[Qemu-devel] [PATCH 28/60] Fixes related to processing of qemu's -numa option

[Michael Tokarev]

From: Chegu Vinod <address@hidden>

The -numa option to qemu is used to create [fake] numa nodes
and expose them to the guest OS instance.

There are a couple of issues with the -numa option:

a) Max VCPU's that can be specified for a guest while using
   the qemu's -numa option is 64. Due to a typecasting issue
   when the number of VCPUs is > 32 the VCPUs don't show up
   under the specified [fake] numa nodes.

b) KVM currently has support for 160VCPUs per guest. The
   qemu's -numa option has only support for upto 64VCPUs
   per guest.
This patch addresses these two issues.

Below are examples of (a) and (b)

a) >32 VCPUs are specified with the -numa option:

/usr/local/bin/qemu-system-x86_64 \
-enable-kvm \
71:01:01 \
-net tap,ifname=tap0,script=no,downscript=no \
-vnc :4

...
Upstream qemu :
--------------

QEMU 1.1.50 monitor - type 'help' for more information
(qemu) info numa
6 nodes
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 32 33 34 35 36 37 38 39 40 41
node 0 size: 131072 MB
node 1 cpus: 10 11 12 13 14 15 16 17 18 19 42 43 44 45 46 47 48 49 50 51
node 1 size: 131072 MB
node 2 cpus: 20 21 22 23 24 25 26 27 28 29 52 53 54 55 56 57 58 59
node 2 size: 131072 MB
node 3 cpus: 30
node 3 size: 131072 MB
node 4 cpus:
node 4 size: 131072 MB
node 5 cpus: 31
node 5 size: 131072 MB

With the patch applied :
-----------------------

QEMU 1.1.50 monitor - type 'help' for more information
(qemu) info numa
6 nodes
node 0 cpus: 0 1 2 3 4 5 6 7 8 9
node 0 size: 131072 MB
node 1 cpus: 10 11 12 13 14 15 16 17 18 19
node 1 size: 131072 MB
node 2 cpus: 20 21 22 23 24 25 26 27 28 29
node 2 size: 131072 MB
node 3 cpus: 30 31 32 33 34 35 36 37 38 39
node 3 size: 131072 MB
node 4 cpus: 40 41 42 43 44 45 46 47 48 49
node 4 size: 131072 MB
node 5 cpus: 50 51 52 53 54 55 56 57 58 59
node 5 size: 131072 MB

b) >64 VCPUs specified with -numa option:

/usr/local/bin/qemu-system-x86_64 \
-enable-kvm \
-cpu 
Westmere,+rdtscp,+pdpe1gb,+dca,+pdcm,+xtpr,+tm2,+est,+smx,+vmx,+ds_cpl,+monitor,+dtes64,+pclmuldq,+pbe,+tm,+ht,+ss,+acpi,+d-vnc
 :4

...

Upstream qemu :
--------------

only 63 CPUs in NUMA mode supported.
only 64 CPUs in NUMA mode supported.
QEMU 1.1.50 monitor - type 'help' for more information
(qemu) info numa
8 nodes
node 0 cpus: 6 7 8 9 38 39 40 41 70 71 72 73
node 0 size: 65536 MB
node 1 cpus: 10 11 12 13 14 15 16 17 18 19 42 43 44 45 46 47 48 49 50 51 74 75 
76 77 78 79
node 1 size: 65536 MB
node 2 cpus: 20 21 22 23 24 25 26 27 28 29 52 53 54 55 56 57 58 59 60 61
node 2 size: 65536 MB
node 3 cpus: 30 62
node 3 size: 65536 MB
node 4 cpus:
node 4 size: 65536 MB
node 5 cpus:
node 5 size: 65536 MB
node 6 cpus: 31 63
node 6 size: 65536 MB
node 7 cpus: 0 1 2 3 4 5 32 33 34 35 36 37 64 65 66 67 68 69
node 7 size: 65536 MB

With the patch applied :
-----------------------

QEMU 1.1.50 monitor - type 'help' for more information
(qemu) info numa
8 nodes
node 0 cpus: 0 1 2 3 4 5 6 7 8 9
node 0 size: 65536 MB
node 1 cpus: 10 11 12 13 14 15 16 17 18 19
node 1 size: 65536 MB
node 2 cpus: 20 21 22 23 24 25 26 27 28 29
node 2 size: 65536 MB
node 3 cpus: 30 31 32 33 34 35 36 37 38 39
node 3 size: 65536 MB
node 4 cpus: 40 41 42 43 44 45 46 47 48 49
node 4 size: 65536 MB
node 5 cpus: 50 51 52 53 54 55 56 57 58 59
node 5 size: 65536 MB
node 6 cpus: 60 61 62 63 64 65 66 67 68 69
node 6 size: 65536 MB
node 7 cpus: 70 71 72 73 74 75 76 77 78 79

Signed-off-by: Chegu Vinod <address@hidden>, Jim Hull <address@hidden>, Craig 
Hada <address@hidden>
Tested-by: Eduardo Habkost <address@hidden>
Reviewed-by: Eduardo Habkost <address@hidden>
Signed-off-by: Blue Swirl <address@hidden>
(cherry picked from commit ee785fed5dd035d4b12142cacec6d3c344426dec)

Signed-off-by: Michael Tokarev <address@hidden>
---
 cpus.c   |    3 ++-
 hw/pc.c  |    3 ++-
 sysemu.h |    3 ++-
 vl.c     |   43 +++++++++++++++++++++----------------------
 4 files changed, 27 insertions(+), 25 deletions(-)

diff --git a/cpus.c b/cpus.c
index b182b3d..acccd08 100644
--- a/cpus.c
+++ b/cpus.c
@@ -36,6 +36,7 @@
 #include "cpus.h"
 #include "qtest.h"
 #include "main-loop.h"
+#include "bitmap.h"
 
 #ifndef _WIN32
 #include "compatfd.h"
@@ -1145,7 +1146,7 @@ void set_numa_modes(void)
 
     for (env = first_cpu; env != NULL; env = env->next_cpu) {
         for (i = 0; i < nb_numa_nodes; i++) {
-            if (node_cpumask[i] & (1 << env->cpu_index)) {
+            if (test_bit(env->cpu_index, node_cpumask[i])) {
                 env->numa_node = i;
             }
         }
diff --git a/hw/pc.c b/hw/pc.c
index 6c4b07b..2aa7551 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -48,6 +48,7 @@
 #include "memory.h"
 #include "exec-memory.h"
 #include "arch_init.h"
+#include "bitmap.h"
 
 /* output Bochs bios info messages */
 //#define DEBUG_BIOS
@@ -644,7 +645,7 @@ static void *bochs_bios_init(void)
     numa_fw_cfg[0] = cpu_to_le64(nb_numa_nodes);
     for (i = 0; i < max_cpus; i++) {
         for (j = 0; j < nb_numa_nodes; j++) {
-            if (node_cpumask[j] & (1 << i)) {
+            if (test_bit(i, node_cpumask[j])) {
                 numa_fw_cfg[i + 1] = cpu_to_le64(j);
                 break;
             }
diff --git a/sysemu.h b/sysemu.h
index bc2c788..2ce63fc 100644
--- a/sysemu.h
+++ b/sysemu.h
@@ -133,9 +133,10 @@ extern uint8_t qemu_extra_params_fw[2];
 extern QEMUClock *rtc_clock;
 
 #define MAX_NODES 64
+#define MAX_CPUMASK_BITS 255
 extern int nb_numa_nodes;
 extern uint64_t node_mem[MAX_NODES];
-extern uint64_t node_cpumask[MAX_NODES];
+extern unsigned long *node_cpumask[MAX_NODES];
 
 #define MAX_OPTION_ROMS 16
 typedef struct QEMUOptionRom {
diff --git a/vl.c b/vl.c
index 1dd4c6b..bbc0815 100644
--- a/vl.c
+++ b/vl.c
@@ -28,6 +28,7 @@
 #include <errno.h>
 #include <sys/time.h>
 #include <zlib.h>
+#include "bitmap.h"
 
 /* Needed early for CONFIG_BSD etc. */
 #include "config-host.h"
@@ -246,7 +247,7 @@ QTAILQ_HEAD(, FWBootEntry) fw_boot_order = 
QTAILQ_HEAD_INITIALIZER(fw_boot_order
 
 int nb_numa_nodes;
 uint64_t node_mem[MAX_NODES];
-uint64_t node_cpumask[MAX_NODES];
+unsigned long *node_cpumask[MAX_NODES];
 
 uint8_t qemu_uuid[16];
 
@@ -957,6 +958,8 @@ static void numa_add(const char *optarg)
     unsigned long long value, endvalue;
     int nodenr;
 
+    value = endvalue = 0ULL;
+
     optarg = get_opt_name(option, 128, optarg, ',') + 1;
     if (!strcmp(option, "node")) {
         if (get_param_value(option, 128, "nodeid", optarg) == 0) {
@@ -976,27 +979,22 @@ static void numa_add(const char *optarg)
             }
             node_mem[nodenr] = sval;
         }
-        if (get_param_value(option, 128, "cpus", optarg) == 0) {
-            node_cpumask[nodenr] = 0;
-        } else {
+        if (get_param_value(option, 128, "cpus", optarg) != 0) {
             value = strtoull(option, &endptr, 10);
-            if (value >= 64) {
-                value = 63;
-                fprintf(stderr, "only 64 CPUs in NUMA mode supported.\n");
+            if (*endptr == '-') {
+                endvalue = strtoull(endptr+1, &endptr, 10);
             } else {
-                if (*endptr == '-') {
-                    endvalue = strtoull(endptr+1, &endptr, 10);
-                    if (endvalue >= 63) {
-                        endvalue = 62;
-                        fprintf(stderr,
-                            "only 63 CPUs in NUMA mode supported.\n");
-                    }
-                    value = (2ULL << endvalue) - (1ULL << value);
-                } else {
-                    value = 1ULL << value;
-                }
+                endvalue = value;
+            }
+
+            if (!(endvalue < MAX_CPUMASK_BITS)) {
+                endvalue = MAX_CPUMASK_BITS - 1;
+                fprintf(stderr,
+                    "A max of %d CPUs are supported in a guest\n",
+                     MAX_CPUMASK_BITS);
             }
-            node_cpumask[nodenr] = value;
+
+            bitmap_set(node_cpumask[nodenr], value, endvalue-value+1);
         }
         nb_numa_nodes++;
     }
@@ -2337,7 +2335,7 @@ int main(int argc, char **argv, char **envp)
 
     for (i = 0; i < MAX_NODES; i++) {
         node_mem[i] = 0;
-        node_cpumask[i] = 0;
+        node_cpumask[i] = bitmap_new(MAX_CPUMASK_BITS);
     }
 
     nb_numa_nodes = 0;
@@ -3468,8 +3466,9 @@ int main(int argc, char **argv, char **envp)
         }
 
         for (i = 0; i < nb_numa_nodes; i++) {
-            if (node_cpumask[i] != 0)
+            if (!bitmap_empty(node_cpumask[i], MAX_CPUMASK_BITS)) {
                 break;
+            }
         }
         /* assigning the VCPUs round-robin is easier to implement, guest OSes
          * must cope with this anyway, because there are BIOSes out there in
@@ -3477,7 +3476,7 @@ int main(int argc, char **argv, char **envp)
          */
         if (i == nb_numa_nodes) {
             for (i = 0; i < max_cpus; i++) {
-                node_cpumask[i % nb_numa_nodes] |= 1 << i;
+                set_bit(i, node_cpumask[i % nb_numa_nodes]);
             }
         }
     }
-- 
1.7.10.4