linux-kernel - Re: [PATCH rfcv1 7/8] iommu/arm-smmu-v3: Add arm_smmu_invs based arm_smmu_domain_inv

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] [day] [month] [year] [list]

Message-ID: <aL8kYo1cHHNg1H3N@nvidia.com>
Date: Mon, 8 Sep 2025 11:45:54 -0700
From: Nicolin Chen <nicolinc@...dia.com>
To: Jason Gunthorpe <jgg@...dia.com>
CC: <will@...nel.org>, <robin.murphy@....com>, <joro@...tes.org>,
	<jean-philippe@...aro.org>, <miko.lenczewski@....com>, <balbirs@...dia.com>,
	<peterz@...radead.org>, <smostafa@...gle.com>, <kevin.tian@...el.com>,
	<praan@...gle.com>, <zhangzekun11@...wei.com>,
	<linux-arm-kernel@...ts.infradead.org>, <iommu@...ts.linux.dev>,
	<linux-kernel@...r.kernel.org>, <patches@...ts.linux.dev>
Subject: Re: [PATCH rfcv1 7/8] iommu/arm-smmu-v3: Add arm_smmu_invs based
 arm_smmu_domain_inv_range()

On Mon, Sep 08, 2025 at 03:24:04PM -0300, Jason Gunthorpe wrote:
> On Mon, Sep 08, 2025 at 11:19:40AM -0700, Nicolin Chen wrote:
> > So, would it be better to just always take the read lock, while
> > applying the ATS condition to the writer side:
> 
> No, the whole optimization is to avoid read side locking on the fairly
> common no-ATS case.
> 
> Always taking the lock destroys that.

OK. I skimmed through the lock_acquire(). It seems to be a bit
heavier than I expected. Perhaps this is the part we wanted to
avoid.

Thanks
Nicolin