Re: [Qemu-devel] [PATCH 2/3] s390/migration: Qemu S390 special register migration

[Alexander Graf <agraf@suse.de>]

On 11/21/2012 03:46 PM, Christian Borntraeger wrote:
> From: "Jason J. herne"<jjherne@us.ibm.com>
>
> Use the KVM ONE_REG capability to save and restore the following special S390
> cpu registers: clock comparator, tod clock programmable register and the cpu
> timer.  Save/loading of these registers is required to enable guest migration on
> the S390 platform.
>
> Signed-off-by: Jason J. herne<jjherne@us.ibm.com>
> Signed-off-by: Christian Borntraeger<borntraeger@de.ibm.com>
> ---
>   target-s390x/cpu.h     |    4 ++++
>   target-s390x/machine.c |   41 +++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 45 insertions(+)
>
> diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
> index ba695dd..de77335 100644
> --- a/target-s390x/cpu.h
> +++ b/target-s390x/cpu.h
> @@ -92,6 +92,10 @@ typedef struct CPUS390XState {
>
>       int ext_index;
>
> +    uint64_t ckc;
> +    uint64_t cputm;
> +    uint32_t todpr;
> +
>       CPU_COMMON
>
>       /* reset does memset(0) up to here */
> diff --git a/target-s390x/machine.c b/target-s390x/machine.c
> index 02706fd..925afb5 100644
> --- a/target-s390x/machine.c
> +++ b/target-s390x/machine.c
> @@ -18,6 +18,7 @@ static void cpu_pre_save(void *opaque)
>   {
>       CPUS390XState *env = opaque;
>       struct kvm_fpu fpu;
> +    struct kvm_one_reg reg;
>       int i, r;
>
>       if (!kvm_enabled()) {
> @@ -30,12 +31,31 @@ static void cpu_pre_save(void *opaque)
>           env->fregs[i].ll = fpu.fprs[i];
>       }
>       env->fpc = fpu.fpc;
> +
> +    /* Retreive cpu timer value from kvm */
> +    reg.id = KVM_REG_S390_CPU_TIMER;
> +    reg.addr = (__u64)&(env->cputm);
> +    r = kvm_vcpu_ioctl(env, KVM_GET_ONE_REG,&reg);
> +    assert(r == 0);
> +
> +    /* Retreive clock comparator value from kvm */
> +    reg.id = KVM_REG_S390_CLOCK_COMP;
> +    reg.addr = (__u64)&(env->ckc);
> +    r = kvm_vcpu_ioctl(env, KVM_GET_ONE_REG,&reg);
> +    assert(r == 0);
> +
> +    /* Retreive clock comparator value from kvm */
> +    reg.id = KVM_REG_S390_TODPR;
> +    reg.addr = (__u64)&(env->todpr);
> +    r = kvm_vcpu_ioctl(env, KVM_GET_ONE_REG,&reg);

Same here. There must not be any KVM specific code in the save/restore path.


Alex

> +    assert(r == 0);
>   }
>
>   static int cpu_post_load(void *opaque, int version_id)
>   {
>       CPUS390XState *env = opaque;
>       struct kvm_fpu fpu;
> +    struct kvm_one_reg reg;
>       int i, r;
>
>       if (!kvm_enabled()) {
> @@ -50,6 +70,24 @@ static int cpu_post_load(void *opaque, int version_id)
>       r = kvm_vcpu_ioctl(env, KVM_SET_FPU,&fpu);
>       assert(r == 0);
>
> +    /* Tell KVM what the new cpu timer value is */
> +    reg.id = KVM_REG_S390_CPU_TIMER;
> +    reg.addr = (__u64)&(env->cputm);
> +    r = kvm_vcpu_ioctl(env, KVM_SET_ONE_REG,&reg);
> +    assert(r == 0);
> +
> +    /* Tell KVM what the new clock comparator value is */
> +    reg.id = KVM_REG_S390_CLOCK_COMP;
> +    reg.addr = (__u64)&(env->ckc);
> +    r = kvm_vcpu_ioctl(env, KVM_SET_ONE_REG,&reg);
> +    assert(r == 0);
> +
> +    /* Tell KVM what the new todpr value is */
> +    reg.id = KVM_REG_S390_TODPR;
> +    reg.addr = (__u64)&(env->todpr);
> +    r = kvm_vcpu_ioctl(env, KVM_SET_ONE_REG,&reg);
> +    assert(r == 0);
> +
>       return 0;
>   }
>   #else
> @@ -93,6 +131,9 @@ static const VMStateDescription vmstate_cpu = {
>           VMSTATE_UINT64(psw.addr, CPUS390XState),
>           VMSTATE_UINT64(psa, CPUS390XState),
>           VMSTATE_UINT32(fpc, CPUS390XState),
> +        VMSTATE_UINT32(todpr, CPUS390XState),
> +        VMSTATE_UINT64(cputm, CPUS390XState),
> +        VMSTATE_UINT64(ckc, CPUS390XState),
>           VMSTATE_UINT32_ARRAY(aregs, CPUS390XState, 16),
>           VMSTATE_UINT64_ARRAY(cregs, CPUS390XState, 16),
>           VMSTATE_END_OF_LIST()