On 3/17/20 12:05 PM, Cornelia Huck wrote:
> On Fri, 13 Mar 2020 14:14:35 +0100
> Christian Borntraeger <borntrae...@de.ibm.com> wrote:
>
>> On 11.03.20 14:21, Janosch Frank wrote:
>>> SCLP for a protected guest is done over the SIDAD, so we need to use
>>> the s390_cpu_pv_mem_* functions to access the SIDAD instead of guest
>>> memory when reading/writing SCBs.
>>>
>>> To not confuse the sclp emulation, we set 0x4000 as the SCCB address,
>>> since the function that injects the sclp external interrupt would
>>> reject a zero sccb address.
>>>
>>> Signed-off-by: Janosch Frank <fran...@linux.ibm.com>
>>> Reviewed-by: David Hildenbrand <da...@redhat.com>
>>> ---
>>> hw/s390x/sclp.c | 30 ++++++++++++++++++++++++++++++
>>> include/hw/s390x/sclp.h | 2 ++
>>> target/s390x/kvm.c | 24 +++++++++++++++++++-----
>>> 3 files changed, 51 insertions(+), 5 deletions(-)
>
>>> +int sclp_service_call_protected(CPUS390XState *env, uint64_t sccb,
>>> + uint32_t code)
>>> +{
>>> + SCLPDevice *sclp = get_sclp_device();
>>> + SCLPDeviceClass *sclp_c = SCLP_GET_CLASS(sclp);
>>> + SCCB work_sccb;
>>> + hwaddr sccb_len = sizeof(SCCB);
>>> +
>>> + /*
>>> + * Only a very limited amount of calls is permitted by the
>>> + * Ultravisor and we support all of them, so we don't check for
>>> + * them. All other specification exceptions are also interpreted
>>> + * by the Ultravisor and hence never cause an exit we need to
>>> + * handle.
>>> + *
>>> + * Setting the CC is also done by the Ultravisor.
>>> + */
>>
>> This is fine for the current architecture which specifies a list of sclp
>> commands that are passed through (and this is fine). Question is still if
>> we replace this comment with an assertion that this is the case?
>> Or maybe even really do the same as sclp_service_call and return 0x1f0 for
>> unknown commands?
>
> That would be a case of older QEMU on newer hardware, right? Signaling
> that the command is unsupported seems the most reasonable to me
> (depending on what the architecture allows.)Question is if we want to check for the non-pv codes as the hardware will currently only allow a smaller subset anyway. Then if the IO codes are passed through by SIE we would support them right away. > >> >> Anyway, whatever you decide. >> >> Reviewed-by: Christian Borntraeger <borntrae...@de.ibm.com> >> >>> + s390_cpu_pv_mem_read(env_archcpu(env), 0, &work_sccb, sccb_len); >>> + sclp_c->execute(sclp, &work_sccb, code); >>> + s390_cpu_pv_mem_write(env_archcpu(env), 0, &work_sccb, >>> + be16_to_cpu(work_sccb.h.length)); >>> + sclp_c->service_interrupt(sclp, SCLP_PV_DUMMY_ADDR); >>> + return 0; >>> +} >>> + > >
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