From: "Tian, Kevin" <kevin.tian@intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: "peter.maydell@linaro.org" <peter.maydell@linaro.org>,
"lushenming@huawei.com" <lushenming@huawei.com>,
"robin.murphy@arm.com" <robin.murphy@arm.com>,
"Raj, Ashok" <ashok.raj@intel.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
"maz@kernel.org" <maz@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"vsethi@nvidia.com" <vsethi@nvidia.com>,
"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
"wangxingang5@huawei.com" <wangxingang5@huawei.com>,
"vivek.gautam@arm.com" <vivek.gautam@arm.com>,
"zhangfei.gao@linaro.org" <zhangfei.gao@linaro.org>,
"eric.auger.pro@gmail.com" <eric.auger.pro@gmail.com>,
"will@kernel.org" <will@kernel.org>,
"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>
Subject: RE: [RFC v16 1/9] iommu: Introduce attach/detach_pasid_table API
Date: Tue, 4 Jan 2022 02:42:39 +0000 [thread overview]
Message-ID: <BN9PR11MB52765F70759C3905177588768C4A9@BN9PR11MB5276.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20211216204831.GD6385@nvidia.com>
> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Friday, December 17, 2021 4:49 AM
>
> On Sat, Dec 11, 2021 at 03:57:45AM +0000, Tian, Kevin wrote:
>
> > This might be the only open as I still didn't see why we need an
> > explicit flag to claim a 'full device' thing. From kernel p.o.v the
> > ARM case is no different from Intel that both allows an user
> > page table attached to vRID, just with different format and
> > addr width (Intel is 64bit, ARM is 84bit where PASID can be
> > considered a sub-handle in the 84bit address space and not
> > the kernel's business).
>
> I think the difference is intention.
>
> In one case the kernel is saying 'attach a RID and I intend to use
> PASID' in which case the kernel user can call the PASID APIs.
>
> The second case is saying 'I will not use PASID'.
>
> They are different things and I think it is a surprising API if the
> kernel user attaches a domain, intends to use PASID and then finds out
> it can't, eg because an ARM user page table was hooked up.
>
> If you imagine the flag as 'I intend to use PASID' I think it makes a
> fair amount of sense from an API design too.
>
> We could probably do without it, at least for VFIO and qemu cases, but
> it seems a little bit peculiar to me.
>
ok, combining the kernel user makes the flag more sensible.
Thanks
Kevin
next prev parent reply other threads:[~2022-01-04 2:42 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-27 10:44 [RFC v16 0/9] SMMUv3 Nested Stage Setup (IOMMU part) Eric Auger
2021-10-27 10:44 ` [RFC v16 1/9] iommu: Introduce attach/detach_pasid_table API Eric Auger
2021-12-06 10:48 ` Joerg Roedel
2021-12-07 10:22 ` Eric Auger
2021-12-08 2:44 ` Lu Baolu
2021-12-08 7:33 ` Eric Auger
2021-12-08 12:56 ` Jason Gunthorpe
2021-12-08 17:20 ` Jean-Philippe Brucker
2021-12-08 18:31 ` Jason Gunthorpe
2021-12-09 2:58 ` Tian, Kevin
[not found] ` <BN9PR11MB527624080CB9302481B74C7A8C709@BN9PR11MB5276.namprd11.prod.outlook.com>
2021-12-09 3:59 ` Tian, Kevin
2021-12-09 16:08 ` Jason Gunthorpe
2021-12-10 8:56 ` Tian, Kevin
2021-12-10 13:23 ` Jason Gunthorpe
2021-12-11 3:57 ` Tian, Kevin
2021-12-16 20:48 ` Jason Gunthorpe
2022-01-04 2:42 ` Tian, Kevin [this message]
2021-12-11 5:18 ` Tian, Kevin
2021-12-09 7:50 ` Eric Auger
2021-12-09 15:40 ` Jason Gunthorpe
2021-12-09 16:37 ` Eric Auger
2021-12-09 3:21 ` Tian, Kevin
2021-12-09 9:44 ` Eric Auger
2021-12-09 8:31 ` Eric Auger
2021-10-27 10:44 ` [RFC v16 2/9] iommu: Introduce iommu_get_nesting Eric Auger
2021-10-27 10:44 ` [RFC v16 3/9] iommu/smmuv3: Allow s1 and s2 configs to coexist Eric Auger
2021-10-27 10:44 ` [RFC v16 4/9] iommu/smmuv3: Get prepared for nested stage support Eric Auger
2021-10-27 10:44 ` [RFC v16 5/9] iommu/smmuv3: Implement attach/detach_pasid_table Eric Auger
2021-10-27 10:44 ` [RFC v16 6/9] iommu/smmuv3: Allow stage 1 invalidation with unmanaged ASIDs Eric Auger
2021-10-27 10:44 ` [RFC v16 7/9] iommu/smmuv3: Implement cache_invalidate Eric Auger
2021-10-27 10:44 ` [RFC v16 8/9] iommu/smmuv3: report additional recoverable faults Eric Auger
2021-10-27 10:44 ` [RFC v16 9/9] iommu/smmuv3: Disallow nested mode in presence of HW MSI regions Eric Auger
2021-12-03 12:27 ` [RFC v16 0/9] SMMUv3 Nested Stage Setup (IOMMU part) Zhangfei Gao
2021-12-07 10:27 ` Eric Auger
2021-12-07 10:35 ` Zhangfei Gao
2021-12-07 11:06 ` Eric Auger
2021-12-08 13:33 ` Shameerali Kolothum Thodi
2021-12-03 13:13 ` Sumit Gupta
2021-12-07 10:28 ` Eric Auger
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=BN9PR11MB52765F70759C3905177588768C4A9@BN9PR11MB5276.namprd11.prod.outlook.com \
--to=kevin.tian@intel.com \
--cc=alex.williamson@redhat.com \
--cc=ashok.raj@intel.com \
--cc=eric.auger.pro@gmail.com \
--cc=jean-philippe@linaro.org \
--cc=jgg@nvidia.com \
--cc=kvm@vger.kernel.org \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=linux-kernel@vger.kernel.org \
--cc=lushenming@huawei.com \
--cc=maz@kernel.org \
--cc=peter.maydell@linaro.org \
--cc=robin.murphy@arm.com \
--cc=vivek.gautam@arm.com \
--cc=vsethi@nvidia.com \
--cc=wangxingang5@huawei.com \
--cc=will@kernel.org \
--cc=zhangfei.gao@linaro.org \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).