From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8D31DC5DF60 for ; Thu, 7 Nov 2019 03:47:36 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id F377B20869 for ; Thu, 7 Nov 2019 03:47:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F377B20869 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 477q9K04S6zF5x2 for ; Thu, 7 Nov 2019 14:47:33 +1100 (AEDT) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 477q731DRmzF5wR for ; Thu, 7 Nov 2019 14:45:35 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: by ozlabs.org (Postfix) id 477q715m7yz9sPT; Thu, 7 Nov 2019 14:45:33 +1100 (AEDT) Received: by ozlabs.org (Postfix, from userid 1034) id 477q7157kFz9sPk; Thu, 7 Nov 2019 14:45:33 +1100 (AEDT) X-powerpc-patch-notification: thanks X-powerpc-patch-commit: c790c3d2b0ec5979d83451d0688d1cd07e23d8ba In-Reply-To: <20190520105520.22274-1-mpe@ellerman.id.au> To: Michael Ellerman , linuxppc-dev@ozlabs.org From: Michael Ellerman Subject: Re: [PATCH] selftests/powerpc: Add a test of spectre_v2 mitigations Message-Id: <477q7157kFz9sPk@ozlabs.org> Date: Thu, 7 Nov 2019 14:45:33 +1100 (AEDT) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: naveen.n.rao@linux.ibm.com, anton@samba.org, npiggin@gmail.com, david@gibson.dropbear.id.au Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, 2019-05-20 at 10:55:20 UTC, Michael Ellerman wrote: > This test uses the PMU to count branch prediction hits/misses for a > known loop, and compare the result to the reported spectre v2 > mitigation. > > This gives us a way of sanity checking that the reported mitigation is > actually in effect. > > Sample output for some cases, eg: > > Power9: > sysfs reports: 'Vulnerable' > PM_BR_PRED_CCACHE: result 368 running/enabled 5792777124 > PM_BR_MPRED_CCACHE: result 319 running/enabled 5792775546 > PM_BR_PRED_PCACHE: result 2147483281 running/enabled 5792773128 > PM_BR_MPRED_PCACHE: result 213604201 running/enabled 5792771640 > Miss percent 9 % > OK - Measured branch prediction rates match reported spectre v2 mitigation. ... > > Signed-off-by: Michael Ellerman Applied to powerpc next. https://git.kernel.org/powerpc/c/c790c3d2b0ec5979d83451d0688d1cd07e23d8ba cheers