On Mon, Apr 22, 2024 at 02:31:36PM +0200, Andrew Jones wrote:
> On Mon, Apr 22, 2024 at 02:42:54PM +0300, 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).
>
> I think something more along the lines of what I wrote in my previous
> reply will help clarify this more. Here's what I wrote
>
> """
> 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 indeed return an error from this function.
> """
>
> Thanks,
> drew
>
> >
> > Added SBI related return code's defines.
> >
> > Signed-off-by: Alexei Filippov <alexei.filip...@syntacore.com>
> > ---
> > Changes since v4-5:
> > -Added new error path in case of qemu_chr_fe_read_all() may not
> > return sizeof(ch).
> > -Added more comments in commit message.
> > 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 f9dbc18a76..5bb7b74d03 100644
> > --- a/target/riscv/kvm/kvm-cpu.c
> > +++ b/target/riscv/kvm/kvm-cpu.c
> > @@ -1173,16 +1173,18 @@ 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;
> > + ret = 0;
> > + } else if (ret == 0) {
> > + run->riscv_sbi.ret[0] = SBI_ERR_FAILURE;
I'd prefer we still explicitly assign ret[0] to -1 here since that's what
the spec explicitly says.
Thanks,
drew
> > } else {
> > - run->riscv_sbi.ret[0] = -1;
> > + ret = -1;
> > }
> > - ret = 0;
> > 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 43899d08f6..a2e21d9b8c 100644
> > --- a/target/riscv/sbi_ecall_interface.h
> > +++ b/target/riscv/sbi_ecall_interface.h
> > @@ -69,4 +69,16 @@
> > #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
> >
