[RFC PATCH v2 2/4] hw/arm/virt: Parse -smp cluster parameter in virt_smp_parse

[Yanan Wang]

There is a separate function virt_smp_parse() in hw/virt/arm.c used
to parse cpu topology for the ARM machines. So add parsing of -smp
cluster parameter in it, then total number of logical cpus will be
calculated like: max_cpus = sockets * clusters * cores * threads.

In virt_smp_parse(), the computing logic of missing values prefers
cores over sockets over threads. And for compatibility, the value
of clusters will be set as default 1 if not explicitly specified.

Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
---
 hw/arm/virt.c | 32 ++++++++++++++++++--------------
 1 file changed, 18 insertions(+), 14 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 57ef961cb5..51797628db 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2639,35 +2639,38 @@ static void virt_smp_parse(MachineState *ms, QemuOpts 
*opts)
     if (opts) {
         unsigned cpus = qemu_opt_get_number(opts, "cpus", 0);
         unsigned sockets = qemu_opt_get_number(opts, "sockets", 0);
+        unsigned clusters = qemu_opt_get_number(opts, "clusters", 1);
         unsigned cores = qemu_opt_get_number(opts, "cores", 0);
         unsigned threads = qemu_opt_get_number(opts, "threads", 0);
+        VirtMachineState *vms = VIRT_MACHINE(ms);
 
         /*
-         * Compute missing values; prefer cores over sockets and
-         * sockets over threads.
+         * Compute missing values; prefer cores over sockets and sockets
+         * over threads. For compatibility, value of clusters will have
+         * been set as default 1 if not explicitly specified.
          */
         if (cpus == 0 || cores == 0) {
             sockets = sockets > 0 ? sockets : 1;
             threads = threads > 0 ? threads : 1;
             if (cpus == 0) {
                 cores = cores > 0 ? cores : 1;
-                cpus = cores * threads * sockets;
+                cpus = sockets * clusters * cores * threads;
             } else {
                 ms->smp.max_cpus = qemu_opt_get_number(opts, "maxcpus", cpus);
-                cores = ms->smp.max_cpus / (sockets * threads);
+                cores = ms->smp.max_cpus / (sockets * clusters * threads);
             }
         } else if (sockets == 0) {
             threads = threads > 0 ? threads : 1;
-            sockets = cpus / (cores * threads);
+            sockets = cpus / (clusters * cores * threads);
             sockets = sockets > 0 ? sockets : 1;
         } else if (threads == 0) {
-            threads = cpus / (cores * sockets);
+            threads = cpus / (sockets * clusters * cores);
             threads = threads > 0 ? threads : 1;
-        } else if (sockets * cores * threads < cpus) {
+        } else if (sockets * clusters * cores * threads < cpus) {
             error_report("cpu topology: "
-                         "sockets (%u) * cores (%u) * threads (%u) < "
-                         "smp_cpus (%u)",
-                         sockets, cores, threads, cpus);
+                         "sockets (%u) * clusters (%u) * cores (%u) * "
+                         "threads (%u) < smp_cpus (%u)",
+                         sockets, clusters, cores, threads, cpus);
             exit(1);
         }
 
@@ -2678,11 +2681,11 @@ static void virt_smp_parse(MachineState *ms, QemuOpts 
*opts)
             exit(1);
         }
 
-        if (sockets * cores * threads != ms->smp.max_cpus) {
+        if (sockets * clusters * cores * threads != ms->smp.max_cpus) {
             error_report("cpu topology: "
-                         "sockets (%u) * cores (%u) * threads (%u)"
-                         "!= maxcpus (%u)",
-                         sockets, cores, threads,
+                         "sockets (%u) * clusters (%u) * cores (%u) * "
+                         "threads (%u) != maxcpus (%u)",
+                         sockets, clusters, cores, threads,
                          ms->smp.max_cpus);
             exit(1);
         }
@@ -2691,6 +2694,7 @@ static void virt_smp_parse(MachineState *ms, QemuOpts 
*opts)
         ms->smp.cores = cores;
         ms->smp.threads = threads;
         ms->smp.sockets = sockets;
+        vms->smp_clusters = clusters;
     }
 
     if (ms->smp.cpus > 1) {
-- 
2.19.1