Re: [PATCH v4] lib: sbi: Enable Ssqosid Ext using mstateen0

From: "Radim Krčmář" <rkrcmar@ventanamicro.com>
To: <cp0613@linux.alibaba.com>, <opensbi@lists.infradead.org>
Cc: <anup@brainfault.org>, <guoren@kernel.org>,
	"opensbi" <opensbi-bounces@lists.infradead.org>
Subject: Re: [PATCH v4] lib: sbi: Enable Ssqosid Ext using mstateen0
Date: Fri, 14 Nov 2025 11:37:56 +0100	[thread overview]
Message-ID: <DE8CP7JNU9LK.32K25AJH9SUU8@ventanamicro.com> (raw)
In-Reply-To: <20251114071359.1492-1-cp0613@linux.alibaba.com>

2025-11-14T15:13:58+08:00, <cp0613@linux.alibaba.com>:
> From: Chen Pei <cp0613@linux.alibaba.com>
>
> The QoS Identifiers extension (Ssqosid) introduces the srmcfg register,
> which configures a hart with two identifiers: a Resource Control ID
> (RCID) and a Monitoring Counter ID (MCID). These identifiers accompany
> each request issued by the hart to shared resource controllers.
>
> If extension Smstateen is implemented together with Ssqosid, then
> Ssqosid also requires the SRMCFG bit in mstateen0 to be implemented. If
> mstateen0.SRMCFG is 0, attempts to access srmcfg in privilege modes less
> privileged than M-mode raise an illegal-instruction exception. If
> mstateen0.SRMCFG is 1 or if extension Smstateen is not implemented,
> attempts to access srmcfg when V=1 raise a virtual-instruction exception.
>
> This extension can be found in the RISC-V Instruction Set Manual:
> https://github.com/riscv/riscv-isa-manual
>
> Signed-off-by: Chen Pei <cp0613@linux.alibaba.com>
> ---

v4: remove extraneous parentheses around SMSTATEEN0_SRMCFG

> diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
> @@ -143,8 +145,11 @@ static int switch_to_next_domain_context(struct hart_context *ctx,
>  	ctx->satp	= csr_swap(CSR_SATP, dom_ctx->satp);
>  	if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_10)
>  		ctx->scounteren = csr_swap(CSR_SCOUNTEREN, dom_ctx->scounteren);
> -	if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_12)
> +	if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_12) {
>  		ctx->senvcfg	= csr_swap(CSR_SENVCFG, dom_ctx->senvcfg);
> +		if (sbi_hart_has_extension(scratch, SBI_HART_EXT_SSQOSID))
> +			ctx->srmcfg	= csr_swap(CSR_SRMCFG, dom_ctx->srmcfg);
> +	}

This should be:

 	if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_12)
 		ctx->senvcfg	= csr_swap(CSR_SENVCFG, dom_ctx->senvcfg);
+	if (sbi_hart_has_extension(scratch, SBI_HART_EXT_SSQOSID))
+		ctx->srmcfg	= csr_swap(CSR_SRMCFG, dom_ctx->srmcfg);

Because SBI_HART_EXT_SSQOSID doesn't depend on SBI_HART_PRIV_VER_1_12.

Thanks.

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