From: Shenming Lu <lushenming@huawei.com>
To: Alex Williamson <alex.williamson@redhat.com>,
Kevin Tian <kevin.tian@intel.com>
Cc: Cornelia Huck <cohuck@redhat.com>, Will Deacon <will@kernel.org>,
"Robin Murphy" <robin.murphy@arm.com>,
Joerg Roedel <joro@8bytes.org>,
"Jean-Philippe Brucker" <jean-philippe@linaro.org>,
Eric Auger <eric.auger@redhat.com>, <kvm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<iommu@lists.linux-foundation.org>, <linux-api@vger.kernel.org>,
Lu Baolu <baolu.lu@linux.intel.com>, <yi.l.liu@intel.com>,
Christoph Hellwig <hch@infradead.org>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>,
Barry Song <song.bao.hua@hisilicon.com>,
<wanghaibin.wang@huawei.com>, <yuzenghui@huawei.com>
Subject: Re: [RFC PATCH v3 7/8] vfio/type1: Add selective DMA faulting support
Date: Fri, 21 May 2021 14:39:12 +0800 [thread overview]
Message-ID: <ee41159c-7adf-6e96-1bb2-9c735512080a@huawei.com> (raw)
In-Reply-To: <20210518125813.7b8a78f1.alex.williamson@redhat.com>
On 2021/5/19 2:58, Alex Williamson wrote:
> On Fri, 9 Apr 2021 11:44:19 +0800
> Shenming Lu <lushenming@huawei.com> wrote:
>
>> Some devices only allow selective DMA faulting. Similar to the selective
>> dirty page tracking, the vendor driver can call vfio_pin_pages() to
>> indicate the non-faultable scope, we add a new struct vfio_range to
>> record it, then when the IOPF handler receives any page request out
>> of the scope, we can directly return with an invalid response.
>
> Seems like this highlights a deficiency in the design, that the user
> can't specify mappings as iopf enabled or disabled. Also, if the
> vendor driver has pinned pages within the range, shouldn't that prevent
> them from faulting in the first place? Why do we need yet more
> tracking structures? Pages pinned by the vendor driver need to count
> against the user's locked memory limits regardless of iopf. Thanks,
Currently we only have a vfio_pfn struct to track the external pinned pages
(single page granularity), so I add a vfio_range struct for efficient lookup.
Yeah, by this patch, for the non-pinned scope, we can directly return INVALID,
but for the pinned(non-faultable) scope, tracking the pinned range doesn't seem
to help more...
Thanks,
Shenming
>
> Alex
>
> .
>
next prev parent reply other threads:[~2021-05-21 6:41 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-09 3:44 [RFC PATCH v3 0/8] Add IOPF support for VFIO passthrough Shenming Lu
2021-04-09 3:44 ` [RFC PATCH v3 1/8] iommu: Evolve the device fault reporting framework Shenming Lu
2021-05-18 18:58 ` Alex Williamson
2021-05-21 6:37 ` Shenming Lu
2021-04-09 3:44 ` [RFC PATCH v3 2/8] vfio/type1: Add a page fault handler Shenming Lu
2021-05-18 18:58 ` Alex Williamson
2021-05-21 6:38 ` Shenming Lu
2021-05-24 22:11 ` Alex Williamson
2021-05-27 11:16 ` Shenming Lu
2021-04-09 3:44 ` [RFC PATCH v3 3/8] vfio/type1: Add an MMU notifier to avoid pinning Shenming Lu
2021-05-18 18:58 ` Alex Williamson
2021-05-21 6:37 ` Shenming Lu
2021-04-09 3:44 ` [RFC PATCH v3 4/8] vfio/type1: Pre-map more pages than requested in the IOPF handling Shenming Lu
2021-05-18 18:58 ` Alex Williamson
2021-05-21 6:37 ` Shenming Lu
2021-04-09 3:44 ` [RFC PATCH v3 5/8] vfio/type1: VFIO_IOMMU_ENABLE_IOPF Shenming Lu
2021-05-18 18:58 ` Alex Williamson
2021-05-21 6:38 ` Shenming Lu
2021-05-24 22:11 ` Alex Williamson
2021-05-27 11:15 ` Shenming Lu
2021-04-09 3:44 ` [RFC PATCH v3 6/8] vfio/type1: No need to statically pin and map if IOPF enabled Shenming Lu
2021-05-18 18:58 ` Alex Williamson
2021-05-21 6:39 ` Shenming Lu
2021-04-09 3:44 ` [RFC PATCH v3 7/8] vfio/type1: Add selective DMA faulting support Shenming Lu
2021-05-18 18:58 ` Alex Williamson
2021-05-21 6:39 ` Shenming Lu [this message]
2021-04-09 3:44 ` [RFC PATCH v3 8/8] vfio: Add nested IOPF support Shenming Lu
2021-05-18 18:58 ` Alex Williamson
2021-05-21 7:59 ` Shenming Lu
2021-05-24 13:11 ` Shenming Lu
2021-05-24 22:11 ` Alex Williamson
2021-05-27 11:03 ` Shenming Lu
2021-05-27 11:18 ` Lu Baolu
2021-06-01 4:36 ` Shenming Lu
2021-04-26 1:41 ` [RFC PATCH v3 0/8] Add IOPF support for VFIO passthrough Shenming Lu
2021-05-11 11:30 ` Shenming Lu
2021-05-18 18:57 ` Alex Williamson
2021-05-21 6:37 ` Shenming Lu
2021-05-24 22:11 ` Alex Williamson
2021-05-27 11:25 ` Shenming Lu
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