_last_bit returns last set bit(0 based). Left

+         * shift(+1) the socket id to represent all the nodes.

+         */

+        nodes = topo.num_nodes - 1;

+        shift = find_last_bit(&nodes, 8);

+        *ecx = ((topo.num_nodes - 1) << 8) | (cpu->socket_id << (shift + 1)) |

+                topo.node_id;

+    }

     *edx = 0;

 }

-- 

1.8.3.1