Re: [Qemu-devel] [PATCH 01/10] ppc: Fix rfi/rfid/hrfi/... emulation

["Cédric Le Goater" <clg@kaod.org>]

On 06/16/2016 03:07 AM, David Gibson wrote:
> On Mon, Jun 13, 2016 at 07:24:47AM +0200, Cédric Le Goater wrote:
>> From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>>
>> This reworks emulation of the various "rfi" variants. I removed
>> some masking bits that I couldn't make sense of, the only bit that
>> I am aware we should mask here is POW, the CPU's MSR mask should
>> take care of the rest.
>>
>> This also fixes some problems when running 32-bit userspace under
>> a 64-bit kernel.
>>
>> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
> 
> I've merged this patch to ppc-for-2.7.
> 
> The reset of the series I'd like to see a respin for, even if it's
> just to clean up the commit messages.

Yes. I noted a couple of commit messages to rephrase, the "inline"
removal patch to keep and a merge of Andrei patches for HV {I,D}SI.

I will get that going once I have a better idea on a block I/O
issue I see with another patchset. I am really pulling my hair 
on this one. Spent the week on it :/ The good thing is that it
made me write a unit test !


Cheers,

C.

>> ---
>>  target-ppc/excp_helper.c | 51 +++++++++++++++++++-----------------------------
>>  target-ppc/translate.c   |  7 +++++++
>>  2 files changed, 27 insertions(+), 31 deletions(-)
>>
>> diff --git a/target-ppc/excp_helper.c b/target-ppc/excp_helper.c
>> index 30e960e30b63..aa0b63f4b0de 100644
>> --- a/target-ppc/excp_helper.c
>> +++ b/target-ppc/excp_helper.c
>> @@ -922,25 +922,20 @@ void helper_store_msr(CPUPPCState *env, target_ulong val)
>>      }
>>  }
>>  
>> -static inline void do_rfi(CPUPPCState *env, target_ulong nip, target_ulong msr,
>> -                          target_ulong msrm, int keep_msrh)
>> +static inline void do_rfi(CPUPPCState *env, target_ulong nip, target_ulong msr)
>>  {
>>      CPUState *cs = CPU(ppc_env_get_cpu(env));
>>  
>> +    /* MSR:POW cannot be set by any form of rfi */
>> +    msr &= ~(1ULL << MSR_POW);
>> +
>>  #if defined(TARGET_PPC64)
>> -    if (msr_is_64bit(env, msr)) {
>> -        nip = (uint64_t)nip;
>> -        msr &= (uint64_t)msrm;
>> -    } else {
>> +    /* Switching to 32-bit ? Crop the nip */
>> +    if (!msr_is_64bit(env, msr)) {
>>          nip = (uint32_t)nip;
>> -        msr = (uint32_t)(msr & msrm);
>> -        if (keep_msrh) {
>> -            msr |= env->msr & ~((uint64_t)0xFFFFFFFF);
>> -        }
>>      }
>>  #else
>>      nip = (uint32_t)nip;
>> -    msr &= (uint32_t)msrm;
>>  #endif
>>      /* XXX: beware: this is false if VLE is supported */
>>      env->nip = nip & ~((target_ulong)0x00000003);
>> @@ -959,26 +954,24 @@ static inline void do_rfi(CPUPPCState *env, target_ulong nip, target_ulong msr,
>>  
>>  void helper_rfi(CPUPPCState *env)
>>  {
>> -    if (env->excp_model == POWERPC_EXCP_BOOKE) {
>> -        do_rfi(env, env->spr[SPR_SRR0], env->spr[SPR_SRR1],
>> -               ~((target_ulong)0), 0);
>> -    } else {
>> -        do_rfi(env, env->spr[SPR_SRR0], env->spr[SPR_SRR1],
>> -               ~((target_ulong)0x783F0000), 1);
>> -    }
>> +    do_rfi(env, env->spr[SPR_SRR0], env->spr[SPR_SRR1] & 0xfffffffful);
>>  }
>>  
>> +#define MSR_BOOK3S_MASK
>>  #if defined(TARGET_PPC64)
>>  void helper_rfid(CPUPPCState *env)
>>  {
>> -    do_rfi(env, env->spr[SPR_SRR0], env->spr[SPR_SRR1],
>> -           ~((target_ulong)0x783F0000), 0);
>> +    /* The architeture defines a number of rules for which bits
>> +     * can change but in practice, we handle this in hreg_store_msr()
>> +     * which will be called by do_rfi(), so there is no need to filter
>> +     * here
>> +     */
>> +    do_rfi(env, env->spr[SPR_SRR0], env->spr[SPR_SRR1]);
>>  }
>>  
>>  void helper_hrfid(CPUPPCState *env)
>>  {
>> -    do_rfi(env, env->spr[SPR_HSRR0], env->spr[SPR_HSRR1],
>> -           ~((target_ulong)0x783F0000), 0);
>> +    do_rfi(env, env->spr[SPR_HSRR0], env->spr[SPR_HSRR1]);
>>  }
>>  #endif
>>  
>> @@ -986,28 +979,24 @@ void helper_hrfid(CPUPPCState *env)
>>  /* Embedded PowerPC specific helpers */
>>  void helper_40x_rfci(CPUPPCState *env)
>>  {
>> -    do_rfi(env, env->spr[SPR_40x_SRR2], env->spr[SPR_40x_SRR3],
>> -           ~((target_ulong)0xFFFF0000), 0);
>> +    do_rfi(env, env->spr[SPR_40x_SRR2], env->spr[SPR_40x_SRR3]);
>>  }
>>  
>>  void helper_rfci(CPUPPCState *env)
>>  {
>> -    do_rfi(env, env->spr[SPR_BOOKE_CSRR0], env->spr[SPR_BOOKE_CSRR1],
>> -           ~((target_ulong)0), 0);
>> +    do_rfi(env, env->spr[SPR_BOOKE_CSRR0], env->spr[SPR_BOOKE_CSRR1]);
>>  }
>>  
>>  void helper_rfdi(CPUPPCState *env)
>>  {
>>      /* FIXME: choose CSRR1 or DSRR1 based on cpu type */
>> -    do_rfi(env, env->spr[SPR_BOOKE_DSRR0], env->spr[SPR_BOOKE_DSRR1],
>> -           ~((target_ulong)0), 0);
>> +    do_rfi(env, env->spr[SPR_BOOKE_DSRR0], env->spr[SPR_BOOKE_DSRR1]);
>>  }
>>  
>>  void helper_rfmci(CPUPPCState *env)
>>  {
>>      /* FIXME: choose CSRR1 or MCSRR1 based on cpu type */
>> -    do_rfi(env, env->spr[SPR_BOOKE_MCSRR0], env->spr[SPR_BOOKE_MCSRR1],
>> -           ~((target_ulong)0), 0);
>> +    do_rfi(env, env->spr[SPR_BOOKE_MCSRR0], env->spr[SPR_BOOKE_MCSRR1]);
>>  }
>>  #endif
>>  
>> @@ -1045,7 +1034,7 @@ void helper_td(CPUPPCState *env, target_ulong arg1, target_ulong arg2,
>>  
>>  void helper_rfsvc(CPUPPCState *env)
>>  {
>> -    do_rfi(env, env->lr, env->ctr, 0x0000FFFF, 0);
>> +    do_rfi(env, env->lr, env->ctr & 0x0000FFFF);
>>  }
>>  
>>  /* Embedded.Processor Control */
>> diff --git a/target-ppc/translate.c b/target-ppc/translate.c
>> index b6894751e8df..a02ddf52bfe6 100644
>> --- a/target-ppc/translate.c
>> +++ b/target-ppc/translate.c
>> @@ -4087,6 +4087,13 @@ static void gen_rfi(DisasContext *ctx)
>>  #if defined(CONFIG_USER_ONLY)
>>      gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
>>  #else
>> +    /* This instruction doesn't exist anymore on 64-bit server
>> +     * processors compliant with arch 2.x
>> +     */
>> +    if (ctx->insns_flags & PPC_SEGMENT_64B) {
>> +        gen_inval_exception(ctx, POWERPC_EXCP_INVAL_INVAL);
>> +        return;
>> +    }
>>      /* Restore CPU state */
>>      if (unlikely(ctx->pr)) {
>>          gen_inval_exception(ctx, POWERPC_EXCP_PRIV_OPC);
>