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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59F8DEE3F06 for ; Tue, 12 Sep 2023 17:37:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236797AbjILRhz (ORCPT ); Tue, 12 Sep 2023 13:37:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53388 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236015AbjILRhy (ORCPT ); Tue, 12 Sep 2023 13:37:54 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 06D4B10E9 for ; Tue, 12 Sep 2023 10:37:50 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 024A6C15; Tue, 12 Sep 2023 10:38:27 -0700 (PDT) Received: from [192.168.4.86] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 918333F738; Tue, 12 Sep 2023 10:37:47 -0700 (PDT) Message-ID: Date: Tue, 12 Sep 2023 18:37:42 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.15.0 Subject: Re: [PATCH v2 2/2] coresight: Allow guests to be traced when FEAT_TRF and VHE are present To: James Clark , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, broonie@kernel.org, Marc Zyngier Cc: maz@kernel.org, Catalin Marinas , Will Deacon , Mike Leach , Leo Yan , Alexander Shishkin , James Morse , Kristina Martsenko , Anshuman Khandual , Rob Herring , Jintack Lim , Joey Gouly , linux-kernel@vger.kernel.org References: <20230904140705.1620708-1-james.clark@arm.com> <20230904140705.1620708-3-james.clark@arm.com> From: Suzuki K Poulose In-Reply-To: <20230904140705.1620708-3-james.clark@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi James On 04/09/2023 15:07, James Clark wrote: > Currently the userspace and kernel filters for guests are never set, so > no trace will be generated for them. Add it by writing to the guest > filters when exclude_guest isn't set. By writing either E1TRE or E0TRE, > filtering on either guest kernel or guest userspace is also supported. > > Since TRFCR_EL1 access is trapped, this can't be modified by the guest. > > This change also brings exclude_host support which is difficult to add > as a separate commit without excess churn and resulting in no trace at > all. > > Testing > ======= > > The addresses were counted with the following: > > $ perf report -D | grep -Eo 'EL2|EL1|EL0' | sort | uniq -c > > Guest kernel only: > > $ perf record -e cs_etm//Gk -a -- true > 535 EL1 > 1 EL2 > > Guest user only (0 addresses expected because the guest OS hasn't reached > userspace yet): > > $ perf record -e cs_etm//Gu -a -- true > > Host kernel only: > > $ perf record -e cs_etm//Hk -a -- true > 3501 EL2 > > Host userspace only: > > $ perf record -e cs_etm//Hu -a -- true > 408 EL0 > 1 EL2 > > Reviewed-by: Mark Brown (sysreg) > Signed-off-by: James Clark > --- > arch/arm64/tools/sysreg | 4 ++ > .../coresight/coresight-etm4x-core.c | 51 ++++++++++++++++--- > drivers/hwtracing/coresight/coresight-etm4x.h | 2 +- > drivers/hwtracing/coresight/coresight-priv.h | 3 ++ > 4 files changed, 53 insertions(+), 7 deletions(-) > > diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg > index 6ca7db69d6c9..cae9139b6c05 100644 > --- a/arch/arm64/tools/sysreg > +++ b/arch/arm64/tools/sysreg > @@ -2531,3 +2531,7 @@ EndSysreg > Sysreg TRFCR_EL2 3 4 1 2 1 > Fields TRFCR_EL2 > EndSysreg > + > +Sysreg TRFCR_EL12 3 5 1 2 1 > +Fields TRFCR_ELx > +EndSysreg > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c > index 77b0271ce6eb..6c16a14d6fbe 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c > @@ -274,6 +274,18 @@ static void etm4x_prohibit_trace(struct etmv4_drvdata *drvdata) > cpu_prohibit_trace(); > } > > +static u64 etm4x_get_kern_user_filter(struct etmv4_drvdata *drvdata) > +{ > + u64 trfcr = drvdata->trfcr; > + > + if (drvdata->config.mode & ETM_MODE_EXCL_KERN) > + trfcr &= ~TRFCR_ELx_ExTRE; > + if (drvdata->config.mode & ETM_MODE_EXCL_USER) > + trfcr &= ~TRFCR_ELx_E0TRE; > + > + return trfcr; > +} > + > /* > * etm4x_allow_trace - Allow CPU tracing in the respective ELs, > * as configured by the drvdata->config.mode for the current > @@ -286,18 +298,39 @@ static void etm4x_prohibit_trace(struct etmv4_drvdata *drvdata) > */ > static void etm4x_allow_trace(struct etmv4_drvdata *drvdata) > { > - u64 trfcr = drvdata->trfcr; > + u64 trfcr; > > /* If the CPU doesn't support FEAT_TRF, nothing to do */ > - if (!trfcr) > + if (!drvdata->trfcr) > return; > > - if (drvdata->config.mode & ETM_MODE_EXCL_KERN) > - trfcr &= ~TRFCR_ELx_ExTRE; > - if (drvdata->config.mode & ETM_MODE_EXCL_USER) > - trfcr &= ~TRFCR_ELx_E0TRE; > + if (drvdata->config.mode & ETM_MODE_EXCL_HOST) > + trfcr = drvdata->trfcr & ~(TRFCR_ELx_ExTRE | TRFCR_ELx_E0TRE); > + else > + trfcr = etm4x_get_kern_user_filter(drvdata); > > write_trfcr(trfcr); > + > + /* > + * Filters for EL1 and EL0 (when running a guest) are stored in > + * TRFCR_EL1 so write it there for VHE. For nVHE, the filters in > + * have to be re-applied when switching to the guest instead. > + */ > + if (!is_kernel_in_hyp_mode()) > + return; > + > + if (drvdata->config.mode & ETM_MODE_EXCL_GUEST) > + trfcr = drvdata->trfcr & ~(TRFCR_ELx_ExTRE | TRFCR_ELx_E0TRE); > + else > + trfcr = etm4x_get_kern_user_filter(drvdata); > + > + /* > + * TRFCR_EL1 doesn't have CX and TRFCR_EL1.TS has no effect when TS is > + * set in EL2 so mask them out. > + */ > + trfcr &= ~(TRFCR_ELx_TS_MASK | TRFCR_EL2_CX); > + > + write_sysreg_s(trfcr, SYS_TRFCR_EL12); While I agree with the intention of the patch, I am not sure if we should do the TRFCR_EL1 (via TRFCR_EL12) updates from CoreSight driver. It might be much better to do it from the KVM for both VHE and nVHE. Marc What are your thoughts on this ? Suzuki > } > > #ifdef CONFIG_ETM4X_IMPDEF_FEATURE > @@ -655,6 +688,12 @@ static int etm4_parse_event_config(struct coresight_device *csdev, > if (attr->exclude_user) > config->mode = ETM_MODE_EXCL_USER; > > + if (attr->exclude_host) > + config->mode |= ETM_MODE_EXCL_HOST; > + > + if (attr->exclude_guest) > + config->mode |= ETM_MODE_EXCL_GUEST; > + > /* Always start from the default config */ > etm4_set_default_config(config); > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h > index 20e2e4cb7614..3f170599822f 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x.h > +++ b/drivers/hwtracing/coresight/coresight-etm4x.h > @@ -841,7 +841,7 @@ enum etm_impdef_type { > * @s_ex_level: Secure ELs where tracing is supported. > */ > struct etmv4_config { > - u32 mode; > + u64 mode; > u32 pe_sel; > u32 cfg; > u32 eventctrl0; > diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h > index 767076e07970..727dd27ba800 100644 > --- a/drivers/hwtracing/coresight/coresight-priv.h > +++ b/drivers/hwtracing/coresight/coresight-priv.h > @@ -39,6 +39,9 @@ > > #define ETM_MODE_EXCL_KERN BIT(30) > #define ETM_MODE_EXCL_USER BIT(31) > +#define ETM_MODE_EXCL_HOST BIT(32) > +#define ETM_MODE_EXCL_GUEST BIT(33) > + > struct cs_pair_attribute { > struct device_attribute attr; > u32 lo_off;