Re: [PATCH 02/13] KVM: arm64: Clarify ESR_ELx_ERET_ISS_ERET*

From: Marc Zyngier <maz@kernel.org>
To: Joey Gouly <joey.gouly@arm.com>
Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Zenghui Yu <yuzenghui@huawei.com>, Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>
Subject: Re: [PATCH 02/13] KVM: arm64: Clarify ESR_ELx_ERET_ISS_ERET*
Date: Tue, 20 Feb 2024 13:41:15 +0000	[thread overview]
Message-ID: <86zfvv2qys.wl-maz@kernel.org> (raw)
In-Reply-To: <20240220132350.GB8575@e124191.cambridge.arm.com>

On Tue, 20 Feb 2024 13:23:50 +0000,
Joey Gouly <joey.gouly@arm.com> wrote:
> 
> On Tue, Feb 20, 2024 at 12:29:30PM +0000, Marc Zyngier wrote:
> > On Tue, 20 Feb 2024 11:31:27 +0000,
> > Joey Gouly <joey.gouly@arm.com> wrote:
> > > 
> > > If this part is confusing due to the name, maybe introduce a function in esr.h
> > > esr_is_pac_eret() (name pending bikeshedding)?
> > 
> > That's indeed a better option. Now for the bikeshed aspect:
> > 
> > - esr_iss_is_eretax(): check for ESR_ELx_ERET_ISS_ERET being set
> > 
> > - esr_iss_is_eretab(): check for ESR_ELx_ERET_ISS_ERETA being set
> > 
> > Thoughts?
> > 
> 
> I was trying to avoid the ERETA* confusion by suggesting 'pac_eret', but if I
> were to pick between your options I'd pick esr_iss_is_eretax().

It's not an either/or situation. We actually need both:

- esr_iss_is_eretax() being true tells you that you need to
  authenticate the ERET

- esr_iss_is_eretab() tells you that you need to use the A or B key

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.