linux-kernel - Re: [PATCH v4 05/19] kvm: arm64: Disable guest access to trace filter controls

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Message-ID: <8cb6eced29d9749d88af6f6d2f649019@kernel.org>
Date:   Tue, 23 Mar 2021 09:16:59 +0000
From:   Marc Zyngier <maz@...nel.org>
To:     Suzuki K Poulose <suzuki.poulose@....com>
Cc:     linux-kernel@...r.kernel.org, mathieu.poirier@...aro.org,
        mike.leach@...aro.org, anshuman.khandual@....com,
        leo.yan@...aro.org, Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v4 05/19] kvm: arm64: Disable guest access to trace filter
 controls

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@...nel.org>
>> Cc: Will Deacon <will@...nel.org>
>> Cc: Mark Rutland <mark.rutland@....com>
>> Cc: Catalin Marinas <catalin.marinas@....com>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@....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...