PowerPC kernel expects the number of SMT threads in a core to be a power
of 2. Since QEMU doesn't enforce this, it leads to an early guest kernel
crash if invalid threads count is specified.
Prevent this crash and make it a graceful exit from QEMU itself by
validating the user-supplied threads count.
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
max_smt, kvm_enabled() ? "KVM" : "TCG");
return;
}
+ if (!is_power_of_2(smp_threads)) {
+ error_setg(errp, "Cannot support %d threads on PPC with %s, "
+ "threads count must be a power of 2.",
+ smp_threads, kvm_enabled() ? "KVM" : "TCG");
+ return;
+ }
cpu->cpu_dt_id = (cs->cpu_index / smp_threads) * max_smt
+ (cs->cpu_index % smp_threads);