From: Auger Eric <eric.auger@redhat.com> To: "Tian, Kevin" <kevin.tian@intel.com>, Jacob Pan <jacob.jun.pan@linux.intel.com> Cc: Yi L <yi.l.liu@linux.intel.com>, Alex Williamson <alex.williamson@redhat.com>, "Raj, Ashok" <ashok.raj@intel.com>, David Woodhouse <dwmw2@infradead.org>, LKML <linux-kernel@vger.kernel.org>, "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>, Jean-Philippe Brucker <jean-philippe@linaro.com>, Jonathan Cameron <jic23@kernel.org> Subject: Re: [PATCH v11 05/10] iommu/vt-d: Add bind guest PASID support Date: Fri, 17 Apr 2020 09:46:55 +0200 [thread overview] Message-ID: <2025736d-e7f2-d746-e030-e609b2f465e2@redhat.com> (raw) In-Reply-To: <AADFC41AFE54684AB9EE6CBC0274A5D19D824106@SHSMSX104.ccr.corp.intel.com> Hi Kevin, On 4/17/20 4:45 AM, Tian, Kevin wrote: >> From: Auger Eric >> Sent: Thursday, April 16, 2020 6:43 PM >> > [...] >>>>> + if (svm) { >>>>> + /* >>>>> + * If we found svm for the PASID, there must be at >>>>> + * least one device bond, otherwise svm should be >>>>> freed. >>>>> + */ >>>>> + if (WARN_ON(list_empty(&svm->devs))) { >>>>> + ret = -EINVAL; >>>>> + goto out; >>>>> + } >>>>> + >>>>> + for_each_svm_dev(sdev, svm, dev) { >>>>> + /* In case of multiple sub-devices of the >>>>> same pdev >>>>> + * assigned, we should allow multiple bind >>>>> calls with >>>>> + * the same PASID and pdev. >>>>> + */ >>>>> + sdev->users++; >>>> What if this is not an mdev device. Is it also allowed? >>> Yes. IOMMU and VT-d driver is not mdev aware. Here mdev is just an >>> example of normal use case. You can bind the same PCI device (PF or >>> SRIOV VF) more than once to the same PASID. Just need to unbind also. >> >> I don't get the point of binding a non mdev device several times with >> the same PASID. Do you intend to allow that at userspace level or >> prevent this from happening in VFIO? > > I feel it's better to prevent this from happening, otherwise VFIO also > needs to track the bind count and do multiple unbinds at mm_exit. > But it's not necessary to prevent it in VFIO. We can check here > upon whether aux_domain is valid, and if not return -EBUSY. Ah OK. So if we can detect the case here it is even better Thanks Eric > >> >> Besides, the comment is a bit misleading as it gives the impression it >> is only true for mdev and there is no associated check. > > Thanks > Kevin >
WARNING: multiple messages have this Message-ID (diff)
From: Auger Eric <eric.auger@redhat.com> To: "Tian, Kevin" <kevin.tian@intel.com>, Jacob Pan <jacob.jun.pan@linux.intel.com> Cc: Yi L <yi.l.liu@linux.intel.com>, "Raj, Ashok" <ashok.raj@intel.com>, Jean-Philippe Brucker <jean-philippe@linaro.com>, "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>, LKML <linux-kernel@vger.kernel.org>, Alex Williamson <alex.williamson@redhat.com>, David Woodhouse <dwmw2@infradead.org>, Jonathan Cameron <jic23@kernel.org> Subject: Re: [PATCH v11 05/10] iommu/vt-d: Add bind guest PASID support Date: Fri, 17 Apr 2020 09:46:55 +0200 [thread overview] Message-ID: <2025736d-e7f2-d746-e030-e609b2f465e2@redhat.com> (raw) In-Reply-To: <AADFC41AFE54684AB9EE6CBC0274A5D19D824106@SHSMSX104.ccr.corp.intel.com> Hi Kevin, On 4/17/20 4:45 AM, Tian, Kevin wrote: >> From: Auger Eric >> Sent: Thursday, April 16, 2020 6:43 PM >> > [...] >>>>> + if (svm) { >>>>> + /* >>>>> + * If we found svm for the PASID, there must be at >>>>> + * least one device bond, otherwise svm should be >>>>> freed. >>>>> + */ >>>>> + if (WARN_ON(list_empty(&svm->devs))) { >>>>> + ret = -EINVAL; >>>>> + goto out; >>>>> + } >>>>> + >>>>> + for_each_svm_dev(sdev, svm, dev) { >>>>> + /* In case of multiple sub-devices of the >>>>> same pdev >>>>> + * assigned, we should allow multiple bind >>>>> calls with >>>>> + * the same PASID and pdev. >>>>> + */ >>>>> + sdev->users++; >>>> What if this is not an mdev device. Is it also allowed? >>> Yes. IOMMU and VT-d driver is not mdev aware. Here mdev is just an >>> example of normal use case. You can bind the same PCI device (PF or >>> SRIOV VF) more than once to the same PASID. Just need to unbind also. >> >> I don't get the point of binding a non mdev device several times with >> the same PASID. Do you intend to allow that at userspace level or >> prevent this from happening in VFIO? > > I feel it's better to prevent this from happening, otherwise VFIO also > needs to track the bind count and do multiple unbinds at mm_exit. > But it's not necessary to prevent it in VFIO. We can check here > upon whether aux_domain is valid, and if not return -EBUSY. Ah OK. So if we can detect the case here it is even better Thanks Eric > >> >> Besides, the comment is a bit misleading as it gives the impression it >> is only true for mdev and there is no associated check. > > Thanks > Kevin > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2020-04-17 7:47 UTC|newest] Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-04-03 18:42 [PATCH v11 00/10] Nested Shared Virtual Address (SVA) VT-d support Jacob Pan 2020-04-03 18:42 ` Jacob Pan 2020-04-03 18:42 ` [PATCH v11 01/10] iommu/vt-d: Move domain helper to header Jacob Pan 2020-04-03 18:42 ` Jacob Pan 2020-04-03 18:42 ` [PATCH v11 02/10] iommu/uapi: Define a mask for bind data Jacob Pan 2020-04-03 18:42 ` Jacob Pan 2020-04-08 13:07 ` Joerg Roedel 2020-04-08 13:07 ` Joerg Roedel 2020-04-08 16:11 ` Jacob Pan 2020-04-08 16:11 ` Jacob Pan 2020-04-03 18:42 ` [PATCH v11 03/10] iommu/vt-d: Use a helper function to skip agaw for SL Jacob Pan 2020-04-03 18:42 ` Jacob Pan 2020-04-05 6:37 ` Auger Eric 2020-04-05 6:37 ` Auger Eric 2020-04-03 18:42 ` [PATCH v11 04/10] iommu/vt-d: Add nested translation helper function Jacob Pan 2020-04-03 18:42 ` Jacob Pan 2020-04-08 13:33 ` Auger Eric 2020-04-08 13:33 ` Auger Eric 2020-04-10 23:54 ` kbuild test robot 2020-04-03 18:42 ` [PATCH v11 05/10] iommu/vt-d: Add bind guest PASID support Jacob Pan 2020-04-03 18:42 ` Jacob Pan 2020-04-09 7:41 ` Auger Eric 2020-04-09 7:41 ` Auger Eric 2020-04-10 19:45 ` Jacob Pan 2020-04-10 19:45 ` Jacob Pan 2020-04-16 10:43 ` Auger Eric 2020-04-16 10:43 ` Auger Eric 2020-04-17 2:45 ` Tian, Kevin 2020-04-17 2:45 ` Tian, Kevin 2020-04-17 7:46 ` Auger Eric [this message] 2020-04-17 7:46 ` Auger Eric 2020-04-17 15:28 ` Jacob Pan 2020-04-17 15:28 ` Jacob Pan 2020-04-17 23:46 ` Tian, Kevin 2020-04-17 23:46 ` Tian, Kevin 2020-04-27 17:28 ` Jacob Pan 2020-04-27 17:28 ` Jacob Pan 2020-04-10 21:06 ` Jacob Pan 2020-04-10 21:06 ` Jacob Pan 2020-04-16 10:46 ` Auger Eric 2020-04-16 10:46 ` Auger Eric 2020-04-03 18:42 ` [PATCH v11 06/10] iommu/vt-d: Support flushing more translation cache types Jacob Pan 2020-04-03 18:42 ` Jacob Pan 2020-04-05 6:37 ` Auger Eric 2020-04-05 6:37 ` Auger Eric 2020-04-03 18:42 ` [PATCH v11 07/10] iommu/vt-d: Add svm/sva invalidate function Jacob Pan 2020-04-03 18:42 ` Jacob Pan 2020-04-09 8:50 ` Auger Eric 2020-04-09 8:50 ` Auger Eric 2020-04-10 21:56 ` Jacob Pan 2020-04-10 21:56 ` Jacob Pan 2020-04-16 10:59 ` Auger Eric 2020-04-16 10:59 ` Auger Eric 2020-04-17 16:14 ` Jacob Pan 2020-04-17 16:14 ` Jacob Pan 2020-04-03 18:42 ` [PATCH v11 08/10] iommu/vt-d: Cache virtual command capability register Jacob Pan 2020-04-03 18:42 ` Jacob Pan 2020-04-09 10:14 ` Auger Eric 2020-04-09 10:14 ` Auger Eric 2020-04-03 18:42 ` [PATCH v11 09/10] iommu/vt-d: Enlightened PASID allocation Jacob Pan 2020-04-03 18:42 ` Jacob Pan 2020-04-03 18:42 ` [PATCH v11 10/10] iommu/vt-d: Add custom allocator for IOASID Jacob Pan 2020-04-03 18:42 ` Jacob Pan 2020-04-09 10:31 ` Auger Eric 2020-04-09 10:31 ` Auger Eric 2020-04-05 8:28 ` [PATCH v11 00/10] Nested Shared Virtual Address (SVA) VT-d support Lu Baolu 2020-04-05 8:28 ` Lu Baolu
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