[Qemu-arm] BUG ALERT: vexpress model + KVM does not boot up with default settings

[Pavel Fedin]

 Hello!

 Unfortunately i don't have much time to investigate this and it is out of my 
project's scope, but from time to time i test vexpress
model on ARM32. And after the recent changes regarding TrustZone support 
vexpress model with direct kernel boot in KVM gets stuck at
this point:

--- cut ---
Uncompressing Linux... done, booting the kernel.
Booting Linux on physical CPU 0x0
Initializing cgroup subsys cpuset
Linux version 4.1.4+ (address@hidden) (gcc version 4.8.3 (Linaro GCC 
4.8-2014.04-1~dev) ) #5 SMP Wed Aug 5 18:47:36 MSK 2015
CPU: ARMv7 Processor [412fc0f3] revision 3 (ARMv7), cr=30c5387d
CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache
Machine model: V2P-CA15
bootconsole [earlycon0] enabled
Forcing write-allocate cache policy for SMP
Memory policy: Data cache writealloc
PERCPU: Embedded 12 pages/cpu @8fdd5000 s16704 r8192 d24256 u49152
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 65024
Kernel command line: console=ttyAMA0,115200n8 root=/dev/vda rw rootwait 
earlyprintk
PID hash table entries: 1024 (order: 0, 4096 bytes)
Dentry cache hash table entries: 32768 (order: 5, 131072 bytes)
Inode-cache hash table entries: 16384 (order: 4, 65536 bytes)
Memory: 252256K/262144K available (5374K kernel code, 158K rwdata, 1448K 
rodata, 272K init, 153K bss, 9888K reserved, 0K
cma-reserved)
Virtual kernel memory layout:
    vector  : 0xffff0000 - 0xffff1000   (   4 kB)
    fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)
    vmalloc : 0x90800000 - 0xff000000   (1768 MB)
    lowmem  : 0x80000000 - 0x90000000   ( 256 MB)
    modules : 0x7f000000 - 0x80000000   (  16 MB)
      .text : 0x80008000 - 0x806b1d28   (6824 kB)
      .init : 0x806b2000 - 0x806f6000   ( 272 kB)
      .data : 0x806f6000 - 0x8071dae0   ( 159 kB)
       .bss : 0x8071dae0 - 0x80743f78   ( 154 kB)
SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=2, Nodes=1
Hierarchical RCU implementation.
        RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=2.
RCU: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=2
NR_IRQS:16 nr_irqs:16 16
L2C: failed to init: -19
NO_HZ: Clearing 0 from nohz_full range for timekeeping
NO_HZ: Full dynticks CPUs: 1.
        Note: kernel parameter 'rcu_nocbs=' contains nonexistent CPUs.
        Offload RCU callbacks from CPUs: 1.
Architected cp15 timer(s) running at 24.00MHz (virt).
clocksource arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x588fe9dc0, 
max_idle_ns: 440795202592 ns
sched_clock: 56 bits at 24MHz, resolution 41ns, wraps every 4398046511097ns
Switching to timer-based delay loop, resolution 41ns
sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns
clocksource arm,sp804: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 
1911260446275 ns
Console: colour dummy device 80x30
Calibrating delay loop (skipped), value calculated using timer frequency.. 
48.00 BogoMIPS (lpj=240000)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
CPU: Testing write buffer coherency: ok
/cpus/address@hidden missing clock-frequency property
/cpus/address@hidden missing clock-frequency property
CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
Setting up static identity map for 0x80008300 - 0x80008358
--- cut ---

 The problem goes away if i add "secure=off" option. "virt" machine is not 
affected.
 By the way, is it legitimate to default to "secure=on" in KVM mode at all? We 
cannot have trustzone inside KVM.

Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia