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.)
>
> 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;
> > +}
> > +
