On Tue, Jun 25, 2024 at 06:02:54PM 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
> Fixes: 4eb47125 ("target/riscv: Handle KVM_EXIT_RISCV_SBI exit")
> ---
> Changes since v7:
> - Fix error handling according to Andrew Jones suggestion.
> target/riscv/kvm/kvm-cpu.c | 9 +
> target/riscv/sbi_ecall_interface.h | 12
> 2 files changed, 17 insertions(+), 4 deletions(-)
>
> diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
> index 235e2cdaca..1afbabe19f 100644
> --- a/target/riscv/kvm/kvm-cpu.c
> +++ b/target/riscv/kvm/kvm-cpu.c
> @@ -1515,19 +1515,20 @@ static int kvm_riscv_handle_sbi(CPUState *cs, struct
> kvm_run *run)
> ret = qemu_chr_fe_read_all(serial_hd(0)->be, , sizeof(ch));
> if (ret == sizeof(ch)) {
> run->riscv_sbi.ret[0] = ch;
> +} else if (ret == 0) {
> +run->riscv_sbi.ret[0] = SBI_ERR_FAILURE;
> } else {
> -run->riscv_sbi.ret[0] = -1;
> +ret = -1;
> }
> -ret = 0;
It should be
diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
index 235e2cdaca1a..9946afb4eade 100644
--- a/target/riscv/kvm/kvm-cpu.c
+++ b/target/riscv/kvm/kvm-cpu.c
@@ -1515,10 +1515,12 @@ static int kvm_riscv_handle_sbi(CPUState *cs, struct
kvm_run *run)
ret = qemu_chr_fe_read_all(serial_hd(0)->be, , 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;
break;
case SBI_EXT_DBCN:
kvm_riscv_handle_sbi_dbcn(cs, run);
I misled you on that first 'ret = 0' addition, we need that, but I've
pointed out a few times that we should use '-1' instead of SBI_ERR_FAILURE
and why.
Thanks,
drew
> 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;
> 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 0x09FF
> /* 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
>
