linux-kernel - Re: [PATCH v8 07/10] iommufd: Fault-capable hwpt attach/detach/replace

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 for Android: free password hash cracker in your pocket

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

Message-ID: <CABQgh9E4XE6G7cK6_77ZsXgvfdOfa4rXXU2VUVxkqRd01tG+Rw@mail.gmail.com>
Date: Wed, 23 Oct 2024 18:22:42 +0800
From: Zhangfei Gao <zhangfei.gao@...aro.org>
To: Jason Gunthorpe <jgg@...dia.com>
Cc: Lu Baolu <baolu.lu@...ux.intel.com>, Kevin Tian <kevin.tian@...el.com>, 
	Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>, 
	Jean-Philippe Brucker <jean-philippe@...aro.org>, Nicolin Chen <nicolinc@...dia.com>, 
	Yi Liu <yi.l.liu@...el.com>, Jacob Pan <jacob.jun.pan@...ux.intel.com>, 
	Joel Granados <j.granados@...sung.com>, iommu@...ts.linux.dev, 
	virtualization@...ts.linux-foundation.org, linux-kernel@...r.kernel.org, 
	Shameerali Kolothum Thodi <shameerali.kolothum.thodi@...wei.com>
Subject: Re: [PATCH v8 07/10] iommufd: Fault-capable hwpt attach/detach/replace

On Tue, 22 Oct 2024 at 22:53, Jason Gunthorpe <jgg@...dia.com> wrote:
>
> On Tue, Oct 22, 2024 at 10:30:10PM +0800, Zhangfei Gao wrote:
> > On Fri, 18 Oct 2024 at 21:53, Jason Gunthorpe <jgg@...dia.com> wrote:
> > >
> > > On Wed, Oct 16, 2024 at 12:25:03PM -0300, Jason Gunthorpe wrote:
> > > > > > smmu-v3 needs some more fixing to move that
> > > > > > arm_smmu_master_enable_sva() logic into domain attachment.
> > > > >
> > > > > Will think about this, Thanks Jason
> > > >
> > > > Can you test it if a patch is made?
> > >
> > > Here it is:
> > >
> > > https://github.com/jgunthorpe/linux/commits/smmuv3_nesting/
> > >
> > > fa1528253d2210 iommu: Remove IOMMU_DEV_FEAT_SVA
> > > 5675560a272cf5 iommu/vt-d: Check if SVA is supported when attaching the SVA domain
> > > 94bc2b9525b508 iommu/arm-smmu-v3: Put iopf enablement in the domain attach path
> > >
> > > Let me know..
> >
> > With these patches, do we still need ops->user_pasid_table?
>
> It makes no change - you need user_pasid_table to make
> IOMMU_DOMAIN_NESTED work.
>
> If you aren't using IOMMU_DOMAIN_NESTED you shouldn't need it.

OK, I misunderstood.

Then with user_pasid_table=1
both with these patches and without patches, user page fault is OK.

>
> > if (fault->prm.flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID) {
> >                 attach_handle = iommu_attach_handle_get(dev->iommu_group,
> >                                 fault->prm.pasid, 0);
> >
> > // is attach_handle expected effect value here?
> >                 if (IS_ERR(attach_handle)) {
> >                         const struct iommu_ops *ops = dev_iommu_ops(dev);
> >
> >                         if (!ops->user_pasid_table)
> >                                 return NULL;
> >                         /*
> >                          * The iommu driver for this device supports user-
> >                          * managed PASID table. Therefore page faults for
> >                          * any PASID should go through the NESTING domain
> >                          * attached to the device RID.
> >                          */
> >                         attach_handle = iommu_attach_handle_get(
> >                                         dev->iommu_group, IOMMU_NO_PASID,
> >                                         IOMMU_DOMAIN_NESTED);
> >
> > Now I still need set ops->user_pasid_table, since attach_handle can not
> > return from the first iommu_attach_handle_get with fault->prm.pasid = 1,
> > but the second iommu_attach_handle_get with  IOMMU_NO_PASID,
> > suppose it is not expected?
>
> The second handle_get will always fail unless you are using
> IOMMU_DOMAIN_NESTED in userspace with iommufd.
>
> What testing are you doing exactly?

I am testing vsva based on Nico's iommufd_viommu_p2-v3 branch,
which requires IOMMU_DOMAIN_NESTED in user space with iommufd.

About the three patches
1. Tested host sva, OK
2. Simply tested vsva on guests, OK, will do more tests.

Thanks