KVM Archive on lore.kernel.org
 help / color / Atom feed
From: "Liu, Yi L" <yi.l.liu@intel.com>
To: Auger Eric <eric.auger@redhat.com>,
	"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
	"baolu.lu@linux.intel.com" <baolu.lu@linux.intel.com>,
	"joro@8bytes.org" <joro@8bytes.org>
Cc: "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>,
	Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>
Subject: RE: [PATCH v4 03/15] iommu/smmu: Report empty domain nesting info
Date: Mon, 6 Jul 2020 12:46:53 +0000
Message-ID: <DM5PR11MB143543A04F5AF15EC7CBEC8BC3690@DM5PR11MB1435.namprd11.prod.outlook.com> (raw)
In-Reply-To: <d791bad4-57b9-8e97-acbb-76b13e4154f8@redhat.com>

Hi Eric,

> From: Auger Eric <eric.auger@redhat.com>
> 
> Hi Yi,
> 
> Please add a commit message: instead of returning a boolean for
> DOMAIN_ATTR_NESTING, arm_smmu_domain_get_attr() returns a
> iommu_nesting_info handle.

will do. thanks for the suggestion.

> 
> On 7/4/20 1:26 PM, Liu Yi L wrote:
> > Cc: Will Deacon <will@kernel.org>
> > Cc: Robin Murphy <robin.murphy@arm.com>
> > Cc: Eric Auger <eric.auger@redhat.com>
> > Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
> > Suggested-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> > Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> > ---
> >  drivers/iommu/arm-smmu-v3.c | 29 +++++++++++++++++++++++++++--
> >  drivers/iommu/arm-smmu.c    | 29 +++++++++++++++++++++++++++--
> >  2 files changed, 54 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> > index f578677..0c45d4d 100644
> > --- a/drivers/iommu/arm-smmu-v3.c
> > +++ b/drivers/iommu/arm-smmu-v3.c
> > @@ -3019,6 +3019,32 @@ static struct iommu_group
> *arm_smmu_device_group(struct device *dev)
> >  	return group;
> >  }
> >
> > +static int arm_smmu_domain_nesting_info(struct arm_smmu_domain
> *smmu_domain,
> > +					void *data)
> > +{
> > +	struct iommu_nesting_info *info = (struct iommu_nesting_info *) data;
> > +	u32 size;
> > +
> > +	if (!info || smmu_domain->stage != ARM_SMMU_DOMAIN_NESTED)
> > +		return -ENODEV;
> > +
> > +	size = sizeof(struct iommu_nesting_info);
> > +
> > +	/*
> > +	 * if provided buffer size is not equal to the size, should
> > +	 * return 0 and also the expected buffer size to caller.
> > +	 */
> > +	if (info->size != size) {
> < size?

< size may work as well. but I'd like the caller provide exact buffer size. not sure
if it is demand in kernel. do you have any suggestion?

> > +		info->size = size;
> > +		return 0;
> > +	}
> > +
> > +	/* report an empty iommu_nesting_info for now */
> > +	memset(info, 0x0, size);
> > +	info->size = size;
> For info, the current SMMU NESTED mode is not enabling any nesting. It just forces
> the usage of the 2st stage instead of stage1 for single stage translation.

yep. The intention is as below:

" However it requires changing the get_attr(NESTING) implementations in both
SMMU drivers as a precursor of this series, to avoid breaking
VFIO_TYPE1_NESTING_IOMMU on Arm. Since we haven't yet defined the
nesting_info structs for SMMUv2 and v3, I suppose we could return an empty
struct iommu_nesting_info for now?"
https://lore.kernel.org/linux-iommu/20200617143909.GA886590@myrica/

do you think any other needs to be done for now?

Regards,
Yi Liu

> Thanks
> 
> Eric
> > +	return 0;
> > +}
> > +
> >  static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
> >  				    enum iommu_attr attr, void *data)  { @@ -
> 3028,8 +3054,7 @@
> > static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
> >  	case IOMMU_DOMAIN_UNMANAGED:
> >  		switch (attr) {
> >  		case DOMAIN_ATTR_NESTING:
> > -			*(int *)data = (smmu_domain->stage ==
> ARM_SMMU_DOMAIN_NESTED);
> > -			return 0;
> > +			return arm_smmu_domain_nesting_info(smmu_domain,
> data);
> >  		default:
> >  			return -ENODEV;
> >  		}
> > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index
> > 243bc4c..908607d 100644
> > --- a/drivers/iommu/arm-smmu.c
> > +++ b/drivers/iommu/arm-smmu.c
> > @@ -1506,6 +1506,32 @@ static struct iommu_group
> *arm_smmu_device_group(struct device *dev)
> >  	return group;
> >  }
> >
> > +static int arm_smmu_domain_nesting_info(struct arm_smmu_domain
> *smmu_domain,
> > +					void *data)
> > +{
> > +	struct iommu_nesting_info *info = (struct iommu_nesting_info *) data;
> > +	u32 size;
> > +
> > +	if (!info || smmu_domain->stage != ARM_SMMU_DOMAIN_NESTED)
> > +		return -ENODEV;
> > +
> > +	size = sizeof(struct iommu_nesting_info);
> > +
> > +	/*
> > +	 * if provided buffer size is not equal to the size, should
> > +	 * return 0 and also the expected buffer size to caller.
> > +	 */
> > +	if (info->size != size) {
> > +		info->size = size;
> > +		return 0;
> > +	}
> > +
> > +	/* report an empty iommu_nesting_info for now */
> > +	memset(info, 0x0, size);
> > +	info->size = size;
> > +	return 0;
> > +}
> > +
> >  static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
> >  				    enum iommu_attr attr, void *data)  { @@ -
> 1515,8 +1541,7 @@
> > static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
> >  	case IOMMU_DOMAIN_UNMANAGED:
> >  		switch (attr) {
> >  		case DOMAIN_ATTR_NESTING:
> > -			*(int *)data = (smmu_domain->stage ==
> ARM_SMMU_DOMAIN_NESTED);
> > -			return 0;
> > +			return arm_smmu_domain_nesting_info(smmu_domain,
> data);
> >  		default:
> >  			return -ENODEV;
> >  		}
> >


  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 [this message]
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
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=DM5PR11MB143543A04F5AF15EC7CBEC8BC3690@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=robin.murphy@arm.com \
    --cc=stefanha@gmail.com \
    --cc=will@kernel.org \
    --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