RE: [PATCH v1 08/12] target/riscv: Handle KVM_EXIT_RISCV_SBI exit
-----Original Message-----
From: Philippe Mathieu-Daudé [mailto:philippe.mathieu.daude@gmail.com]
On Behalf Of Philippe Mathieu-Daudé
Sent: Saturday, November 20, 2021 8:25 PM
To: Jiangyifei <jiangyifei(a)huawei.com>; qemu-devel(a)nongnu.org;
qemu-riscv(a)nongnu.org
Cc: bin.meng(a)windriver.com; limingwang (A) <limingwang(a)huawei.com>;
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<fanliang(a)huawei.com>; Wubin (H) <wu.wubin(a)huawei.com>; Alex Bennée
<alex.bennee(a)linaro.org>
Subject: Re: [PATCH v1 08/12] target/riscv: Handle KVM_EXIT_RISCV_SBI exit
Hi,
On 11/20/21 08:46, Yifei Jiang wrote:
> Use char-fe to handle console sbi call, which implement early console
> io while apply 'earlycon=sbi' into kernel parameters.
>
> Signed-off-by: Yifei Jiang <jiangyifei(a)huawei.com>
> Signed-off-by: Mingwang Li <limingwang(a)huawei.com>
> ---
> target/riscv/kvm.c | 42 ++++++++++++++++-
> target/riscv/sbi_ecall_interface.h | 72
> ++++++++++++++++++++++++++++++
> 2 files changed, 113 insertions(+), 1 deletion(-) create mode 100644
> target/riscv/sbi_ecall_interface.h
>
> diff --git a/target/riscv/kvm.c b/target/riscv/kvm.c index
> 8da2648d1a..6d419ba02e 100644
> --- a/target/riscv/kvm.c
> +++ b/target/riscv/kvm.c
> @@ -38,6 +38,8 @@
> #include "qemu/log.h"
> #include "hw/loader.h"
> #include "kvm_riscv.h"
> +#include "sbi_ecall_interface.h"
> +#include "chardev/char-fe.h"
>
> static uint64_t kvm_riscv_reg_id(CPURISCVState *env, uint64_t type,
> uint64_t idx) { @@ -440,9 +442,47 @@ 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;
Shouldn't this code use the Semihosting Console API from
"semihosting/console.h" instead?
Thanks, I will use this API in the next series.
Yifei