On 02.09.2016 08:32, Nikunj A Dadhania wrote:
> Signed-off-by: Nikunj A Dadhania <nik...@linux.vnet.ibm.com>
> ---
> hw/ppc/spapr_hcall.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index e5eca67..daea7a0 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -1075,20 +1075,27 @@ target_ulong spapr_hypercall(PowerPCCPU *cpu,
> target_ulong opcode,
> target_ulong *args)
> {
> sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
> + target_ulong ret;
>
> if ((opcode <= MAX_HCALL_OPCODE)
> && ((opcode & 0x3) == 0)) {
> spapr_hcall_fn fn = papr_hypercall_table[opcode / 4];
>
> if (fn) {
> - return fn(cpu, spapr, opcode, args);
> + qemu_mutex_lock_iothread();
> + ret = fn(cpu, spapr, opcode, args);
> + qemu_mutex_unlock_iothread();
> + return ret;
> }
> } else if ((opcode >= KVMPPC_HCALL_BASE) &&
> (opcode <= KVMPPC_HCALL_MAX)) {
> spapr_hcall_fn fn = kvmppc_hypercall_table[opcode -
> KVMPPC_HCALL_BASE];
>
> if (fn) {
> - return fn(cpu, spapr, opcode, args);
> + qemu_mutex_lock_iothread();
> + ret = fn(cpu, spapr, opcode, args);
> + qemu_mutex_unlock_iothread();
> + return ret;
> }
> }
I think this will cause a deadlock when running on KVM since the lock is
already taken in kvm_arch_handle_exit() - which calls spapr_hypercall()!
Thomas
