linux-kernel - Re: [PATCH v3 13/17] x86/mce: Unify AMD DFR handler with MCA Polling

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250507092042.GLaBsl6pczL50Qdr3e@fat_crate.local>
Date: Wed, 7 May 2025 11:20:42 +0200
From: Borislav Petkov <bp@...en8.de>
To: Yazen Ghannam <yazen.ghannam@....com>
Cc: x86@...nel.org, Tony Luck <tony.luck@...el.com>,
	linux-kernel@...r.kernel.org, linux-edac@...r.kernel.org,
	Smita.KoralahalliChannabasappa@....com,
	Qiuxu Zhuo <qiuxu.zhuo@...el.com>
Subject: Re: [PATCH v3 13/17] x86/mce: Unify AMD DFR handler with MCA Polling

On Tue, Apr 15, 2025 at 02:55:08PM +0000, Yazen Ghannam wrote:
> +static bool smca_should_log_poll_error(enum mcp_flags flags, struct mce_hw_err *err)
> +{
> +	struct mce *m = &err->m;
> +
> +	/*
> +	 * If this is a deferred error found in MCA_STATUS, then clear
> +	 * the redundant data from the MCA_DESTAT register.
> +	 */
> +	if (m->status & MCI_STATUS_VAL) {
> +		if (m->status & MCI_STATUS_DEFERRED)
> +			mce_wrmsrq(MSR_AMD64_SMCA_MCx_DESTAT(m->bank), 0);
> +
> +		return true;
> +	}
> +
> +	/*
> +	 * If the MCA_DESTAT register has valid data, then use
> +	 * it as the status register.
> +	 */
> +	m->status = mce_rdmsrq(MSR_AMD64_SMCA_MCx_DESTAT(m->bank));
> +

Superfluous newline.

> +	if (!(m->status & MCI_STATUS_VAL))
> +		return false;
> +
> +	/*
> +	 * Gather all relevant data now and log the record before clearing
> +	 * the deferred status register. This avoids needing to go back to
> +	 * the polling function for these actions.
> +	 */
> +	mce_read_aux(err, m->bank);
> +
> +	if (m->status & MCI_STATUS_ADDRV)
> +		m->addr = mce_rdmsrq(MSR_AMD64_SMCA_MCx_DEADDR(m->bank));
> +
> +	smca_extract_err_addr(m);
> +	m->severity = mce_severity(m, NULL, NULL, false);
> +
> +	if (flags & MCP_QUEUE_LOG)
> +		mce_gen_pool_add(err);
> +	else
> +		mce_log(err);

Except you have a function which is called "should log" which also does the
logging.

And you have that same logging being done in machine_check_poll().

This code needs more designing.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette