Re: [PATCH v1 04/12] target/riscv: Implement kvm_arch_get_registers

[Anup Patel <anup@xxxxxxxxxxxxxx>]

On Sat, Nov 20, 2021 at 1:17 PM Yifei Jiang <jiangyifei@xxxxxxxxxx> wrote:
>
> Get GPR CSR and FP registers from kvm by KVM_GET_ONE_REG ioctl.
>
> Signed-off-by: Yifei Jiang <jiangyifei@xxxxxxxxxx>
> Signed-off-by: Mingwang Li <limingwang@xxxxxxxxxx>
> Reviewed-by: Alistair Francis <alistair.francis@xxxxxxx>
> ---
>  target/riscv/kvm.c | 150 ++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 149 insertions(+), 1 deletion(-)
>
> diff --git a/target/riscv/kvm.c b/target/riscv/kvm.c
> index 9f9692fb9e..b49c24be0a 100644
> --- a/target/riscv/kvm.c
> +++ b/target/riscv/kvm.c
> @@ -55,13 +55,161 @@ static uint64_t kvm_riscv_reg_id(CPURISCVState *env, uint64_t type, uint64_t idx
>      return id;
>  }
>
> +#define RISCV_CORE_REG(env, name)  kvm_riscv_reg_id(env, KVM_REG_RISCV_CORE, \
> +                 KVM_REG_RISCV_CORE_REG(name))
> +
> +#define RISCV_CSR_REG(env, name)  kvm_riscv_reg_id(env, KVM_REG_RISCV_CSR, \
> +                 KVM_REG_RISCV_CSR_REG(name))
> +
> +#define RISCV_FP_F_REG(env, idx)  kvm_riscv_reg_id(env, KVM_REG_RISCV_FP_F, idx)
> +
> +#define RISCV_FP_D_REG(env, idx)  kvm_riscv_reg_id(env, KVM_REG_RISCV_FP_D, idx)
> +
> +static int kvm_riscv_get_regs_core(CPUState *cs)
> +{
> +    int ret = 0;
> +    int i;
> +    target_ulong reg;
> +    CPURISCVState *env = &RISCV_CPU(cs)->env;
> +
> +    ret = kvm_get_one_reg(cs, RISCV_CORE_REG(env, regs.pc), &reg);
> +    if (ret) {
> +        return ret;
> +    }
> +    env->pc = reg;
> +
> +    for (i = 1; i < 32; i++) {
> +        uint64_t id = kvm_riscv_reg_id(env, KVM_REG_RISCV_CORE, i);
> +        ret = kvm_get_one_reg(cs, id, &reg);
> +        if (ret) {
> +            return ret;
> +        }
> +        env->gpr[i] = reg;
> +    }
> +
> +    return ret;
> +}
> +
> +static int kvm_riscv_get_regs_csr(CPUState *cs)
> +{
> +    int ret = 0;
> +    target_ulong reg;
> +    CPURISCVState *env = &RISCV_CPU(cs)->env;
> +
> +    ret = kvm_get_one_reg(cs, RISCV_CSR_REG(env, sstatus), &reg);
> +    if (ret) {
> +        return ret;
> +    }
> +    env->mstatus = reg;
> +
> +    ret = kvm_get_one_reg(cs, RISCV_CSR_REG(env, sie), &reg);
> +    if (ret) {
> +        return ret;
> +    }
> +    env->mie = reg;
> +
> +    ret = kvm_get_one_reg(cs, RISCV_CSR_REG(env, stvec), &reg);
> +    if (ret) {
> +        return ret;
> +    }
> +    env->stvec = reg;
> +
> +    ret = kvm_get_one_reg(cs, RISCV_CSR_REG(env, sscratch), &reg);
> +    if (ret) {
> +        return ret;
> +    }
> +    env->sscratch = reg;
> +
> +    ret = kvm_get_one_reg(cs, RISCV_CSR_REG(env, sepc), &reg);
> +    if (ret) {
> +        return ret;
> +    }
> +    env->sepc = reg;
> +
> +    ret = kvm_get_one_reg(cs, RISCV_CSR_REG(env, scause), &reg);
> +    if (ret) {
> +        return ret;
> +    }
> +    env->scause = reg;
> +
> +    ret = kvm_get_one_reg(cs, RISCV_CSR_REG(env, stval), &reg);
> +    if (ret) {
> +        return ret;
> +    }
> +    env->stval = reg;
> +
> +    ret = kvm_get_one_reg(cs, RISCV_CSR_REG(env, sip), &reg);
> +    if (ret) {
> +        return ret;
> +    }
> +    env->mip = reg;
> +
> +    ret = kvm_get_one_reg(cs, RISCV_CSR_REG(env, satp), &reg);
> +    if (ret) {
> +        return ret;
> +    }
> +    env->satp = reg;

There is a common pattern in above kvm_get_one_reg() calls so I suggest
creating a macro for repeating code patterns. This can help us to have one
line for each CSR and in future it is easy to add more CSRs.

Regards,
Anup

> +
> +    return ret;
> +}
> +
> +static int kvm_riscv_get_regs_fp(CPUState *cs)
> +{
> +    int ret = 0;
> +    int i;
> +    CPURISCVState *env = &RISCV_CPU(cs)->env;
> +
> +    if (riscv_has_ext(env, RVD)) {
> +        uint64_t reg;
> +        for (i = 0; i < 32; i++) {
> +            ret = kvm_get_one_reg(cs, RISCV_FP_D_REG(env, i), &reg);
> +            if (ret) {
> +                return ret;
> +            }
> +            env->fpr[i] = reg;
> +        }
> +        return ret;
> +    }
> +
> +    if (riscv_has_ext(env, RVF)) {
> +        uint32_t reg;
> +        for (i = 0; i < 32; i++) {
> +            ret = kvm_get_one_reg(cs, RISCV_FP_F_REG(env, i), &reg);
> +            if (ret) {
> +                return ret;
> +            }
> +            env->fpr[i] = reg;
> +        }
> +        return ret;
> +    }
> +
> +    return ret;
> +}
> +
>  const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
>      KVM_CAP_LAST_INFO
>  };
>
>  int kvm_arch_get_registers(CPUState *cs)
>  {
> -    return 0;
> +    int ret = 0;
> +
> +    ret = kvm_riscv_get_regs_core(cs);
> +    if (ret) {
> +        return ret;
> +    }
> +
> +    ret = kvm_riscv_get_regs_csr(cs);
> +    if (ret) {
> +        return ret;
> +    }
> +
> +    ret = kvm_riscv_get_regs_fp(cs);
> +    if (ret) {
> +        return ret;
> +    }
> +
> +    return ret;
>  }
>
>  int kvm_arch_put_registers(CPUState *cs, int level)
> --
> 2.19.1
>
>
> --
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