Re: [PATCH v10 10/16] s390x: protvirt: Set guest IPL PSW

[Cornelia Huck <cohuck@redhat.com>]

On Wed, 18 Mar 2020 10:30:41 -0400
Janosch Frank <frankja@linux.ibm.com> wrote:

> Handling of CPU reset and setting of the IPL psw from guest storage at
> offset 0 is done by a Ultravisor call. Let's only fetch it if
> necessary.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> ---
>  target/s390x/cpu.c | 26 +++++++++++++++++---------
>  1 file changed, 17 insertions(+), 9 deletions(-)
> 
> diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
> index 84029f14814b4980..3ec7d4b2ec1e938f 100644
> --- a/target/s390x/cpu.c
> +++ b/target/s390x/cpu.c
> @@ -78,16 +78,24 @@ static bool s390_cpu_has_work(CPUState *cs)
>  static void s390_cpu_load_normal(CPUState *s)
>  {
>      S390CPU *cpu = S390_CPU(s);
> -    uint64_t spsw = ldq_phys(s->as, 0);
> -
> -    cpu->env.psw.mask = spsw & PSW_MASK_SHORT_CTRL;
> -    /*
> -     * Invert short psw indication, so SIE will report a specification
> -     * exception if it was not set.
> -     */
> -    cpu->env.psw.mask ^= PSW_MASK_SHORTPSW;
> -    cpu->env.psw.addr = spsw & PSW_MASK_SHORT_ADDR;
> +    uint64_t spsw;
>  
> +    if (!s390_is_pv()) {
> +        spsw = ldq_phys(s->as, 0);
> +        cpu->env.psw.mask = spsw & PSW_MASK_SHORT_CTRL;
> +        /*
> +         * Invert short psw indication, so SIE will report a specification
> +         * exception if it was not set.
> +         */
> +        cpu->env.psw.mask ^= PSW_MASK_SHORTPSW;
> +        cpu->env.psw.addr = spsw & PSW_MASK_SHORT_ADDR;
> +    } else {
> +        /*
> +         * Firmware requires us to set the load state before we set
> +         * the cpu to operating on protected guests.
> +         */
> +        s390_cpu_set_state(S390_CPU_STATE_LOAD, cpu);

We probably could do that unconditionally, but this is fine.

> +    }
>      s390_cpu_set_state(S390_CPU_STATE_OPERATING, cpu);
>  }
>  #endif

Reviewed-by: Cornelia Huck <cohuck@redhat.com>