[Qemu-devel] [PATCH v2 3/5] vl.c: Add -smp, dies=* command line support and update -smp doc

[Like Xu <like.xu@linux.intel.com>]

For PC target, users could configure the number of dies per one package
via command line with this patch, such as "-smp dies=2,cores=4".

A new pc-specified pc_smp_parse() is introduced and to keep the interface
consistent, refactoring legacy smp_parse() to __smp_parse() is necessary.

The parsing rules of new cpu-topology model obey the same restrictions/logic
as the legacy socket/core/thread model especially on missing values computing.

Signed-off-by: Like Xu <like.xu@linux.intel.com>
---
 qemu-options.hx | 17 +++++-----
 vl.c            | 89 ++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 97 insertions(+), 9 deletions(-)

diff --git a/qemu-options.hx b/qemu-options.hx
index 5daa5a8fb0..7fad5b50ff 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -138,25 +138,26 @@ no incompatible TCG features have been enabled (e.g. icount/replay).
 ETEXI
 
 DEF("smp", HAS_ARG, QEMU_OPTION_smp,
-    "-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,sockets=sockets]\n"
+    "-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,dies=dies][,sockets=sockets]\n"
     "                set the number of CPUs to 'n' [default=1]\n"
     "                maxcpus= maximum number of total cpus, including\n"
     "                offline CPUs for hotplug, etc\n"
-    "                cores= number of CPU cores on one socket\n"
+    "                cores= number of CPU cores on one socket (for PC, it's on one die)\n"
     "                threads= number of threads on one CPU core\n"
+    "                dies= number of CPU dies on one socket (for PC only)\n"
     "                sockets= number of discrete sockets in the system\n",
         QEMU_ARCH_ALL)
 STEXI
-@item -smp [cpus=]@var{n}[,cores=@var{cores}][,threads=@var{threads}][,sockets=@var{sockets}][,maxcpus=@var{maxcpus}]
+@item -smp [cpus=]@var{n}[,cores=@var{cores}][,threads=@var{threads}][,dies=dies][,sockets=@var{sockets}][,maxcpus=@var{maxcpus}]
 @findex -smp
 Simulate an SMP system with @var{n} CPUs. On the PC target, up to 255
 CPUs are supported. On Sparc32 target, Linux limits the number of usable CPUs
 to 4.
-For the PC target, the number of @var{cores} per socket, the number
-of @var{threads} per cores and the total number of @var{sockets} can be
-specified. Missing values will be computed. If any on the three values is
-given, the total number of CPUs @var{n} can be omitted. @var{maxcpus}
-specifies the maximum number of hotpluggable CPUs.
+For the PC target, the number of @var{cores} per die, the number of @var{threads}
+per cores, the number of @var{dies} per packages and the total number of
+@var{sockets} can be specified. Missing values will be computed.
+If any on the three values is given, the total number of CPUs @var{n} can be omitted.
+@var{maxcpus} specifies the maximum number of hotpluggable CPUs.
 ETEXI
 
 DEF("numa", HAS_ARG, QEMU_OPTION_numa,
diff --git a/vl.c b/vl.c
index 8d92e2d209..66b577f447 100644
--- a/vl.c
+++ b/vl.c
@@ -63,6 +63,7 @@ int main(int argc, char **argv)
 #include "sysemu/watchdog.h"
 #include "hw/firmware/smbios.h"
 #include "hw/acpi/acpi.h"
+#include "hw/i386/pc.h"
 #include "hw/xen/xen.h"
 #include "hw/qdev.h"
 #include "hw/loader.h"
@@ -1248,6 +1249,9 @@ static QemuOptsList qemu_smp_opts = {
         }, {
             .name = "sockets",
             .type = QEMU_OPT_NUMBER,
+        }, {
+            .name = "dies",
+            .type = QEMU_OPT_NUMBER,
         }, {
             .name = "cores",
             .type = QEMU_OPT_NUMBER,
@@ -1262,7 +1266,7 @@ static QemuOptsList qemu_smp_opts = {
     },
 };
 
-static void smp_parse(QemuOpts *opts)
+static void __smp_parse(QemuOpts *opts)
 {
     if (opts) {
         unsigned cpus    = qemu_opt_get_number(opts, "cpus", 0);
@@ -1334,6 +1338,89 @@ static void smp_parse(QemuOpts *opts)
     }
 }
 
+static void pc_smp_parse(QemuOpts *opts)
+{
+    PCMachineState *pcms = (PCMachineState *)
+        object_dynamic_cast(OBJECT(current_machine), TYPE_PC_MACHINE);
+
+    unsigned cpus    = qemu_opt_get_number(opts, "cpus", 0);
+    unsigned sockets = qemu_opt_get_number(opts, "sockets", 0);
+    unsigned dies = qemu_opt_get_number(opts, "dies", 1);
+    unsigned cores   = qemu_opt_get_number(opts, "cores", 0);
+    unsigned threads = qemu_opt_get_number(opts, "threads", 0);
+
+    /* compute missing values, prefer sockets over cores over threads */
+    if (cpus == 0 || sockets == 0) {
+        cores = cores > 0 ? cores : 1;
+        threads = threads > 0 ? threads : 1;
+        if (cpus == 0) {
+            sockets = sockets > 0 ? sockets : 1;
+            cpus = cores * threads * dies * sockets;
+        } else {
+            current_machine->smp.max_cpus =
+                    qemu_opt_get_number(opts, "maxcpus", cpus);
+            sockets = current_machine->smp.max_cpus / (cores * threads * dies);
+        }
+    } else if (cores == 0) {
+        threads = threads > 0 ? threads : 1;
+        cores = cpus / (sockets * dies * threads);
+        cores = cores > 0 ? cores : 1;
+    } else if (threads == 0) {
+        threads = cpus / (cores * dies * sockets);
+        threads = threads > 0 ? threads : 1;
+    } else if (sockets * dies * cores * threads < cpus) {
+        error_report("cpu topology: "
+                        "sockets (%u) * dies (%u) * cores (%u) * threads (%u) < "
+                        "smp_cpus (%u)",
+                        sockets, dies, cores, threads, cpus);
+        exit(1);
+    }
+
+    current_machine->smp.max_cpus =
+            qemu_opt_get_number(opts, "maxcpus", cpus);
+
+    if (current_machine->smp.max_cpus < cpus) {
+        error_report("maxcpus must be equal to or greater than smp");
+        exit(1);
+    }
+
+    if (sockets * dies * cores * threads > current_machine->smp.max_cpus) {
+        error_report("cpu topology: "
+                        "sockets (%u) * dies (%u) * cores (%u) * threads (%u) > "
+                        "maxcpus (%u)",
+                        sockets, dies, cores, threads,
+                        current_machine->smp.max_cpus);
+        exit(1);
+    }
+
+    if (sockets * dies * cores * threads != current_machine->smp.max_cpus) {
+        warn_report("Invalid CPU topology deprecated: "
+                    "sockets (%u) * dies (%u) * cores (%u) * threads (%u) "
+                    "!= maxcpus (%u)",
+                    sockets, dies, cores, threads,
+                    current_machine->smp.max_cpus);
+    }
+
+    current_machine->smp.cpus = cpus;
+    current_machine->smp.cores = cores;
+    current_machine->smp.threads = threads;
+    pcms->smp_dies = dies;
+
+    if (current_machine->smp.cpus > 1) {
+        Error *blocker = NULL;
+        error_setg(&blocker, QERR_REPLAY_NOT_SUPPORTED, "smp");
+        replay_add_blocker(blocker);
+    }
+}
+
+static void smp_parse(QemuOpts *opts)
+{
+    if (object_dynamic_cast(OBJECT(current_machine), TYPE_PC_MACHINE))
+        pc_smp_parse(opts);
+    else
+        __smp_parse(opts);
+}
+
 static void realtime_init(void)
 {
     if (enable_mlock) {
-- 
2.21.0