On Tue, Sep 17, 2024 at 02:54:33PM GMT, Alexei Filippov wrote:
> kvm_riscv_handle_sbi() may return not supported return code to not
> trigger qemu abort with vendor-specific sbi.
>
> Add new error path to provide proper error in case of
> qemu_chr_fe_read_all() may not return sizeof(ch), because exactly zero
> just means we failed to read input, which can happen, so
> telling the SBI caller we failed to read, but telling the caller of this
> function that we successfully emulated the SBI call, is correct. However,
> anything else, other than sizeof(ch), means something unexpected happened,
> so we should return an error.
>
> Added SBI related return code's defines.
>
> Signed-off-by: Alexei Filippov <alexei.filip...@syntacore.com>
> Fixes: 4eb47125 ("target/riscv: Handle KVM_EXIT_RISCV_SBI exit")
Fixes tag goes above s-o-b and 8 hex digits is a bit small. Most
commit references in QEMU are using 10 or 12 digits.
> ---
> target/riscv/kvm/kvm-cpu.c | 10 ++++++----
> target/riscv/sbi_ecall_interface.h | 12 ++++++++++++
> 2 files changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
> index f6e3156b8d..9f2ca67c9f 100644
> --- a/target/riscv/kvm/kvm-cpu.c
> +++ b/target/riscv/kvm/kvm-cpu.c
> @@ -1517,19 +1517,21 @@ static int kvm_riscv_handle_sbi(CPUState *cs, struct
> kvm_run *run)
> ret = qemu_chr_fe_read_all(serial_hd(0)->be, &ch, sizeof(ch));
> if (ret == sizeof(ch)) {
> run->riscv_sbi.ret[0] = ch;
> - } else {
> + ret = 0;
> + } else if (ret == 0) {
> run->riscv_sbi.ret[0] = -1;
> + } else {
> + ret = -1;
> }
> - ret = 0;
Looks good!
> break;
> case SBI_EXT_DBCN:
> kvm_riscv_handle_sbi_dbcn(cs, run);
> break;
> default:
> qemu_log_mask(LOG_UNIMP,
> - "%s: un-handled SBI EXIT, specific reasons is %lu\n",
> + "%s: Unhandled SBI exit with extension-id %lu\n",
> __func__, run->riscv_sbi.extension_id);
> - ret = -1;
> + run->riscv_sbi.ret[0] = SBI_ERR_NOT_SUPPORTED;
This, along with the addition of the SBI_* defines below, should be a
separate patch. If we were just naming the -1, then I wouldn't mind it
slipping in with the same patch, but this is changing behavior since
SBI_ERR_NOT_SUPPORTED is -2. I agree with the change, though, it just
needs to be a separate patch. And the separate patch should have the
same Fixes tag.
Thanks,
drew
> break;
> }
> return ret;
> diff --git a/target/riscv/sbi_ecall_interface.h
> b/target/riscv/sbi_ecall_interface.h
> index 7dfe5f72c6..4df0accd78 100644
> --- a/target/riscv/sbi_ecall_interface.h
> +++ b/target/riscv/sbi_ecall_interface.h
> @@ -86,4 +86,16 @@
> #define SBI_EXT_VENDOR_END 0x09FFFFFF
> /* clang-format on */
>
> +/* SBI return error codes */
> +#define SBI_SUCCESS 0
> +#define SBI_ERR_FAILURE -1
> +#define SBI_ERR_NOT_SUPPORTED -2
> +#define SBI_ERR_INVALID_PARAM -3
> +#define SBI_ERR_DENIED -4
> +#define SBI_ERR_INVALID_ADDRESS -5
> +#define SBI_ERR_ALREADY_AVAILABLE -6
> +#define SBI_ERR_ALREADY_STARTED -7
> +#define SBI_ERR_ALREADY_STOPPED -8
> +#define SBI_ERR_NO_SHMEM -9
> +
> #endif
> --
> 2.34.1
>
