[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH v9 19/19] target/riscv/tcg: do not support profiles for 'max'
From: |
Andrew Jones |
Subject: |
Re: [PATCH v9 19/19] target/riscv/tcg: do not support profiles for 'max' CPU |
Date: |
Fri, 3 Nov 2023 10:01:04 +0100 |
On Thu, Nov 02, 2023 at 07:44:45PM -0300, Daniel Henrique Barboza wrote:
> There's no gain in allowing the 'max' CPU to support profiles, since it
> already contains everything that QEMU can support. And we'll open the
> door for 'unorthodox' stuff like users disabling profiles of the 'max'
> CPU.
I don't see a lot of value in this patch, but maybe I'm just too cruel to
users that don't know what they're doing. I even see a negative value to
this patch because I can conceive of writing a script where I generally
want to use rv64i with my explicit list of profiles/extensions, but then
I may want to temporarily "boost" my CPU to 'max' for some reason. If
I write my script like
CPU=rv64i
EXTENSIONS=profile=on,extension=on
qemu -cpu $CPU,$EXTENSIONS ...
then I can't just do
CPU=max ./my-script
to boost my CPU, since max will error out when it sees profiles being
enabled (even though that should be no-op for it). Instead, I need to
do
CPU=max EXTENSIONS= ./my-script
which isn't horrible, but a bit annoying.
So, personally, I would drop this patch.
Thanks,
drew
>
> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
> ---
> target/riscv/tcg/tcg-cpu.c | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
> index 553fb337e7..9a964a426e 100644
> --- a/target/riscv/tcg/tcg-cpu.c
> +++ b/target/riscv/tcg/tcg-cpu.c
> @@ -825,6 +825,11 @@ static bool riscv_cpu_is_vendor(Object *cpu_obj)
> return object_dynamic_cast(cpu_obj, TYPE_RISCV_VENDOR_CPU) != NULL;
> }
>
> +static bool riscv_cpu_has_max_extensions(Object *cpu_obj)
> +{
> + return object_dynamic_cast(cpu_obj, TYPE_RISCV_CPU_MAX) != NULL;
> +}
> +
> /*
> * We'll get here via the following path:
> *
> @@ -1003,6 +1008,12 @@ static void cpu_set_profile(Object *obj, Visitor *v,
> const char *name,
> return;
> }
>
> + if (riscv_cpu_has_max_extensions(obj)) {
> + error_setg(errp, "Profile %s is not available for the 'max' CPU",
> + profile->name);
> + return;
> + }
> +
> if (cpu->env.misa_mxl != MXL_RV64) {
> error_setg(errp, "Profile %s only available for 64 bit CPUs",
> profile->name);
> @@ -1251,11 +1262,6 @@ static void riscv_init_max_cpu_extensions(Object *obj)
> }
> }
>
> -static bool riscv_cpu_has_max_extensions(Object *cpu_obj)
> -{
> - return object_dynamic_cast(cpu_obj, TYPE_RISCV_CPU_MAX) != NULL;
> -}
> -
> static void tcg_cpu_instance_init(CPUState *cs)
> {
> RISCVCPU *cpu = RISCV_CPU(cs);
> --
> 2.41.0
>
- [PATCH v9 11/19] target/riscv/tcg: add MISA user options hash, (continued)
- [PATCH v9 11/19] target/riscv/tcg: add MISA user options hash, Daniel Henrique Barboza, 2023/11/02
- [PATCH v9 14/19] target/riscv/tcg: add hash table insert helpers, Daniel Henrique Barboza, 2023/11/02
- [PATCH v9 12/19] target/riscv/tcg: add riscv_cpu_write_misa_bit(), Daniel Henrique Barboza, 2023/11/02
- [PATCH v9 10/19] target/riscv/tcg: add user flag for profile support, Daniel Henrique Barboza, 2023/11/02
- [PATCH v9 18/19] target/riscv: add 'rva22u64' CPU, Daniel Henrique Barboza, 2023/11/02
- [PATCH v9 05/19] target/riscv: add zicbop extension flag, Daniel Henrique Barboza, 2023/11/02
- [PATCH v9 17/19] riscv-qmp-cmds.c: add profile flags in cpu-model-expansion, Daniel Henrique Barboza, 2023/11/02
- [PATCH v9 19/19] target/riscv/tcg: do not support profiles for 'max' CPU, Daniel Henrique Barboza, 2023/11/02
- Re: [PATCH v9 19/19] target/riscv/tcg: do not support profiles for 'max' CPU,
Andrew Jones <=
- [PATCH v9 13/19] target/riscv/tcg: handle profile MISA bits, Daniel Henrique Barboza, 2023/11/02
- [PATCH v9 16/19] target/riscv/tcg: validate profiles during finalize, Daniel Henrique Barboza, 2023/11/02
- [PATCH v9 15/19] target/riscv/tcg: honor user choice for G MISA bits, Daniel Henrique Barboza, 2023/11/02