From: Vasilis Liaskovitis <vasilis.liaskovitis@xxxxxxxxxxxxxxxx>
qemu-kvm passes numa/SRAT topology information for smp_cpus to SeaBIOS. However
SeaBIOS always expects to setup max_cpus number of SRAT cpu entries
(MaxCountCPUs variable in build_srat function of Seabios). When qemu-kvm runs
with smp_cpus != max_cpus (e.g. -smp 2,maxcpus=4), Seabios will mistakenly use
memory SRAT info for setting up CPU SRAT entries for the offline CPUs. Wrong
SRAT memory entries are also created. This breaks NUMA in a guest.
Fix by setting up SRAT info for max_cpus in qemu-kvm.
Signed-off-by: Vasilis Liaskovitis <vasilis.liaskovitis@xxxxxxxxxxxxxxxx>
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
---
hw/pc.c | 8 ++++----
vl.c | 2 +-
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/hw/pc.c b/hw/pc.c
index 3a71992..f51afa8 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -624,9 +624,9 @@ static void *bochs_bios_init(void)
* of nodes, one word for each VCPU->node and one word for each node to
* hold the amount of memory.
*/
- numa_fw_cfg = g_malloc0((1 + smp_cpus + nb_numa_nodes) * 8);
+ numa_fw_cfg = g_malloc0((1 + max_cpus + nb_numa_nodes) * 8);
numa_fw_cfg[0] = cpu_to_le64(nb_numa_nodes);
- for (i = 0; i < smp_cpus; i++) {
+ for (i = 0; i < max_cpus; i++) {
for (j = 0; j < nb_numa_nodes; j++) {
if (node_cpumask[j] & (1 << i)) {
numa_fw_cfg[i + 1] = cpu_to_le64(j);
@@ -635,10 +635,10 @@ static void *bochs_bios_init(void)
}
}
for (i = 0; i < nb_numa_nodes; i++) {
- numa_fw_cfg[smp_cpus + 1 + i] = cpu_to_le64(node_mem[i]);
+ numa_fw_cfg[max_cpus + 1 + i] = cpu_to_le64(node_mem[i]);
}
fw_cfg_add_bytes(fw_cfg, FW_CFG_NUMA, (uint8_t *)numa_fw_cfg,
- (1 + smp_cpus + nb_numa_nodes) * 8);
+ (1 + max_cpus + nb_numa_nodes) * 8);
return fw_cfg;
}
diff --git a/vl.c b/vl.c
index c03abb6..d925424 100644
--- a/vl.c
+++ b/vl.c
@@ -3305,7 +3305,7 @@ int main(int argc, char **argv, char **envp)
* real machines which also use this scheme.
*/
if (i == nb_numa_nodes) {
- for (i = 0; i < smp_cpus; i++) {
+ for (i = 0; i < max_cpus; i++) {
node_cpumask[i % nb_numa_nodes] |= 1 << i;
}
}
--
1.7.6.4
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