From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: Auger Eric <eric.auger@redhat.com>
Cc: "Liu, Yi L" <yi.l.liu@intel.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Joerg Roedel <joro@8bytes.org>,
David Woodhouse <dwmw2@infradead.org>,
Alex Williamson <alex.williamson@redhat.com>,
Jean-Philippe Brucker <jean-philippe.brucker@arm.com>,
"Tian, Kevin" <kevin.tian@intel.com>,
"Raj, Ashok" <ashok.raj@intel.com>,
Christoph Hellwig <hch@infradead.org>,
Lu Baolu <baolu.lu@linux.intel.com>,
Andriy Shevchenko <andriy.shevchenko@linux.intel.com>,
jacob.jun.pan@linux.intel.com
Subject: Re: [PATCH v2 09/19] iommu/vt-d: Enlightened PASID allocation
Date: Thu, 25 Apr 2019 16:01:56 -0700 [thread overview]
Message-ID: <20190425160156.4f5decaa@jacob-builder> (raw)
In-Reply-To: <c847182b-6e5c-5344-a162-29e273a489fb@redhat.com>
On Thu, 25 Apr 2019 09:40:31 +0200
Auger Eric <eric.auger@redhat.com> wrote:
> Hi Liu,
>
> On 4/25/19 9:12 AM, Liu, Yi L wrote:
> > Hi Eric,
> >
> >> From: Auger Eric [mailto:eric.auger@redhat.com]
> >> Sent: Thursday, April 25, 2019 1:28 AM
> >> To: Jacob Pan <jacob.jun.pan@linux.intel.com>;
> >> iommu@lists.linux-foundation.org; Subject: Re: [PATCH v2 09/19]
> >> iommu/vt-d: Enlightened PASID allocation
> >>
> >> Hi Jacob,
> >>
> >> On 4/24/19 1:31 AM, Jacob Pan wrote:
> >>> From: Lu Baolu <baolu.lu@linux.intel.com>
> >>>
> >>> If Intel IOMMU runs in caching mode, a.k.a. virtual IOMMU, the
> >>> IOMMU driver should rely on the emulation software to allocate
> >>> and free PASID IDs.
> >> Do we make the decision depending on the CM or depending on the
> >> VCCAP_REG?
> >>
> >> VCCAP_REG description says:
> >>
> >> If Set, software must use Virtual Command Register interface to
> >> allocate and free PASIDs.
> >
> > The answer is it depends on the ECAP.VCS and then the PASID
> > allocation bit in VCCAP_REG. But VCS bit implies the iommu is a
> > software implementation (vIOMMU) of vt-d architecture. Pls refer to
> > the descriptions of "Virtual Command Support" in vt-d 3.0 spec.
> >
> > "Hardware implementations of this architecture report a value of 0
> > in this field. Software implementations (emulation) of this
> > architecture may report VCS=1."
>
> OK I understand. But strictly speaking a vIOMMU may not implement CM.
> But that's nitpicking ;-)
>
CAP.CM (caching mode) and ECAP.VCS(virtual command support) are
separate. I think we are mixing the two here since both are sufficient
condition to indicate whether we are running in a guest.
> Thanks
>
> Eric
> >
> > Thanks,
> > Yi Liu
> >
[Jacob Pan]
next prev parent reply other threads:[~2019-04-25 23:00 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-23 23:31 [PATCH v2 00/19] Shared virtual address IOMMU and VT-d support Jacob Pan
2019-04-23 23:31 ` [PATCH v2 01/19] driver core: add per device iommu param Jacob Pan
2019-04-23 23:31 ` [PATCH v2 02/19] iommu: introduce device fault data Jacob Pan
2019-04-25 12:46 ` Jean-Philippe Brucker
2019-04-25 13:21 ` Auger Eric
2019-04-25 14:33 ` Jean-Philippe Brucker
2019-04-25 18:07 ` Jacob Pan
2019-04-23 23:31 ` [PATCH v2 03/19] iommu: introduce device fault report API Jacob Pan
2019-04-23 23:31 ` [PATCH v2 04/19] iommu: Introduce attach/detach_pasid_table API Jacob Pan
2019-04-23 23:31 ` [PATCH v2 05/19] iommu: Introduce cache_invalidate API Jacob Pan
2019-04-23 23:31 ` [PATCH v2 06/19] drivers core: Add I/O ASID allocator Jacob Pan
2019-04-24 6:19 ` Christoph Hellwig
2019-04-25 18:19 ` Jacob Pan
2019-04-26 11:47 ` Jean-Philippe Brucker
2019-04-26 12:21 ` Christoph Hellwig
2019-04-26 16:58 ` Jacob Pan
2019-04-25 10:17 ` Auger Eric
2019-04-25 10:41 ` Jean-Philippe Brucker
2019-04-30 20:24 ` Jacob Pan
2019-05-01 17:40 ` Jean-Philippe Brucker
2019-04-23 23:31 ` [PATCH v2 07/19] ioasid: Convert ioasid_idr to XArray Jacob Pan
2019-04-23 23:31 ` [PATCH v2 08/19] ioasid: Add custom IOASID allocator Jacob Pan
2019-04-25 10:03 ` Auger Eric
2019-04-25 21:29 ` Jacob Pan
2019-04-26 9:06 ` Auger Eric
2019-04-26 15:19 ` Jacob Pan
2019-05-06 17:59 ` Jacob Pan
2019-04-23 23:31 ` [PATCH v2 09/19] iommu/vt-d: Enlightened PASID allocation Jacob Pan
2019-04-24 17:27 ` Auger Eric
2019-04-25 7:12 ` Liu, Yi L
2019-04-25 7:40 ` Auger Eric
2019-04-25 23:01 ` Jacob Pan [this message]
2019-04-25 23:40 ` Jacob Pan
2019-04-26 7:24 ` Auger Eric
2019-04-26 15:05 ` Jacob Pan
2019-04-23 23:31 ` [PATCH v2 10/19] iommu/vt-d: Add custom allocator for IOASID Jacob Pan
2019-04-24 17:27 ` Auger Eric
2019-04-26 20:11 ` Jacob Pan
2019-04-23 23:31 ` [PATCH v2 11/19] iommu/vt-d: Replace Intel specific PASID allocator with IOASID Jacob Pan
2019-04-25 10:04 ` Auger Eric
[not found] ` <20190426140133.6d445315@jacob-builder>
2019-04-27 8:38 ` Auger Eric
2019-04-29 10:00 ` Jean-Philippe Brucker
2019-04-23 23:31 ` [PATCH v2 12/19] iommu/vt-d: Move domain helper to header Jacob Pan
2019-04-24 17:27 ` Auger Eric
2019-04-23 23:31 ` [PATCH v2 13/19] iommu/vt-d: Add nested translation support Jacob Pan
2019-04-26 15:42 ` Auger Eric
2019-04-26 21:57 ` Jacob Pan
2019-04-23 23:31 ` [PATCH v2 14/19] iommu: Add guest PASID bind function Jacob Pan
2019-04-26 15:53 ` Auger Eric
2019-04-26 22:11 ` Jacob Pan
2019-04-27 8:37 ` Auger Eric
2019-04-23 23:31 ` [PATCH v2 15/19] iommu/vt-d: Add bind guest PASID support Jacob Pan
2019-04-26 16:15 ` Auger Eric
2019-04-29 15:25 ` Jacob Pan
2019-04-30 7:05 ` Auger Eric
2019-04-30 17:49 ` Jacob Pan
2019-04-23 23:31 ` [PATCH v2 16/19] iommu/vtd: Clean up for SVM device list Jacob Pan
2019-04-26 16:19 ` Auger Eric
2019-04-23 23:31 ` [PATCH v2 17/19] iommu: Add max num of cache and granu types Jacob Pan
2019-04-26 16:22 ` Auger Eric
2019-04-29 16:17 ` Jacob Pan
2019-04-30 5:15 ` Auger Eric
2019-04-23 23:31 ` [PATCH v2 18/19] iommu/vt-d: Support flushing more translation cache types Jacob Pan
2019-04-27 9:04 ` Auger Eric
2019-04-29 21:29 ` Jacob Pan
2019-04-30 4:41 ` Auger Eric
2019-04-30 17:15 ` Jacob Pan
2019-04-30 17:41 ` Auger Eric
2019-04-23 23:31 ` [PATCH v2 19/19] iommu/vt-d: Add svm/sva invalidate function Jacob Pan
2019-04-26 17:23 ` Auger Eric
2019-04-29 22:41 ` Jacob Pan
2019-04-30 6:57 ` Auger Eric
2019-04-30 17:22 ` Jacob Pan
2019-04-30 17:36 ` Auger Eric
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