Re: [RFC v3 8/8] cpus: extract out hvf-specific code to target/i386/hvf/

[Claudio Fontana]

On 8/11/20 11:00 AM, Roman Bolshakov wrote:
> On Mon, Aug 03, 2020 at 11:05:33AM +0200, Claudio Fontana wrote:
>> register a "CpusAccel" interface for HVF as well.
>>
>> Signed-off-by: Claudio Fontana <cfontana@suse.de>
>> ---
>>  softmmu/cpus.c                |  63 --------------------
>>  target/i386/hvf/Makefile.objs |   2 +-
>>  target/i386/hvf/hvf-cpus.c    | 131 
>> ++++++++++++++++++++++++++++++++++++++++++
>>  target/i386/hvf/hvf-cpus.h    |  17 ++++++
>>  target/i386/hvf/hvf.c         |   3 +
>>  5 files changed, 152 insertions(+), 64 deletions(-)
>>  create mode 100644 target/i386/hvf/hvf-cpus.c
>>  create mode 100644 target/i386/hvf/hvf-cpus.h
>>
>> diff --git a/softmmu/cpus.c b/softmmu/cpus.c
>> index 586b4acaab..d327b2685c 100644
>> --- a/softmmu/cpus.c
>> +++ b/softmmu/cpus.c
>> @@ -33,7 +33,6 @@
>>  #include "exec/gdbstub.h"
>>  #include "sysemu/hw_accel.h"
>>  #include "sysemu/kvm.h"
>> -#include "sysemu/hvf.h"
> 
> I wonder if the declarations should be moved from sysemu/hvf.h to
> someplace inside target/i386/hvf/:
> 
> int hvf_init_vcpu(CPUState *);
> int hvf_vcpu_exec(CPUState *);
> void hvf_cpu_synchronize_state(CPUState *);
> void hvf_cpu_synchronize_post_reset(CPUState *);
> void hvf_cpu_synchronize_post_init(CPUState *);
> void hvf_cpu_synchronize_pre_loadvm(CPUState *);
> void hvf_vcpu_destroy(CPUState *);
> 
> They're not used outside of target/i386/hvf/
> 
> I also wonder if we need stubs at all?
> 
>>  #include "exec/exec-all.h"
>>  #include "qemu/thread.h"
>>  #include "qemu/plugin.h"
>> @@ -391,48 +390,6 @@ void qemu_wait_io_event(CPUState *cpu)
>>      qemu_wait_io_event_common(cpu);
>>  }
>>  
>> -/* The HVF-specific vCPU thread function. This one should only run when the 
>> host
>> - * CPU supports the VMX "unrestricted guest" feature. */
>> -static void *qemu_hvf_cpu_thread_fn(void *arg)
>> -{
>> -    CPUState *cpu = arg;
>> -
>> -    int r;
>> -
>> -    assert(hvf_enabled());
>> -
>> -    rcu_register_thread();
>> -
>> -    qemu_mutex_lock_iothread();
>> -    qemu_thread_get_self(cpu->thread);
>> -
>> -    cpu->thread_id = qemu_get_thread_id();
>> -    cpu->can_do_io = 1;
>> -    current_cpu = cpu;
>> -
>> -    hvf_init_vcpu(cpu);
>> -
>> -    /* signal CPU creation */
>> -    cpu_thread_signal_created(cpu);
>> -    qemu_guest_random_seed_thread_part2(cpu->random_seed);
>> -
>> -    do {
>> -        if (cpu_can_run(cpu)) {
>> -            r = hvf_vcpu_exec(cpu);
>> -            if (r == EXCP_DEBUG) {
>> -                cpu_handle_guest_debug(cpu);
>> -            }
>> -        }
>> -        qemu_wait_io_event(cpu);
>> -    } while (!cpu->unplug || cpu_can_run(cpu));
>> -
>> -    hvf_vcpu_destroy(cpu);
>> -    cpu_thread_signal_destroyed(cpu);
>> -    qemu_mutex_unlock_iothread();
>> -    rcu_unregister_thread();
>> -    return NULL;
>> -}
>> -
>>  void cpus_kick_thread(CPUState *cpu)
>>  {
>>  #ifndef _WIN32
>> @@ -603,24 +560,6 @@ void cpu_remove_sync(CPUState *cpu)
>>      qemu_mutex_lock_iothread();
>>  }
>>  
>> -static void qemu_hvf_start_vcpu(CPUState *cpu)
>> -{
>> -    char thread_name[VCPU_THREAD_NAME_SIZE];
>> -
>> -    /* HVF currently does not support TCG, and only runs in
>> -     * unrestricted-guest mode. */
>> -    assert(hvf_enabled());
>> -
>> -    cpu->thread = g_malloc0(sizeof(QemuThread));
>> -    cpu->halt_cond = g_malloc0(sizeof(QemuCond));
>> -    qemu_cond_init(cpu->halt_cond);
>> -
>> -    snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/HVF",
>> -             cpu->cpu_index);
>> -    qemu_thread_create(cpu->thread, thread_name, qemu_hvf_cpu_thread_fn,
>> -                       cpu, QEMU_THREAD_JOINABLE);
>> -}
>> -
>>  void cpus_register_accel(CpusAccel *ca)
>>  {
>>      assert(ca != NULL);
>> @@ -648,8 +587,6 @@ void qemu_init_vcpu(CPUState *cpu)
>>      if (cpus_accel) {
>>          /* accelerator already implements the CpusAccel interface */
>>          cpus_accel->create_vcpu_thread(cpu);
>> -    } else if (hvf_enabled()) {
>> -        qemu_hvf_start_vcpu(cpu);
>>      } else {
>>          assert(0);
>>      }
>> diff --git a/target/i386/hvf/Makefile.objs b/target/i386/hvf/Makefile.objs
>> index 927b86bc67..af9f7dcfc1 100644
>> --- a/target/i386/hvf/Makefile.objs
>> +++ b/target/i386/hvf/Makefile.objs
>> @@ -1,2 +1,2 @@
>> -obj-y += hvf.o
>> +obj-y += hvf.o hvf-cpus.o
>>  obj-y += x86.o x86_cpuid.o x86_decode.o x86_descr.o x86_emu.o x86_flags.o 
>> x86_mmu.o x86hvf.o x86_task.o
>> diff --git a/target/i386/hvf/hvf-cpus.c b/target/i386/hvf/hvf-cpus.c
>> new file mode 100644
>> index 0000000000..9540157f1e
>> --- /dev/null
>> +++ b/target/i386/hvf/hvf-cpus.c
> 
> I'd prefer singular form in variables and file names. More on that in
> the comment to patch 2.
> 
> Besides that it works fine,
> 
> Reviewed-by: Roman Bolshakov <r.bolshakov@yadro.com>
> Tested-by: Roman Bolshakov <r.bolshakov@yadro.com>
> 
> Regards,
> Roman
> 

Hi Roman,

thanks, sure lets discuss more the naming stuff on patch 2.

I noticed a missing chunk in this patch, ie, it leaves a lingering

} else if (hvf_enabled()) {

in cpu_synchronize_pre_loadvm().

that needs to be elided, should not change the behavior, but who knows. I will 
respin this one in the next version.

Thank you!

Claudio