Re: [Qemu-devel] [PATCH 2/3] s390: Add CPU reset handler

[Alexander Graf]

On 18.12.2012, at 18:50, Jens Freimann wrote:

> Add a CPU reset handler to have all CPUs in a PoP compliant
> state.
> 
> Signed-off-by: Jens Freimann <address@hidden>
> 
> ---
> v2 -> v3:
> * remove FIXME
> * separate parent reset from local reset by adding a while line
> * use defines for register reset values
> 
> v1 -> v2:
> * move setting of control registers and psa to s390_cpu_reset
>  and call it from the new s390_machine_cpu_reset_cb()
>  This makes it more similar to how it is done on x86
> * in s390_cpu_reset() set env->halted state of cpu after
>  the memset. This is needed to keep our s390_cpu_running
>  counter in sync when s390_cpu_reset is called via the
>  qemu_devices_reset path
> * set env->halted state in s390_cpu_initfn to 1 to avoid
>  decrementing the cpu counter during first reset
> ---
> target-s390x/cpu.c | 35 +++++++++++++++++++++++++++++++++--
> target-s390x/kvm.c |  9 ++++++++-
> 2 files changed, 41 insertions(+), 3 deletions(-)
> 
> diff --git a/target-s390x/cpu.c b/target-s390x/cpu.c
> index 619b202..58e412a 100644
> --- a/target-s390x/cpu.c
> +++ b/target-s390x/cpu.c
> @@ -4,6 +4,7 @@
>  * Copyright (c) 2009 Ulrich Hecht
>  * Copyright (c) 2011 Alexander Graf
>  * Copyright (c) 2012 SUSE LINUX Products GmbH
> + * Copyright (c) 2012 IBM Corp.
>  *
>  * This library is free software; you can redistribute it and/or
>  * modify it under the terms of the GNU Lesser General Public
> @@ -18,12 +19,19 @@
>  * You should have received a copy of the GNU Lesser General Public
>  * License along with this library; if not, see
>  * <http://www.gnu.org/licenses/lgpl-2.1.html>
> + * Contributions after 2012-12-11 are licensed under the terms of the
> + * GNU GPL, version 2 or (at your option) any later version.
> + *
>  */
> 
> #include "cpu.h"
> +#include "hw/hw.h"
> #include "qemu-common.h"
> #include "qemu-timer.h"
> 
> +#define IPL_PSW_MASK    0x0000000180000000ULL
> +#define CR0_RESET       0xE0UL
> +#define CR14_RESET      0xC2000000UL;
> 
> /* CPUClass::reset() */
> static void s390_cpu_reset(CPUState *s)
> @@ -37,12 +45,30 @@ static void s390_cpu_reset(CPUState *s)
>         log_cpu_state(env, 0);
>     }
> 
> +    s390_del_running_cpu(env);
> +
>     scc->parent_reset(s);
> 
>     memset(env, 0, offsetof(CPUS390XState, breakpoints));
> -    /* FIXME: reset vector? */
> +
> +    /* architectured initial values for CR 0 and 14 */
> +    env->cregs[0] = CR0_RESET;
> +    env->cregs[14] = CR14_RESET;
> +    /* set to z/Architecture mode */
> +    env->psw.mask = IPL_PSW_MASK;

Why would we set psw.mask, but not psw.addr? In fact, why are we setting psw at 
all here? Shouldn't we just leave it at 0 from the memset and simply override 
it in the ipl device?

Alex