From: Alex Williamson <alex.williamson@redhat.com>
To: "Liu, Yi L" <yi.l.liu@intel.com>
Cc: kevin.tian@intel.com, ashok.raj@intel.com, kvm@vger.kernel.org,
jean-philippe.brucker@arm.com, jun.j.tian@intel.com,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
yi.y.sun@intel.com
Subject: Re: [RFC v3 4/8] vfio/type1: Add VFIO_NESTING_GET_IOMMU_UAPI_VERSION
Date: Wed, 29 Jan 2020 16:56:49 -0700 [thread overview]
Message-ID: <20200129165649.43008300@w520.home> (raw)
In-Reply-To: <1580299912-86084-5-git-send-email-yi.l.liu@intel.com>
On Wed, 29 Jan 2020 04:11:48 -0800
"Liu, Yi L" <yi.l.liu@intel.com> wrote:
> From: Liu Yi L <yi.l.liu@intel.com>
>
> In Linux Kernel, the IOMMU nesting translation (a.k.a. IOMMU dual stage
> translation capability) is abstracted in uapi/iommu.h, in which the uAPIs
> like bind_gpasid/iommu_cache_invalidate/fault_report/pgreq_resp are defined.
>
> VFIO_TYPE1_NESTING_IOMMU stands for the vfio iommu type which is backed by
> IOMMU nesting translation capability. VFIO exposes the nesting capability
> to userspace and also exposes uAPIs (will be added in later patches) to user
> space for setting up nesting translation from userspace. Thus applications
> like QEMU could support vIOMMU for pass-through devices with IOMMU nesting
> translation capability.
>
> As VFIO expose the nesting IOMMU programming to userspace, it also needs to
> provide an API for the uapi/iommu.h version check to ensure compatibility.
> This patch reports the iommu uapi version to userspace. Applications could
> use this API to do version check before further using the nesting uAPIs.
>
> Cc: Kevin Tian <kevin.tian@intel.com>
> CC: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Cc: Alex Williamson <alex.williamson@redhat.com>
> Cc: Eric Auger <eric.auger@redhat.com>
> Cc: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
> Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> ---
> drivers/vfio/vfio.c | 3 +++
> include/uapi/linux/vfio.h | 10 ++++++++++
> 2 files changed, 13 insertions(+)
>
> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
> index 425d60a..9087ad4 100644
> --- a/drivers/vfio/vfio.c
> +++ b/drivers/vfio/vfio.c
> @@ -1170,6 +1170,9 @@ static long vfio_fops_unl_ioctl(struct file *filep,
> case VFIO_GET_API_VERSION:
> ret = VFIO_API_VERSION;
> break;
> + case VFIO_NESTING_GET_IOMMU_UAPI_VERSION:
> + ret = iommu_get_uapi_version();
> + break;
Shouldn't the type1 backend report this? It doesn't make much sense
that the spapr backend reports a version for something it doesn't
support. Better yet, provide this info gratuitously in the
VFIO_IOMMU_GET_INFO ioctl return like you do with nesting in the next
patch, then it can help the user figure out if this support is present.
Thanks,
Alex
> case VFIO_CHECK_EXTENSION:
> ret = vfio_ioctl_check_extension(container, arg);
> break;
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index d4bf415..62113be 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -857,6 +857,16 @@ struct vfio_iommu_type1_pasid_quota {
> */
> #define VFIO_IOMMU_SET_PASID_QUOTA _IO(VFIO_TYPE, VFIO_BASE + 23)
>
> +/**
> + * VFIO_NESTING_GET_IOMMU_UAPI_VERSION - _IO(VFIO_TYPE, VFIO_BASE + 24)
> + *
> + * Report the version of the IOMMU UAPI when dual stage IOMMU is supported.
> + * In VFIO, it is needed for VFIO_TYPE1_NESTING_IOMMU.
> + * Availability: Always.
> + * Return: IOMMU UAPI version
> + */
> +#define VFIO_NESTING_GET_IOMMU_UAPI_VERSION _IO(VFIO_TYPE, VFIO_BASE + 24)
> +
> /* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */
>
> /*
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2020-01-29 23:57 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-29 12:11 [RFC v3 0/8] vfio: expose virtual Shared Virtual Addressing to VMs Liu, Yi L
2020-01-29 12:11 ` [RFC v3 1/8] vfio: Add VFIO_IOMMU_PASID_REQUEST(alloc/free) Liu, Yi L
2020-01-29 23:55 ` Alex Williamson
2020-01-31 12:41 ` Liu, Yi L
2020-02-06 9:41 ` Liu, Yi L
2020-02-06 18:12 ` Jacob Pan
2020-02-18 5:07 ` Liu, Yi L
2020-01-29 12:11 ` [RFC v3 2/8] vfio/type1: Make per-application (VM) PASID quota tunable Liu, Yi L
2020-01-29 23:56 ` Alex Williamson
2020-02-05 6:23 ` Liu, Yi L
2020-02-07 19:43 ` Jacob Pan
2020-02-08 8:46 ` Liu, Yi L
2020-01-29 12:11 ` [RFC v3 3/8] vfio: Reclaim PASIDs when application is down Liu, Yi L
2020-01-29 23:56 ` Alex Williamson
2020-01-31 12:42 ` Liu, Yi L
2020-01-29 12:11 ` [RFC v3 4/8] vfio/type1: Add VFIO_NESTING_GET_IOMMU_UAPI_VERSION Liu, Yi L
2020-01-29 23:56 ` Alex Williamson [this message]
2020-01-31 13:04 ` Liu, Yi L
2020-02-03 18:00 ` Alex Williamson
2020-02-05 6:19 ` Liu, Yi L
2020-01-29 12:11 ` [RFC v3 5/8] vfio/type1: Report 1st-level/stage-1 page table format to userspace Liu, Yi L
2020-01-29 12:11 ` [RFC v3 6/8] vfio/type1: Bind guest page tables to host Liu, Yi L
2020-01-29 12:11 ` [RFC v3 7/8] vfio/type1: Add VFIO_IOMMU_CACHE_INVALIDATE Liu, Yi L
2020-01-29 12:11 ` [RFC v3 8/8] vfio/type1: Add vSVA support for IOMMU-backed mdevs 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=20200129165649.43008300@w520.home \
--to=alex.williamson@redhat.com \
--cc=ashok.raj@intel.com \
--cc=iommu@lists.linux-foundation.org \
--cc=jean-philippe.brucker@arm.com \
--cc=jun.j.tian@intel.com \
--cc=kevin.tian@intel.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=yi.l.liu@intel.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
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).