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From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: Auger Eric <eric.auger@redhat.com>
Cc: iommu@lists.linux-foundation.org,
	LKML <linux-kernel@vger.kernel.org>,
	Joerg Roedel <joro@8bytes.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alex Williamson <alex.williamson@redhat.com>,
	Jean-Philippe Brucker <jean-philippe.brucker@arm.com>,
	Yi L <yi.l.liu@linux.intel.com>, Raj Ashok <ashok.raj@intel.com>,
	Rafael Wysocki <rafael.j.wysocki@intel.com>,
	Liu@mail.linuxfoundation.org, Jean Delvare <khali@linux-fr.org>,
	jacob.jun.pan@linux.intel.com
Subject: Re: [PATCH v5 01/23] iommu: introduce bind_pasid_table API function
Date: Mon, 27 Aug 2018 22:14:22 -0700	[thread overview]
Message-ID: <20180827221422.57e233df@jacob-builder> (raw)
In-Reply-To: <b6621306-fd32-7ede-ae88-7345898eb134@redhat.com>

On Fri, 24 Aug 2018 17:00:51 +0200
Auger Eric <eric.auger@redhat.com> wrote:

> Hi Jacob,
> 
> On 05/11/2018 10:53 PM, Jacob Pan wrote:
> > Virtual IOMMU was proposed to support Shared Virtual Memory (SVM)
> > use in the guest:
> > https://lists.gnu.org/archive/html/qemu-devel/2016-11/msg05311.html
> > 
> > As part of the proposed architecture, when an SVM capable PCI
> > device is assigned to a guest, nested mode is turned on. Guest owns
> > the first level page tables (request with PASID) which performs
> > GVA->GPA translation. Second level page tables are owned by the
> > host for GPA->HPA translation for both request with and without
> > PASID.
> > 
> > A new IOMMU driver interface is therefore needed to perform tasks as
> > follows:
> > * Enable nested translation and appropriate translation type
> > * Assign guest PASID table pointer (in GPA) and size to host IOMMU
> > 
> > This patch introduces new API functions to perform bind/unbind
> > guest PASID tables. Based on common data, model specific IOMMU
> > drivers can be extended to perform the specific steps for binding
> > pasid table of assigned devices.
> > 
> > Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
> > Signed-off-by: Liu, Yi L <yi.l.liu@linux.intel.com>
> > Signed-off-by: Ashok Raj <ashok.raj@intel.com>
> > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> > ---
> >  drivers/iommu/iommu.c      | 19 +++++++++++++++++++
> >  include/linux/iommu.h      | 24 ++++++++++++++++++++++++
> >  include/uapi/linux/iommu.h | 33 +++++++++++++++++++++++++++++++++
> >  3 files changed, 76 insertions(+)
> >  create mode 100644 include/uapi/linux/iommu.h
> > 
> > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> > index d2aa2320..3a69620 100644
> > --- a/drivers/iommu/iommu.c
> > +++ b/drivers/iommu/iommu.c
> > @@ -1325,6 +1325,25 @@ int iommu_attach_device(struct iommu_domain
> > *domain, struct device *dev) }
> >  EXPORT_SYMBOL_GPL(iommu_attach_device);
> >  
> > +int iommu_bind_pasid_table(struct iommu_domain *domain, struct
> > device *dev,
> > +			struct pasid_table_config *pasidt_binfo)  
> As Jean-Philippe, I must confessed i am very confused by having both
> the iommu_domain and dev passed as argument.
> 
> I know this was discussed when the RFC was submitted and maybe I
> missed the main justification behind that choice. I understand that
> at the HW level we want to change the context entry or ARM CD in my
> case for a specific device. But on other hand, at the logical level,
> I understand the iommu_domain is representing a set of translation
> config & page tables shared by all the devices within the domain
> (hope this is fundamentally correct ?!). So to me we can't change the
> device translation setup without changing the whole iommu_device setup
> otherwise this would mean this device has a translation configuration
> that is not consistent anymore with the other devices in the same
> domain. Is that correct? So can't we only keep the iommu_domain arg?
> 
I agree with you on your understanding of HW and logical level. I think
there is a new twist to the definition of domain introduced by having
PASID and vSVA. Up until now, domain only means 2nd level mapping. In
that sense, bind guest PASID table does not alter domain. For VT-d 2.5
spec. implementation of the bind_pasid_table(), we needed some per
device data, also flags such as indication for IO page fault handling.

Anyway, for the new VT-d 3.0 spec. we no longer need this API. In
stead, I will introduce bind_guest_pasid() API, where per device PASID
table is allocated by the host.

> > +{
> > +	if (unlikely(!domain->ops->bind_pasid_table))
> > +		return -ENODEV;
> > +
> > +	return domain->ops->bind_pasid_table(domain, dev,
> > pasidt_binfo); +}
> > +EXPORT_SYMBOL_GPL(iommu_bind_pasid_table);
> > +
> > +void iommu_unbind_pasid_table(struct iommu_domain *domain, struct
> > device *dev) +{
> > +	if (unlikely(!domain->ops->unbind_pasid_table))
> > +		return;
> > +
> > +	domain->ops->unbind_pasid_table(domain, dev);
> > +}
> > +EXPORT_SYMBOL_GPL(iommu_unbind_pasid_table);
> > +
> >  static void __iommu_detach_device(struct iommu_domain *domain,
> >  				  struct device *dev)
> >  {
> > diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> > index 19938ee..5199ca4 100644
> > --- a/include/linux/iommu.h
> > +++ b/include/linux/iommu.h
> > @@ -25,6 +25,7 @@
> >  #include <linux/errno.h>
> >  #include <linux/err.h>
> >  #include <linux/of.h>
> > +#include <uapi/linux/iommu.h>
> >  
> >  #define IOMMU_READ	(1 << 0)
> >  #define IOMMU_WRITE	(1 << 1)
> > @@ -187,6 +188,8 @@ struct iommu_resv_region {
> >   * @domain_get_windows: Return the number of windows for a domain
> >   * @of_xlate: add OF master IDs to iommu grouping
> >   * @pgsize_bitmap: bitmap of all possible supported page sizes
> > + * @bind_pasid_table: bind pasid table pointer for guest SVM
> > + * @unbind_pasid_table: unbind pasid table pointer and restore
> > defaults */
> >  struct iommu_ops {
> >  	bool (*capable)(enum iommu_cap);
> > @@ -233,8 +236,14 @@ struct iommu_ops {
> >  	u32 (*domain_get_windows)(struct iommu_domain *domain);
> >  
> >  	int (*of_xlate)(struct device *dev, struct of_phandle_args
> > *args); +
> >  	bool (*is_attach_deferred)(struct iommu_domain *domain,
> > struct device *dev); 
> > +	int (*bind_pasid_table)(struct iommu_domain *domain,
> > struct device *dev,
> > +				struct pasid_table_config
> > *pasidt_binfo);
> > +	void (*unbind_pasid_table)(struct iommu_domain *domain,
> > +				struct device *dev);
> > +
> >  	unsigned long pgsize_bitmap;
> >  };
> >  
> > @@ -296,6 +305,10 @@ extern int iommu_attach_device(struct
> > iommu_domain *domain, struct device *dev);
> >  extern void iommu_detach_device(struct iommu_domain *domain,
> >  				struct device *dev);
> > +extern int iommu_bind_pasid_table(struct iommu_domain *domain,
> > +		struct device *dev, struct pasid_table_config
> > *pasidt_binfo); +extern void iommu_unbind_pasid_table(struct
> > iommu_domain *domain,
> > +				struct device *dev);
> >  extern struct iommu_domain *iommu_get_domain_for_dev(struct device
> > *dev); extern int iommu_map(struct iommu_domain *domain, unsigned
> > long iova, phys_addr_t paddr, size_t size, int prot);
> > @@ -696,6 +709,17 @@ const struct iommu_ops
> > *iommu_ops_from_fwnode(struct fwnode_handle *fwnode) return NULL;
> >  }
> >  
> > +static inline
> > +int iommu_bind_pasid_table(struct iommu_domain *domain, struct
> > device *dev,
> > +			struct pasid_table_config *pasidt_binfo)
> > +{
> > +	return -ENODEV;
> > +}
> > +static inline
> > +void iommu_unbind_pasid_table(struct iommu_domain *domain, struct
> > device *dev) +{
> > +}
> > +
> >  #endif /* CONFIG_IOMMU_API */
> >  
> >  #endif /* __LINUX_IOMMU_H */
> > diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
> > new file mode 100644
> > index 0000000..cb2d625
> > --- /dev/null
> > +++ b/include/uapi/linux/iommu.h
> > @@ -0,0 +1,33 @@
> > +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> > +/*
> > + * IOMMU user API definitions
> > + *
> > + *
> > + * This program is free software; you can redistribute it and/or
> > modify
> > + * it under the terms of the GNU General Public License version 2
> > as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#ifndef _UAPI_IOMMU_H
> > +#define _UAPI_IOMMU_H
> > +
> > +#include <linux/types.h>
> > +
> > +/**
> > + * PASID table data used to bind guest PASID table to the host
> > IOMMU. This will
> > + * enable guest managed first level page tables.
> > + * @version: for future extensions and identification of the data
> > format
> > + * @bytes: size of this structure
> > + * @base_ptr:	PASID table pointer
> > + * @pasid_bits:	number of bits supported in the guest PASID
> > table, must be less
> > + *		or equal than the host supported PASID size.
> > + */
> > +struct pasid_table_config {
> > +	__u32 version;
> > +#define PASID_TABLE_CFG_VERSION_1 1
> > +	__u32 bytes;
> > +	__u64 base_ptr;
> > +	__u8 pasid_bits;
> > +};  
> Don't we need to index all structs with iommu_ to protect the naming
> spaces? Same comment on other patches impacting the uapi.
> 
yeah, it would be better to use iommu_ prefix, i was thinking vfio also
uses it and pasid itself is a industry standard.
> A question about the alignment. Don't we need to be 64b aligned? VFIO
> uapi structs are.
> 
I am not sure about the benefit, this is not a HW interface nor on
speed path.
> Thanks
> 
> Eric
> > +
> > +#endif /* _UAPI_IOMMU_H */
> >   

[Jacob Pan]

  reply	other threads:[~2018-08-28  5:12 UTC|newest]

Thread overview: 81+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-11 20:53 [PATCH v5 00/23] IOMMU and VT-d driver support for Shared Virtual Address (SVA) Jacob Pan
2018-05-11 20:53 ` [PATCH v5 01/23] iommu: introduce bind_pasid_table API function Jacob Pan
2018-08-23 16:34   ` Auger Eric
2018-08-24 12:47     ` Liu, Yi L
2018-08-24 13:20       ` Auger Eric
2018-08-28 17:04         ` Jacob Pan
2018-08-24 15:00   ` Auger Eric
2018-08-28  5:14     ` Jacob Pan [this message]
2018-08-28  8:34       ` Auger Eric
2018-08-28 16:36         ` Jacob Pan
2018-05-11 20:53 ` [PATCH v5 02/23] iommu/vt-d: move device_domain_info to header Jacob Pan
2018-05-11 20:53 ` [PATCH v5 03/23] iommu/vt-d: add a flag for pasid table bound status Jacob Pan
2018-05-13  7:33   ` Lu Baolu
2018-05-14 18:51     ` Jacob Pan
2018-05-13  8:01   ` Lu Baolu
2018-05-14 18:52     ` Jacob Pan
2018-05-11 20:53 ` [PATCH v5 04/23] iommu/vt-d: add bind_pasid_table function Jacob Pan
2018-05-13  9:29   ` Lu Baolu
2018-05-14 20:22     ` Jacob Pan
2018-05-11 20:53 ` [PATCH v5 05/23] iommu: introduce iommu invalidate API function Jacob Pan
2018-05-11 20:53 ` [PATCH v5 06/23] iommu/vt-d: add definitions for PFSID Jacob Pan
2018-05-14  1:36   ` Lu Baolu
2018-05-14 20:30     ` Jacob Pan
2018-05-11 20:53 ` [PATCH v5 07/23] iommu/vt-d: fix dev iotlb pfsid use Jacob Pan
2018-05-14  1:52   ` Lu Baolu
2018-05-14 20:38     ` Jacob Pan
2018-05-11 20:54 ` [PATCH v5 08/23] iommu/vt-d: support flushing more translation cache types Jacob Pan
2018-05-14  2:18   ` Lu Baolu
2018-05-14 20:46     ` Jacob Pan
2018-05-17  8:44   ` kbuild test robot
2018-05-11 20:54 ` [PATCH v5 09/23] iommu/vt-d: add svm/sva invalidate function Jacob Pan
2018-05-14  3:35   ` Lu Baolu
2018-05-14 20:49     ` Jacob Pan
2018-05-11 20:54 ` [PATCH v5 10/23] iommu: introduce device fault data Jacob Pan
2018-09-21 10:07   ` Auger Eric
2018-09-21 17:05     ` Jacob Pan
2018-09-26 10:20       ` Auger Eric
2018-05-11 20:54 ` [PATCH v5 11/23] driver core: add per device iommu param Jacob Pan
2018-05-14  5:27   ` Lu Baolu
2018-05-14 20:52     ` Jacob Pan
2018-05-11 20:54 ` [PATCH v5 12/23] iommu: add a timeout parameter for prq response Jacob Pan
2018-05-11 20:54 ` [PATCH v5 13/23] iommu: introduce device fault report API Jacob Pan
2018-05-14  6:01   ` Lu Baolu
2018-05-14 20:55     ` Jacob Pan
2018-05-15  6:52       ` Lu Baolu
2018-05-17 11:41   ` Liu, Yi L
2018-05-17 15:59     ` Jacob Pan
2018-05-17 23:22       ` Liu, Yi L
2018-05-21 23:03         ` Jacob Pan
2018-09-06  9:25   ` Auger Eric
2018-09-06 12:42     ` Jean-Philippe Brucker
2018-09-06 13:14       ` Auger Eric
2018-09-06 17:06         ` Jean-Philippe Brucker
2018-09-07  7:11           ` Auger Eric
2018-09-07 11:23             ` Jean-Philippe Brucker
2018-09-14 13:24   ` Auger Eric
2018-09-17 16:57     ` Jacob Pan
2018-09-25 14:58   ` Jean-Philippe Brucker
2018-09-25 22:17     ` Jacob Pan
2018-09-26 10:14       ` Jean-Philippe Brucker
2018-05-11 20:54 ` [PATCH v5 14/23] iommu: introduce page response function Jacob Pan
2018-05-14  6:39   ` Lu Baolu
2018-05-29 16:13     ` Jacob Pan
2018-09-10 14:52   ` Auger Eric
2018-09-10 17:50     ` Jacob Pan
2018-09-10 19:06       ` Auger Eric
2018-05-11 20:54 ` [PATCH v5 15/23] iommu: handle page response timeout Jacob Pan
2018-05-14  7:43   ` Lu Baolu
2018-05-29 16:20     ` Jacob Pan
2018-05-30  7:46       ` Lu Baolu
2018-05-11 20:54 ` [PATCH v5 16/23] iommu/config: add build dependency for dmar Jacob Pan
2018-05-11 20:54 ` [PATCH v5 17/23] iommu/vt-d: report non-recoverable faults to device Jacob Pan
2018-05-14  8:17   ` Lu Baolu
2018-05-29 17:33     ` Jacob Pan
2018-05-11 20:54 ` [PATCH v5 18/23] iommu/intel-svm: report device page request Jacob Pan
2018-05-11 20:54 ` [PATCH v5 19/23] iommu/intel-svm: replace dev ops with fault report API Jacob Pan
2018-05-11 20:54 ` [PATCH v5 20/23] iommu/intel-svm: do not flush iotlb for viommu Jacob Pan
2018-05-11 20:54 ` [PATCH v5 21/23] iommu/vt-d: add intel iommu page response function Jacob Pan
2018-05-11 20:54 ` [PATCH v5 22/23] trace/iommu: add sva trace events Jacob Pan
2018-05-11 20:54 ` [PATCH v5 23/23] iommu: use sva invalidate and device fault trace event Jacob Pan
2018-05-29 15:54 ` [PATCH v5 00/23] IOMMU and VT-d driver support for Shared Virtual Address (SVA) Jacob Pan

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