linux-kernel - RE: [PATCH 6/6] iommu/vt-d: Add domain_alloc

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: <DS0PR11MB75290582F647AB035FB3E301C3F9A@DS0PR11MB7529.namprd11.prod.outlook.com>
Date:   Wed, 20 Sep 2023 13:15:10 +0000
From:   "Liu, Yi L" <yi.l.liu@...el.com>
To:     "Yang, Weijiang" <weijiang.yang@...el.com>,
        "joro@...tes.org" <joro@...tes.org>,
        "alex.williamson@...hat.com" <alex.williamson@...hat.com>,
        "jgg@...dia.com" <jgg@...dia.com>,
        "Tian, Kevin" <kevin.tian@...el.com>,
        "robin.murphy@....com" <robin.murphy@....com>,
        "baolu.lu@...ux.intel.com" <baolu.lu@...ux.intel.com>
CC:     "cohuck@...hat.com" <cohuck@...hat.com>,
        "eric.auger@...hat.com" <eric.auger@...hat.com>,
        "nicolinc@...dia.com" <nicolinc@...dia.com>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "mjrosato@...ux.ibm.com" <mjrosato@...ux.ibm.com>,
        "chao.p.peng@...ux.intel.com" <chao.p.peng@...ux.intel.com>,
        "yi.y.sun@...ux.intel.com" <yi.y.sun@...ux.intel.com>,
        "peterx@...hat.com" <peterx@...hat.com>,
        "jasowang@...hat.com" <jasowang@...hat.com>,
        "shameerali.kolothum.thodi@...wei.com" 
        <shameerali.kolothum.thodi@...wei.com>,
        "lulu@...hat.com" <lulu@...hat.com>,
        "suravee.suthikulpanit@....com" <suravee.suthikulpanit@....com>,
        "iommu@...ts.linux.dev" <iommu@...ts.linux.dev>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-kselftest@...r.kernel.org" <linux-kselftest@...r.kernel.org>,
        "Duan, Zhenzhong" <zhenzhong.duan@...el.com>,
        "Martins, Joao" <joao.m.martins@...cle.com>
Subject: RE: [PATCH 6/6] iommu/vt-d: Add domain_alloc_user op

> From: Yang, Weijiang <weijiang.yang@...el.com>
> Sent: Wednesday, September 20, 2023 1:41 PM
> On 9/19/2023 5:25 PM, Yi Liu wrote:
> > This adds the domain_alloc_user op implementation. It supports allocating
> > domains to be used as parent under nested translation.
> >
> > Signed-off-by: Yi Liu <yi.l.liu@...el.com>
> > ---
> >   drivers/iommu/intel/iommu.c | 20 ++++++++++++++++++++
> >   1 file changed, 20 insertions(+)
> >
> > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> > index 5db283c17e0d..491bcde1ff96 100644
> > --- a/drivers/iommu/intel/iommu.c
> > +++ b/drivers/iommu/intel/iommu.c
> > @@ -4074,6 +4074,25 @@ static struct iommu_domain
> *intel_iommu_domain_alloc(unsigned type)
> >   	return NULL;
> >   }
> >
> > +static struct iommu_domain *
> > +intel_iommu_domain_alloc_user(struct device *dev, u32 flags)
> > +{
> > +	struct iommu_domain *domain;
> > +	struct intel_iommu *iommu;
> > +
> > +	iommu = device_to_iommu(dev, NULL, NULL);
> > +	if (!iommu)
> > +		return ERR_PTR(-ENODEV);
> > +
> > +	if ((flags & IOMMU_HWPT_ALLOC_NEST_PARENT) && !ecap_nest(iommu-
> >ecap))
> > +		return ERR_PTR(-EOPNOTSUPP);
> 
> The outer caller has checked (flags & IOMMU_HWPT_ALLOC_NEST_PARENT) before it
> comes here.
> If this callback is dedicated for nested domain allocation, then you may omit the
> condition here.

This check is different. It aims to fail the call if iommu hw does not support nested.
I just realized that it may need to check if scalable mode is enabled. This should
be more accurate.

Regards,
Yi Liu