linux-kernel - RE: [RFC] /dev/ioasid uAPI proposal

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: <MWHPR11MB1886BA2258AFD92D5249AC488C309@MWHPR11MB1886.namprd11.prod.outlook.com>
Date:   Tue, 15 Jun 2021 08:59:25 +0000
From:   "Tian, Kevin" <kevin.tian@...el.com>
To:     Jason Gunthorpe <jgg@...dia.com>
CC:     Jean-Philippe Brucker <jean-philippe@...aro.org>,
        "Alex Williamson (alex.williamson@...hat.com)" 
        <alex.williamson@...hat.com>, "Raj, Ashok" <ashok.raj@...el.com>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "Jonathan Corbet" <corbet@....net>,
        Robin Murphy <robin.murphy@....com>,
        LKML <linux-kernel@...r.kernel.org>,
        Kirti Wankhede <kwankhede@...dia.com>,
        "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
        "David Gibson" <david@...son.dropbear.id.au>,
        "Jiang, Dave" <dave.jiang@...el.com>,
        David Woodhouse <dwmw2@...radead.org>,
        Jason Wang <jasowang@...hat.com>
Subject: RE: [RFC] /dev/ioasid uAPI proposal

Hi, Jason,

> From: Jason Gunthorpe
> Sent: Thursday, June 3, 2021 9:05 PM
> 
> On Thu, Jun 03, 2021 at 06:39:30AM +0000, Tian, Kevin wrote:
> > > > Two helper functions are provided to support VFIO_ATTACH_IOASID:
> > > >
> > > > 	struct attach_info {
> > > > 		u32	ioasid;
> > > > 		// If valid, the PASID to be used physically
> > > > 		u32	pasid;
> > > > 	};
> > > > 	int ioasid_device_attach(struct ioasid_dev *dev,
> > > > 		struct attach_info info);
> > > > 	int ioasid_device_detach(struct ioasid_dev *dev, u32 ioasid);
> > >
> > > Honestly, I still prefer this to be highly explicit as this is where
> > > all device driver authors get invovled:
> > >
> > > ioasid_pci_device_attach(struct pci_device *pdev, struct ioasid_dev *dev,
> > > u32 ioasid);
> > > ioasid_pci_device_pasid_attach(struct pci_device *pdev, u32
> *physical_pasid,
> > > struct ioasid_dev *dev, u32 ioasid);
> >
> > Then better naming it as pci_device_attach_ioasid since the 1st parameter
> > is struct pci_device?
> 
> No, the leading tag indicates the API's primary subystem, in this case
> it is iommu (and if you prefer list the iommu related arguments first)
> 

I have a question on this suggestion when working on v2.

Within IOMMU fd it uses only the generic struct device pointer, which
is already saved in struct ioasid_dev at device bind time:

	struct ioasid_dev *ioasid_register_device(struct ioasid_ctx *ctx,
		struct device *device, u64 device_label);

What does this additional struct pci_device bring when it's specified in
the attach call? If we save it in attach_data, at which point will it be
used or checked? 

Can you help elaborate?

Thanks
Kevin