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From: "Raj, Ashok" <ashok.raj@intel.com>
To: Auger Eric <eric.auger@redhat.com>
Cc: Yi L <yi.l.liu@linux.intel.com>,
	"Tian, Kevin" <kevin.tian@intel.com>,
	Ashok Raj <ashok.raj@intel.com>,
	Jean-Philippe Brucker <jean-philippe.brucker@arm.com>,
	iommu@lists.linux-foundation.org,
	LKML <linux-kernel@vger.kernel.org>,
	Alex Williamson <alex.williamson@redhat.com>,
	Andriy Shevchenko <andriy.shevchenko@linux.intel.com>,
	David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH v4 20/22] iommu/vt-d: Add bind guest PASID support
Date: Tue, 16 Jul 2019 10:04:53 -0700
Message-ID: <20190716170453.GA54873@otc-nc-03> (raw)
In-Reply-To: <2c5a7686-aef7-f98f-cb1c-8e0eb31b2bfa@redhat.com>

Hi Eric

Jacob is on sabbatical, so i'll give it my best shot :-)

Yi/Kevin can jump in...

On Tue, Jul 16, 2019 at 06:45:51PM +0200, Auger Eric wrote:
> Hi Jacob,
> 
> On 6/9/19 3:44 PM, Jacob Pan wrote:
> > When supporting guest SVA with emulated IOMMU, the guest PASID
> > table is shadowed in VMM. Updates to guest vIOMMU PASID table
> > will result in PASID cache flush which will be passed down to
> > the host as bind guest PASID calls.
> > 
> > For the SL page tables, it will be harvested from device's
> > default domain (request w/o PASID), or aux domain in case of
> > mediated device.
> > 
> >     .-------------.  .---------------------------.
> >     |   vIOMMU    |  | Guest process CR3, FL only|
> >     |             |  '---------------------------'
> >     .----------------/
> >     | PASID Entry |--- PASID cache flush -
> >     '-------------'                       |
> >     |             |                       V
> >     |             |                CR3 in GPA
> >     '-------------'
> > Guest
> > ------| Shadow |--------------------------|--------
> >       v        v                          v
> > Host
> >     .-------------.  .----------------------.
> >     |   pIOMMU    |  | Bind FL for GVA-GPA  |
> >     |             |  '----------------------'
> >     .----------------/  |
> >     | PASID Entry |     V (Nested xlate)
> >     '----------------\.------------------------------.
> >     |             |   |SL for GPA-HPA, default domain|
> >     |             |   '------------------------------'
> >     '-------------'
> > Where:
> >  - FL = First level/stage one page tables
> >  - SL = Second level/stage two page tables
> > 
> > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> > Signed-off-by: Liu, Yi L <yi.l.liu@linux.intel.com>
> > ---
> >  drivers/iommu/intel-iommu.c |   4 +
> >  drivers/iommu/intel-svm.c   | 187 ++++++++++++++++++++++++++++++++++++++++++++
> >  include/linux/intel-iommu.h |  13 ++-
> >  include/linux/intel-svm.h   |  17 ++++
> >  4 files changed, 219 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> > index 7cfa0eb..3b4d712 100644
> > --- a/drivers/iommu/intel-iommu.c
> > +++ b/drivers/iommu/intel-iommu.c
> > @@ -5782,6 +5782,10 @@ const struct iommu_ops intel_iommu_ops = {
> >  	.dev_enable_feat	= intel_iommu_dev_enable_feat,
> >  	.dev_disable_feat	= intel_iommu_dev_disable_feat,
> >  	.pgsize_bitmap		= INTEL_IOMMU_PGSIZES,
> > +#ifdef CONFIG_INTEL_IOMMU_SVM
> > +	.sva_bind_gpasid	= intel_svm_bind_gpasid,
> > +	.sva_unbind_gpasid	= intel_svm_unbind_gpasid,
> > +#endif
> >  };
> >  
> >  static void quirk_iommu_g4x_gfx(struct pci_dev *dev)
> > diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
> > index 66d98e1..f06a82f 100644
> > --- a/drivers/iommu/intel-svm.c
> > +++ b/drivers/iommu/intel-svm.c
> > @@ -229,6 +229,193 @@ static LIST_HEAD(global_svm_list);
> >  	list_for_each_entry(sdev, &svm->devs, list)	\
> >  	if (dev == sdev->dev)				\
> >  
> > +int intel_svm_bind_gpasid(struct iommu_domain *domain,
> > +			struct device *dev,
> > +			struct gpasid_bind_data *data)
> > +{
> > +	struct intel_iommu *iommu = intel_svm_device_to_iommu(dev);
> > +	struct intel_svm_dev *sdev;
> > +	struct intel_svm *svm = NULL;
> not requested
> > +	struct dmar_domain *ddomain;
> > +	int ret = 0;
> > +
> > +	if (WARN_ON(!iommu) || !data)
> > +		return -EINVAL;
> > +
> > +	if (data->version != IOMMU_GPASID_BIND_VERSION_1 ||
> > +		data->format != IOMMU_PASID_FORMAT_INTEL_VTD)
> > +		return -EINVAL;
> > +
> > +	if (dev_is_pci(dev)) {
> > +		/* VT-d supports devices with full 20 bit PASIDs only */
> > +		if (pci_max_pasids(to_pci_dev(dev)) != PASID_MAX)
> > +			return -EINVAL;
> > +	}
> > +
> > +	/*
> > +	 * We only check host PASID range, we have no knowledge to check
> > +	 * guest PASID range nor do we use the guest PASID.
> guest pasid is set below in svm->gpasid.
> So I am confused, do you handle gpasid or not? If you don't use gpasid
> at the moment, then you may return -EINVAL if data->flags &
> IOMMU_SVA_GPASID_VAL.
> 
> I confess I don't really understand gpasid as I thought you use
> enlightened PASID allocation to use a system wide PASID allocator on
> host so in which case guest and host PASID do differ?

Correct, from within the guest, we only use the enlightned allocator.

Guest PASID can be managed via Qemu, and it will also associate
guest pasid's with appropriate host pasids. Sort of how guest bdf
and host bdf are managed for page-request etc.

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  reply index

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-09 13:44 [PATCH v4 00/22] Shared virtual address IOMMU and VT-d support Jacob Pan
2019-06-09 13:44 ` [PATCH v4 01/22] driver core: Add per device iommu param Jacob Pan
2019-06-09 13:44 ` [PATCH v4 02/22] iommu: Introduce device fault data Jacob Pan
2019-06-18 15:42   ` Jonathan Cameron
2019-06-09 13:44 ` [PATCH v4 03/22] iommu: Introduce device fault report API Jacob Pan
2019-06-18 15:41   ` Jonathan Cameron
2019-06-09 13:44 ` [PATCH v4 04/22] iommu: Add recoverable fault reporting Jacob Pan
2019-06-18 15:44   ` Jonathan Cameron
2019-06-09 13:44 ` [PATCH v4 05/22] iommu: Add a timeout parameter for PRQ response Jacob Pan
2019-06-09 13:44 ` [PATCH v4 06/22] trace/iommu: Add sva trace events Jacob Pan
2019-06-09 13:44 ` [PATCH v4 07/22] iommu: Use device fault trace event Jacob Pan
2019-06-09 13:44 ` [PATCH v4 08/22] iommu: Introduce attach/detach_pasid_table API Jacob Pan
2019-06-18 15:41   ` Jonathan Cameron
2019-06-24 15:06     ` Auger Eric
2019-06-24 15:23       ` Jean-Philippe Brucker
2019-06-09 13:44 ` [PATCH v4 09/22] iommu: Introduce cache_invalidate API Jacob Pan
2019-06-18 15:41   ` Jonathan Cameron
2019-06-09 13:44 ` [PATCH v4 10/22] iommu: Fix compile error without IOMMU_API Jacob Pan
2019-06-18 14:10   ` Jonathan Cameron
2019-06-24 22:28     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 11/22] iommu: Introduce guest PASID bind function Jacob Pan
2019-06-18 15:36   ` Jean-Philippe Brucker
2019-06-24 22:24     ` Jacob Pan
2019-07-16 16:44   ` Auger Eric
2019-08-05 21:02     ` Jacob Pan
2019-08-05 23:13     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 12/22] iommu: Add I/O ASID allocator Jacob Pan
2019-06-18 16:50   ` Jonathan Cameron
2019-06-25 18:55     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 13/22] iommu/vt-d: Enlightened PASID allocation Jacob Pan
2019-07-16  9:29   ` Auger Eric
2019-08-13 16:57     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 14/22] iommu/vt-d: Add custom allocator for IOASID Jacob Pan
2019-07-16  9:30   ` Auger Eric
2019-08-05 20:02     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 15/22] iommu/vt-d: Replace Intel specific PASID allocator with IOASID Jacob Pan
2019-06-18 15:57   ` Jonathan Cameron
2019-06-24 21:36     ` Jacob Pan
2019-06-27  1:53   ` Lu Baolu
2019-06-27 15:40     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 16/22] iommu/vt-d: Move domain helper to header Jacob Pan
2019-07-16  9:33   ` Auger Eric
2019-06-09 13:44 ` [PATCH v4 17/22] iommu/vt-d: Avoid duplicated code for PASID setup Jacob Pan
2019-06-18 16:03   ` Jonathan Cameron
2019-06-24 23:44     ` Jacob Pan
2019-07-16  9:52   ` Auger Eric
2019-06-09 13:44 ` [PATCH v4 18/22] iommu/vt-d: Add nested translation helper function Jacob Pan
2019-06-09 13:44 ` [PATCH v4 19/22] iommu/vt-d: Clean up for SVM device list Jacob Pan
2019-06-18 16:42   ` Jonathan Cameron
2019-06-24 23:59     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 20/22] iommu/vt-d: Add bind guest PASID support Jacob Pan
2019-06-18 16:44   ` Jonathan Cameron
2019-06-24 22:41     ` Jacob Pan
2019-06-27  2:50   ` Lu Baolu
2019-06-27 20:22     ` Jacob Pan
2019-07-05  2:21       ` Lu Baolu
2019-08-14 17:20         ` Jacob Pan
2019-07-16 16:45   ` Auger Eric
2019-07-16 17:04     ` Raj, Ashok [this message]
2019-07-18  7:47       ` Auger Eric
2019-06-09 13:44 ` [PATCH v4 21/22] iommu/vt-d: Support flushing more translation cache types Jacob Pan
2019-07-18  8:35   ` Auger Eric
2019-08-14 20:17     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 22/22] iommu/vt-d: Add svm/sva invalidate function Jacob Pan

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