All of lore.kernel.org
 help / color / mirror / Atom feed
From: Marc Zyngier <maz@kernel.org>
To: James Clark <james.clark@arm.com>
Cc: coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.linux.dev, Oliver Upton <oliver.upton@linux.dev>,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Mike Leach <mike.leach@linaro.org>,
	Leo Yan <leo.yan@linaro.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Rob Herring <robh@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 0/3] coresight: Support exclude_guest with Feat_TRF and nVHE
Date: Fri, 04 Aug 2023 20:09:20 +0100	[thread overview]
Message-ID: <86edki62vz.wl-maz@kernel.org> (raw)
In-Reply-To: <20230804101317.460697-1-james.clark@arm.com>

On Fri, 04 Aug 2023 11:13:10 +0100,
James Clark <james.clark@arm.com> wrote:
> 
> Hi,
> 
> I'm looking for help in testing this and for feedback on whether it's
> useful to anyone. Testing it requires hardware that has Feat_TRF (v8.4)
> but no TRBE. This is because TRBE usage is disabled in nVHE guests.
>
> I don't currently have any access to any hardware, and the FVP model
> can only do self hosted trace using TRBE.
> 
> Currently with nVHE you would always get trace from guests, and
> filtering out isn't possible without this patchset. In comparison, with
> VHE guests, they never generate guest trace without [1]. I think the
> existence of trace rather than lack of could suggest that this change is
> less useful than [1]. Also the restricted set of hardware that it works
> on supports that too.

It'd be nice to have some sort of feature parity, but it seems like a
vanishingly small target of users having access to an ETM sink.

> 
> Apart from compilation and checking that the exclude guest settings
> are correctly programmed on guest switch, this is untested by me.

I'll have a look at the series, but none of my HW fits in this
description (my ARMv8.4+ boxes don't have any form of tracing).

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: James Clark <james.clark@arm.com>
Cc: coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.linux.dev, Oliver Upton <oliver.upton@linux.dev>,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Mike Leach <mike.leach@linaro.org>,
	Leo Yan <leo.yan@linaro.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Rob Herring <robh@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 0/3] coresight: Support exclude_guest with Feat_TRF and nVHE
Date: Fri, 04 Aug 2023 20:09:20 +0100	[thread overview]
Message-ID: <86edki62vz.wl-maz@kernel.org> (raw)
In-Reply-To: <20230804101317.460697-1-james.clark@arm.com>

On Fri, 04 Aug 2023 11:13:10 +0100,
James Clark <james.clark@arm.com> wrote:
> 
> Hi,
> 
> I'm looking for help in testing this and for feedback on whether it's
> useful to anyone. Testing it requires hardware that has Feat_TRF (v8.4)
> but no TRBE. This is because TRBE usage is disabled in nVHE guests.
>
> I don't currently have any access to any hardware, and the FVP model
> can only do self hosted trace using TRBE.
> 
> Currently with nVHE you would always get trace from guests, and
> filtering out isn't possible without this patchset. In comparison, with
> VHE guests, they never generate guest trace without [1]. I think the
> existence of trace rather than lack of could suggest that this change is
> less useful than [1]. Also the restricted set of hardware that it works
> on supports that too.

It'd be nice to have some sort of feature parity, but it seems like a
vanishingly small target of users having access to an ETM sink.

> 
> Apart from compilation and checking that the exclude guest settings
> are correctly programmed on guest switch, this is untested by me.

I'll have a look at the series, but none of my HW fits in this
description (my ARMv8.4+ boxes don't have any form of tracing).

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2023-08-04 19:09 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-04 10:13 [RFC PATCH 0/3] coresight: Support exclude_guest with Feat_TRF and nVHE James Clark
2023-08-04 10:13 ` James Clark
2023-08-04 10:13 ` [RFC PATCH 1/3] arm64: KVM: Add support for exclude_guest and exclude_host for ETM James Clark
2023-08-04 10:13   ` James Clark
2023-08-08  8:27   ` Marc Zyngier
2023-08-08  8:27     ` Marc Zyngier
2023-08-09 14:17     ` James Clark
2023-08-09 14:17       ` James Clark
2023-08-04 10:13 ` [RFC PATCH 2/3] arm64: KVM: Support exclude_guest for Coresight trace in nVHE James Clark
2023-08-04 10:13   ` James Clark
2023-08-08 11:04   ` Marc Zyngier
2023-08-08 11:04     ` Marc Zyngier
2023-08-09 14:20     ` James Clark
2023-08-09 14:20       ` James Clark
2023-08-04 10:13 ` [RFC PATCH 3/3] coresight: Support exclude_guest with Feat_TRF and nVHE James Clark
2023-08-04 10:13   ` James Clark
2023-08-04 19:09 ` Marc Zyngier [this message]
2023-08-04 19:09   ` [RFC PATCH 0/3] " Marc Zyngier
2023-08-05 10:28   ` Suzuki K Poulose
2023-08-05 10:28     ` Suzuki K Poulose
2023-08-08 11:06     ` Marc Zyngier
2023-08-08 11:06       ` Marc Zyngier
2023-08-05 10:14 ` Suzuki K Poulose
2023-08-05 10:14   ` Suzuki K Poulose

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=86edki62vz.wl-maz@kernel.org \
    --to=maz@kernel.org \
    --cc=alexander.shishkin@linux.intel.com \
    --cc=anshuman.khandual@arm.com \
    --cc=catalin.marinas@arm.com \
    --cc=coresight@lists.linaro.org \
    --cc=james.clark@arm.com \
    --cc=james.morse@arm.com \
    --cc=kvmarm@lists.linux.dev \
    --cc=leo.yan@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mike.leach@linaro.org \
    --cc=oliver.upton@linux.dev \
    --cc=robh@kernel.org \
    --cc=suzuki.poulose@arm.com \
    --cc=will@kernel.org \
    --cc=yuzenghui@huawei.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.