linux-kernel - Re: [PATCH v6 3/4] iommufd: Add IOMMU_GET_HW

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]

Date:   Wed, 9 Aug 2023 13:16:36 -0300
From:   Jason Gunthorpe <jgg@...dia.com>
To:     Baolu Lu <baolu.lu@...ux.intel.com>
Cc:     Yi Liu <yi.l.liu@...el.com>, joro@...tes.org,
        alex.williamson@...hat.com, kevin.tian@...el.com,
        robin.murphy@....com, cohuck@...hat.com, eric.auger@...hat.com,
        nicolinc@...dia.com, kvm@...r.kernel.org, mjrosato@...ux.ibm.com,
        chao.p.peng@...ux.intel.com, yi.y.sun@...ux.intel.com,
        peterx@...hat.com, jasowang@...hat.com,
        shameerali.kolothum.thodi@...wei.com, lulu@...hat.com,
        suravee.suthikulpanit@....com, iommu@...ts.linux.dev,
        linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org,
        zhenzhong.duan@...el.com
Subject: Re: [PATCH v6 3/4] iommufd: Add IOMMU_GET_HW_INFO

On Wed, Aug 09, 2023 at 06:16:19PM +0800, Baolu Lu wrote:
> On 2023/8/8 23:35, Yi Liu wrote:
> > +static int iommufd_fill_hw_info(struct device *dev, void __user *user_ptr,
> > +				unsigned int *length, u32 *type)
> > +{
> > +	const struct iommu_ops *ops;
> > +	unsigned int data_len;
> > +	void *data;
> > +	int rc = 0;
> > +
> > +	ops = dev_iommu_ops(dev);
> > +	if (!ops->hw_info) {
> > +		*length = 0;
> > +		*type = IOMMU_HW_INFO_TYPE_NONE;
> > +		return 0;
> > +	}
> > +
> > +	data = ops->hw_info(dev, &data_len, type);
> > +	if (IS_ERR(data))
> > +		return PTR_ERR(data);
> > +
> > +	/*
> > +	 * drivers that have hw_info callback should have a unique
> > +	 * iommu_hw_info_type.
> > +	 */
> > +	if (WARN_ON_ONCE(*type == IOMMU_HW_INFO_TYPE_NONE)) {
> > +		rc = -ENODEV;
> > +		goto err_free;
> > +	}
> > +
> > +	*length = min(*length, data_len);
> > +	if (copy_to_user(user_ptr, data, *length)) {
> 
> copy_to_user() returns the number of bytes that were successfully
> copied, right?

It returns length on failure and 0 on success

Jason