Re: [Qemu-devel] [PATCH v1 for-2-12 09/15] s390x/tcg: implement TEST PENDING INTERRUPTION

[Cornelia Huck <cohuck@redhat.com>]

On Mon, 11 Dec 2017 14:47:34 +0100
David Hildenbrand <david@redhat.com> wrote:

> Use s390_cpu_virt_mem_write() so we can actually revert what we did
> (re-inject the dequeued IO interrupt).
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  target/s390x/helper.h      |  1 +
>  target/s390x/insn-data.def |  1 +
>  target/s390x/misc_helper.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++
>  target/s390x/translate.c   |  8 +++++++
>  4 files changed, 63 insertions(+)
> 

> +uint32_t HELPER(tpi)(CPUS390XState *env, uint64_t addr)
> +{
> +    const uintptr_t ra = GETPC();
> +    S390CPU *cpu = s390_env_get_cpu(env);
> +    QEMUS390FLICState *flic = QEMU_S390_FLIC(s390_get_flic());
> +    QEMUS390FlicIO *io = NULL;
> +    LowCore *lowcore;
> +
> +    if (addr & 0x3) {
> +        s390_program_interrupt(env, PGM_SPECIFICATION, 4, ra);
> +    }
> +
> +    qemu_mutex_lock_iothread();
> +    io = qemu_s390_flic_dequeue_io(flic, env->cregs[6]);
> +    if (!io) {
> +        qemu_mutex_unlock_iothread();
> +        return 0;
> +    }
> +
> +    if (addr) {
> +        struct {
> +            uint16_t id;
> +            uint16_t nr;
> +            uint32_t parm;
> +        } tmp = {
> +            .id = cpu_to_be16(io->id),
> +            .nr = cpu_to_be16(io->nr),
> +            .parm = cpu_to_be32(io->parm),
> +        };

That's a two-word interruption code; can you call this something better
than 'tmp'?

> +
> +        if (s390_cpu_virt_mem_write(cpu, addr, 0, &tmp, sizeof(tmp))) {
> +            /* writing failed, reinject and properly clean up */
> +            s390_io_interrupt(io->id, io->nr, io->parm, io->word);
> +            qemu_mutex_unlock_iothread();
> +            g_free(io);
> +            s390_cpu_virt_mem_handle_exc(cpu, ra);
> +            return 0;
> +        }
> +    } else {
> +        /* no protection applies */
> +        lowcore = cpu_map_lowcore(env);
> +        lowcore->subchannel_id = cpu_to_be16(io->id);
> +        lowcore->subchannel_nr = cpu_to_be16(io->nr);
> +        lowcore->io_int_parm = cpu_to_be32(io->parm);
> +        lowcore->io_int_word = cpu_to_be32(io->word);
> +        cpu_unmap_lowcore(lowcore);
> +    }
> +
> +    g_free(io);
> +    qemu_mutex_unlock_iothread();
> +    return 1;
> +}
> +
>  void HELPER(tsch)(CPUS390XState *env, uint64_t r1, uint64_t inst)
>  {
>      S390CPU *cpu = s390_env_get_cpu(env);