Re: [RFC v18 08/15] i386: split smm helper (softmmu)

From: "Alex Bennée" <alex.bennee@linaro.org>
To: Claudio Fontana <cfontana@suse.de>
Cc: "Laurent Vivier" <lvivier@redhat.com>,
	"Peter Maydell" <peter.maydell@linaro.org>,
	"Thomas Huth" <thuth@redhat.com>,
	"Eduardo Habkost" <ehabkost@redhat.com>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	qemu-devel@nongnu.org, "Roman Bolshakov" <r.bolshakov@yadro.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Philippe Mathieu-Daudé" <philmd@redhat.com>
Subject: Re: [RFC v18 08/15] i386: split smm helper (softmmu)
Date: Mon, 15 Feb 2021 12:32:35 +0000	[thread overview]
Message-ID: <87y2fptss2.fsf@linaro.org> (raw)
In-Reply-To: <b6b053ef-998e-08ef-4354-27cdcfb331e9@suse.de>

Claudio Fontana <cfontana@suse.de> writes:

> On 2/12/21 1:36 PM, Claudio Fontana wrote:
>> smm is only really useful for softmmu, split in two modules
>> around the CONFIG_USER_ONLY, in order to remove the ifdef
>> and use the build system instead.
>> 
>> Signed-off-by: Claudio Fontana <cfontana@suse.de>
>> ---
>>  target/i386/helper.h                       |  4 ++++
>>  target/i386/tcg/seg_helper.c               |  2 ++
>>  target/i386/tcg/{ => softmmu}/smm_helper.c | 19 ++-----------------
>>  target/i386/tcg/translate.c                |  2 ++
>>  target/i386/tcg/meson.build                |  1 -
>>  target/i386/tcg/softmmu/meson.build        |  1 +
>>  6 files changed, 11 insertions(+), 18 deletions(-)
>>  rename target/i386/tcg/{ => softmmu}/smm_helper.c (98%)
>> 
>> diff --git a/target/i386/helper.h b/target/i386/helper.h
>> index c2ae2f7e61..8ffda4cdc6 100644
>> --- a/target/i386/helper.h
>> +++ b/target/i386/helper.h
>> @@ -70,7 +70,11 @@ DEF_HELPER_1(clac, void, env)
>>  DEF_HELPER_1(stac, void, env)
>>  DEF_HELPER_3(boundw, void, env, tl, int)
>>  DEF_HELPER_3(boundl, void, env, tl, int)
>> +
>> +#ifndef CONFIG_USER_ONLY
>>  DEF_HELPER_1(rsm, void, env)
>> +#endif /* !CONFIG_USER_ONLY */
>> +
>>  DEF_HELPER_2(into, void, env, int)
>>  DEF_HELPER_2(cmpxchg8b_unlocked, void, env, tl)
>>  DEF_HELPER_2(cmpxchg8b, void, env, tl)
>> diff --git a/target/i386/tcg/seg_helper.c b/target/i386/tcg/seg_helper.c
>> index 180d47f0e9..f0cb1bffe7 100644
>> --- a/target/i386/tcg/seg_helper.c
>> +++ b/target/i386/tcg/seg_helper.c
>> @@ -1351,7 +1351,9 @@ bool x86_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
>>      case CPU_INTERRUPT_SMI:
>>          cpu_svm_check_intercept_param(env, SVM_EXIT_SMI, 0, 0);
>>          cs->interrupt_request &= ~CPU_INTERRUPT_SMI;
>> +#ifndef CONFIG_USER_ONLY
>>          do_smm_enter(cpu);
>> +#endif
>>          break;
>>      case CPU_INTERRUPT_NMI:
>>          cpu_svm_check_intercept_param(env, SVM_EXIT_NMI, 0, 0);
>> diff --git a/target/i386/tcg/smm_helper.c b/target/i386/tcg/softmmu/smm_helper.c
>> similarity index 98%
>> rename from target/i386/tcg/smm_helper.c
>> rename to target/i386/tcg/softmmu/smm_helper.c
>> index 62d027abd3..ee53b26629 100644
>> --- a/target/i386/tcg/smm_helper.c
>> +++ b/target/i386/tcg/softmmu/smm_helper.c
>> @@ -1,5 +1,5 @@
>>  /*
>> - *  x86 SMM helpers
>> + *  x86 SMM helpers (softmmu-only)
>>   *
>>   *  Copyright (c) 2003 Fabrice Bellard
>>   *
>> @@ -18,27 +18,14 @@
>>   */
>>  
>>  #include "qemu/osdep.h"
>> -#include "qemu/main-loop.h"
>>  #include "cpu.h"
>>  #include "exec/helper-proto.h"
>>  #include "exec/log.h"
>> -#include "helper-tcg.h"
>> +#include "tcg/helper-tcg.h"
>>  
>>  
>>  /* SMM support */
>>  
>> -#if defined(CONFIG_USER_ONLY)
>> -
>> -void do_smm_enter(X86CPU *cpu)
>> -{
>> -}
>> -
>> -void helper_rsm(CPUX86State *env)
>> -{
>> -}
>> -
>> -#else
>> -
>>  #ifdef TARGET_X86_64
>>  #define SMM_REVISION_ID 0x00020064
>>  #else
>> @@ -330,5 +317,3 @@ void helper_rsm(CPUX86State *env)
>>      qemu_log_mask(CPU_LOG_INT, "SMM: after RSM\n");
>>      log_cpu_state_mask(CPU_LOG_INT, CPU(cpu), CPU_DUMP_CCOP);
>>  }
>> -
>> -#endif /* !CONFIG_USER_ONLY */
>> diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
>> index af1faf9342..5075ac4830 100644
>> --- a/target/i386/tcg/translate.c
>> +++ b/target/i386/tcg/translate.c
>> @@ -8321,7 +8321,9 @@ static target_ulong disas_insn(DisasContext *s, CPUState *cpu)
>>              goto illegal_op;
>>          gen_update_cc_op(s);
>>          gen_jmp_im(s, s->pc - s->cs_base);
>> +#ifndef CONFIG_USER_ONLY
>>          gen_helper_rsm(cpu_env);
>> +#endif /* CONFIG_USER_ONLY */
>>          gen_eob(s);
>>          break;
>
> Hello Alex,
>
> this is something I wanted to bring in the foreground:
>
> while before we were generating an empty helper call for CONFIG_USER_ONLY,
> now we are not generating anything.

Surely that says we only generate the helper call when we are not
CONFIG_USER_ONLY?

>
>
>
>>      case 0x1b8: /* SSE4.2 popcnt */
>> diff --git a/target/i386/tcg/meson.build b/target/i386/tcg/meson.build
>> index 68fa0c3187..ec5daa1edc 100644
>> --- a/target/i386/tcg/meson.build
>> +++ b/target/i386/tcg/meson.build
>> @@ -8,7 +8,6 @@ i386_ss.add(when: 'CONFIG_TCG', if_true: files(
>>    'misc_helper.c',
>>    'mpx_helper.c',
>>    'seg_helper.c',
>> -  'smm_helper.c',
>>    'svm_helper.c',
>>    'tcg-cpu.c',
>>    'translate.c'), if_false: files('tcg-stub.c'))
>> diff --git a/target/i386/tcg/softmmu/meson.build b/target/i386/tcg/softmmu/meson.build
>> index 4ab30cc32e..35ba16dc3d 100644
>> --- a/target/i386/tcg/softmmu/meson.build
>> +++ b/target/i386/tcg/softmmu/meson.build
>> @@ -1,3 +1,4 @@
>>  i386_softmmu_ss.add(when: ['CONFIG_TCG', 'CONFIG_SOFTMMU'], if_true: files(
>>    'tcg-cpu.c',
>> +  'smm_helper.c',
>>  ))
>> 

-- 
Alex Bennée