linux-kernel - Re: [PATCH v2 01/10] iommu/arm-smmu-v3: Store IOTLB cache tags in struct arm_smmu_attach

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20260127150848.GG1134360@nvidia.com>
Date: Tue, 27 Jan 2026 11:08:48 -0400
From: Jason Gunthorpe <jgg@...dia.com>
To: Nicolin Chen <nicolinc@...dia.com>
Cc: will@...nel.org, robin.murphy@....com, joro@...tes.org, jpb@...nel.org,
	praan@...gle.com, miko.lenczewski@....com,
	linux-arm-kernel@...ts.infradead.org, iommu@...ts.linux.dev,
	linux-kernel@...r.kernel.org, patches@...ts.linux.dev
Subject: Re: [PATCH v2 01/10] iommu/arm-smmu-v3: Store IOTLB cache tags in
 struct arm_smmu_attach_state

On Mon, Jan 26, 2026 at 07:23:58PM -0800, Nicolin Chen wrote:
> On Mon, Jan 26, 2026 at 04:44:43PM -0400, Jason Gunthorpe wrote:
> > On Wed, Jan 21, 2026 at 05:24:19PM -0800, Nicolin Chen wrote:
> > > +int arm_smmu_domain_get_iotlb_tag(struct arm_smmu_domain *smmu_domain,
> > > +				  struct arm_smmu_device *smmu,
> > > +				  struct arm_smmu_inv *tag)
> > > +{
> > > +	/* Decide the type of the iotlb cache tag */
> > > +	switch (smmu_domain->stage) {
> > > +	case ARM_SMMU_DOMAIN_SVA:
> > > +	case ARM_SMMU_DOMAIN_S1:
> > > +		tag->type = INV_TYPE_S1_ASID;
> > > +		break;
> > > +	case ARM_SMMU_DOMAIN_S2:
> > > +		tag->type = INV_TYPE_S2_VMID;
> > > +		break;
> > > +	default:
> > > +		return -EINVAL;
> > > +	}
> > > +
> > > +	tag->smmu = smmu;
> > > +
> > > +	if (tag->type == INV_TYPE_S1_ASID)
> > > +		tag->id = smmu_domain->cd.asid;
> > > +	else
> > > +		tag->id = smmu_domain->s2_cfg.vmid;
> > 
> > Would be tidier to move these up into the case
> 
> This will act as a fake allocation path in PATCh-3 and eventually
> get replaced with a real allocation piece in PATCH-4. So, I wrote
> like this in a transitory manner.

I'd still write it in the nice way, you can remove the lines later
when you add the allocation logic.

Jason