From: Jason Gunthorpe <jgg@nvidia.com> To: "Raj, Ashok" <ashok.raj@intel.com> Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>, Jason Wang <jasowang@redhat.com>, Liu Yi L <yi.l.liu@intel.com>, <alex.williamson@redhat.com>, <eric.auger@redhat.com>, <baolu.lu@linux.intel.com>, <joro@8bytes.org>, <kevin.tian@intel.com>, <jacob.jun.pan@linux.intel.com>, <jun.j.tian@intel.com>, <yi.y.sun@intel.com>, <peterx@redhat.com>, <hao.wu@intel.com>, <stefanha@gmail.com>, <iommu@lists.linux-foundation.org>, <kvm@vger.kernel.org>, "Michael S. Tsirkin" <mst@redhat.com> Subject: Re: [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs Date: Mon, 14 Sep 2020 13:33:54 -0300 [thread overview] Message-ID: <20200914163354.GG904879@nvidia.com> (raw) In-Reply-To: <20200914162247.GA63399@otc-nc-03> On Mon, Sep 14, 2020 at 09:22:47AM -0700, Raj, Ashok wrote: > Hi Jason, > > On Mon, Sep 14, 2020 at 10:47:38AM -0300, Jason Gunthorpe wrote: > > On Mon, Sep 14, 2020 at 03:31:13PM +0200, Jean-Philippe Brucker wrote: > > > > > > Jason suggest something like /dev/sva. There will be a lot of other > > > > subsystems that could benefit from this (e.g vDPA). > > > > > > Do you have a more precise idea of the interface /dev/sva would provide, > > > how it would interact with VFIO and others? vDPA could transport the > > > generic iommu.h structures via its own uAPI, and call the IOMMU API > > > directly without going through an intermediate /dev/sva handle. > > > > Prior to PASID IOMMU really only makes sense as part of vfio-pci > > because the iommu can only key on the BDF. That can't work unless the > > whole PCI function can be assigned. It is hard to see how a shared PCI > > device can work with IOMMU like this, so may as well use vfio. > > > > SVA and various vIOMMU models change this, a shared PCI driver can > > absoultely work with a PASID that is assigned to a VM safely, and > > actually don't need to know if their PASID maps a mm_struct or > > something else. > > Well, IOMMU does care if its a native mm_struct or something that belongs > to guest. Because you need ability to forward page-requests and pickup > page-responses from guest. Since there is just one PRQ on the IOMMU and > responses can't be sent directly. You have to depend on vIOMMU type > interface in guest to make all of this magic work right? Yes, IOMMU cares, but not the PCI Driver. It just knows it has a PASID. Details on how page faultings is handled or how the mapping is setup is abstracted by the PASID. > > This new PASID allocator would match the guest memory layout and > > Not sure what you mean by "match guest memory layout"? > Probably, meaning first level is gVA or gIOVA? It means whatever the qemu/viommu/guest/etc needs across all the IOMMU/arch implementations. Basically, there should only be two ways to get a PASID - From mm_struct that mirrors the creating process - Via '/dev/sva' which has an complete interface to create and control a PASID suitable for virtualization and more VFIO should not have its own special way to get a PASID. Jason
WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@nvidia.com> To: "Raj, Ashok" <ashok.raj@intel.com> Cc: yi.y.sun@intel.com, Jean-Philippe Brucker <jean-philippe@linaro.org>, kevin.tian@intel.com, kvm@vger.kernel.org, iommu@lists.linux-foundation.org, stefanha@gmail.com, Jason Wang <jasowang@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, jun.j.tian@intel.com, alex.williamson@redhat.com, hao.wu@intel.com Subject: Re: [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs Date: Mon, 14 Sep 2020 13:33:54 -0300 [thread overview] Message-ID: <20200914163354.GG904879@nvidia.com> (raw) In-Reply-To: <20200914162247.GA63399@otc-nc-03> On Mon, Sep 14, 2020 at 09:22:47AM -0700, Raj, Ashok wrote: > Hi Jason, > > On Mon, Sep 14, 2020 at 10:47:38AM -0300, Jason Gunthorpe wrote: > > On Mon, Sep 14, 2020 at 03:31:13PM +0200, Jean-Philippe Brucker wrote: > > > > > > Jason suggest something like /dev/sva. There will be a lot of other > > > > subsystems that could benefit from this (e.g vDPA). > > > > > > Do you have a more precise idea of the interface /dev/sva would provide, > > > how it would interact with VFIO and others? vDPA could transport the > > > generic iommu.h structures via its own uAPI, and call the IOMMU API > > > directly without going through an intermediate /dev/sva handle. > > > > Prior to PASID IOMMU really only makes sense as part of vfio-pci > > because the iommu can only key on the BDF. That can't work unless the > > whole PCI function can be assigned. It is hard to see how a shared PCI > > device can work with IOMMU like this, so may as well use vfio. > > > > SVA and various vIOMMU models change this, a shared PCI driver can > > absoultely work with a PASID that is assigned to a VM safely, and > > actually don't need to know if their PASID maps a mm_struct or > > something else. > > Well, IOMMU does care if its a native mm_struct or something that belongs > to guest. Because you need ability to forward page-requests and pickup > page-responses from guest. Since there is just one PRQ on the IOMMU and > responses can't be sent directly. You have to depend on vIOMMU type > interface in guest to make all of this magic work right? Yes, IOMMU cares, but not the PCI Driver. It just knows it has a PASID. Details on how page faultings is handled or how the mapping is setup is abstracted by the PASID. > > This new PASID allocator would match the guest memory layout and > > Not sure what you mean by "match guest memory layout"? > Probably, meaning first level is gVA or gIOVA? It means whatever the qemu/viommu/guest/etc needs across all the IOMMU/arch implementations. Basically, there should only be two ways to get a PASID - From mm_struct that mirrors the creating process - Via '/dev/sva' which has an complete interface to create and control a PASID suitable for virtualization and more VFIO should not have its own special way to get a PASID. Jason _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2020-09-14 16:34 UTC|newest] Thread overview: 165+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-09-10 10:45 [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-10 10:45 ` [PATCH v7 01/16] iommu: Report domain nesting info Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-11 19:38 ` Alex Williamson 2020-09-11 19:38 ` Alex Williamson 2020-09-10 10:45 ` [PATCH v7 02/16] iommu/smmu: Report empty " Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2021-01-12 6:50 ` Vivek Gautam 2021-01-12 6:50 ` Vivek Gautam 2021-01-12 9:21 ` Liu, Yi L 2021-01-12 9:21 ` Liu, Yi L 2021-01-12 11:05 ` Vivek Gautam 2021-01-12 11:05 ` Vivek Gautam 2021-01-13 5:56 ` Liu, Yi L 2021-01-13 5:56 ` Liu, Yi L 2021-01-19 10:03 ` Auger Eric 2021-01-19 10:03 ` Auger Eric 2021-01-23 8:59 ` Liu, Yi L 2021-01-23 8:59 ` Liu, Yi L 2021-02-12 7:14 ` Vivek Gautam 2021-02-12 7:14 ` Vivek Gautam 2021-02-12 9:57 ` Auger Eric 2021-02-12 9:57 ` Auger Eric 2021-02-12 10:18 ` Vivek Kumar Gautam 2021-02-12 10:18 ` Vivek Kumar Gautam 2021-02-12 11:01 ` Vivek Kumar Gautam 2021-02-12 11:01 ` Vivek Kumar Gautam 2021-03-03 9:44 ` Liu, Yi L 2021-03-03 9:44 ` Liu, Yi L 2020-09-10 10:45 ` [PATCH v7 03/16] vfio/type1: Report iommu nesting info to userspace Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-11 20:16 ` Alex Williamson 2020-09-11 20:16 ` Alex Williamson 2020-09-12 8:24 ` Liu, Yi L 2020-09-12 8:24 ` Liu, Yi L 2020-09-10 10:45 ` [PATCH v7 04/16] vfio: Add PASID allocation/free support Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-11 20:54 ` Alex Williamson 2020-09-11 20:54 ` Alex Williamson 2020-09-15 4:03 ` Liu, Yi L 2020-09-15 4:03 ` Liu, Yi L 2020-09-10 10:45 ` [PATCH v7 05/16] iommu/vt-d: Support setting ioasid set to domain Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-10 10:45 ` [PATCH v7 06/16] iommu/vt-d: Remove get_task_mm() in bind_gpasid() Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-10 10:45 ` [PATCH v7 07/16] vfio/type1: Add VFIO_IOMMU_PASID_REQUEST (alloc/free) Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-11 21:38 ` Alex Williamson 2020-09-11 21:38 ` Alex Williamson 2020-09-12 6:17 ` Liu, Yi L 2020-09-10 10:45 ` [PATCH v7 08/16] iommu: Pass domain to sva_unbind_gpasid() Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-10 10:45 ` [PATCH v7 09/16] iommu/vt-d: Check ownership for PASIDs from user-space Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-10 10:45 ` [PATCH v7 10/16] vfio/type1: Support binding guest page tables to PASID Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-11 22:03 ` Alex Williamson 2020-09-11 22:03 ` Alex Williamson 2020-09-12 6:02 ` Liu, Yi L 2020-09-12 6:02 ` Liu, Yi L 2020-09-10 10:45 ` [PATCH v7 11/16] vfio/type1: Allow invalidating first-level/stage IOMMU cache Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-10 10:45 ` [PATCH v7 12/16] vfio/type1: Add vSVA support for IOMMU-backed mdevs Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-10 10:45 ` [PATCH v7 13/16] vfio/pci: Expose PCIe PASID capability to guest Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-11 22:13 ` Alex Williamson 2020-09-11 22:13 ` Alex Williamson 2020-09-12 7:17 ` Liu, Yi L 2020-09-12 7:17 ` Liu, Yi L 2020-09-10 10:45 ` [PATCH v7 14/16] vfio: Document dual stage control Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-10 10:45 ` [PATCH v7 15/16] iommu/vt-d: Only support nesting when nesting caps are consistent across iommu units Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-10 10:45 ` [PATCH v7 16/16] iommu/vt-d: Support reporting nesting capability info Liu Yi L 2020-09-10 10:45 ` Liu Yi L 2020-09-14 4:20 ` [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs Jason Wang 2020-09-14 4:20 ` Jason Wang 2020-09-14 8:01 ` Tian, Kevin 2020-09-14 8:01 ` Tian, Kevin 2020-09-14 8:57 ` Jason Wang 2020-09-14 8:57 ` Jason Wang 2020-09-14 10:38 ` Tian, Kevin 2020-09-14 10:38 ` Tian, Kevin 2020-09-14 11:38 ` Jason Gunthorpe 2020-09-14 11:38 ` Jason Gunthorpe 2020-09-14 13:31 ` Jean-Philippe Brucker 2020-09-14 13:31 ` Jean-Philippe Brucker 2020-09-14 13:47 ` Jason Gunthorpe 2020-09-14 13:47 ` Jason Gunthorpe 2020-09-14 16:22 ` Raj, Ashok 2020-09-14 16:22 ` Raj, Ashok 2020-09-14 16:33 ` Jason Gunthorpe [this message] 2020-09-14 16:33 ` Jason Gunthorpe 2020-09-14 16:58 ` Alex Williamson 2020-09-14 16:58 ` Alex Williamson 2020-09-14 17:41 ` Jason Gunthorpe 2020-09-14 17:41 ` Jason Gunthorpe 2020-09-14 18:23 ` Alex Williamson 2020-09-14 18:23 ` Alex Williamson 2020-09-14 19:00 ` Jason Gunthorpe 2020-09-14 19:00 ` Jason Gunthorpe 2020-09-14 22:33 ` Alex Williamson 2020-09-14 22:33 ` Alex Williamson 2020-09-15 14:29 ` Jason Gunthorpe 2020-09-15 14:29 ` Jason Gunthorpe 2020-09-16 1:19 ` Tian, Kevin 2020-09-16 1:19 ` Tian, Kevin 2020-09-16 8:32 ` Jean-Philippe Brucker 2020-09-16 8:32 ` Jean-Philippe Brucker 2020-09-16 14:51 ` Jason Gunthorpe 2020-09-16 14:51 ` Jason Gunthorpe 2020-09-16 16:20 ` Jean-Philippe Brucker 2020-09-16 16:20 ` Jean-Philippe Brucker 2020-09-16 16:32 ` Jason Gunthorpe 2020-09-16 16:32 ` Jason Gunthorpe 2020-09-16 16:50 ` Auger Eric 2020-09-16 16:50 ` Auger Eric 2020-09-16 14:44 ` Jason Gunthorpe 2020-09-16 14:44 ` Jason Gunthorpe 2020-09-17 6:01 ` Tian, Kevin 2020-09-17 6:01 ` Tian, Kevin 2020-09-14 22:44 ` Raj, Ashok 2020-09-15 11:33 ` Jason Gunthorpe 2020-09-15 11:33 ` Jason Gunthorpe 2020-09-15 18:11 ` Raj, Ashok 2020-09-15 18:11 ` Raj, Ashok 2020-09-15 18:45 ` Jason Gunthorpe 2020-09-15 18:45 ` Jason Gunthorpe 2020-09-15 19:26 ` Raj, Ashok 2020-09-15 19:26 ` Raj, Ashok 2020-09-15 23:45 ` Jason Gunthorpe 2020-09-15 23:45 ` Jason Gunthorpe 2020-09-16 2:33 ` Jason Wang 2020-09-16 2:33 ` Jason Wang 2020-09-15 22:08 ` Jacob Pan 2020-09-15 22:08 ` Jacob Pan 2020-09-15 23:51 ` Jason Gunthorpe 2020-09-15 23:51 ` Jason Gunthorpe 2020-09-16 0:22 ` Jacob Pan (Jun) 2020-09-16 1:46 ` Lu Baolu 2020-09-16 1:46 ` Lu Baolu 2020-09-16 15:07 ` Jason Gunthorpe 2020-09-16 15:07 ` Jason Gunthorpe 2020-09-16 16:33 ` Raj, Ashok 2020-09-16 16:33 ` Raj, Ashok 2020-09-16 17:01 ` Jason Gunthorpe 2020-09-16 17:01 ` Jason Gunthorpe 2020-09-16 18:21 ` Jacob Pan (Jun) 2020-09-16 18:21 ` Jacob Pan (Jun) 2020-09-16 18:38 ` Jason Gunthorpe 2020-09-16 18:38 ` Jason Gunthorpe 2020-09-16 23:09 ` Jacob Pan (Jun) 2020-09-16 23:09 ` Jacob Pan (Jun) 2020-09-17 3:53 ` Jason Wang 2020-09-17 3:53 ` Jason Wang 2020-09-17 17:31 ` Jason Gunthorpe 2020-09-17 17:31 ` Jason Gunthorpe 2020-09-17 18:17 ` Jacob Pan (Jun) 2020-09-17 18:17 ` Jacob Pan (Jun) 2020-09-18 3:58 ` Jason Wang 2020-09-18 3:58 ` Jason Wang 2020-09-16 2:29 ` Jason Wang 2020-09-16 2:29 ` Jason Wang
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