linux-kernel - Re: [PATCH v9 03/10] arm64/kvm: expose FEAT_MTE_TAGGED

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Message-ID: <877c11f4yk.wl-maz@kernel.org>
Date: Tue, 24 Jun 2025 18:02:27 +0100
From: Marc Zyngier <maz@...nel.org>
To: Catalin Marinas <catalin.marinas@....com>
Cc: Yeoreum Yun <yeoreum.yun@....com>,
	pcc@...gle.com,
	will@...nel.org,
	broonie@...nel.org,
	anshuman.khandual@....com,
	joey.gouly@....com,
	yury.khrustalev@....com,
	oliver.upton@...ux.dev,
	frederic@...nel.org,
	akpm@...ux-foundation.org,
	surenb@...gle.com,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-doc@...r.kernel.org
Subject: Re: [PATCH v9 03/10] arm64/kvm: expose FEAT_MTE_TAGGED_FAR feature to guest

On Tue, 24 Jun 2025 17:33:52 +0100,
Catalin Marinas <catalin.marinas@....com> wrote:
> 
> Hi Marc,
> 
> On Wed, Jun 18, 2025 at 05:43:07PM +0100, Marc Zyngier wrote:
> > In general, please use a patch title format that matches the one used
> > for the subsystem. For KVM, that'd be "KVM: arm64: Expose ..."/
> [...]
> > >  	case SYS_ID_AA64PFR2_EL1:
> > > -		/* We only expose FPMR */
> > > -		val &= ID_AA64PFR2_EL1_FPMR;
> > > +		mask = ID_AA64PFR2_EL1_FPMR;
> > > +
> > > +		if (kvm_has_mte(vcpu->kvm))
> > > +			mask |= ID_AA64PFR2_EL1_MTEFAR;
> > > +
> > > +		val &= mask;
> > 
> > I don't think there is a need for an extra variable, and you could
> > follow the pattern established in this file by writing this as:
> > 
> > 	val &= (ID_AA64PFR2_EL1_FPMR |
> > 		(kvm_has_mte(vcpu->kvm) ? ID_AA64PFR2_EL1_MTEFAR : 0));
> > 
> > Not a big deal though.
> 
> I can make the changes locally. Are you ok with the patch otherwise?

Yup, that'd fine by me. With this fixed:

Acked-by: Marc Zyngier <maz@...nel.org>

	M.

-- 
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