qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed
From: Andrew Jones <ajones@ventanamicro.com>
To: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Cc: qemu-devel@nongnu.org, qemu-riscv@nongnu.org,
	alistair.francis@wdc.com,  bmeng@tinylab.org,
	liweiwei@iscas.ac.cn, zhiwei_liu@linux.alibaba.com,
	 palmer@rivosinc.com
Subject: Re: [PATCH v8 05/19] target/riscv/tcg: update priv_ver on user_set extensions
Date: Thu, 2 Nov 2023 10:47:15 +0100	[thread overview]
Message-ID: <20231102-bdcd40a9183dbbfe6667a304@orel> (raw)
In-Reply-To: <20231101204204.345470-6-dbarboza@ventanamicro.com>

On Wed, Nov 01, 2023 at 05:41:50PM -0300, Daniel Henrique Barboza wrote:
> We'll add a new bare CPU type that won't have any default priv_ver. This
> means that the CPU will default to priv_ver = 0, i.e. 1.10.0.
> 
> At the same we'll allow these CPUs to enable extensions at will, but
> then, if the extension has a priv_ver newer than 1.10, we'll end up
> disabling it. Users will then need to manually set priv_ver to something
> other than 1.10 to enable the extensions they want, which is not ideal.
> 
> Change the setter() of multi letter extensions to allow user enabled
> extensions to bump the priv_ver of the CPU. This will make it
> conveniente for users to enable extensions for CPUs that doesn't set a
> default priv_ver.
> 
> This change does not affect any existing CPU: vendor CPUs does not allow
> extensions to be enabled, and generic CPUs are already set to priv_ver
> LATEST.
> 
> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
> ---
>  target/riscv/tcg/tcg-cpu.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
> index f54069d06f..b88fce98a4 100644
> --- a/target/riscv/tcg/tcg-cpu.c
> +++ b/target/riscv/tcg/tcg-cpu.c
> @@ -114,6 +114,22 @@ static int cpu_cfg_ext_get_min_version(uint32_t ext_offset)
>      g_assert_not_reached();
>  }
>  
> +static void cpu_validate_multi_ext_priv_ver(CPURISCVState *env,
> +                                            uint32_t ext_offset)
> +{
> +    int ext_priv_ver;
> +
> +    if (env->priv_ver == PRIV_VERSION_LATEST) {
> +        return;
> +    }
> +
> +    ext_priv_ver = cpu_cfg_ext_get_min_version(ext_offset);
> +
> +    if (env->priv_ver < ext_priv_ver) {
> +        env->priv_ver = ext_priv_ver;
> +    }

This will ignore user input. If the user, for example, does

 -cpu rv64,priv_spec=v1.10.0,zicbom=on

then, afaict, priv_spec will be silently bumped to 1.12. I think we should
error out in that case instead. And, we should also error out for

 -cpu rv64,zicbom=on,priv_spec=v1.10.0

which means we should know when priv_spec is either

 - its default value
 - has been bumped by an extension
 - has been explicitly set by the user

> +}
> +
>  static void cpu_cfg_ext_auto_update(RISCVCPU *cpu, uint32_t ext_offset,
>                                      bool value)
>  {
> @@ -829,6 +845,10 @@ static void cpu_set_multi_ext_cfg(Object *obj, Visitor *v, const char *name,
>          return;
>      }
>  
> +    if (value) {
> +        cpu_validate_multi_ext_priv_ver(&cpu->env, multi_ext_cfg->offset);
> +    }

Some misa extensions also have priv spec version dependencies. See
riscv_cpu_validate_misa_priv()

> +
>      isa_ext_update_enabled(cpu, multi_ext_cfg->offset, value);
>  }
>  
> -- 
> 2.41.0
>

Thanks,
drew


  reply	other threads:[~2023-11-02  9:48 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-01 20:41 [PATCH v8 00/19] rv64i CPU, RVA22U64 profile support Daniel Henrique Barboza
2023-11-01 20:41 ` [PATCH v8 01/19] target/riscv: create TYPE_RISCV_VENDOR_CPU Daniel Henrique Barboza
2023-11-02  2:32   ` Alistair Francis
2023-11-01 20:41 ` [PATCH v8 02/19] target/riscv/tcg: do not use "!generic" CPU checks Daniel Henrique Barboza
2023-11-02  2:38   ` Alistair Francis
2023-11-01 20:41 ` [PATCH v8 03/19] target/riscv/cpu.c: set satp_max_supported in cpu_riscv_set_satp() Daniel Henrique Barboza
2023-11-02  9:24   ` Andrew Jones
2023-11-02 12:53     ` Daniel Henrique Barboza
2023-11-02 13:11       ` Andrew Jones
2023-11-01 20:41 ` [PATCH v8 04/19] target/riscv/cpu.c: set satp_mode_max MBARE during satp_finalize() Daniel Henrique Barboza
2023-11-02  9:32   ` Andrew Jones
2023-11-01 20:41 ` [PATCH v8 05/19] target/riscv/tcg: update priv_ver on user_set extensions Daniel Henrique Barboza
2023-11-02  9:47   ` Andrew Jones [this message]
2023-11-02 13:42     ` Daniel Henrique Barboza
2023-11-02 13:48       ` Andrew Jones
2023-11-01 20:41 ` [PATCH v8 06/19] target/riscv: add rv64i CPU Daniel Henrique Barboza
2023-11-02  9:59   ` Andrew Jones
2023-11-02 14:23     ` Daniel Henrique Barboza
2023-11-01 20:41 ` [PATCH v8 07/19] target/riscv: add zicbop extension flag Daniel Henrique Barboza
2023-11-01 20:41 ` [PATCH v8 08/19] target/riscv/tcg: add 'zic64b' support Daniel Henrique Barboza
2023-11-01 20:41 ` [PATCH v8 09/19] riscv-qmp-cmds.c: expose named features in cpu_model_expansion Daniel Henrique Barboza
2023-11-01 20:41 ` [PATCH v8 10/19] target/riscv: add rva22u64 profile definition Daniel Henrique Barboza
2023-11-01 20:41 ` [PATCH v8 11/19] target/riscv/kvm: add 'rva22u64' flag as unavailable Daniel Henrique Barboza
2023-11-01 20:41 ` [PATCH v8 12/19] target/riscv/tcg: add user flag for profile support Daniel Henrique Barboza
2023-11-01 20:41 ` [PATCH v8 13/19] target/riscv/tcg: add MISA user options hash Daniel Henrique Barboza
2023-11-01 20:41 ` [PATCH v8 14/19] target/riscv/tcg: add riscv_cpu_write_misa_bit() Daniel Henrique Barboza
2023-11-01 20:42 ` [PATCH v8 15/19] target/riscv/tcg: handle profile MISA bits Daniel Henrique Barboza
2023-11-01 20:42 ` [PATCH v8 16/19] target/riscv/tcg: add hash table insert helpers Daniel Henrique Barboza
2023-11-01 20:42 ` [PATCH v8 17/19] target/riscv/tcg: honor user choice for G MISA bits Daniel Henrique Barboza
2023-11-01 20:42 ` [PATCH v8 18/19] target/riscv/tcg: validate profiles during finalize Daniel Henrique Barboza
2023-11-01 20:42 ` [PATCH v8 19/19] riscv-qmp-cmds.c: add profile flags in cpu-model-expansion Daniel Henrique Barboza

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20231102-bdcd40a9183dbbfe6667a304@orel \
    --to=ajones@ventanamicro.com \
    --cc=alistair.francis@wdc.com \
    --cc=bmeng@tinylab.org \
    --cc=dbarboza@ventanamicro.com \
    --cc=liweiwei@iscas.ac.cn \
    --cc=palmer@rivosinc.com \
    --cc=qemu-devel@nongnu.org \
    --cc=qemu-riscv@nongnu.org \
    --cc=zhiwei_liu@linux.alibaba.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).