In this patch, we modify the decoder to be a freely composable data
structure instead of a hardcoded one. It can be dynamically builded up
according to the extensions.
This approach has several benefits:
1. Provides support for heterogeneous cpu architectures. As we add decoder in
RISCVCPU, each cpu can have their own decoder, and the decoders can be
different due to cpu's features.
2. Improve the decoding efficiency. We run the guard_func to see if the decoder
can be added to the dynamic_decoder when building up the decoder. Therefore,
there is no need to run the guard_func when decoding each instruction. It can
improve the decoding efficiency
3. For vendor or dynamic cpus, it allows them to customize their own decoder
functions to improve decoding efficiency, especially when vendor-defined
instruction sets increase. Because of dynamic building up, it can skip the other
decoder guard functions when decoding.
4. Pre patch for allowing adding a vendor decoder before decode_insn32() with minimal
overhead for users that don't need this particular vendor decoder.
Signed-off-by: Huang Tao <eric.huang@linux.alibaba.com>
Suggested-by: Christoph Muellner <christoph.muellner@vrull.eu>
Co-authored-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240506023607.29544-1-eric.huang@linux.alibaba.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Add an API to check if a given CPU is compatible with the current
accelerator.
This will allow query-cpu-model-expansion to work properly in conditions
where QEMU supports both accelerators (TCG and KVM), QEMU is then
launched using TCG, and the API requests information about a KVM only
CPU (e.g. 'host' CPU).
KVM doesn't have such restrictions and, at least in theory, all CPUs
models should work with KVM. We will revisit this API in case we decide
to restrict the amount of KVM CPUs we support.
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20231018195638.211151-6-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The query-cpu-model-expansion API is capable of passing extra properties
to a given CPU model and tell callers if this custom configuration is
valid.
The RISC-V version of the API is not quite there yet. The reason is the
realize() flow in the TCG driver, where most of the validation is done
in tcg_cpu_realizefn(). riscv_cpu_finalize_features() is then used to
validate satp_mode for both TCG and KVM CPUs.
Our ARM friends uses a concept of 'finalize_features()', a step done in
the end of realize() where the CPU features are validated. We have a
riscv_cpu_finalize_features() helper that, at this moment, is only
validating satp_mode.
Re-use this existing helper to do all CPU extension validation we
required after at the end of realize(). Make it public to allow APIs to
use it. At this moment only the TCG driver requires a realize() time
validation, thus, to avoid adding accelerator specific helpers in the
API, riscv_cpu_finalize_features() uses
riscv_tcg_cpu_finalize_features() if we are running TCG. The API will
then use riscv_cpu_finalize_features() regardless of the current
accelerator.
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20231018195638.211151-4-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
This function is the core of the RISC-V validations for TCG CPUs, and it
has a lot going on.
Functions in cpu.c were made public to allow them to be used by the KVM
accelerator class later on. 'cpu_cfg_ext_get_min_version()' is notably
hard to move it to another file due to its dependency with isa_edata_arr[]
array, thus make it public and use it as is for now.
riscv_cpu_validate_set_extensions() is kept public because it's used by
csr.c in write_misa().
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20230925175709.35696-4-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
