Re: [PATCH v10 13/16] s390x: protvirt: Move IO control structures over SIDA

[Cornelia Huck <cohuck@redhat.com>]

On Wed, 18 Mar 2020 10:30:44 -0400
Janosch Frank <frankja@linux.ibm.com> wrote:

> For protected guests, we need to put the IO emulation results into the
> SIDA, so SIE will write them into the guest at the next entry.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> ---
>  target/s390x/ioinst.c | 61 +++++++++++++++++++++++++++++++------------
>  1 file changed, 45 insertions(+), 16 deletions(-)
> 

> @@ -260,6 +269,13 @@ void ioinst_handle_stsch(S390CPU *cpu, uint64_t reg1, uint32_t ipb,
>      }
>  
>      if (ioinst_disassemble_sch_ident(reg1, &m, &cssid, &ssid, &schid)) {
> +        /*
> +         * The Ultravisor checks schid bit 16 to be one and bits 0-12
> +         * to be 0 and injects a operand exception itself.

As a side remark, that also implies that the ultravisor doesn't support
MCSS-E, which is highly unsurprising :)

Do we want to fence off enabling MCSS-E in the sda chsc for pv guests?
Probably not really needed, as Linux does not support it anyway.

> +         *
> +         * Hence we should never end up here.
> +         */
> +        g_assert(!s390_is_pv());
>          /*
>           * As operand exceptions have a lower priority than access exceptions,
>           * we check whether the memory area is writeable (injecting the

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