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Date:   Tue, 23 Mar 2021 09:16:59 +0000
From:   Marc Zyngier <maz@kernel.org>
To:     Suzuki K Poulose <suzuki.poulose@arm.com>
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
Subject: Re: [PATCH v4 05/19] kvm: arm64: Disable guest access to trace filter
 controls
In-Reply-To: <cbe4ef17-38f9-c555-d838-796be752d4a3@arm.com>
References: <20210225193543.2920532-1-suzuki.poulose@arm.com>
 <20210225193543.2920532-6-suzuki.poulose@arm.com>
 <cbe4ef17-38f9-c555-d838-796be752d4a3@arm.com>
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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?

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...