Re: [PATCH RFC 8/9] target/riscv: Handler KVM_EXIT_RISCV_SBI exit

[Anup Patel]

On Fri, Mar 13, 2020 at 9:23 AM Yifei Jiang <address@hidden> wrote:
>
> Use char-fe handler console sbi call, which implement early
> console io while apply 'earlycon=sbi' into kernel parameters.
>
> Signed-off-by: Yifei Jiang <address@hidden>
> Signed-off-by: Yipeng Yin <address@hidden>
> ---
>  target/riscv/kvm.c | 54 +++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 53 insertions(+), 1 deletion(-)
>
> diff --git a/target/riscv/kvm.c b/target/riscv/kvm.c
> index 0f429fd802..1df70fbb29 100644
> --- a/target/riscv/kvm.c
> +++ b/target/riscv/kvm.c
> @@ -38,6 +38,7 @@
>  #include "qemu/log.h"
>  #include "hw/loader.h"
>  #include "kvm_riscv.h"
> +#include "chardev/char-fe.h"
>
>  static __u64 kvm_riscv_reg_id(__u64 type, __u64 idx)
>  {
> @@ -61,6 +62,19 @@ static __u64 kvm_riscv_reg_id(__u64 type, __u64 idx)
>
>  #define RISCV_FP_D_REG(idx)  kvm_riscv_reg_id(KVM_REG_RISCV_FP_D, idx)
>
> +enum sbi_ext_id {
> +    SBI_EXT_0_1_SET_TIMER = 0x0,
> +    SBI_EXT_0_1_CONSOLE_PUTCHAR = 0x1,
> +    SBI_EXT_0_1_CONSOLE_GETCHAR = 0x2,
> +    SBI_EXT_0_1_CLEAR_IPI = 0x3,
> +    SBI_EXT_0_1_SEND_IPI = 0x4,
> +    SBI_EXT_0_1_REMOTE_FENCE_I = 0x5,
> +    SBI_EXT_0_1_REMOTE_SFENCE_VMA = 0x6,
> +    SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID = 0x7,
> +    SBI_EXT_0_1_SHUTDOWN = 0x8,
> +    SBI_EXT_BASE = 0x10,
> +};
> +

Please add separate SBI ecall interface header (similar to OpenSBI).
This header will only have SBI spec related defines.

Refer,
https://github.com/riscv/opensbi/blob/master/include/sbi/sbi_ecall_interface.h

>  static int kvm_riscv_get_regs_core(CPUState *cs)
>  {
>      int ret = 0;
> @@ -423,9 +437,47 @@ bool kvm_arch_stop_on_emulation_error(CPUState *cs)
>      return true;
>  }
>
> +static int kvm_riscv_handle_sbi(struct kvm_run *run)
> +{
> +    int ret = 0;
> +    unsigned char ch;
> +    switch (run->riscv_sbi.extension_id) {
> +    case SBI_EXT_0_1_CONSOLE_PUTCHAR:
> +        ch = run->riscv_sbi.args[0];
> +        qemu_chr_fe_write(serial_hd(0)->be, &ch, sizeof(ch));
> +        break;
> +    case SBI_EXT_0_1_CONSOLE_GETCHAR:
> +        ret = qemu_chr_fe_read_all(serial_hd(0)->be, &ch, sizeof(ch));
> +        if (ret == sizeof(ch)) {
> +            run->riscv_sbi.args[0] = ch;
> +        } else {
> +            run->riscv_sbi.args[0] = -1;
> +        }
> +        break;

Please emulate SBI v0.1 Shutdown call as well.

> +    default:
> +        qemu_log_mask(LOG_UNIMP,
> +                      "%s: un-handled SBI EXIT, specific reasons is %lu\n",
> +                      __func__, run->riscv_sbi.extension_id);
> +        ret = -1;
> +        break;
> +    }
> +    return ret;
> +}
> +
>  int kvm_arch_handle_exit(CPUState *cs, struct kvm_run *run)
>  {
> -    return 0;
> +    int ret = 0;
> +    switch (run->exit_reason) {
> +    case KVM_EXIT_RISCV_SBI:
> +        ret = kvm_riscv_handle_sbi(run);
> +        break;
> +    default:
> +        qemu_log_mask(LOG_UNIMP, "%s: un-handled exit reason %d\n",
> +                      __func__, run->exit_reason);
> +        ret = -1;
> +        break;
> +    }
> +    return ret;
>  }
>
>  void kvm_riscv_reset_vcpu(RISCVCPU *cpu)
> --
> 2.19.1
>
>
>

Regards,
Anup