IOMMU Archive on lore.kernel.org
 help / color / Atom feed
From: "Tian, Kevin" <kevin.tian@intel.com>
To: Lu Baolu <baolu.lu@linux.intel.com>, Peter Xu <peterx@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
	Yi Sun <yi.y.sun@linux.intel.com>,
	"Raj, Ashok" <ashok.raj@intel.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"Kumar, Sanjay K" <sanjay.k.kumar@intel.com>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Sun, Yi Y" <yi.y.sun@intel.com>,
	David Woodhouse <dwmw2@infradead.org>
Subject: RE: [RFC PATCH 2/4] iommu/vt-d: Add first level page table interfaces
Date: Wed, 25 Sep 2019 07:32:48 +0000
Message-ID: <AADFC41AFE54684AB9EE6CBC0274A5D19D58F4EA@SHSMSX104.ccr.corp.intel.com> (raw)
In-Reply-To: <1713f03c-4d47-34ad-f36d-882645c36389@linux.intel.com>

> From: Lu Baolu [mailto:baolu.lu@linux.intel.com]
> Sent: Wednesday, September 25, 2019 2:52 PM
> 
> Hi Peter and Kevin,
> 
> On 9/25/19 1:24 PM, Peter Xu wrote:
> > On Wed, Sep 25, 2019 at 04:38:31AM +0000, Tian, Kevin wrote:
> >>> From: Peter Xu [mailto:peterx@redhat.com]
> >>> Sent: Wednesday, September 25, 2019 12:31 PM
> >>>
> >>> On Tue, Sep 24, 2019 at 09:38:53AM +0800, Lu Baolu wrote:
> >>>>>> intel_mmmap_range(domain, addr, end, phys_addr, prot)
> >>>>>
> >>>>> Maybe think of a different name..? mmmap seems a bit weird :-)
> >>>>
> >>>> Yes. I don't like it either. I've thought about it and haven't
> >>>> figured out a satisfied one. Do you have any suggestions?
> >>>
> >>> How about at least split the word using "_"?  Like "mm_map", then
> >>> apply it to all the "mmm*" prefixes.  Otherwise it'll be easily
> >>> misread as mmap() which is totally irrelevant to this...
> >>>
> >>
> >> what is the point of keeping 'mm' here? replace it with 'iommu'?
> >
> > I'm not sure of what Baolu thought, but to me "mm" makes sense itself
> > to identify this from real IOMMU page tables (because IIUC these will
> > be MMU page tables).  We can come up with better names, but IMHO
> > "iommu" can be a bit misleading to let people refer to the 2nd level
> > page table.
> 
> "mm" represents a CPU (first level) page table;
> 
> vs.
> 
> "io" represents an IOMMU (second level) page table.
> 

IOMMU first level is not equivalent to CPU page table, though you can
use the latter as the first level (e.g. in SVA). Especially here you are
making IOVA->GPA as the first level, which is not CPU page table.

btw both levels are for "io" i.e. DMA purposes from VT-d p.o.v. They
are just hierarchical structures implemented by VT-d, with slightly
different format. The specification doesn't limit how you use them for.
In a hypothetical case, an IOMMU may implement exactly same CPU-page-
table format and support page faults for both levels. Then you can even
link the CPU page table to the 2nd level for sure.

Maybe we just name it from VT-d context, e.g. intel_map_first_level_range,
Intel_map_second_level_range, and then register them as dmar domain
callback as you replied in another mail.

Thanks
Kevin
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply index

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-23 12:24 [RFC PATCH 0/4] Use 1st-level for DMA remapping in guest Lu Baolu
2019-09-23 12:24 ` [RFC PATCH 1/4] iommu/vt-d: Move domain_flush_cache helper into header Lu Baolu
2019-09-23 12:24 ` [RFC PATCH 2/4] iommu/vt-d: Add first level page table interfaces Lu Baolu
2019-09-23 20:31   ` Raj, Ashok
2019-09-24  1:38     ` Lu Baolu
2019-09-25  4:30       ` Peter Xu
2019-09-25  4:38         ` Tian, Kevin
2019-09-25  5:24           ` Peter Xu
2019-09-25  6:52             ` Lu Baolu
2019-09-25  7:32               ` Tian, Kevin [this message]
2019-09-25  8:35                 ` Peter Xu
2019-09-26  1:42                 ` Lu Baolu
2019-09-25  5:21   ` Peter Xu
2019-09-26  2:35     ` Lu Baolu
2019-09-26  3:49       ` Peter Xu
2019-09-27  2:27         ` Lu Baolu
2019-09-27  5:34           ` Peter Xu
2019-09-28  8:23             ` Lu Baolu
2019-09-29  5:25               ` Peter Xu
2019-10-08  2:20                 ` Lu Baolu
2019-09-23 12:24 ` [RFC PATCH 3/4] iommu/vt-d: Map/unmap domain with mmmap/mmunmap Lu Baolu
2019-09-25  5:00   ` Tian, Kevin
2019-09-25  7:06     ` Lu Baolu
2019-09-23 12:24 ` [RFC PATCH 4/4] iommu/vt-d: Identify domains using first level page table Lu Baolu
2019-09-25  6:50   ` Peter Xu
2019-09-25  7:35     ` Tian, Kevin
2019-09-23 19:27 ` [RFC PATCH 0/4] Use 1st-level for DMA remapping in guest Jacob Pan
2019-09-23 20:25   ` Raj, Ashok
2019-09-24  4:40     ` Lu Baolu
2019-09-24  7:00     ` Tian, Kevin
2019-09-25  2:48       ` Lu Baolu
2019-09-25  6:56         ` Peter Xu
2019-09-25  7:21           ` Tian, Kevin
2019-09-25  7:45             ` Peter Xu
2019-09-25  8:02               ` Tian, Kevin
2019-09-25  8:52                 ` Peter Xu
2019-09-26  1:37                   ` Lu Baolu
2019-09-24  4:27   ` Lu Baolu

Reply instructions:

You may reply publically 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=AADFC41AFE54684AB9EE6CBC0274A5D19D58F4EA@SHSMSX104.ccr.corp.intel.com \
    --to=kevin.tian@intel.com \
    --cc=alex.williamson@redhat.com \
    --cc=ashok.raj@intel.com \
    --cc=baolu.lu@linux.intel.com \
    --cc=dwmw2@infradead.org \
    --cc=iommu@lists.linux-foundation.org \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=peterx@redhat.com \
    --cc=sanjay.k.kumar@intel.com \
    --cc=yi.y.sun@intel.com \
    --cc=yi.y.sun@linux.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

IOMMU Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-iommu/0 linux-iommu/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 linux-iommu linux-iommu/ https://lore.kernel.org/linux-iommu \
		iommu@lists.linux-foundation.org
	public-inbox-index linux-iommu

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.linux-foundation.lists.iommu


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