Re: [PATCH v9 12/15] s390x: protvirt: Move IO control structures over SIDA

[Janosch Frank]

On 3/13/20 1:57 PM, Claudio Imbrenda wrote:
> On Wed, 11 Mar 2020 09:21:48 -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>
>> ---
>>  target/s390x/ioinst.c | 87
>> ++++++++++++++++++++++++++++++------------- 1 file changed, 61
>> insertions(+), 26 deletions(-)
>>
>> diff --git a/target/s390x/ioinst.c b/target/s390x/ioinst.c
>> index 481d789de9e09a04..61095bdc9ffef436 100644
>> --- a/target/s390x/ioinst.c
>> +++ b/target/s390x/ioinst.c
>> @@ -136,9 +136,13 @@ void ioinst_handle_msch(S390CPU *cpu, uint64_t
>> reg1, uint32_t ipb, uintptr_t ra) s390_program_interrupt(env,
>> PGM_SPECIFICATION, ra); return;
>>      }
>> -    if (s390_cpu_virt_mem_read(cpu, addr, ar, &schib,
>> sizeof(schib))) {
>> -        s390_cpu_virt_mem_handle_exc(cpu, ra);
>> -        return;
>> +    if (s390_is_pv()) {
>> +        s390_cpu_pv_mem_read(cpu, addr, &schib, sizeof(schib));
>> +    } else {
>> +        if (s390_cpu_virt_mem_read(cpu, addr, ar, &schib,
>> sizeof(schib))) {
>> +            s390_cpu_virt_mem_handle_exc(cpu, ra);
>> +            return;
>> +        }
>>      }
>>      if (ioinst_disassemble_sch_ident(reg1, &m, &cssid, &ssid,
>> &schid) || !ioinst_schib_valid(&schib)) {
>> @@ -193,9 +197,13 @@ void ioinst_handle_ssch(S390CPU *cpu, uint64_t
>> reg1, uint32_t ipb, uintptr_t ra) s390_program_interrupt(env,
>> PGM_SPECIFICATION, ra); return;
>>      }
>> -    if (s390_cpu_virt_mem_read(cpu, addr, ar, &orig_orb,
>> sizeof(orb))) {
>> -        s390_cpu_virt_mem_handle_exc(cpu, ra);
>> -        return;
>> +    if (s390_is_pv()) {
>> +        s390_cpu_pv_mem_read(cpu, addr, &orig_orb, sizeof(orb));
>> +    } else {
>> +        if (s390_cpu_virt_mem_read(cpu, addr, ar, &orig_orb,
>> sizeof(orb))) {
>> +            s390_cpu_virt_mem_handle_exc(cpu, ra);
>> +            return;
>> +        }
>>      }
>>      copy_orb_from_guest(&orb, &orig_orb);
>>      if (ioinst_disassemble_sch_ident(reg1, &m, &cssid, &ssid,
>> &schid) || @@ -229,14 +237,19 @@ void ioinst_handle_stcrw(S390CPU
>> *cpu, uint32_t ipb, uintptr_t ra) cc = css_do_stcrw(&crw);
>>      /* 0 - crw stored, 1 - zeroes stored */
>>  
>> -    if (s390_cpu_virt_mem_write(cpu, addr, ar, &crw, sizeof(crw)) ==
>> 0) {
>> +    if (s390_is_pv()) {
>> +        s390_cpu_pv_mem_write(cpu, addr, &crw, sizeof(crw));
>>          setcc(cpu, cc);
>>      } else {
>> -        if (cc == 0) {
>> -            /* Write failed: requeue CRW since STCRW is suppressing
>> */
>> -            css_undo_stcrw(&crw);
>> +        if (s390_cpu_virt_mem_write(cpu, addr, ar, &crw,
>> sizeof(crw)) == 0) {
>> +            setcc(cpu, cc);
>> +        } else {
>> +            if (cc == 0) {
>> +                /* Write failed: requeue CRW since STCRW is
>> suppressing */
>> +                css_undo_stcrw(&crw);
>> +            }
>> +            s390_cpu_virt_mem_handle_exc(cpu, ra);
>>          }
>> -        s390_cpu_virt_mem_handle_exc(cpu, ra);
>>      }
>>  }
>>  
>> @@ -258,6 +271,9 @@ void ioinst_handle_stsch(S390CPU *cpu, uint64_t
>> reg1, uint32_t ipb, }
>>  
>>      if (ioinst_disassemble_sch_ident(reg1, &m, &cssid, &ssid,
>> &schid)) {
>> +        if (s390_is_pv()) {
>> +            return;
>> +        }
> 
> If the operand is invalid, should we not inject an operand exception?
> 
> If instead the Ultravisor or KVM make sure that we don't end up here,
> then, why handle this at all?

Currently the specs specify that we may inject an operand exception but
I'm not able to find any exception that would still apply after all of
the ones that SIE already handles.

I've already asked for clarification and I'm considering to make this a
g_assert(!s390_is_pv())

So I hope we can clear this up in the next architecture call.

> 
>>          /*
>>           * As operand exceptions have a lower priority than access
>> exceptions,
>>           * we check whether the memory area is writeable (injecting
>> the @@ -290,14 +306,19 @@ void ioinst_handle_stsch(S390CPU *cpu,
>> uint64_t reg1, uint32_t ipb, }
>>      }
>>      if (cc != 3) {
>> -        if (s390_cpu_virt_mem_write(cpu, addr, ar, &schib,
>> -                                    sizeof(schib)) != 0) {
>> -            s390_cpu_virt_mem_handle_exc(cpu, ra);
>> -            return;
>> +        if (s390_is_pv()) {
>> +            s390_cpu_pv_mem_write(cpu, addr, &schib, sizeof(schib));
>> +        } else {
>> +            if (s390_cpu_virt_mem_write(cpu, addr, ar, &schib,
>> +                                        sizeof(schib)) != 0) {
>> +                s390_cpu_virt_mem_handle_exc(cpu, ra);
>> +                return;
>> +            }
>>          }
>>      } else {
>>          /* Access exceptions have a higher priority than cc3 */
>> -        if (s390_cpu_virt_mem_check_write(cpu, addr, ar,
>> sizeof(schib)) != 0) {
>> +        if (!s390_is_pv() &&
>> +            s390_cpu_virt_mem_check_write(cpu, addr, ar,
>> sizeof(schib)) != 0) { s390_cpu_virt_mem_handle_exc(cpu, ra);
>>              return;
>>          }
>> @@ -334,15 +355,20 @@ int ioinst_handle_tsch(S390CPU *cpu, uint64_t
>> reg1, uint32_t ipb, uintptr_t ra) }
>>      /* 0 - status pending, 1 - not status pending, 3 - not
>> operational */ if (cc != 3) {
>> -        if (s390_cpu_virt_mem_write(cpu, addr, ar, &irb, irb_len) !=
>> 0) {
>> -            s390_cpu_virt_mem_handle_exc(cpu, ra);
>> -            return -EFAULT;
>> +        if (s390_is_pv()) {
>> +            s390_cpu_pv_mem_write(cpu, addr, &irb, irb_len);
>> +        } else {
>> +            if (s390_cpu_virt_mem_write(cpu, addr, ar, &irb,
>> irb_len) != 0) {
>> +                s390_cpu_virt_mem_handle_exc(cpu, ra);
>> +                return -EFAULT;
>> +            }
>>          }
>>          css_do_tsch_update_subch(sch);
>>      } else {
>>          irb_len = sizeof(irb) - sizeof(irb.emw);
>>          /* Access exceptions have a higher priority than cc3 */
>> -        if (s390_cpu_virt_mem_check_write(cpu, addr, ar, irb_len) !=
>> 0) {
>> +        if (!s390_is_pv() &&
>> +            s390_cpu_virt_mem_check_write(cpu, addr, ar, irb_len) !=
>> 0) { s390_cpu_virt_mem_handle_exc(cpu, ra);
>>              return -EFAULT;
>>          }
>> @@ -640,9 +666,13 @@ void ioinst_handle_chsc(S390CPU *cpu, uint32_t
>> ipb, uintptr_t ra)
>>       * present CHSC sub-handlers ... if we ever need more, we should
>> take
>>       * care of req->len here first.
>>       */
>> -    if (s390_cpu_virt_mem_read(cpu, addr, reg, buf,
>> sizeof(ChscReq))) {
>> -        s390_cpu_virt_mem_handle_exc(cpu, ra);
>> -        return;
>> +    if (s390_is_pv()) {
>> +        s390_cpu_pv_mem_read(cpu, addr, buf, sizeof(ChscReq));
>> +    } else {
>> +        if (s390_cpu_virt_mem_read(cpu, addr, reg, buf,
>> sizeof(ChscReq))) {
>> +            s390_cpu_virt_mem_handle_exc(cpu, ra);
>> +            return;
>> +        }
>>      }
>>      req = (ChscReq *)buf;
>>      len = be16_to_cpu(req->len);
>> @@ -673,11 +703,16 @@ void ioinst_handle_chsc(S390CPU *cpu, uint32_t
>> ipb, uintptr_t ra) break;
>>      }
>>  
>> -    if (!s390_cpu_virt_mem_write(cpu, addr + len, reg, res,
>> -                                 be16_to_cpu(res->len))) {
>> +    if (s390_is_pv()) {
>> +        s390_cpu_pv_mem_write(cpu, addr + len, res,
>> be16_to_cpu(res->len)); setcc(cpu, 0);    /* Command execution
>> complete */ } else {
>> -        s390_cpu_virt_mem_handle_exc(cpu, ra);
>> +        if (!s390_cpu_virt_mem_write(cpu, addr + len, reg, res,
>> +                                     be16_to_cpu(res->len))) {
>> +            setcc(cpu, 0);    /* Command execution complete */
>> +        } else {
>> +            s390_cpu_virt_mem_handle_exc(cpu, ra);
>> +        }
>>      }
>>  }
>>  
> 
>

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