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

[Janosch Frank]

On 3/19/20 1:23 PM, Cornelia Huck wrote:
> On Wed, 18 Mar 2020 10:30:44 -0400
> Janosch Frank <address@hidden> 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 <address@hidden>
>> Reviewed-by: David Hildenbrand <address@hidden>
>> ---
>>  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 :)

Yup

> 
> 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.

If possible I'd leave that to Halil or you.
IO is currently not my stronghold.

> 
>> +         *
>> +         * 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 <address@hidden>
> 
Thanks!

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