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Subject: Re: [PATCH v4 05/19] kvm: arm64: Disable guest access to trace filter
 controls
To:     Marc Zyngier <maz@kernel.org>
Cc:     linux-kernel@vger.kernel.org, mathieu.poirier@linaro.org,
        mike.leach@linaro.org, anshuman.khandual@arm.com,
        leo.yan@linaro.org, Will Deacon <will@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        linux-arm-kernel@lists.infradead.org
References: <20210225193543.2920532-1-suzuki.poulose@arm.com>
 <20210225193543.2920532-6-suzuki.poulose@arm.com>
 <cbe4ef17-38f9-c555-d838-796be752d4a3@arm.com>
 <8cb6eced29d9749d88af6f6d2f649019@kernel.org>
From:   Suzuki K Poulose <suzuki.poulose@arm.com>
Message-ID: <59682421-a985-ec71-3ade-09c17aa58b5a@arm.com>
Date:   Tue, 23 Mar 2021 09:44:41 +0000
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On 23/03/2021 09:16, Marc Zyngier wrote:
> Hi Suzuki,
> 
> On 2021-03-22 22:24, Suzuki K Poulose wrote:
>> Hi Marc,
>>
>> On 25/02/2021 19:35, Suzuki K Poulose wrote:
>>> Disable guest access to the Trace Filter control registers.
>>> We do not advertise the Trace filter feature to the guest
>>> (ID_AA64DFR0_EL1: TRACE_FILT is cleared) already, but the guest
>>> can still access the TRFCR_EL1 unless we trap it.
>>>
>>> This will also make sure that the guest cannot fiddle with
>>> the filtering controls set by a nvhe host.
>>>
>>> Cc: Marc Zyngier <maz@kernel.org>
>>> Cc: Will Deacon <will@kernel.org>
>>> Cc: Mark Rutland <mark.rutland@arm.com>
>>> Cc: Catalin Marinas <catalin.marinas@arm.com>
>>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>>
>> We have already have the v8.4 self hosted tracing support in 5.12-rcX.
>> Do you think you can pick this up for this 5.12 ?
> 
> Sure, no problem. Shall I pick patch #3 at the same time?

Yes please.

Thanks !
Suzuki