Re: [Qemu-devel] [PATCH 01/11] S/390 CPU fake emulation

[Alexander Graf]

On 30.11.2009, at 19:18, Aurelien Jarno wrote:

> On Thu, Nov 26, 2009 at 02:23:10PM +0100, Alexander Graf wrote:
>> Because Qemu currently requires a TCG target to exist and there are quite 
>> some
>> useful helpers here to lay the groundwork for out KVM target, let's create a
>> stub TCG emulation target for S390X CPUs.
>> 
>> This is required to make tcg happy. The emulation target itself won't work
>> though.
> 
> Please find the comments below.
> 
>> Signed-off-by: Alexander Graf <address@hidden>
>> ---
>> cpu-exec.c               |    2 +
>> target-s390x/cpu.h       |  119 
>> ++++++++++++++++++++++++++++++++++++++++++++++
>> target-s390x/exec.h      |   51 ++++++++++++++++++++
>> target-s390x/helper.c    |   57 ++++++++++++++++++++++
>> target-s390x/op_helper.c |   74 ++++++++++++++++++++++++++++
>> target-s390x/translate.c |   57 ++++++++++++++++++++++
>> 6 files changed, 360 insertions(+), 0 deletions(-)
>> create mode 100644 target-s390x/cpu.h
>> create mode 100644 target-s390x/exec.h
>> create mode 100644 target-s390x/helper.c
>> create mode 100644 target-s390x/op_helper.c
>> create mode 100644 target-s390x/translate.c
>> 
>> diff --git a/cpu-exec.c b/cpu-exec.c
>> index 2c0765c..af4595b 100644
>> --- a/cpu-exec.c
>> +++ b/cpu-exec.c
>> @@ -249,6 +249,7 @@ int cpu_exec(CPUState *env1)
>> #elif defined(TARGET_MIPS)
>> #elif defined(TARGET_SH4)
>> #elif defined(TARGET_CRIS)
>> +#elif defined(TARGET_S390X)
>>     /* XXXXX */
>> #else
>> #error unsupported target CPU
>> @@ -673,6 +674,7 @@ int cpu_exec(CPUState *env1)
>> #elif defined(TARGET_SH4)
>> #elif defined(TARGET_ALPHA)
>> #elif defined(TARGET_CRIS)
>> +#elif defined(TARGET_S390X)
>>     /* XXXXX */
>> #else
>> #error unsupported target CPU
>> diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
>> new file mode 100644
>> index 0000000..f45b00c
>> --- /dev/null
>> +++ b/target-s390x/cpu.h
>> @@ -0,0 +1,119 @@
>> +/*
>> + * S/390 virtual CPU header
>> + *
>> + *  Copyright (c) 2009 Ulrich Hecht
>> + *
>> + * This library is free software; you can redistribute it and/or
>> + * modify it under the terms of the GNU Lesser General Public
>> + * License as published by the Free Software Foundation; either
>> + * version 2 of the License, or (at your option) any later version.
>> + *
>> + * This library is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> + * Lesser General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU Lesser General Public
>> + * License along with this library; if not, write to the Free Software
>> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA  02110-1301 
>> USA
>> + */
>> +#ifndef CPU_S390X_H
>> +#define CPU_S390X_H
>> +
>> +#define TARGET_LONG_BITS 64
>> +
>> +#define ELF_MACHINE EM_S390
>> +
>> +#define CPUState struct CPUS390XState
>> +
>> +#include "cpu-defs.h"
>> +
>> +#include "softfloat.h"
>> +
>> +#define NB_MMU_MODES 2 // guess
>> +#define MMU_USER_IDX 0 // guess
>> +
>> +typedef union FPReg {
>> +    struct {
>> +#ifdef WORDS_BIGENDIAN
>> +        float32 e;
>> +        int32_t __pad;
>> +#else
>> +        int32_t __pad;
>> +        float32 e;
>> +#endif
>> +    };
>> +    float64 d;
>> +    uint64_t i;
>> +} FPReg;
>> +
>> +typedef struct CPUS390XState {
>> +    uint64_t regs[16];      /* GP registers */
>> +    
>> +    uint32_t aregs[16];     /* access registers */
>> +    
>> +    uint32_t fpc;   /* floating-point control register */
>> +    FPReg fregs[16]; /* FP registers */
>> +    float_status fpu_status; /* passed to softfloat lib */
>> +    
>> +    struct {
>> +        uint64_t mask;
>> +        uint64_t addr;
>> +    } psw;
>> +    
>> +    int cc; /* condition code (0-3) */
>> +    
>> +    uint64_t __excp_addr;
>> +    
>> +    CPU_COMMON
>> +} CPUS390XState;
>> +
>> +#if defined(CONFIG_USER_ONLY)
>> +static inline void cpu_clone_regs(CPUState *env, target_ulong newsp)
>> +{
>> +    if (newsp)
>> +        env->regs[15] = newsp;
> 
> Coding style.
> 
>> +    env->regs[0] = 0;
>> +}
>> +#endif
>> +
>> +CPUS390XState *cpu_s390x_init(const char *cpu_model);
>> +int cpu_s390x_exec(CPUS390XState *s);
>> +void cpu_s390x_close(CPUS390XState *s);
>> +
>> +/* you can call this signal handler from your SIGBUS and SIGSEGV
>> +   signal handlers to inform the virtual CPU of exceptions. non zero
>> +   is returned if the signal was handled by the virtual CPU.  */
>> +int cpu_s390x_signal_handler(int host_signum, void *pinfo,
>> +                           void *puc);
>> +int cpu_s390x_handle_mmu_fault (CPUS390XState *env, target_ulong address, 
>> int rw,
>> +                              int mmu_idx, int is_softmuu);
>> +#define cpu_handle_mmu_fault cpu_s390x_handle_mmu_fault
>> +
>> +#define TARGET_PAGE_BITS 12
>> +
>> +#define cpu_init cpu_s390x_init
>> +#define cpu_exec cpu_s390x_exec
>> +#define cpu_gen_code cpu_s390x_gen_code
>> +
>> +#include "cpu-all.h"
>> +#include "exec-all.h"
>> +
>> +#define EXCP_OPEX 1 /* operation exception (sigill) */
>> +#define EXCP_SVC 2 /* supervisor call (syscall) */
>> +#define EXCP_ADDR 5 /* addressing exception */
>> +#define EXCP_EXECUTE_SVC 0xff00000 /* supervisor call via execute insn */
>> +
>> +static inline void cpu_pc_from_tb(CPUState *env, TranslationBlock* tb)
>> +{
>> +    env->psw.addr = tb->pc;
>> +}
>> +
>> +static inline void cpu_get_tb_cpu_state(CPUState* env, target_ulong *pc,
>> +                                        target_ulong *cs_base, int *flags)
>> +{
>> +    *pc = env->psw.addr;
>> +    *cs_base = 0;
>> +    *flags = env->psw.mask; // guess
> 
> I don't know what psw.mask represent, but it may be wrong. It should be
> a way to identify which TB can be reused, that is they have been
> generated in the same CPU mode.

psw.mask is rougly the same as RFLAGS, cr0 and cr4 on x86_64 combined. So IMHO 
it looked like a pretty good identifier for TB uniqueness.

Alex