Re: [Qemu-devel] [PATCH] don't call reset functions on cpu initialization

[Laurent Desnogues <laurent.desnogues@gmail.com>]

On Tue, Nov 3, 2009 at 8:50 PM, Glauber Costa <glommer@redhat.com> wrote:
> There is absolutely no need to call reset functions when initializing
> devices. Since we are already registering them, calling qemu_system_reset()
> should suffice. Actually, it is what happens when we reboot the machine,
> and using the same process instead of a special case semantics will even
> allow us to find bugs easier.
>
> Furthermore, the fact that we initialize things like the cpu quite early,
> leads to the need to introduce synchronization stuff like qemu_system_cond.
> This patch removes it entirely. All we need to do is call qemu_system_reset()
> only when we're already sure the system is up and running
>
> I tested it with qemu (with and without io-thread) and qemu-kvm, and it
> seems to be doing okay - although qemu-kvm uses a slightly different patch.
>
> Signed-off-by: Glauber Costa <glommer@redhat.com>
> ---
>  hw/apic.c            |    1 -
>  hw/e1000.c           |    1 -
>  hw/hpet.c            |    1 -
>  hw/i8254.c           |    2 --
>  hw/ide/piix.c        |    1 -
>  hw/piix4.c           |    1 -
>  hw/piix_pci.c        |    1 -
>  hw/rtl8139.c         |    2 +-
>  hw/serial.c          |    1 -
>  hw/usb-ohci.c        |    1 -
>  hw/usb-uhci.c        |    1 -
>  hw/vga.c             |    1 -
>  target-i386/helper.c |    1 -
>  vl.c                 |   15 +--------------
>  14 files changed, 2 insertions(+), 28 deletions(-)
[...]
> diff --git a/target-i386/helper.c b/target-i386/helper.c
> index c961544..957b3fc 100644
> --- a/target-i386/helper.c
> +++ b/target-i386/helper.c
> @@ -1885,7 +1885,6 @@ CPUX86State *cpu_x86_init(const char *cpu_model)
>         return NULL;
>     }
>     mce_init(env);
> -    cpu_reset(env);

Who will call cpu_reset for user mode QEMU then?


Laurent