From: Marc Zyngier <maz@kernel.org>
To: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, coresight@lists.linaro.org,
mathieu.poirier@linaro.org, mike.leach@linaro.org,
leo.yan@linaro.org, anshuman.khandual@arm.com,
catalin.marinas@arm.com, Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexandru Elisei <Alexandru.Elisei@arm.com>
Subject: Re: [PATCH v5 07/19] arm64: kvm: Enable access to TRBE support for host
Date: Tue, 30 Mar 2021 15:00:16 +0100 [thread overview]
Message-ID: <87ft0crbbj.wl-maz@kernel.org> (raw)
In-Reply-To: <ad570007-404b-0c42-3f8e-fe3c537716be@arm.com>
On Tue, 30 Mar 2021 14:34:23 +0100,
Suzuki K Poulose <suzuki.poulose@arm.com> wrote:
>
> On 30/03/2021 13:15, Marc Zyngier wrote:
> > On Tue, 30 Mar 2021 12:12:49 +0100,
> > Suzuki K Poulose <suzuki.poulose@arm.com> wrote:
[...]
> >> May be we could do this check at kvm_arch_vcpu_load()/put() ?
> >
> > That would extend the tracing blackout period enormously, wouldn't it?
> > I'm not sure that's the best thing to do...
>
> Sorry for not making this clear. We could check if the SPE/TRBE is
> available on this CPU (including the PMB/TRB_IDR bits and a set a flag
> in the VCPU on every kvm_arch_vcpu_load() and cleared on put.
> The actual switching code could check this flag and check if the unit
> is enabled and then do the actual save/restore as we do below.
> (We may be able to even check if unit is enabled there, need to double
> check this.)
Ah, gotcha. Yes, this seems like a reasonable thing to do. We have the
per-vcpu debug flags already, and you could piggy-back on that.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
next prev parent reply other threads:[~2021-03-30 14:00 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-23 12:06 [PATCH v5 00/19] coresight: Add support for ETE and TRBE Suzuki K Poulose
2021-03-23 12:06 ` [PATCH v5 01/19] [Queued] kvm: arm64: Hide system instruction access to Trace registers Suzuki K Poulose
2021-03-23 12:06 ` [PATCH v5 02/19] [Queued] kvm: arm64: Disable guest access to trace filter controls Suzuki K Poulose
2021-03-23 12:06 ` [PATCH v5 03/19] perf: aux: Add flags for the buffer format Suzuki K Poulose
2021-03-23 12:06 ` [PATCH v5 04/19] perf: aux: Add CoreSight PMU buffer formats Suzuki K Poulose
2021-03-29 16:56 ` Mathieu Poirier
2021-04-19 7:46 ` Peter Zijlstra
2021-03-23 12:06 ` [PATCH v5 05/19] arm64: Add support for trace synchronization barrier Suzuki K Poulose
2021-03-23 18:21 ` Catalin Marinas
2021-03-24 9:39 ` Suzuki K Poulose
2021-03-24 13:49 ` Marc Zyngier
2021-03-24 15:51 ` Suzuki K Poulose
2021-03-24 16:16 ` Marc Zyngier
2021-03-24 16:25 ` Suzuki K Poulose
2021-03-24 16:30 ` Marc Zyngier
2021-03-24 17:06 ` Suzuki K Poulose
2021-03-24 17:19 ` Catalin Marinas
2021-03-24 17:40 ` Marc Zyngier
2021-03-26 16:31 ` Mathieu Poirier
2021-03-23 12:06 ` [PATCH v5 06/19] arm64: Add TRBE definitions Suzuki K Poulose
2021-03-23 12:06 ` [PATCH v5 07/19] arm64: kvm: Enable access to TRBE support for host Suzuki K Poulose
2021-03-26 16:55 ` Mathieu Poirier
2021-03-30 10:16 ` Marc Zyngier
2021-03-30 10:38 ` Suzuki K Poulose
2021-03-30 15:23 ` Mathieu Poirier
2021-03-30 15:34 ` Marc Zyngier
2021-03-30 15:35 ` Greg KH
2021-03-30 16:33 ` Mathieu Poirier
2021-03-30 16:47 ` Greg KH
2021-03-30 16:51 ` Mathieu Poirier
2021-03-30 10:12 ` Marc Zyngier
2021-03-30 11:12 ` Suzuki K Poulose
2021-03-30 12:15 ` Marc Zyngier
2021-03-30 13:34 ` Suzuki K Poulose
2021-03-30 14:00 ` Marc Zyngier [this message]
2021-03-31 15:28 ` Alexandru Elisei
2021-03-31 15:37 ` Marc Zyngier
2021-03-23 12:06 ` [PATCH v5 08/19] coresight: etm4x: Move ETM to prohibited region for disable Suzuki K Poulose
2021-03-23 12:06 ` [PATCH v5 09/19] coresight: etm-perf: Allow an event to use different sinks Suzuki K Poulose
2021-03-23 12:06 ` [PATCH v5 10/19] coresight: Do not scan for graph if none is present Suzuki K Poulose
2021-03-23 12:06 ` [PATCH v5 11/19] coresight: etm4x: Add support for PE OS lock Suzuki K Poulose
2021-03-23 12:06 ` [PATCH v5 12/19] coresight: ete: Add support for ETE tracing Suzuki K Poulose
2021-03-23 12:06 ` [PATCH v5 13/19] dts: bindings: Document device tree bindings for ETE Suzuki K Poulose
2021-03-23 22:46 ` Rob Herring
2021-03-23 12:06 ` [PATCH v5 14/19] coresight: etm-perf: Handle stale output handles Suzuki K Poulose
2021-03-23 12:06 ` [PATCH v5 15/19] coresight: core: Add support for dedicated percpu sinks Suzuki K Poulose
2021-03-23 12:06 ` [PATCH v5 16/19] coresight: sink: Add TRBE driver Suzuki K Poulose
2021-03-23 12:06 ` [PATCH v5 17/19] Documentation: coresight: trbe: Sysfs ABI description Suzuki K Poulose
2021-03-23 12:06 ` [PATCH v5 18/19] Documentation: trace: Add documentation for TRBE Suzuki K Poulose
2021-03-23 12:06 ` [PATCH v5 19/19] dts: bindings: Document device tree bindings for Arm TRBE Suzuki K Poulose
2021-03-23 16:33 ` (subset) [PATCH v5 00/19] coresight: Add support for ETE and TRBE Marc Zyngier
2021-03-23 16:34 ` Marc Zyngier
2021-03-23 17:05 ` Suzuki K Poulose
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