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From: Ingo Molnar <mingo@kernel.org>
To: Kim Phillips <kim.phillips@amd.com>
Cc: bp@alien8.de, x86@kernel.org, peterz@infradead.org, bp@suse.de,
	bpf@vger.kernel.org, jpoimboe@redhat.com,
	andrew.cooper3@citrix.com, linux-kernel@vger.kernel.org,
	thomas.lendacky@amd.com
Subject: Re: [PATCH v2] x86/bugs: Enable STIBP for IBPB mitigated RetBleed
Date: Sat, 6 Aug 2022 21:00:50 +0200	[thread overview]
Message-ID: <Yu66YlFzd4VRZq6/@gmail.com> (raw)
In-Reply-To: <20220805215009.498407-1-kim.phillips@amd.com>


* Kim Phillips <kim.phillips@amd.com> wrote:

>  			Speculative Code Execution with Return Instructions)
>  			vulnerability.
>  
> +			AMD-based unret and ibpb mitigations alone do not stop
> +			sibling threads influencing the predictions of other sibling
> +			threads.  For that reason, we use STIBP on processors
> +			that support it, and mitigate SMT on processors that don't.

>  	 * retbleed_select_mitigation(); specifically the STIBP selection is
> -	 * forced for UNRET.
> +	 * forced for UNRET or IBPB.

Nit: could you please capitalize the acronyms & instruction names 
consistently? Human eyesight is case sensitive.

Ie. it should be UNRET and IBPB everywhere.

Thanks,

	Ingo

  reply	other threads:[~2022-08-06 19:01 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-04 19:22 [PATCH] x86/bugs: Enable STIBP for IBPB mitigated RetBleed Kim Phillips
2022-08-05 14:42 ` Borislav Petkov
2022-08-05 17:04   ` Kim Phillips
2022-08-05 17:55     ` Borislav Petkov
2022-08-05 21:50       ` [PATCH v2] " Kim Phillips
2022-08-06 19:00         ` Ingo Molnar [this message]
2022-08-08 14:17           ` [PATCH v3] " Kim Phillips
2022-08-08 14:23             ` Greg KH
2022-08-08 14:32               ` [PATCH v4] " Kim Phillips
2022-08-08 18:10 ` [tip: x86/urgent] x86/bugs: Enable STIBP for IBPB mitigated RETBleed tip-bot2 for Kim Phillips

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