Re: [Qemu-devel] [Qemu-riscv] [PATCH v1 02/28] target/riscv: Add the virtulisation mode

[Chih-Min Chao <chihmin.chao@sifive.com>]

On Sat, Aug 24, 2019 at 7:41 AM Alistair Francis <alistair.francis@wdc.com>
wrote:

> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
> ---
>  target/riscv/cpu.h        |  4 ++++
>  target/riscv/cpu_bits.h   |  6 ++++++
>  target/riscv/cpu_helper.c | 23 +++++++++++++++++++++++
>  3 files changed, 33 insertions(+)
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 7f54fb8c87..0ef1ecb0e0 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -117,6 +117,8 @@ struct CPURISCVState {
>
>  #ifndef CONFIG_USER_ONLY
>      target_ulong priv;
> +    /* This contains QEMU specific information about the virt state. */
> +    target_ulong virt;
>      target_ulong resetvec;
>
>      target_ulong mhartid;
> @@ -257,6 +259,8 @@ int riscv_cpu_gdb_read_register(CPUState *cpu, uint8_t
> *buf, int reg);
>  int riscv_cpu_gdb_write_register(CPUState *cpu, uint8_t *buf, int reg);
>  bool riscv_cpu_exec_interrupt(CPUState *cs, int interrupt_request);
>  bool riscv_cpu_fp_enabled(CPURISCVState *env);
> +bool riscv_cpu_virt_enabled(CPURISCVState *env);
> +void riscv_cpu_set_virt_enabled(CPURISCVState *env, bool enable);
>  int riscv_cpu_mmu_index(CPURISCVState *env, bool ifetch);
>  hwaddr riscv_cpu_get_phys_page_debug(CPUState *cpu, vaddr addr);
>  void  riscv_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
> diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
> index e99834856c..1fbde516be 100644
> --- a/target/riscv/cpu_bits.h
> +++ b/target/riscv/cpu_bits.h
> @@ -422,6 +422,12 @@
>  #define PRV_H 2 /* Reserved */
>  #define PRV_M 3
>
> +/* Virtulisation modes */
> +#define VIRT_OFF            0
> +#define VIRT_ON             1
> +#define VIRT_MODE_SHIFT     0
> +#define VIRT_MODE_MASK      (1 << VIRT_MODE_SHIFT)
> +
>
 /* RV32 satp CSR field masks */
>  #define SATP32_MODE         0x80000000
>  #define SATP32_ASID         0x7fc00000
> diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> index 225e407cff..7b0bb14c01 100644
> --- a/target/riscv/cpu_helper.c
> +++ b/target/riscv/cpu_helper.c
> @@ -81,6 +81,29 @@ bool riscv_cpu_fp_enabled(CPURISCVState *env)
>      return false;
>  }
>
> +bool riscv_cpu_virt_enabled(CPURISCVState *env)
> +{
> +    bool tmp;
> +
> +    if (!riscv_has_ext(env, RVH)) {
> +        return false;
> +    }
> +
> +    tmp = (env->virt & VIRT_MODE_MASK) >> VIRT_MODE_SHIFT;
> +
> +    return tmp == VIRT_ON;
> +}
> +
> +void riscv_cpu_set_virt_enabled(CPURISCVState *env, bool enable)
> +{
> +    if (!riscv_has_ext(env, RVH)) {
> +        return;
> +    }
> +
> +    env->virt &= ~VIRT_MODE_MASK;
> +    env->virt |= enable << VIRT_MODE_SHIFT;
> +}
> +
>  int riscv_cpu_claim_interrupts(RISCVCPU *cpu, uint32_t interrupts)
>  {
>      CPURISCVState *env = &cpu->env;
> --
> 2.22.0
>
> Why not to use get_field and set_field though it is not a real register
but an internal state

#define VIRT_ONOFF            0x01
#define VIRT_OFF             0
#define VIRT_ON             1

access
       get_field(env->virt, VIRT_ONOFF);
       set_field(env->virt, VIRT_ONOFF, enable);


chihmin