From e392e5516e6ae66db0f05775a22c0abf39f033f0 Mon Sep 17 00:00:00 2001
From: Saverio Miroddi <saverio.pub2@gmail.com>
Date: Tue, 31 Oct 2017 20:59:05 +0100
Subject: [PATCH] Current pinning patch

Changes 2017/10/31:

- Fix: the MAX_VCPUS was arbitrary; it's now set to CPU_SETSIZE
- Fix: the allowed vcpus were equated to the cores number, without accounting sockets and threads
- Change: removed all the debug information, and a now unneded warning
- Change: cleaned spacing
---
 cpus.c          | 12 +++++++++++
 qemu-options.hx | 10 ++++++++++
 vl.c            | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 84 insertions(+)

diff --git a/cpus.c b/cpus.c
index 9bed61eefcc..7437e3a00c7 100644
--- a/cpus.c
+++ b/cpus.c
@@ -55,6 +55,9 @@
 #ifdef CONFIG_LINUX
 
 #include <sys/prctl.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <inttypes.h>
 
 #ifndef PR_MCE_KILL
 #define PR_MCE_KILL 33
@@ -1722,9 +1725,11 @@ static void qemu_hax_start_vcpu(CPUState *cpu)
     }
 }
 
+extern int vcpu_affinity[];
 static void qemu_kvm_start_vcpu(CPUState *cpu)
 {
     char thread_name[VCPU_THREAD_NAME_SIZE];
+    cpu_set_t cpuset;
 
     cpu->thread = g_malloc0(sizeof(QemuThread));
     cpu->halt_cond = g_malloc0(sizeof(QemuCond));
@@ -1733,6 +1738,13 @@ static void qemu_kvm_start_vcpu(CPUState *cpu)
              cpu->cpu_index);
     qemu_thread_create(cpu->thread, thread_name, qemu_kvm_cpu_thread_fn,
                        cpu, QEMU_THREAD_JOINABLE);
+
+    if (vcpu_affinity[cpu->cpu_index] != -1) {
+      CPU_ZERO(&cpuset);
+      CPU_SET(vcpu_affinity[cpu->cpu_index], &cpuset);
+      pthread_setaffinity_np((cpu->thread)->thread, sizeof(cpu_set_t), &cpuset);
+    }
+
     while (!cpu->created) {
         qemu_cond_wait(&qemu_cpu_cond, &qemu_global_mutex);
     }
diff --git a/qemu-options.hx b/qemu-options.hx
index 9f6e2adfffb..1d38fc86c81 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -160,6 +160,16 @@ given, the total number of CPUs @var{n} can be omitted. @var{maxcpus}
 specifies the maximum number of hotpluggable CPUs.
 ETEXI
 
+DEF("vcpu", HAS_ARG, QEMU_OPTION_vcpu,
+    "-vcpu [vcpunum=]n[,affinity=affinity]\n"
+    "-vcpu [vcpunum=]n[,affinity=affinity]\n", QEMU_ARCH_ALL)
+STEXI
+@item -vcpu [vcpunum=]@var{n}[,affinity=@var{affinity}]
+@itemx -vcpu [vcpunum=]@var{n}[,affinity=@var{affinity}]
+@findex -vcpu
+VCPU Affinity. If specified, specify for all the CPUs.
+ETEXI
+
 DEF("numa", HAS_ARG, QEMU_OPTION_numa,
     "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node]\n"
     "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node]\n"
diff --git a/vl.c b/vl.c
index d63269332fe..754a03c9a5f 100644
--- a/vl.c
+++ b/vl.c
@@ -135,6 +135,7 @@ int main(int argc, char **argv)
 #define MAX_VIRTIO_CONSOLES 1
 #define MAX_SCLP_CONSOLES 1
 
+#define MAX_VCPUS CPU_SETSIZE
 static const char *data_dir[16];
 static int data_dir_idx;
 const char *bios_name = NULL;
@@ -167,6 +168,8 @@ int smp_cpus = 1;
 int max_cpus = 1;
 int smp_cores = 1;
 int smp_threads = 1;
+int vcpu_affinity[MAX_VCPUS];
+int num_affinity = 0;
 int acpi_enabled = 1;
 int no_hpet = 0;
 int fd_bootchk = 1;
@@ -1212,6 +1215,57 @@ static QemuOptsList qemu_smp_opts = {
     },
 };
 
+static QemuOptsList qemu_vcpu_opts = {
+    .name = "vcpu-opts",
+    .implied_opt_name = "vcpunum",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_vcpu_opts.head),
+    .desc = {
+        {
+            .name = "vcpunum",
+            .type = QEMU_OPT_NUMBER,
+        }, {
+            .name = "affinity",
+            .type = QEMU_OPT_NUMBER,
+        },
+        { /*End of list */ }
+    },
+};
+
+static int parse_vcpu(void *opaque, QemuOpts *opts, Error **errp)
+{
+    if (opts) {
+      unsigned vcpu = qemu_opt_get_number(opts, "vcpunum", 0);
+      unsigned affinity = qemu_opt_get_number(opts,"affinity", 0);
+
+      if (vcpu < smp_cpus * smp_cores * smp_threads) {
+        if (vcpu_affinity[vcpu] == -1) {
+          vcpu_affinity[vcpu] = affinity;
+        }
+        else {
+          error_report("Duplicate affinity statement for vcpu %d\n", vcpu);
+          return -1;
+        }
+        num_affinity += 1;
+      }
+      else {
+        error_report("VCPU %d is more than allowed %d VCPUs in the system\n", vcpu, smp_cores);
+        return -1;
+      }
+    }
+    return 0;
+}
+
+static void parse_vcpu_opts(MachineClass *mc)
+{
+    int i;
+    for (i = 0; i < MAX_VCPUS; i++)
+      vcpu_affinity[i] = -1;
+
+    if (qemu_opts_foreach(qemu_find_opts("vcpu-opts"), parse_vcpu, NULL, NULL)) {
+        exit(1);
+    }
+}
+
 static void smp_parse(QemuOpts *opts)
 {
     if (opts) {
@@ -3067,6 +3121,7 @@ int main(int argc, char **argv, char **envp)
     qemu_add_opts(&qemu_accel_opts);
     qemu_add_opts(&qemu_mem_opts);
     qemu_add_opts(&qemu_smp_opts);
+    qemu_add_opts(&qemu_vcpu_opts);
     qemu_add_opts(&qemu_boot_opts);
     qemu_add_opts(&qemu_sandbox_opts);
     qemu_add_opts(&qemu_add_fd_opts);
@@ -3818,6 +3873,12 @@ int main(int argc, char **argv, char **envp)
                     exit(1);
                 }
                 break;
+            case QEMU_OPTION_vcpu:
+                if (!qemu_opts_parse_noisily(qemu_find_opts("vcpu-opts"),
+                                             optarg, true)) {
+                    exit(1);
+                }
+                break;
             case QEMU_OPTION_vnc:
                 vnc_parse(optarg, &error_fatal);
                 break;
@@ -4243,6 +4304,7 @@ int main(int argc, char **argv, char **envp)
         exit(1);
     }
 
+    parse_vcpu_opts(machine_class);
     /*
      * Get the default machine options from the machine if it is not already
      * specified either by the configuration file or by the command line.