From 41264b385c2b324fea026204e5de9bef980733b1 Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Tue, 26 Apr 2016 15:41:04 +0200 Subject: PPC/KVM: early validation of vcpu id The KVM API restricts vcpu ids to be < KVM_CAP_MAX_VCPUS. On PowerPC targets, depending on the number of threads per core in the host and in the guest, some topologies do generate higher vcpu ids actually. When this happens, QEMU bails out with the following error: kvm_init_vcpu failed: Invalid argument The KVM_CREATE_VCPU ioctl has several EINVAL return paths, so it is not possible to fully disambiguate. This patch adds a check in the code that computes vcpu ids, so that we can detect the error earlier, and print a friendlier message instead of calling KVM_CREATE_VCPU with an obviously bogus vcpu id. Signed-off-by: Greg Kurz Signed-off-by: David Gibson --- target-ppc/translate_init.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'target-ppc/translate_init.c') diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c index 954195f5e4..a003c1029d 100644 --- a/target-ppc/translate_init.c +++ b/target-ppc/translate_init.c @@ -9231,6 +9231,14 @@ static void ppc_cpu_realizefn(DeviceState *dev, Error **errp) #if !defined(CONFIG_USER_ONLY) cpu->cpu_dt_id = (cs->cpu_index / smp_threads) * max_smt + (cs->cpu_index % smp_threads); + + if (kvm_enabled() && !kvm_vcpu_id_is_valid(cpu->cpu_dt_id)) { + error_setg(errp, "Can't create CPU with id %d in KVM", cpu->cpu_dt_id); + error_append_hint(errp, "Adjust the number of cpus to %d " + "or try to raise the number of threads per core\n", + cpu->cpu_dt_id * smp_threads / max_smt); + return; + } #endif if (tcg_enabled()) { -- cgit v1.2.3