Patchwork [2/3] s390: Add CPU reset handler

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Submitter Jens Freimann
Date Dec. 18, 2012, 5:50 p.m.
Message ID <1355853059-37453-3-git-send-email-jfrei@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/207165/
State New
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Jens Freimann - Dec. 18, 2012, 5:50 p.m.
Add a CPU reset handler to have all CPUs in a PoP compliant
state.

Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>

---
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(-)
Alexander Graf - Jan. 3, 2013, 12:50 p.m.
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 <jfrei@linux.vnet.ibm.com>
> 
> ---
> 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
Alexander Graf - Jan. 3, 2013, 12:55 p.m.
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 <jfrei@linux.vnet.ibm.com>
> 
> ---
> 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"

Also, have you verified that this doesn't break s390x-linux-user?

> #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;

In fact this one is correct for CONFIG_USER_ONLY.

> +    env->psa = 0;
> +    /* set halted to 1 to make sure we can add the cpu in
> +     * s390_ipl_cpu code, where env->halted is set back to 0
> +     * after incrementing the cpu counter */
> +    env->halted = 1;

While this again probably breaks s390x-linux-user, no?


Alex

>     tlb_flush(env, 1);
> -    s390_add_running_cpu(env);
> +}
> +
> +static void s390_cpu_machine_reset_cb(void *opaque)
> +{
> +    S390CPU *cpu = opaque;
> +
> +    cpu_reset(CPU(cpu));
> }
> 
> static void s390_cpu_initfn(Object *obj)
> @@ -66,7 +92,12 @@ static void s390_cpu_initfn(Object *obj)
>     env->cpu_num = cpu_num++;
>     env->ext_index = -1;
> 
> +    /* set env->halted state to 1 to avoid decrementing the running
> +     * cpu counter in s390_cpu_reset to a negative number at 
> +     * initial ipl */
> +    env->halted = 1;
>     cpu_reset(CPU(cpu));
> +    qemu_register_reset(s390_cpu_machine_reset_cb, cpu);
> }
> 
> static void s390_cpu_class_init(ObjectClass *oc, void *data)
> diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
> index 94de764..fda9f1f 100644
> --- a/target-s390x/kvm.c
> +++ b/target-s390x/kvm.c
> @@ -85,7 +85,14 @@ int kvm_arch_init_vcpu(CPUS390XState *env)
> 
> void kvm_arch_reset_vcpu(CPUS390XState *env)
> {
> -    /* FIXME: add code to reset vcpu. */
> +   /* The initial reset call is needed here to reset in-kernel
> +    * vcpu data that we can't access directly from QEMU
> +    * (i.e. with older kernels which don't support sync_regs/ONE_REG).
> +    * Before this ioctl cpu_synchronize_state() is called in common kvm
> +    * code (kvm-all) */
> +    if (kvm_vcpu_ioctl(env, KVM_S390_INITIAL_RESET, NULL)) {
> +        perror("Can't reset vcpu\n");
> +    }
> }
> 
> int kvm_arch_put_registers(CPUS390XState *env, int level)
> -- 
> 1.7.12.4
>
Jens Freimann - Jan. 4, 2013, 1:55 p.m.
On Thu, Jan 03, 2013 at 01:50:22PM +0100, Alexander Graf wrote:
> 
> 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 <jfrei@linux.vnet.ibm.com>
> > 
> > ---
> > 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?

I agree that it's redundand as we set it in the ipl device code and that it would work without setting
the mask here. I put it in here because I consider it part of the CPU reset code since we always want to start
in z/Architecture mode regardless of what code runs after the reset.

Jens

> 
> Alex
>
Jens Freimann - Jan. 4, 2013, 2:09 p.m.
On Thu, Jan 03, 2013 at 01:55:19PM +0100, Alexander Graf wrote:
> 
> 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 <jfrei@linux.vnet.ibm.com>
> > 
> > ---
> > 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"
> 
> Also, have you verified that this doesn't break s390x-linux-user?

I verified s390x-linux-user still builds. 
 
> > #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;
> 
> In fact this one is correct for CONFIG_USER_ONLY.
> 
> > +    env->psa = 0;
> > +    /* set halted to 1 to make sure we can add the cpu in
> > +     * s390_ipl_cpu code, where env->halted is set back to 0
> > +     * after incrementing the cpu counter */
> > +    env->halted = 1;
> 
> While this again probably breaks s390x-linux-user, no?

It still builds fine, if that's what you mean? env->halted is
not within an #ifdef !CONFIG_USER_ONLY clause.

Jens
 
> 
> Alex
> 
> >     tlb_flush(env, 1);
> > -    s390_add_running_cpu(env);
> > +}
> > +
> > +static void s390_cpu_machine_reset_cb(void *opaque)
> > +{
> > +    S390CPU *cpu = opaque;
> > +
> > +    cpu_reset(CPU(cpu));
> > }
> > 
> > static void s390_cpu_initfn(Object *obj)
> > @@ -66,7 +92,12 @@ static void s390_cpu_initfn(Object *obj)
> >     env->cpu_num = cpu_num++;
> >     env->ext_index = -1;
> > 
> > +    /* set env->halted state to 1 to avoid decrementing the running
> > +     * cpu counter in s390_cpu_reset to a negative number at 
> > +     * initial ipl */
> > +    env->halted = 1;
> >     cpu_reset(CPU(cpu));
> > +    qemu_register_reset(s390_cpu_machine_reset_cb, cpu);
> > }
> > 
> > static void s390_cpu_class_init(ObjectClass *oc, void *data)
> > diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
> > index 94de764..fda9f1f 100644
> > --- a/target-s390x/kvm.c
> > +++ b/target-s390x/kvm.c
> > @@ -85,7 +85,14 @@ int kvm_arch_init_vcpu(CPUS390XState *env)
> > 
> > void kvm_arch_reset_vcpu(CPUS390XState *env)
> > {
> > -    /* FIXME: add code to reset vcpu. */
> > +   /* The initial reset call is needed here to reset in-kernel
> > +    * vcpu data that we can't access directly from QEMU
> > +    * (i.e. with older kernels which don't support sync_regs/ONE_REG).
> > +    * Before this ioctl cpu_synchronize_state() is called in common kvm
> > +    * code (kvm-all) */
> > +    if (kvm_vcpu_ioctl(env, KVM_S390_INITIAL_RESET, NULL)) {
> > +        perror("Can't reset vcpu\n");
> > +    }
> > }
> > 
> > int kvm_arch_put_registers(CPUS390XState *env, int level)
> > -- 
> > 1.7.12.4
> > 
>
Alexander Graf - Jan. 4, 2013, 2:11 p.m.
On 04.01.2013, at 15:09, Jens Freimann wrote:

> On Thu, Jan 03, 2013 at 01:55:19PM +0100, Alexander Graf wrote:
>> 
>> 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 <jfrei@linux.vnet.ibm.com>
>>> 
>>> ---
>>> 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"
>> 
>> Also, have you verified that this doesn't break s390x-linux-user?
> 
> I verified s390x-linux-user still builds. 
> 
>>> #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;
>> 
>> In fact this one is correct for CONFIG_USER_ONLY.
>> 
>>> +    env->psa = 0;
>>> +    /* set halted to 1 to make sure we can add the cpu in
>>> +     * s390_ipl_cpu code, where env->halted is set back to 0
>>> +     * after incrementing the cpu counter */
>>> +    env->halted = 1;
>> 
>> While this again probably breaks s390x-linux-user, no?
> 
> It still builds fine, if that's what you mean? env->halted is
> not within an #ifdef !CONFIG_USER_ONLY clause.

Does it run? Or does the vcpu come up halted and never gets around to execute code?


Alex

Patch

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;
+    env->psa = 0;
+    /* set halted to 1 to make sure we can add the cpu in
+     * s390_ipl_cpu code, where env->halted is set back to 0
+     * after incrementing the cpu counter */
+    env->halted = 1;
     tlb_flush(env, 1);
-    s390_add_running_cpu(env);
+}
+
+static void s390_cpu_machine_reset_cb(void *opaque)
+{
+    S390CPU *cpu = opaque;
+
+    cpu_reset(CPU(cpu));
 }
 
 static void s390_cpu_initfn(Object *obj)
@@ -66,7 +92,12 @@  static void s390_cpu_initfn(Object *obj)
     env->cpu_num = cpu_num++;
     env->ext_index = -1;
 
+    /* set env->halted state to 1 to avoid decrementing the running
+     * cpu counter in s390_cpu_reset to a negative number at 
+     * initial ipl */
+    env->halted = 1;
     cpu_reset(CPU(cpu));
+    qemu_register_reset(s390_cpu_machine_reset_cb, cpu);
 }
 
 static void s390_cpu_class_init(ObjectClass *oc, void *data)
diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index 94de764..fda9f1f 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -85,7 +85,14 @@  int kvm_arch_init_vcpu(CPUS390XState *env)
 
 void kvm_arch_reset_vcpu(CPUS390XState *env)
 {
-    /* FIXME: add code to reset vcpu. */
+   /* The initial reset call is needed here to reset in-kernel
+    * vcpu data that we can't access directly from QEMU
+    * (i.e. with older kernels which don't support sync_regs/ONE_REG).
+    * Before this ioctl cpu_synchronize_state() is called in common kvm
+    * code (kvm-all) */
+    if (kvm_vcpu_ioctl(env, KVM_S390_INITIAL_RESET, NULL)) {
+        perror("Can't reset vcpu\n");
+    }
 }
 
 int kvm_arch_put_registers(CPUS390XState *env, int level)