KVM Archive on lore.kernel.org
 help / color / Atom feed
From: "Liu, Yi L" <yi.l.liu@intel.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: Auger Eric <eric.auger@redhat.com>,
	"baolu.lu@linux.intel.com" <baolu.lu@linux.intel.com>,
	"joro@8bytes.org" <joro@8bytes.org>,
	"Tian, Kevin" <kevin.tian@intel.com>,
	"jacob.jun.pan@linux.intel.com" <jacob.jun.pan@linux.intel.com>,
	"Raj, Ashok" <ashok.raj@intel.com>,
	"Tian, Jun J" <jun.j.tian@intel.com>,
	"Sun, Yi Y" <yi.y.sun@intel.com>,
	"jean-philippe@linaro.org" <jean-philippe@linaro.org>,
	"peterx@redhat.com" <peterx@redhat.com>,
	"Wu, Hao" <hao.wu@intel.com>,
	"stefanha@gmail.com" <stefanha@gmail.com>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v4 04/15] vfio/type1: Report iommu nesting info to userspace
Date: Thu, 9 Jul 2020 00:25:24 +0000
Message-ID: <DM5PR11MB1435130A8C66F625F0F34C79C3640@DM5PR11MB1435.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20200708132947.5b7ee954@x1.home>

Hi Alex,

> From: Alex Williamson <alex.williamson@redhat.com>
> Sent: Thursday, July 9, 2020 3:30 AM
> 
> On Wed, 8 Jul 2020 08:08:40 +0000
> "Liu, Yi L" <yi.l.liu@intel.com> wrote:
> 
> > Hi Alex,
> >
> > Eric asked if we will to have data strcut other than struct iommu_nesting_info
> > type in the struct vfio_iommu_type1_info_cap_nesting @info[] field. I'm not
> > quit sure on it. I guess the answer may be not as VFIO's nesting support should
> > based on IOMMU UAPI. how about your opinion?
> >
> > +#define VFIO_IOMMU_TYPE1_INFO_CAP_NESTING  3
> > +
> > +/*
> > + * Reporting nesting info to user space.
> > + *
> > + * @info:	the nesting info provided by IOMMU driver. Today
> > + *		it is expected to be a struct iommu_nesting_info
> > + *		data.
> > + */
> > +struct vfio_iommu_type1_info_cap_nesting {
> > +	struct	vfio_info_cap_header header;
> > +	__u32	flags;
> > +	__u32	padding;
> > +	__u8	info[];
> > +};
> 
> It's not a very useful uAPI if the user can't be sure what they're
> getting out of it.  Info capabilities are "cheap", they don't need to
> be as extensible as an ioctl.  It's not clear that we really even need
> the flags (and therefore the padding), just define it to return the
> IOMMU uAPI structure with no extensibility.  If we need to expose
> something else, create a new capability.  Thanks,

thanks for the guiding, then I may embed the struct iommu_nesting_info
here. :-)

Regards,
Yi Liu

> Alex
> 
> >
> > https://lore.kernel.org/linux-
> iommu/DM5PR11MB1435290B6CD561EC61027892C3690@DM5PR11MB1435.nam
> prd11.prod.outlook.com/
> >
> > Regards,
> > Yi Liu
> >
> > > From: Liu, Yi L
> > > Sent: Tuesday, July 7, 2020 5:32 PM
> > >
> > [...]
> > > > >
> > > > >>> +
> > > > >>> +/*
> > > > >>> + * Reporting nesting info to user space.
> > > > >>> + *
> > > > >>> + * @info:	the nesting info provided by IOMMU driver. Today
> > > > >>> + *		it is expected to be a struct iommu_nesting_info
> > > > >>> + *		data.
> > > > >> Is it expected to change?
> > > > >
> > > > > honestly, I'm not quite sure on it. I did considered to embed struct
> > > > > iommu_nesting_info here instead of using info[]. but I hesitated as
> > > > > using info[] may leave more flexibility on this struct. how about
> > > > > your opinion? perhaps it's fine to embed the struct
> > > > > iommu_nesting_info here as long as VFIO is setup nesting based on
> > > > > IOMMU UAPI.
> > > > >
> > > > >>> + */
> > > > >>> +struct vfio_iommu_type1_info_cap_nesting {
> > > > >>> +	struct	vfio_info_cap_header header;
> > > > >>> +	__u32	flags;
> > > > >> You may document flags.
> > > > >
> > > > > sure. it's reserved for future.
> > > > >
> > > > > Regards,
> > > > > Yi Liu
> > > > >
> > > > >>> +	__u32	padding;
> > > > >>> +	__u8	info[];
> > > > >>> +};
> > > > >>> +
> > > > >>>  #define VFIO_IOMMU_GET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12)
> > > > >>>
> > > > >>>  /**
> > > > >>>
> > > > >> Thanks
> > > > >>
> > > > >> Eric
> > > > >
> >


  reply index

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-04 11:26 [PATCH v4 00/15] vfio: expose virtual Shared Virtual Addressing to VMs Liu Yi L
2020-07-04 11:26 ` [PATCH v4 01/15] vfio/type1: Refactor vfio_iommu_type1_ioctl() Liu Yi L
2020-07-06  9:34   ` Auger Eric
2020-07-06 12:27     ` Liu, Yi L
2020-07-06 12:55       ` Auger Eric
2020-07-06 13:00         ` Liu, Yi L
2020-07-04 11:26 ` [PATCH v4 02/15] iommu: Report domain nesting info Liu Yi L
2020-07-06  9:34   ` Auger Eric
2020-07-06 12:20     ` Liu, Yi L
2020-07-06 13:00       ` Auger Eric
2020-07-06 13:17         ` Liu, Yi L
2020-07-04 11:26 ` [PATCH v4 03/15] iommu/smmu: Report empty " Liu Yi L
2020-07-06 10:37   ` Auger Eric
2020-07-06 12:46     ` Liu, Yi L
2020-07-06 13:21       ` Auger Eric
2020-07-06 13:26         ` Liu, Yi L
2020-07-04 11:26 ` [PATCH v4 04/15] vfio/type1: Report iommu nesting info to userspace Liu Yi L
2020-07-06 10:37   ` Auger Eric
2020-07-06 13:10     ` Liu, Yi L
2020-07-06 13:45       ` Auger Eric
2020-07-07  9:31         ` Liu, Yi L
2020-07-08  8:08           ` Liu, Yi L
2020-07-08 19:29             ` Alex Williamson
2020-07-09  0:25               ` Liu, Yi L [this message]
2020-07-06 14:06   ` Auger Eric
2020-07-07  9:34     ` Liu, Yi L
2020-07-04 11:26 ` [PATCH v4 05/15] vfio: Add PASID allocation/free support Liu Yi L
2020-07-06 14:52   ` Auger Eric
2020-07-07  9:45     ` Liu, Yi L
2020-07-04 11:26 ` [PATCH v4 06/15] iommu/vt-d: Support setting ioasid set to domain Liu Yi L
2020-07-06 14:52   ` Auger Eric
2020-07-07  9:37     ` Liu, Yi L
2020-07-04 11:26 ` [PATCH v4 07/15] vfio/type1: Add VFIO_IOMMU_PASID_REQUEST (alloc/free) Liu Yi L
2020-07-06 15:17   ` Auger Eric
2020-07-07  9:51     ` Liu, Yi L
2020-07-04 11:26 ` [PATCH v4 08/15] iommu: Pass domain to sva_unbind_gpasid() Liu Yi L
2020-07-04 11:26 ` [PATCH v4 09/15] iommu/vt-d: Check ownership for PASIDs from user-space Liu Yi L
2020-07-04 11:26 ` [PATCH v4 10/15] vfio/type1: Support binding guest page tables to PASID Liu Yi L
2020-07-04 11:26 ` [PATCH v4 11/15] vfio/type1: Allow invalidating first-level/stage IOMMU cache Liu Yi L
2020-07-04 11:26 ` [PATCH v4 12/15] vfio/type1: Add vSVA support for IOMMU-backed mdevs Liu Yi L
2020-07-04 11:26 ` [PATCH v4 13/15] vfio/pci: Expose PCIe PASID capability to guest Liu Yi L
2020-07-04 11:26 ` [PATCH v4 14/15] vfio: Document dual stage control Liu Yi L
2020-07-04 11:26 ` [PATCH v4 15/15] iommu/vt-d: Support reporting nesting capability info Liu Yi L

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=DM5PR11MB1435130A8C66F625F0F34C79C3640@DM5PR11MB1435.namprd11.prod.outlook.com \
    --to=yi.l.liu@intel.com \
    --cc=alex.williamson@redhat.com \
    --cc=ashok.raj@intel.com \
    --cc=baolu.lu@linux.intel.com \
    --cc=eric.auger@redhat.com \
    --cc=hao.wu@intel.com \
    --cc=iommu@lists.linux-foundation.org \
    --cc=jacob.jun.pan@linux.intel.com \
    --cc=jean-philippe@linaro.org \
    --cc=joro@8bytes.org \
    --cc=jun.j.tian@intel.com \
    --cc=kevin.tian@intel.com \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=peterx@redhat.com \
    --cc=stefanha@gmail.com \
    --cc=yi.y.sun@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

KVM Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/kvm/0 kvm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 kvm kvm/ https://lore.kernel.org/kvm \
		kvm@vger.kernel.org
	public-inbox-index kvm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.kvm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git