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Subject: Re: [PATCH v7 9/10] KVM: arm64: docs: document KVM support of pointer
 authentication
To:     Dave Martin <Dave.Martin@arm.com>,
        Kristina Martsenko <kristina.martsenko@arm.com>
Cc:     linux-arm-kernel@lists.infradead.org,
        Marc Zyngier <marc.zyngier@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        kvmarm@lists.cs.columbia.edu,
        Ramana Radhakrishnan <ramana.radhakrishnan@arm.com>,
        linux-kernel@vger.kernel.org
References: <1552984243-7689-1-git-send-email-amit.kachhap@arm.com>
 <1552984243-7689-10-git-send-email-amit.kachhap@arm.com>
 <23e4a9d4-e9e1-2c1f-32ce-e7fd96080437@arm.com>
 <20190327104428.GV3567@e103592.cambridge.arm.com>
From:   Amit Daniel Kachhap <amit.kachhap@arm.com>
Message-ID: <bdd480a4-44b3-7ddf-44f5-5b55e6251ced@arm.com>
Date:   Wed, 27 Mar 2019 17:19:28 +0530
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Hi,

On 3/27/19 4:14 PM, Dave Martin wrote:
> On Mon, Mar 25, 2019 at 08:05:49PM +0000, Kristina Martsenko wrote:
>> On 19/03/2019 08:30, Amit Daniel Kachhap wrote:
>>> This adds sections for KVM API extension for pointer authentication.
>>> A brief description about usage of pointer authentication for KVM guests
>>> is added in the arm64 documentations.
>>>
>>> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
>>> Cc: Mark Rutland <mark.rutland@arm.com>
>>> Cc: Christoffer Dall <christoffer.dall@arm.com>
>>> Cc: Marc Zyngier <marc.zyngier@arm.com>
>>> Cc: kvmarm@lists.cs.columbia.edu
>>
>> I think it makes sense to also update the Kconfig symbol description for
>> CONFIG_ARM64_PTR_AUTH, since it currently only mentions userspace
>> support, but now the option also enables KVM guest support.
>>
>> It's also worth mentioning that CONFIG_ARM64_VHE=y is required for guest
>> support.
> 
> Is it worth making this dependency explicit in Kconfig?
Currently there is discrepancy that userspace supports ptrauth in both 
nVHE/VHE mode and KVM guest only in VHE mode. I suppose adding explicit 
dependency flag here makes both of them similar.

Thanks,
Amit D
> 
> For SVE, I have
> 
> config ARM64_SVE
> 	depends on !KVM || ARM64_VHE
> 
> to implement this.
> 
> Cheers
> ---Dave
>