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

[Aurelien Jarno <aurelien@aurel32.net>]

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 <agraf@suse.de>
> ---
>  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.

> +}
> +#endif
> diff --git a/target-s390x/exec.h b/target-s390x/exec.h
> new file mode 100644
> index 0000000..5198359
> --- /dev/null
> +++ b/target-s390x/exec.h
> @@ -0,0 +1,51 @@
> +/*
> + *  S/390 execution defines
> + *
> + *  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
> + */
> +
> +#include "dyngen-exec.h"
> +
> +register struct CPUS390XState *env asm(AREG0);
> +
> +#include "cpu.h"
> +#include "exec-all.h"
> +
> +static inline int cpu_has_work(CPUState *env)
> +{
> +    return env->interrupt_request & CPU_INTERRUPT_HARD; // guess
> +}
> +
> +static inline void regs_to_env(void)
> +{
> +}
> +
> +static inline void env_to_regs(void)
> +{
> +}
> +
> +static inline int cpu_halted(CPUState *env)
> +{
> +    if (!env->halted) {
> +       return 0;
> +    }
> +    if (cpu_has_work(env)) {
> +        env->halted = 0;
> +        return 0;
> +    }
> +    return EXCP_HALTED;
> +}
> diff --git a/target-s390x/helper.c b/target-s390x/helper.c
> new file mode 100644
> index 0000000..4e23b4a
> --- /dev/null
> +++ b/target-s390x/helper.c
> @@ -0,0 +1,57 @@
> +/*
> + *  S/390 helpers
> + *
> + *  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
> + */
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +
> +#include "cpu.h"
> +#include "exec-all.h"
> +#include "gdbstub.h"
> +#include "qemu-common.h"
> +
> +CPUS390XState *cpu_s390x_init(const char *cpu_model)
> +{
> +    CPUS390XState *env;
> +    static int inited = 0;
> +    
> +    env = qemu_mallocz(sizeof(CPUS390XState));
> +    cpu_exec_init(env);
> +    if (!inited) {
> +        inited = 1;
> +    }
> +    
> +    env->cpu_model_str = cpu_model;
> +    cpu_reset(env);
> +    qemu_init_vcpu(env);
> +    return env;
> +}
> +
> +void cpu_reset(CPUS390XState *env)
> +{
> +    if (qemu_loglevel_mask(CPU_LOG_RESET)) {
> +        qemu_log("CPU Reset (CPU %d)\n", env->cpu_index);
> +        log_cpu_state(env, 0);
> +    }
> +    
> +    memset(env, 0, offsetof(CPUS390XState, breakpoints));
> +    /* FIXME: reset vector? */

Isn't it also needed by kvm to make reset working?

> +    tlb_flush(env, 1);
> +}
> diff --git a/target-s390x/op_helper.c b/target-s390x/op_helper.c
> new file mode 100644
> index 0000000..e623de9
> --- /dev/null
> +++ b/target-s390x/op_helper.c
> @@ -0,0 +1,74 @@
> +/*
> + *  S/390 helper routines
> + *
> + *  Copyright (c) 2009 Alexander Graf
> + *
> + * 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
> + */
> +
> +#include "exec.h"
> +
> +/*****************************************************************************/
> +/* Softmmu support */
> +#if !defined (CONFIG_USER_ONLY)
> +
> +#define MMUSUFFIX _mmu
> +
> +#define SHIFT 0
> +#include "softmmu_template.h"
> +
> +#define SHIFT 1
> +#include "softmmu_template.h"
> +
> +#define SHIFT 2
> +#include "softmmu_template.h"
> +
> +#define SHIFT 3
> +#include "softmmu_template.h"
> +
> +/* try to fill the TLB and return an exception if error. If retaddr is
> +   NULL, it means that the function was called in C code (i.e. not
> +   from generated code or from helper.c) */
> +/* XXX: fix it to restore all registers */
> +void tlb_fill (target_ulong addr, int is_write, int mmu_idx, void *retaddr)
> +{
> +    TranslationBlock *tb;
> +    CPUState *saved_env;
> +    unsigned long pc;
> +    int ret;
> +
> +    /* XXX: hack to restore env in all cases, even if not called from
> +       generated code */
> +    saved_env = env;
> +    env = cpu_single_env;
> +    ret = cpu_s390x_handle_mmu_fault(env, addr, is_write, mmu_idx, 1);
> +    if (unlikely(ret != 0)) {
> +        if (likely(retaddr)) {
> +            /* now we have a real cpu fault */
> +            pc = (unsigned long)retaddr;
> +            tb = tb_find_pc(pc);
> +            if (likely(tb)) {
> +                /* the PC is inside the translated code. It means that we have
> +                   a virtual CPU fault */
> +                cpu_restore_state(tb, env, pc, NULL);
> +            }
> +        }
> +        /* XXX */
> +        /* helper_raise_exception_err(env->exception_index, env->error_code); */
> +    }
> +    env = saved_env;
> +}
> +
> +#endif
> diff --git a/target-s390x/translate.c b/target-s390x/translate.c
> new file mode 100644
> index 0000000..f304411
> --- /dev/null
> +++ b/target-s390x/translate.c
> @@ -0,0 +1,57 @@
> +/*
> + *  S/390 translation
> + *
> + *  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
> + */
> +
> +#include "cpu.h"
> +#include "exec-all.h"
> +#include "disas.h"
> +#include "tcg-op.h"
> +#include "qemu-log.h"
> +
> +void cpu_dump_state(CPUState *env, FILE *f,
> +                    int (*cpu_fprintf)(FILE *f, const char *fmt, ...),
> +                    int flags)
> +{
> +    int i;
> +    for (i = 0; i < 16; i++) {
> +        cpu_fprintf(f, "R%02d=%016lx", i, env->regs[i]);
> +        if ((i % 4) == 3) cpu_fprintf(f, "\n");
> +        else cpu_fprintf(f, " ");
> +    }
> +    for (i = 0; i < 16; i++) {
> +        cpu_fprintf(f, "F%02d=%016lx", i, env->fregs[i]);
> +        if ((i % 4) == 3) cpu_fprintf(f, "\n");
> +        else cpu_fprintf(f, " ");
> +    }
> +    cpu_fprintf(f, "PSW=mask %016lx addr %016lx cc %02x\n", env->psw.mask, env->psw.addr, env->cc);
> +}
> +
> +void gen_intermediate_code (CPUState *env, struct TranslationBlock *tb)
> +{
> +}
> +
> +void gen_intermediate_code_pc (CPUState *env, struct TranslationBlock *tb)
> +{
> +}
> +
> +void gen_pc_load(CPUState *env, TranslationBlock *tb,
> +                unsigned long searched_pc, int pc_pos, void *puc)
> +{
> +    env->psw.addr = gen_opc_pc[pc_pos];
> +}
> -- 
> 1.6.0.2
> 
> 
> 
> 

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net