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Wed, 20 May 2020 10:29:02 +0000 (UTC) Date: Wed, 20 May 2020 12:27:38 +0200 From: Cornelia Huck To: Kirti Wankhede Subject: Re: [PATCH Kernel v22 6/8] vfio iommu: Update UNMAP_DMA ioctl to get dirty bitmap before unmap Message-ID: <20200520122738.351985a3.cohuck@redhat.com> In-Reply-To: <1589871253-10650-1-git-send-email-kwankhede@nvidia.com> References: <1589781397-28368-7-git-send-email-kwankhede@nvidia.com> <1589871253-10650-1-git-send-email-kwankhede@nvidia.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Received-SPF: pass client-ip=207.211.31.81; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/20 04:09:34 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kevin.tian@intel.com, yi.l.liu@intel.com, cjia@nvidia.com, kvm@vger.kernel.org, eskultet@redhat.com, ziye.yang@intel.com, qemu-devel@nongnu.org, Zhengxiao.zx@Alibaba-inc.com, shuangtai.tst@alibaba-inc.com, dgilbert@redhat.com, zhi.a.wang@intel.com, mlevitsk@redhat.com, pasic@linux.ibm.com, aik@ozlabs.ru, alex.williamson@redhat.com, eauger@redhat.com, felipe@nutanix.com, jonathan.davies@nutanix.com, yan.y.zhao@intel.com, changpeng.liu@intel.com, Ken.Xue@amd.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, 19 May 2020 12:24:13 +0530 Kirti Wankhede wrote: > DMA mapped pages, including those pinned by mdev vendor drivers, might > get unpinned and unmapped while migration is active and device is still > running. For example, in pre-copy phase while guest driver could access > those pages, host device or vendor driver can dirty these mapped pages. > Such pages should be marked dirty so as to maintain memory consistency > for a user making use of dirty page tracking. > > To get bitmap during unmap, user should allocate memory for bitmap, set > it all zeros, set size of allocated memory, set page size to be > considered for bitmap and set flag VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP. > > Signed-off-by: Kirti Wankhede > Reviewed-by: Neo Jia > --- > drivers/vfio/vfio_iommu_type1.c | 62 +++++++++++++++++++++++++++++++++-------- > include/uapi/linux/vfio.h | 10 +++++++ > 2 files changed, 61 insertions(+), 11 deletions(-) (...) > @@ -1085,6 +1093,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, > ret = -EINVAL; > goto unlock; > } > + Nit: unrelated whitespace change. > dma = vfio_find_dma(iommu, unmap->iova + unmap->size - 1, 0); > if (dma && dma->iova + dma->size != unmap->iova + unmap->size) { > ret = -EINVAL; (...) > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > index 4850c1fef1f8..a1dd2150971e 100644 > --- a/include/uapi/linux/vfio.h > +++ b/include/uapi/linux/vfio.h > @@ -1048,12 +1048,22 @@ struct vfio_bitmap { > * field. No guarantee is made to the user that arbitrary unmaps of iova > * or size different from those used in the original mapping call will > * succeed. > + * VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP should be set to get dirty bitmap s/dirty bitmap/the dirty bitmap/ > + * before unmapping IO virtual addresses. When this flag is set, user must s/user/the user/ > + * provide data[] as structure vfio_bitmap. User must allocate memory to get "provide a struct vfio_bitmap in data[]" ? > + * bitmap, zero the bitmap memory and must set size of allocated memory in > + * vfio_bitmap.size field. "The user must provide zero-allocated memory via vfio_bitmap.data and its size in the vfio_bitmap.size field." ? > A bit in bitmap represents one page of user provided s/bitmap/the bitmap/ > + * page size in 'pgsize', consecutively starting from iova offset. Bit set s/Bit set/A set bit/ > + * indicates page at that offset from iova is dirty. Bitmap of pages in the s/indicates page/indicates that the page/ > + * range of unmapped size is returned in vfio_bitmap.data "A bitmap of the pages in the range of the unmapped size is returned in the user-provided vfio_bitmap.data." ? > */ > struct vfio_iommu_type1_dma_unmap { > __u32 argsz; > __u32 flags; > +#define VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP (1 << 0) > __u64 iova; /* IO virtual address */ > __u64 size; /* Size of mapping (bytes) */ > + __u8 data[]; > }; > > #define VFIO_IOMMU_UNMAP_DMA _IO(VFIO_TYPE, VFIO_BASE + 14) With the nits addressed, Reviewed-by: Cornelia Huck